Getting the Most from a Small Off-Grid PV System

Although my off-grid system is small, I’m proud to say that by using it I’m reducing the amount of CO2 that would otherwise be released into the atmosphere and I’m reducing my electric bill. However, it’s a challenge to use as much solar-generated energy as possible, while still being gentle to the batteries. Allowing too much power to be sucked out of the batteries each night will shorten their life. On the other hand, I don’t want to under-use the system by not using enough of the available energy each day. Unused energy is wasted energy. The purpose of this article is to explore strategies for getting the most from a small off-grid PV system.

Strategy #1

A 100-watt solar panel might produce 500-watt/hours of electricity on a sunny day. But, due to system inefficiencies, it’s likely that only about 300-watt/hours of energy will make it to the load. Using solar-generated energy during peak sunlight hours is one way to improve efficiency. When power from the solar panels goes straight to the inverter, overall efficiency is much greater, since the losses associated with storing and retrieving electrical energy in batteries are eliminated.

The AC load can be plugged into the PV system’s inverter during the day and then to grid-supplied power at night, or switched automatically via a timer as illustrated below. A refrigerator or freezer is an ideal load for this scenario, since the amount of electricity required is about the same from day-to-day. The timer can be adjusted to match the power generated by the PV system to the power required by the load.


Strategy #2

A no-cost way to squeeze every available electron from an off-grid system is to constantly monitor battery voltage, disconnecting the load when the battery falls to a certain level, and reconnecting it when the battery is once again fully charged. Obviously, monitoring the system 24 hours a day is not practical. However, most DC to AC inverters include a low-battery “alarm” feature. The alarm sounds when the battery voltage drops below a certain level, eliminating the need for constant monitoring. Still, listening for an alarm is only a modest improvement over constant monitoring. No one wants to respond to an alarm in the middle of the night. Another drawback of this strategy is that the low-voltage alarm level is usually not adjustable. Typically, the alarm threshold voltage is about 10.6 volts (for a 12-volt inverter), which, depending upon battery type, translates to about a 75% depth of discharge. Most inverters will shut-down when battery voltage falls a little below the alarm threshold. While this strategy will work to a certain extent, you shouldn’t allow your battery state of charge (SOC) to fall that low. Allowing battery voltage to drop to those depths on a frequent basis will shorten the life of the battery. This strategy is not recommended on a day-to-day basis, but could be used in emergency situations, such as a grid power failure.

Strategy #3

To automate the process of disconnecting and reconnecting the load based on battery voltage, a charge controller with built-in low voltage disconnect (LVD) capabilities can be used. An LVD-capable charge controller is a great strategy for unattended systems, such as a weekend cottage. If a load is accidentally left on, the battery will be protected.

Although this is a good solution for applications where power to the load flows through the charge controller, it is not viable in systems where power to the load does not. The input current of an inverter is usually higher that the charge controller can handle, making it necessary to connect the inverter directly to the battery.

The diagram below shows typical wiring for a small, off-grid, PV system. Notice that the inverter is connected directly to the battery, and therefore will not be shut down when the Charge Controller’s low voltage disconnect kicks in. Only the DC output from the Charge Controller will be shut down in this scenario. Battery voltage will continue to decline (because of the AC load), even after the Low Voltage Disconnect kicks in. At some point the inverter will stop functioning. This is not a good strategy unless you’re only using the DC output of the Charge Controller to power a load, or unless you’re carefully monitoring the battery voltage while powering an AC load.


Strategy #4

Some Charge Controllers can be configured as “Load Controllers”, providing another strategy for getting the most from a small system. A Load Controller does not replace a Charge Controller, it is an add-on to the system. An advantage of using a Load Controller is that disconnect and reconnect thresholds can be precisely set. Settings are determined by the type of batteries, and by the size of the load. When properly set, the disconnect set-point prevents the battery from discharging too much, and the reconnect set-point value is high enough to ensure that the battery is not damaged by chronic undercharging. In other words, the disconnect and reconnect settings are optimized. The extra hardware does, of course, add considerable cost to the system.

Shown below is a typical application of a Load Controller. In the example, the Load Controller uses the batteries as the primary source of energy, but switches to a secondary source of energy when the batteries are depleted to a preset level. Once the batteries are recharged, they are again used to power the load. The beauty of this system is that it uses as much “free” energy from the sun as is available, only using a more costly source of energy when necessary.


Strategy #5

Those with electronics skills may consider the solution outlined below. This diagram represents a simple circuit that can replace the “Load Controller” and relay in the diagram above. Disconnect and reconnect voltage levels are set via two potentiometers. The potentiometers could be replaced by thumbwheel switches and precision resistors, providing better control of the threshold voltages. Notice that the relay wiring doesn’t allow AC from the inverter and AC from the power grid to be applied to the load simultaneously. Allowing that to happen would probably result in damage to the inverter.


Strategy #6

The battery-protecting switchover functions described above are also available in equipment designed for larger systems, but that equipment may not be appropriate for small systems. In addition to the high cost, this equipment typically uses more power for its operation than equipment designed for smaller systems. While this power drain may not be significant for a large system, it represents a significant percentage of the overall energy production of a small system.

Conclusion

In compiling this information it has been my intention to demonstrate optimization while holding down the cost. You may benefit from using one or more of the strategies outlined here. I welcome other suggestions for accomplishing the task.

John

Driving a PHEV is Like Buying Gasoline at 20 Cents a Gallon

While you might think a Plug-in-Hybrid-Electric-Vehicle (PHEV) is simply an ordinary hybrid with a plug added for charging, there is another significant difference between the two. Typical hybrid cars on the road today have a gasoline motor and an electric motor, and either of them can be used to drive the wheels. On the other hand, power to the wheels on the new breed of PHEV’s will come ONLY from the electric motor. The gasoline motor is used to recharge batteries. This design is inherently more fuel-efficient, since the gasoline motor will run at a constant speed. It’s called a “series” hybrid, and the Chevrolet Volt is an example. The plug-in Volt is expected to be available in 2010. It will have a 16kwh lithium-ion battery that will take 6 to 6 ½ hours to charge, and a fully-charged battery can propel the car for the first 40 miles. The gasoline motor kicks-in after that, extending the range of the car. For those who drive less than 40 miles per day, which is most of us, the car will use no gasoline at all.

Based on that information, it’s easy to calculate operating expenses. Assuming that electricity costs ten cents per kwh, the cost to charge the battery should not exceed $1.60, which is ten cents per kwh times 16kwh. In reality, the battery will not be fully drained, and therefore the actual cost will be less than that. But for no more than $1.60 worth of electricity, the car will go 40 miles. It takes $3.00 to $6.00 worth of gasoline to go that far in a typical gasoline-powered car!

Nighttime electric rates are much less than daytime rates in many locations, and I’ve signed up for a plan that gives me rates as low as two cents per kwh in the early morning hours. My rate will change from day to day and hour to hour, but if it averages less than four cents per kwh at night, I’ll be able to charge my Volt for as little as twenty six cents. Needless to say, I can hardly wait to own one. When compared to a car that gets 30 mpg, this is equivalent to gasoline at 20 cents per gallon for the first 40 miles of driving each day!

In reality, state and federal legislators will soon realize that I’m not paying my fair share of road use taxes, and somehow I’ll be forced to make up the difference, but I’ll certainly have some unbelievably inexpensive transportation in the mean time.

Here’s the info from Chevy: http://www.chevrolet.com/pop/electriccar/2007/process_en.jsp

John

Renewable Energy Survey Results

Money saved by using energy-efficient appliances is often used to buy additional appliances and vehicles, resulting in an even greater use of energy. Respondents to my survey overwhelmingly said that the solution to this problem is generous rebates and incentives for the purchase of hybrid cars and renewable energy systems. And, of the choices listed in the survey, I agree that this was the best one. Some respondents selected “Other”, suggesting that they have even better ideas. I hope those folks will submit comments to this post, telling us what those ideas are. It seems that almost no one wants laws or penalties, but some of us favor higher taxes for those who consume the most.

Tax incentives are great, but that choice is in the hands of politicians. Rebates will help to sell more energy-efficient cars, but that decision is in the hands of auto makers. There’s an even better solution than those listed; each of us can lead by example. And while only a few of us are ready to install windmills or solar panels, every one of us can contribute in some way. The important thing is to just do something. If you do, someone will notice. If millions of people will install just one compact fluorescent bulb, the benefit to the planet will be tremendous. The best solution is for each us to lead by example.

When the people lead, leaders follow

Hopefully we’ll all do more than to just replace light bulbs. When appliances wear out, replace them with energy-efficient ones. Don’t wait for legislation, and don’t wait for your neighbor to lead the way. Start a movement to save the planet and to preserve natural resources for future generations. Global warming, air and water pollution, and peak oil are all problems that won’t go away without action. Don’t wait for solutions, create them. It’s a good feeling to do the right thing.

Once you’ve made a commitment to do your part, you might begin with an energy audit. You can call a professional, but that’s usually not necessary. You probably already know what needs to be done in your own home. If your list is long, attend to the easiest and less costly improvements first, or as Ed Begley Jr. puts it, the “low hanging fruit.”

John

Power Smart Pricing from Ameren

My electric utility company now has a real-time pricing program and I’ve enrolled. Instead of a paying a flat rate for electricity, my rate will vary by the hour depending upon demand at the time. I'll minimize my electricity use during peak demand times. Tasks like washing and drying clothes can be done late at night when rates are low.

My current electric bill is hard to understand, but from a recent one this is what I’ve been able to determine:

I am charged 0.072 per kwh of electricity of electricity I use.

With taxes, customer charge, distribution charge, and other miscellaneous charges and credits, I am actually paying 0.1016 per kwh.

Based on program information from the utility’s website, I’ll be paying as little as 0.015 per kwh when demand is low, or as much as 0.15 per kwh when demand is high. In addition to the rate information available to me over the Internet, I’ll be alerted when rates are expected to exceed 0.13 per kwh.

A new electric meter was installed on December 3rd, allowing my electricity use to be monitored by time-of-day.

To get the most from this program I’ll run as many daytime loads as possible off of my solar photovoltaic (PV) system. To the extent that my small system can keep up, I’ll run my refrigerator and chest freezer off of it. At night, when rates are low, I’ll run them off of grid-supplied power. Fortunately, the PV system operates most efficiently during the day because energy goes straight to the load, instead of being stored in and retrieved from batteries. As I add solar panels to my existing array, I’ll add electrical items to the daytime load when utility rates are highest.

Perhaps the easiest way to switch between the grid and solar is by way of a simple timer and relay as illustrated below:

The circuit above will work, but for safety and NEC code compliance a transfer switch should be used. The inverter can be switched on and off via a timer as shown below:

The transfer switch can be wired so that it selects the inverter when AC is present, and switches to grid-supplied power when necessary. The timer can be programmed to switch the inverter on during the day, and off at night.

With nightly electricity rates below 0.035 per kwh, I’ll have to reevaluate my Plug-In-Electric-Vehicle (PHEV) recharging strategy. It no longer seems practical to purchase extra solar panels for this. I’ll buy extra panels for the daytime loads instead.

I might also benefit from this plan by using the grid to charge batteries. I'll charge batteries at night when rates are low, and use the stored energy to power household loads during the day when rates are high. I suspect that the losses associated with storing and retrieving energy will be more than offset by the low nighttime electric rates.

As I gain experience, I suspect that I’ll discover other ways to get the most from this plan. I welcome suggestions and comments from others.

For more information about the plan I’ve signed up for, click here: http://www.powersmartpricing.org/

John

Renewable Energy Project Progress Report

It was approximately on today’s date, two years ago, that I first decided to install solar panels on my roof. This plan evolved into an effort to become more self-sufficient, and then to a mission to eliminate my use of fossil fuels altogether. And although I have a long way to go, I’ve made significant progress toward my goals. The following paragraphs outline my progress:

PV System Upgrades:

As finances allow, I continue to expand my PV system. I now have 4 solar panels on my roof, 420ah of battery capacity, a 60-amp charge controller, and an 1100-watt pure sinewave inverter.

Using the PV System on a Daily Basis:

The PV system is now used to power a chest freezer on a daily basis. The resulting reduction of my grid-supplied energy use eases the load on a coal-fired power plant, reduces my electric bill, and is consistent with my goals to use less fossil fuel and to become more self-sufficient. As I continue to enlarge the PV system, I’ll add additional appliances to the solar-powered load.

The Corn-burning Stove:

I installed and began using a corn-burning stove in 2006. By using the stove I’ve greatly reduced my use of natural gas, cutting my home heating cost at the same time. The money I save on my heating bill is used to help pay for PV system upgrades.

Energy-saving Lights:

I’ve replaced nearly all of the incandescent light bulbs in my home with energy-saving compact fluorescent ones. Having done that, I noticed a reduction of my electric bill.

Home Improvements:

I’ve added insulation and replaced old windows with energy-efficient ones.

Appliances:

I’ve replaced my old refrigerator with an energy-star-rated one. Although my new refrigerator is larger, it uses about 65% less energy than the old one. I've also replaced two televisions with energy-star-rated TV's.

Growing Food and Fuel:

I've significantly enlarged the size of my garden over the past two years, and preserve more of what I grow. I have successfully grown tomatoes indoors, and I've grown a small amount of corn that can be used as fuel in my stove.

My Blog:

I include my blog as an accomplishment for several reasons. I hope to inspire others to do similar work. When they do, everyone benefits. Not only do readers comments show that I’ve helped others, they are also my opportunity to learn from them.

Conclusion:

I’ve made significant progress toward my mission over the past two years, and I now have a good emergency power system as a bonus. When grid-power fails, I have electricity and can generate heat if necessary. I’ve investigated electric vehicle technology, and am preparing to purchase a PHEV when they become available. My work and my research will become even more relevant as gasoline prices continue to climb.

John

I Burn Corn to Heat My Home

If you visit this blog frequently you know that I supplement my home heat by burning corn. The corn-burning stove is part of an overall strategy to reduce my use of fossil fuels, and to become more self-sufficient. The stove uses electricity for the blowers and an auger motor, and my photovoltaic (PV) system supplies that energy if the grid is down. My stove must be lit manually, and will not relight itself if the fire goes out. While this is somewhat of an inconvenience, it also keeps the power requirements of the stove low, making it possible to get by with fewer solar panels and batteries. And although the stove doesn’t have a thermostat, it does have individual controls for the corn feed rate and for the room air blower motor. When properly set, these controls help to maintain a comfortable indoor temperature regardless of the outside temperature.

I buy shelled corn in 50-pound bags, and use the stove when the outside temperature drops into the 30’s. I usually start the stove in the evening and stop using it mid-day as the outside temperature rises. This is my second season with the stove. Here are some details from last winter:

I purchased (and burned) 2 ½ tons of corn.
My natural gas bill for the heating season was $524.97
My natural gas bill for the same period, one year before getting the stove, was $1140.71
Because I burn corn, I cut my natural gas bill by $615.74
For this period my cost for corn was: $397.45
My net savings was $218.29

People sometimes ask me if the extra work involved in heating with corn is worthwhile. I believe it is. I’ve calculated that corn-handling and stove-related chores take about 10 minutes per 50 pound bag of corn. Or to put it another way, these chores took about 15 hours during the entire heating season. If I divide my time by the money I saved, I conclude that I’ve saved about $15.00 dollars per hour. I call that worthwhile. And, for a variety of reasons, it’s likely that my savings will dramatically increase in the future.

Some say that burning a source of food is immoral. I disagree. Blowing up mountains in order to harvest coal is immoral. Since that coal is used in power plants, purchasing electricity from those power plants is immoral. Any step taken to reduce energy consumption is a step in the right direction. Solar panels, compact fluorescent lighting, energy-saving appliances, recycling, and alternative heating and cooling are a few of the steps you can take to do your part.

Is burning corn immoral? I will ponder that as I sit in front of my stove on a cold winter day.

John

Another Renewable Energy Myth

I’ve heard it said that it takes more energy to create a solar panel than the panel will produce in its lifetime. That’s absurd! Here are some facts:

A 100 watt solar panel can produce about 400-watt hours on a sunny day.

In one year, that single panel can produce about 146 killowatt hours.

The life expectancy of a solar panel is more than 20 years. In 20 years, that single panel can produce almost 3 thousand kilowatt hours of electricity, enough to prevent 6,600 pounds of CO2 from entering the atmosphere. Source: National Renewable Energy Labs (NREL). Keep in mind however that these figures are for a solar panel that is in service everyday, used to its capacity. An underused panel, one on an RV that is only used a few weeks each year for example, will not measure up over its lifetime.

And, for the benefit of anyone still skeptical, consider this:

It’s better to use fossil fuel to manufacture a solar panel than to just burn it, and still have the problem.

John

Are You Ready for a Winter Emergency?

Winter is almost here, and that brings back memories of last years extended power failure. It was obvious at the moment the failure occurred that this was going to be a worst-case scenario. With sub-freezing temperatures outside, I knew it wouldn’t be long before it would be unbearably cold inside. Fortunately I had plenty of corn on hand for the corn-burning stove, and electricity available from my small off-grid photovoltaic (PV) system. We survived the first night comfortably, but I knew the PV system would not be able to keep up with the electrical demand of the stove.

That power failure taught me a valuable lesson. When the grid fails, you use the systems you have, not the ones you wish you had. And although that may sound obvious, you’ll understand the significance of that statement once you’ve experienced it for yourself. You’ll find yourself wishing you had installed eight PV panels instead of four, and you’ll wish you had a bigger battery bank. As you make do with what you have, you’ll vow to make the needed upgrades before the next emergency.

My PV system was too small to supply the electrical needs of the stove and the chest freezer last winter, so I purchased a small gasoline-powered generator. I was fortunate in that the electrical outage was spotty, and I only had to drive one mile to find a source of gasoline. With winter approaching once again, this is a good time to assess preparedness.


When last-year’s power failure occurred, I had 2 PV panels (170-watts of PV), while now I have four panels (340-watts of PV). I still have the same amount of batteries, a total of 420ah. In practical terms this means that I can charge my batteries faster, but I have no more storage capacity than I did last winter. Based on my previous experience, I should be able to run the stove for at least 8 hours, but I may be able to fully charge the batteries with only one day of sunshine. Previously, it has taken two days. This means, of course, that I could have as much as eight hours of heat per night, every night, as long as the sun shines during the day. That’s great progress, but I obviously need to do much more.

I’ve recently replaced my 20-amp charge controller with a 60-amp one, paving the way for additional solar panels. I’m very pleased with my 1100-watt sine wave inverter, so no upgrades are needed in that area. My goal before the end of the year is to add at least one more panel, and another 210ah of battery capacity. In addition to the electrical demands of the corn stove, being able to run the chest freezer means that I can keep food from spoiling. Additionally, I’ll need lights, the ability to charge a cell-phone, and the limited use of other household appliances.

Because my system will remain small in the short term, I need to incorporate other strategies in the event of an extended power failure occurring in the winter. Closing off unused rooms is one way I can cut back on heating. I can use an electric blanket, and therefore tolerate cooler indoor temperatures as I sleep. Instead of running a refrigerator, I'll place perishables in an ice-chest, and use an energy-efficient chest freezer. While these inconveniences are annoying, at least I can remain relatively comfortable in my home. Some of my neighbors had to abandon their homes during last-years power outage. With each system upgrade, living through an extended power failure becomes less of an annoyance.

John

PV System Upgrade

While I’m looking forward to adding PV panels to my array, I’ll first have to replace my 20 amp charge controller with a bigger one. After careful consideration of available products, I’ve selected the Morningstar TriStar-60. I considered the Outback MX-60, but decided that the TriStar would be a better choice for my small system.

The Outback is a maximum power point tracking (MPPT) charge controller, which means that it can convert DC voltage to a higher or lower value. In some cases, this can result in more efficiency, but it probably wouldn’t benefit me much because my PV array is small. The TriStar is a pulse width modulation (PWM) charge controller, and it charges batteries in four stages. The strength of the charging signal is controlled by varying the pulse width. This has proven to be an efficient charging scheme for small systems.

The Outback charge controller can match any common PV array voltage to any common battery voltage. This feature allows the user to economize on wiring, and minimize losses that would otherwise occur. The TriStar can operate at 12, 24, or 48 volts, but cannot convert a high PV panel voltage to a lower battery voltage as the Outback can. While the Outback MX-60 is also a four-stage charge controller, its dc voltage conversion feature would not benefit me greatly, considering the limited wiring options I have with my small system.

The TriStar-60 uses less than 20ma (0.02amp) of current for its operation, much less than the Outback, an important consideration for a small system. More of the solar-generated power will be applied to the load. And the TriStar-60 comes with a 5-year warranty, while the Outback MX-60 controller is only warranted for two years.

Perhaps the most interesting feature of the TriStar-60 is its digital meter (option). I’ll be able to monitor system performance more easily, and I’ll return my digital multimeter to the toolbox where it belongs. In addition to instantaneous readings, the TriStar-60’s meter can display performance over time (data logging), and remote monitoring via the Internet is possible.

Before the year ends I’ll install at least one more solar panel. My ultimate goal is not only to power my home with PV-generated electricity, but to eliminate my use of fossil fuels entirely. I already burn corn to supplement natural gas heating, and I hope to purchase a plug-in car (PHEV) within the next two years. Using cfl lighting and replacing old appliances are other ways that I’m moving closer to my goal. I might just be the first person in my town to accomplish this. How cool is that!

John

Environmentally-Friendly Products - Are They Any Good?

The energy crunch of the 1970’s resulted in a sudden influx of alternative products, many of which did not perform as advertised. As a result, the public was left with a perception that alternative products were not as good as traditional ones that serve the same purpose. Sadly, it seems that many environmentally-friendly products currently available also fail to live up to their advertised claims, and it’s easy to understand why the general public is slow to accept them. Here are a few examples:

Compact fluorescent lights:

I’ve experienced a high failure rate on the cfl’s used in my bathrooms. Perhaps the frequent on/off cycles shorten their life. I’ve cut my electric bill, but I’m not sure I’m really saving money or helping the environment due to the frequent cfl failures I’m experiencing.

I’ve observed that a cfl takes a minute or two to reach full brightness, but I’m not troubled by this. I use 19- to 25-watt cfl’s in locations where 13-watt cfl’s don’t supply enough light.

Energy-Star-rated appliances:

I suspect that Energy Star ratings are similar to gas mileage ratings on cars. We never achieve the posted gas mileage in real life, and we’ll never achieve the posted killawatt/hour per year figure posted on our Energy Star-rated appliances. I’ve tested my new refrigerator with a Kill-A-Watt meter, and found that it uses nearly twice as much energy as the Energy-Star tag says it should. I suppose that it might approach the posted rating if I seldom opened the refrigerator door, but that certainly isn’t practical. Or perhaps the energy use will be lower this winter, when it’s cooler in the house. While I am pleased that my new refrigerator uses much less energy than my old one, I wish that the ratings were more accurate.

Tankless Water Heaters:

While some people love them, my personal experience was not good. My contractor had little experience with tankless water heaters, and that’s where the problem began. I was willing to accept the high cost of the unit itself, but was unaware of the additional costs that I incurred when the unit was installed. I learned that I couldn’t simply tie-in to the existing furnace flue, I had to run a separate one using expensive stainless steel fittings. Then, I found that the unit would only produce a trickle of hot water. This problem was due to an insufficient supply of natural gas. For safety reasons, increasing the natural gas pressure was not an option. I was going to need a separate gas line from the meter to the water heater. Another option was to use several smaller tankless heaters, each one installed near the point of use. Instead, I decided to send the unit back, and return to a traditional water heater.

Washing Machines:

According to Consumer Reports, the U.S. Department of Energy now requires washers to use 21 percent less energy. Cleaning ability was compromised in order to meet those goals.

TerrorFreeOil.org:

Terror Free Oil is not a product, it’s a company dedicated to purchasing oil only from countries that don’t export terrorism. Unfortunately, this well-intentioned effort will not work. It doesn’t matter where we get our oil from; the amount we use is the problem.

Products that DO work:

My corn-burning stove is one product that I am pleased with. Not only is it good for the environment, I’ve significantly reduced my home heating costs. See previous blog posts on this topic for details.

Since I’m trying to power my home with PV I’ll continue to use cfl’s and energy-efficient appliances to lighten the load. These measures allow me to get by with a smaller PV system, and in that context I am saving money.

Please feel free to comment on my observations, and add to the list based on your own experiences. Maybe this article can be the start of a renewable energy product database. After all, there are many sources of information, but few of them are unbiased.

John

Off-Grid vs. Grid-Tied, My Survey

By more than a two to one margin, visitors to my blog prefer grid-tied over off-grid. This came as somewhat of a surprise to me. I expected more people to opt for off-grid. I thought that being self-sufficient and having a reliable source of electricity would have steered more folks toward an off-grid system. I chose off-grid because of budget constraints, and because of an unreliable grid. I was able to build a “starter” system on a small budget, and as a result I have a limited amount of power when the grid is down. My goals were; to avoid being in the dark, to have the capability to keep warm in the winter and cool in the summer, to keep food from spoiling, and to have the limited use of other appliances. I’ve already met those goals to a certain extent. My small system can’t keep up during temperature extremes or during extended periods of cloud cover, but its benefits are impressive nevertheless when considering the size of my investment. And it’s always exciting when I upgrade the system and extend its capabilities. (I don’t know how I’d amuse myself if I were rich).

If money were no object, I’d opt for a grid-tied system with batteries. While such a system provides the best of both worlds, it is also the most costly. A grid-tied system with batteries must be able to automatically disconnect from the electrical grid when the power fails. If not, it could be dangerous for utility workers in the area. As a major advantage of such a system, it uses all of the free-power available, only switching to costly grid-supplied power as a last resort. Switching is automatic, based on setup parameters. The system can be set to be very gentle on the batteries, extending their life, or be set to use them to a greater extent, resulting in a lower electric bill. It must be great to have choices like that!

I think it’s reasonable to assume that while grid reliability problems may increase in the future, the grid is never going to disappear completely. As long as it is there part of the time, those attached can take from it and contribute to it. And those who supply power to the grid are paid, or at least credited, for their contributions. So unless electric rates or grid-connection charges are prohibitively high, being grid-tied makes more sense from a financial standpoint than an off-grid system does. And since an off-grid system with batteries efficiently uses the energy generated by the sun, it’s a good “green” choice.

While a batteryless grid-tied system is efficient and cost-effective, it must be embarrassing to have a large PV array, but no power when the grid goes down. What would the neighbors think? Still, this type of system is the best “green” choice, and it requires the least maintenance. On the other hand, I like my independence. If I could disconnect from the grid completely, I’d do it, even though that is not the most economical way to go. Unused power is wasted, so it’s a challenge to use as much of it as possible, while not stressing my batteries. I like the idea of using free energy from the sun, and not from a coal-burning power plant. I’m being kind to the planet, and preserving natural resources for future generations. Perhaps even more importantly, I’m setting a good example. Some things are more important than saving money.

John

Weekend Chores

Our corn-burning stove is clean, and ready for the upcoming heating season. I’ve cut the top off of a 55-gallon plastic drum, and will be using it as a storage bin for corn. Because the bagged corn contains cob and stem pieces that could clog the stove’s auger, I screen the corn as I fill the bin. I’ll store additional bagged corn in my shed, and screen it into the bin as necessary.


While I once used fire starting blocks to light the stove, I’ve found that alcohol-soaked wood pellets are a much less expensive alternative. The bucket of pellets (below) should last all season.


Check this blog’s archives for more information about our corn-burning stove.

Julie and I finally decided to get a new refrigerator. I’ve tested our old one with a Kill-A-Watt meter and found that it uses over 2000Kwh of electricity per year. We selected an Energy-Star-Rated 25 cubic foot Kenmore model that uses only 499Kwh per year. Not only will this save $$ on our electric bill, I can use the PV system to power it in the event of a grid power failure. And, when I add a few more panels to my array, I’ll be able to run the new refrigerator full-time off of solar power. For additional information, see my blog post of July 27th.

As we go from summer to fall, the sun’s position in the sky is noticeably more southern. I’ve adjusted the tilt of my solar panels to better align them with the sun during the fall and winter months. My blog post of February 15th provides additional details.


I have a few tomato plants started in my sunroom, and I expect to have fresh tomatoes before Christmas. I don’t bother to grow tomatoes indoors during the summer, because my outdoor garden provides an abundance of them. For more information about growing tomatoes indoors all-year-long, see my August 24th blog post.


It’s a little early for leaves to be turning, but Julie and I had a pleasant drive in the country anyway. I’m hoping to find a three to five acre piece of land where I can build a retirement home. An ideal location will have wind and hydro resources, as well as unobstructed sunlight, allowing me to continue toward my goal of sustainable living.

John

Change or Die!

"It is not the strongest of the species that survives, nor the most
intelligent, but the one most responsive to change."

Charles Darwin

Many believe that global warming is responsible for climate change, including extreme weather, such as storms of greater intensity. If Darwin is right, then the people of New Orleans are among those who should be more responsive to change. Instead, many choose to rebuild again in the same location. While this group is an obvious candidate for change, could it be that the rest of us fail to see the dangers that lie ahead? Is this the time to respond to the changes we see happening today? The answer is yes, absolutely! Just because you don’t live in a costal city doesn’t mean you’re out of harms way. Perhaps costal areas will be the first victims of the effects of global warming, but the rest of the country will surely follow.

Sadly, our government lacks the wisdom needed to formulate an intelligent plan. Its solution is to build bigger levees and help people rebuild in areas where nature doesn’t want them to. Money that could be spent in a sensible relocation effort is instead wasted on projects that are destined to fail. Money that could be spent to develop sustainable energy is instead spent on projects aimed at finding and using what little fossil fuels remain. In the absence of intelligent leadership, it is up to us as individuals to take the necessary actions to enhance our chances for survival. Stockpiling food and water will help to ride out the storm, but we need to plan beyond that. We need to think long-term.

The people most likely to survive are those who’ve already started to adapt. They’re not just moving out of costal areas, they’re moving out of heavily populated areas altogether. They’re growing their own food, and reducing or eliminating their need for public utilities. They realize that, in the event of a major disaster, it will be difficult to get food when a million of their neighbors are also looking for it. They’re learning skills that their great-grandparents knew well, such as growing food, food preservation, raising animals for food, hunting and fishing. And unlike their ancestors, they’re making their own electricity with solar panels, windmills, and micro-hydro systems. Life in a rural area presents an abundance of opportunities for sustainable living, many of which are not available in the city.

Besides our failure to plan for long-term emergencies, and our lack of survival skills, many of us lack the stamina to survive without automobiles and other modern conveniences. If you’re among this group, now would be a good time to get into shape. Walk, or ride a bicycle to work, if possible, or at least get some exercise several times a week. Eat healthy, and get plenty of rest. Don’t abuse alcohol, tobacco, or other drugs.

The idea of becoming self-sufficient might be a bit overwhelming if you haven’t worked at it in the past, but don’t let that stop you. The important thing is to get started. Think about your basic needs, and what you can do to meet those needs if traditional sources are no longer an option. You may have the additional task of taking care of very old or very young family members.

If a sudden change forces you into an emergency survival situation, you’ll enhance your chances for survival if you belong to a group of like-minded folks. You need not be an expert in every aspect of survival, as long as another member of your group is. You should be able to barter for goods and services.

Survival in the event of a major disaster is not the only reason to embrace sustainable living. For example, Les and Jane Oke were simply looking for a better way of life fourteen years ago when they decided to go off-grid. They managed to get out of debt, and replace noise and strife with contentment and a purpose for life. They, of course, understand doomsday scenarios, as indicated by these comments:

“….. the joy is in the fact that we could go on, endure if you will, any major blowout of industrial society.”

Or this one:

“When we run out of fossil fuel we will still be able to feed ourselves and produce our own power – we have achieved a state of sustainability in our life.”

Their website and online magazine offers some interesting insight into the pleasures and the hardships of this kind of lifestyle. You can find it here: http://www.off-grid-living.com/

On the other hand, you may choose to do nothing. If so, have you given any thought to what would happen to you and your family if a pandemic, natural disaster or a major terrorist attack were to occur? Imagine empty grocery store shelves, no gasoline, no running water, no electricity, and no natural gas service. Looting and riots will be common in many cities, and you’ll be afraid to leave your home. You may have enough food and water to last a few days, but what do you do after that?

John

Rethinking Solar Power (PV) for Your Home

When considering a solar photovoltaic (PV) system for your home, the first step is to reduce your energy needs by making your home more energy efficient. Improvements might include an upgrade to energy efficient windows and doors, the addition of insulation, and the replacement of older appliances and inefficient lighting. Because these improvements reduce your energy needs, you’ll be able to reduce the size of your PV system and save money. Unfortunately, the overall costs of the improvements, when added to the cost of the PV system, may be more than you want to spend. Instead of discarding the idea entirely, why not consider a small to mid-size system. At least make a thoughtful evaluation of the benefits of a scaled-down system versus its cost before making a decision.

Generally speaking, there are three reasons for considering an alternative to the power supplied by your electric company; saving money, environmental concerns, and reliability issues.

The monetary concern is self-explanatory, everyone likes a bargain. Electric service is available at a reasonable rate for most of us, but not for everyone. In areas where electric rates are excessive, alternatives to grid-supplied electricity make financial sense. A grid-tied system is usually the best choice for those wanting to cut their electric bill, but you can also benefit from a small, and therefore less-costly, off-grid system.

Environmental concerns may mean a desire to use a non-polluting source of power, or a passion to preserve natural resources for future generations. Since the majority of the electricity produced in the United States comes from coal-fired power plants, your decision not to use electricity that originates at those power plants goes a long way toward reducing pollution. From the mine to the fire, coal pollutes every step of the way. Subsidence, contamination of ground water, and even the tragic death of mine workers remind us of the true cost of using coal.

Reliability is more important to some of us than it is to others. Most of us can tolerate a few hours, or even days, without power, but an extended loss of power can be life-threatening to some. Just losing the ability to make an emergency phone call can be dangerous. Climate control is not only important for your safety and comfort, temperature extremes can result in damage to your home. And don’t forget about food spoilage when there’s no electricity to run the refrigerator and freezer.

If you’ve decided to install a PV system for the purpose of saving money, first make reasonable energy-saving improvements to your home. Then size the system so that it produces a little more than your total energy needs. If space constraints or your budget won’t allow you to do that, your next best option is to install the largest system possible. If you’re billed for electricity on a tiered rate, perhaps you can install a PV system large enough to keep your grid-supplied electricity usage within the lowest tier. A sophisticated controller switches between alternative power and grid power in a way that optimizes system performance.

If reliability is the reason for installing a PV system, first consider the electrical needs that you can’t live without. If you live in a cold climate, the greatest need will probably be during the winter months. For home heating you might consider a wood-burning stove or fireplace. A heat exchanger, or even a portable fan, will help to distribute heat to other parts of the house. As an alternative to wood, you might consider a pellet or corn-burning stove. Both require electricity for their operation, but those needs can easily be met by a small PV system. Your summer needs might include cooling, but don’t plan to run a central air conditioning system with your small PV system. You might choose a window air conditioner if your PV system is big enough to handle it, or simply use fans for cooling. Your goal should be to keep at least one room comfortable in the event of a power outage.

When sizing your system (with your budget in mind), don’t forget about your other needs. You should consider a system big enough to power a chest freezer to keep food from spoiling, and to power a microwave oven. The microwave oven not only makes it possible to prepare meals, but also to boil water for drinking should that become necessary. Remember, one of your reasons for installing the PV system is to serve as an emergency source of power. Don’t underestimate your needs in the event of a disaster.

An advantage of making your system large enough to supply power during worst-case conditions is that you’ll have an abundance of power at other times. If you’ve sized your system to get you through power outages during harsh weather, power outages during mild weather are no problem at all. You’ll be able to watch TV, make phone calls, prepare meals, keep food from spoiling, etc. Trust me; it’s a good feeling to light up your house at night when your neighbors are using candles. But don’t be cruel; invite them over for a hot meal and to watch TV.

Using alternative power doesn’t mean that you have to be uncomfortable, but it is important to recognize the limits of your system. If family members practice conservation, you may be able to disconnect from the utility grid entirely when the weather is mild. It’s good to see the disk in the electric meter stop turning. Practices like turning off lights and other devices when they’re not in use will help to ensure a steady, uninterrupted source of power. If you’ve chosen to install an undersized system with plans to upgrade in the future, your good conservation habits will be beneficial later, as your system grows. If your children complain about the limited power your system provides, remind them what life would be like without it.

Some say that there are better ways to spend your money. A generator with an ample fuel supply may appear to be a better alternative. A generator is less expensive than even a small PV system. However, the fuel to run the generator needs to be fresh, and enough of it stored to get you through an extended power outage. The cost for fuel to keep the generator running can exceed the cost of a PV system in a short time. Some New Orleans residents reported generator fuel bills exceeding $900.00 per months after the Katrina disaster. A generator is good for a short-term power outage, but you’ll quickly grow tired of the noise, and refueling chores. Remember also that fuel may not be available locally in the event of a disaster. On the other hand, your solar panels provide quiet and steady power which is renewed each day by the sun.

The recommended way to design a PV system is to first calculate your energy needs. Instead of that approach, why not calculate how much energy you can get from a system that falls within your budget. For under $1000.00 you can build a system that will give you light, recharge your cell phone batteries and power a radio, but not much more. For another $1000.00 you can add some TV viewing, a fan, and other low-power appliances for a short duration. For a little more you can keep a small refrigerator or chest freezer running to protect your food from spoiling, use a microwave oven, and keep warm in the winter. You can live comfortably through an extended power outage with a relatively modest system. Start small if you must, and add to the system as additional funds become available. While you’re saving money on your electric bill, you can be proud that your efforts help to reduce pollution and preserve natural resources.

Be sure to check this blog's archives for additonal information.

sj

More BS about Plug In Hybrid-Electric Vehicles

Plug-in-Electric-Vehicles are in the news again, and I’m a little puzzled by Toyota’s recent test of a plug-in-Prius. The low electric-only operating range, 8 miles, is far below that of the Tesla Roadster’s 200 mile range. The Tesla car shows what can be done when a vehicle is designed from the ground up, and with the best available technology. The main reason for the performance difference is that the Tesla car doesn’t have an internal combustion engine, and that it uses the best currently available batteries. Toyota uses a much smaller battery pack in a vehicle that also has the extra weight and space limitations of an internal combustion engine.

Toyota, GM, or any other car company could easily build a decent plug-in-electric vehicle if they wanted to, so why don’t they? Conspiracy theorists claim that Cobasys, a battery manufacturer that holds patents on batteries that could be used in plug-in vehicles, is partly owned by an oil company and will not allow their battery technology to be used in automobiles. Others believe that the big automakers are purposely creating cars that no one will want so that legislators will not tighten CAFÉ’ standards. After all, car manufacturers make their money on gas guzzlers. Have you seen “Who Killed the Electric Car?”?

Car makers claim that not enough people want them, they’ll be too expensive, and that the best battery technology is not good enough. These claims are false. People do want them, and problems with early versions of Lithium Ion batteries have been resolved. Additionally, an electric motor is less costly than an internal combustion engine and all that comes with it (pollution control components, transmission, muffler, etc.).

I guess we’ll just have to wait and watch as small companies, like Tesla and Phoenix Motor Cars, show the big automakers how it’s done.

Can’t wait for a PHEV? Here’s some info on conversions: http://www.calcars.org/

Recommended Reading: “Plug-in Hybrids – the Cars that Will Recharge America” by Sherry Boschert.

SJ

A Refrigerator-Freezer Strategy for Energy Efficiency, Saving Money, and Eating Healthy

At first glance it might seem that a small refrigerator is a better “green” choice than a larger one, but for most households this is simply not true. While a small refrigerator probably uses less energy than a larger one, you’ll also find yourself making more trips to the grocery store. You might save a few dollars on your electric bill to operate the smaller fridge, but you’ll spend much more than that on gasoline for the extra trips to the store.

A properly-sized refrigerator and a chest freezer is the best overall strategy for most families. A top-loading freezer is inherently energy-efficient because the cold air doesn’t “fall out” when the door is opened as it does with any freezer that has a side door. Adding to their efficiency, a typical chest freezer doesn’t have other energy-consuming features such as a light or a fan.

Not only does a chest freezer allow you to stock up on long-lasting items from the grocery store, it also allows you to preserve items grown in your garden during the summer months. Growing your own food not only cuts your grocery bill, home-grown foods are usually healthier and tastier than the same items when purchased at the grocery store. Since I’ve started using a freezer, I’ve increased the size of my garden. This ensures that I’ll have plenty of fresh produce and plenty to save in the freezer. And since I save seeds, my home-grown produce is almost free! If you’re not into gardening, you can stock up on locally grown food in the summer by visiting a farmer’s market.

If you’re about to purchase a refrigerator or freezer, be sure to look for those that have earned the “energy star”. If you’re replacing one that is over ten years old, you might save 50% or more on your electric bill. A 21 cubic foot energy star-rated refrigerator might use 430 kWh per year, or about 1.2 kWh per day. At ten cents per kWh, it will cost about $43.00 per year to operate. Actual results depend not only on your electric rate, but also on how you use it and where it’s located in your home. A small energy star-rated chest freezer might require 300 kWh per year, costing you about $30.00 per year to operate. The basement is a better location for the freezer than the garage because it’s cooler there, causing the compressor to run less frequently. The heat that the freezer produces is often desirable in a cool basement.

A small photovoltaic (PV) system can be used to provide backup power in order to prevent your food from spoiling during an extended power outage. I chose a PV system instead of a generator because it is quieter, less expensive to operate, and I don’t have to store fuel. As a bonus, my PV system provides power to the freezer on a continuous basis, cutting my electric bill. Since my PV system is not large enough to power both the freezer and refrigerator, I’ll use the PV-powered freezer to produce ice which can be used to keep refrigerated food from spoiling during an extended power outage. When I’m able to enlarge the PV system, I’ll add the refrigerator to the load. Currently, I have 340-Watts of solar panels, and 420ah of battery capacity. The PV system is able to meet the energy requirements of the freezer, except when cloudy conditions persist for several consecutive days. When that happens, I run the freezer on grid-supplied power until the batteries are recharged by one or two days of sun.

Transitioning into a future where fossil fuels are declining does not necessarily mean that we will have to do without comforts that we’ve become accustomed to, but we’ll have to do things differently. Recent innovations, like compact fluorescent lights and energy efficient appliances, show that we’re able to adjust to these conditions without giving up anything. This trend is likely to continue, radically changing the vehicles we drive and other products we use. Changing your food preservation strategy is a good, healthy way to begin your journey into the future.

My Garden - July 2007

*

*

*

*

*

*

Solar John

Hey GM, Bring Back the Electric Car!

If GM's EV-1 electric car were to be manufactured today, it would have a battery pack that weighs half as much as it did in the old EV-1. Great strides in battery technology have been realized since the demise of the EV-1, making this possible. Faster recharge time and longer life are additional benefits of the best currently available batteries. The new breed of Plug-In-Electric Vehicles (PHEV's) would include a backup generator to extend the range, but most owners wouldn't use it for day-to-day commutes. In other words, most of the time they wouldn't use any fossil fuel at all, instead using power stored in the vehicle's batteries. And while using grid-supplied power to recharge the vehicle is not truely a "Green" solution, it's better than the millions of gas and diesel-powered cars that pollute our air today.

Unlike today's hybrids, the fuel-powered engine would recharge the batteries, not directly drive the wheels. GM could be a leader in electric vehicle technology, and a profitable company once again. But more importantly, the world would be different. There would be no need for oil wars, and gasoline would be less expensive due to decreased demand.

Critics of the electric car worry that a suden influx of plug-in cars would overload the already-strained electrical grid, and in some parts of the country this is certainly true. Still, it makes more sense to increase electrical generation and distribution capabilities than it does to continue to use fossil fuels, which are declining and non-renewable. For those who can't wait for power infrastructure upgrades, alternative energy such as solar and wind is an option. Although the cost of such systems is high, the savings over fossil fuel-powered alternatives are significant, and the payback is quicker than you might expect.

SJ

Inventions That Change the Way we Live

It’s easy to name inventions that have changed our lives. The electric light, radio, and television are among the most notable, and the personal computer is among the most recent. It seems that each of these devices appeared suddenly, but they were actually perfected over time. With that in mind, it’s interesting to contemplate life-changing devices on the horizon.

We may eventually look back and realize that the photovoltaic panel (PV) was the life-changing invention of the present time. While solar photovoltaic panels were once only used in the space program, now they can be found almost anywhere around the world. They not only provide power for lights, they provide the energy needed to pump water for people, as well as for cattle, in locations far from power lines. Thanks to PV panels, remote villages and vacation homes can use the same electrical appliances that city-dwellers use. And now, as electric rates are increasing and reliability is an issue in some parts of the country, many grid-connected homeowners are also installing solar panels.

Some utilities have imposed a tiered-rate structure for electrical usage. While the first 300KWH per month is relatively inexpensive, electricity use in excess of 600KWH is billed at a much higher rate. A PV system can be designed to use solar power as the primary source of electricity, only using grid-supplied power when the PV system’s capacity is exceeded. Switching is automatic, and the homeowner may not even be aware that it has happened. Other sophisticated PV system components protect the batteries from over charging or over discharging, and coax the best possible performance from the system.

Fossil fuel supplies are on the decline, resulting in escalating costs to bring electricity into our homes, but there are other factors that are beginning to make PV systems more appealing to the average household. Newer consumer electrical devices require less power than their older counterparts, making it possible to get by with a smaller PV system. From light-bulbs to major appliances, it’s rare to find an increase in electrical consumption in a newer device. The exception to this rule is the plug-in-electric vehicle. If these become popular in the future, we’ll need sufficient capacity to charge them. Still, the cost of PV panels is expected to decline sharply within the next two years, further increasing their popularity.

The PV panel is not like other life-changing inventions, it simply provides power for them. And, unlike other life-changing inventions, we usually keep solar panels out of sight, rather than on display. As we transition to PV systems, our lives may not have been altered per-se, but without PV all of our electrical devices will be useless, or to costly to use.

President Bush said recently “we’re addicted to oil.” The truth is, were addicted not to oil, but to our cars. By the same token we’re not addicted to electricity, but rather to our lights, radios, TV’s, microwave ovens, dishwashers, and other appliances. And it’s hard to imagine how tradesmen would perform without their power tools and equipment. Because a transition to PV will be gradual, we may not recognize it as a life-changing invention until when we think of what life would be like without it.

John

My Backyard Garden

It’s mid-July, and my garden is in full-swing once again. Here’s a brief tour:

Tomatoes are on the left. Pole beans are in the background. From left to right the raised bed is home to: Sweet Snap Pea’s, Eggplant, Green Pepper, Basil, Dill, Parsley, Carrots, and Honeydew Melon.

More than anything else, I like to grow tomatoes. We eat them fresh, and can them for use all-year-long. Nothing you can buy at the grocery store in the winter compares to the great taste of canned tomatoes.

I grow “heirloom” tomatoes, and they come in a variety of colors, shapes, and sizes. Cherokee Purple (leftmost tomato), is a great tasting variety that grows well in my environment. Shown next to it is a Better Boy.

The ugly-shaped tomato on the right is a French variety, Cuostralee.

My corn crop was ruined by squirrels last year. To deal with the problem I started a “Squirrel Relocation” project. It looks like I’ll be eating sweet corn from my garden this year.

I’ve had good luck with cucumbers this year. Here are some of the dill pickles I made. I also grow the “dill”, used to give the pickles their flavor.

Raspberries were nearly ready for picking when this picture was taken. I'm getting about a pint of raspberries per day, as of July 8th.

The photo on the right is a closer look at a dill plant.

*

*

*

*

In addition to great taste, it’s good to know that my family is eating food that has not been genetically engineered, and is free of pesticides and preservatives. I save “open-pollinated” seeds from my own crops each year, just to be sure. My post of 9/6/2006 provides additional information about my gardening practices.

John

The Practical and Efficient Use of a Small PV System

Since the primary role of my small photovoltaic (PV) system has been to serve as an alternate source of electricity during grid power failures, a great deal of power was unused, and therefore wasted. To minimize the waste, I decided to put the system to use on a daily basis. After all, I reasoned, shouldn’t I be using this energy to reduce my electric bill?

My first task was to determine how much energy I could expect from the system. Since I have 340 Watts of PV capacity (4 – 85 Watt Panels), and I can expect about 4 hours of peak sunlight each day, the overall production will be 340 times 4, or 1360 Watt/Hours per day. Because I’ll be storing some of this energy in batteries, and because I’ll be converting DC to AC, system losses must be considered. Clouds will also limit production. With all of these things in mind, I’ll estimate that my daily capacity averages 900 Watt/Hours.

Looking over a list of appliances in my home, I decided to use a chest freezer as the load. The chest freezer is an ideal load for several reasons: It requires about 800 Watt/Hours per day and the energy requirements change very little from day to day. Because it uses a little less energy than the anticipated daily output of the PV system, the freezer could theoretically be powered indefinitely. I decided to carefully monitor system parameters for a few weeks, and log the results with comments. Here are some log excerpts:

May 6, 2007
Power up inverter and connect chest freezer.

May 13, 2007
Observed that in addition to providing power to the chest freezer, the PV array is able to fully charge the battery bank.

May 31, 2007
The past six days have been mostly rainy and overcast. Switch off inverter due to low battery voltage.

I predicted that the PV system would be able to produce more energy than needed to run the freezer, but six days of mostly cloudy weather depleted the battery bank.

June 2, 2007
Sunny weather has returned and batteries are fully charged. Switch on inverter and connect chest freezer.

June 7th, 2007
Severe thunderstorms are predicted. Switch off inverter in order to preserve batteries in the event they are needed in the event of a grid power failure.

No grid power failure occurred, but it was good to know that a fully charged battery bank was available just in case.

June 8th, 2007
Stormy weather has passed. Switch on inverter and reconnect freezer.

June 10th, 2007
Due to mostly overcast conditions, battery voltage has again declined. Switch off inverter and freezer load.

Overall the system performed pretty much as I expected it to. If not for an extended period of cloudy weather, it could have continued to provide enough energy to power the chest freezer for a very long time. I suspect that the short and cloudy days of winter will create the same situation.

Overall efficiency may seem to be optimized in this example, since the load is about equal to the capacity of the PV system, but a significant increase in efficiency is possible. The freezer could be put on a timer, set to allow the freezer to run only during daylight hours. If the compressor runs during the day, when energy comes directly from the solar panels, the losses associated with storing power in batteries and using power from the batteries are eliminated.

Based on the results of this test, I believe I can improve PV system performance by increasing the size of the battery bank. It is important to note that the battery bank must not be enlarged to a point where the existing PV array cannot fully recharge it. Chronic undercharging will shorten the life of the battery bank. It is also important to remember that in addition to charging the batteries, the PV array needs to provide power to the load.

The system continues to serve as an emergency source of electricity, and most days provides power to the freezer therefore reducing my electric bill. Additional opportunities to enhance system efficiency will surface as I enlarge the system. At this point it's good to know that I've reduced the waste.

Here's a picture of the freezer:




Visitors usually ask about the sign, giving me an opportunity to show-off my PV system.

John

What to Expect from a Midsize PV System

As I continue to add to my PV system, I look forward to the day when I can stop describing it as small. My short-term goal is a system large enough to get me comfortably through an extended power-outage, and lower my electric bills all-year-long. Perhaps someday I can disconnect from the grid entirely, but that’s a long-term goal. Nevertheless, my system becomes more useful with each upgrade. With these things in mind, it’s interesting to take a closer look at the system I hope to have in the not-too-distant future.

I Have:

4 – 85 Watt Solar Panels
1 – Morningstar SunSaver 20 Charge Controller
4 – 105ah Deep Cycle Marine Batteries
1 – 1100 Watt Exeltech DC to AC Sine Wave Inverter

I Want:

8 – 85 Watt Solar Panels
1 – Morningstar TriStar TS-60 Charge Controller with meter
4 – S530 Rolls 6v 400ah Batteries
1 – Xantrex 2500 Watt Sine Wave Inverter

Additional items include mounting hardware, wire, a lightning protection device, fuses, and perhaps a breaker box or combiner. I hope to become grid-tied eventually, but I’ll avoid that discussion at the present time for the sake of simplicity. To examine the capabilities of the system I hope to have, let’s start with the solar panels.

Under ideal conditions, the eight panels will generate 680 watts. A somewhat more realistic estimate would be 600 watts for 4 hours per day in my geographical location, or a daily production of 2400 watt/hours. This, of course, will vary from day to day and season to season. Next, let’s look at the battery bank.

Because I've selected six-volt batteries, I'll connect the four of them in series to create a 24-volt system. As a result of using batteries better suited for solar power systems, and by changing from a 12-volt system to a 24-volt system, I'll expect a performance increase.

Since the solar panel array is able to produce 2400 watt/hours per day, it follows that a constant 100 watt load would fully use the solar-produced power. Stated another way; 2400 watt/hours divided by 24 hours equals 100 watts per hour. To allow for conversion losses, we’ll assume that only 85 watts is available on a continuous basis. That brings our daily total to 85 times 24 hours, or 2040 watt/hours per day. This power can go a long way if it’s used wisely. This is how I might use the available power during a grid-power failure:

3 – 13 watt cf bulbs – 39 watts – 4 hours per day = 156 watt/hours per day
2 – 19 watt cf bulbs – 38 watts – 2 hours per day = 76 watt/hours per day
1 – Chest-type freezer – 34 watts (avg) – 24 hours per day = 816 watt/hours per day
1 – Radio – 5 watts – 4 hours per day = 20 watt/hours per day
1 – Portable Color TV – 60 watts – 2 hours per day = 120 watt/hours per day
1 – VCR or DVD player – 40 watts – 2 hours per day = 80 watt/hours per day
1 – Fan – 25 watts – 4 hours per day = 100 watt/hours per day
1 – Microwave oven – 1000 watts – 0.20 hours per day = 200 watt/hours per day
1 – Toaster – 850 watts – 0.10 hours per day = 85 watt/hours per day
1 – Vacuum cleaner – 750 watts – 0.20 hours per day = 150 watt/hours per day
1 – Blow dryer – 1000 watts – 0.10 hours per day = 100 watt/hours per day
1 – Laptop Computer – 25 watts – 3 hours per day = 75 watt/hours per day
1 – Cell phone charger – 25 watts – 1 hour per day = 25 watt/hours per day

Alternatively, I can use power from this system to run the motors in my corn-burning stove. Should a grid power failure occur when outside temperatures are low, I’ll gladly opt for heat, instead of using other appliances on the list. I might also use more of the available power for fans to keep cool in the summer. During mild weather, when I don’t need extra heating or cooling, the surplus power can be applied to more frivolous uses. Remember, this modest system was not designed to meet the electrical needs of the average American home.

The Xantrex inverter upgrade offers several advantages:

1. Its higher capacity allows me to run heavier loads, and to run several devices at the same time. I should be able to charge my PHEV (plug in electric hybrid vehicle) with it. My Exeltech inverter has trouble powering devices like my washing machine, and would probably be inadequate for recharging the PHEV.

2. The Xantrex inverter can be set to use power from the PV system until battery voltage drops to a preset level, and then switch to utility power. This allows me to get the most from my PV system while protecting my batteries from over-discharging, and minimizes my grid-supplied electrical consumption.

3. The Xantrex inverter will be connected to my existing home wiring, and can automatically take over in the event of a grid power failure. Eliminating the need to run extension cords when the grid power fails is a bonus.

Because I'll be adding solar panels, and because I'll be changing from a 12-volt system to a 24-volt system, I'll need to replace my present charge controller. The Morningstar TriStar TS-60 meets all of my requirements, and it allows me to better control battery charging. The digital meter option not only measures array and battery voltage, it displays additonal system information not currently available. I'll also be able to remotely monitor system statistics via the Internet.

An off-grid home or cabin with a PV system of this size would probably have a gas-powered refrigerator and stove, and additional capacity will be needed to accommodate appliances such as a clothes washer and dryer. While this system may not seem to provide a lot of power for its cost (about $6500), imagine what life would be like without it.

John

Renewable Energy Opponents

If you’ve ever wondered why anyone would have issues with the pursuit of a technology that preserves natural resources, minimizes pollution, curtails global warming, cuts transportation costs, makes wars for oil unnecessary, and reduces the amount of cash getting into the hands of terrorists, you’re not alone. It’s surprising to observe that people are quick to find fault with renewable energy technology, and often display a great deal of emotion when expressing their views.

A closer look at their objections reveals some reasons for this attitude:

· A natural resistance to change is one piece of the puzzle. Risk is inherent with change, and a fear of failure is understandable. A notion exists that actions by radical environmentalists will cause a collapse of the economy.

· We tend to want our children to have the same opportunities that we had. I remember the thrill of getting behind the wheel of a “muscle car” for the first time, and feeling the acceleration as I ran through the gears. You just have to love the sound of a well-tuned V-8 engine, and the thought of replacing that with the high-pitched whine of an electric motor is a bit much to accept. Could it be that those who hold on tightest to overpowered cars and drive monster trucks for no apparent reason are just compensating?

· Some are concerned that a rapid switch to plug-in electric vehicles will cause an overload of the electrical grid, causing even more misery for utility customers.

· Not everyone can afford to spend $25,000 for a Prius. A used Chevy Nova gets reasonably good gas mileage, and costs a heck-of-a-lot less. No one wants to be forced into a situation that doesn’t make economic sense.

To some, the solution to our energy problems includes stepping up oil exploration and production, including drilling off of the Gulf Coast and in the Anwar region. They believe that this will buy us time that could be used for the development of alternative technologies. Unfortunately little progress will be made in alternative technology as long as demand is low. Meanwhile, fossil fuel reserves will continue to decline. No good can possibly come from increasing our dependence on oil, even if we produce more locally.

You’ll likely find that the hard-core renewable energy opponents are among the 10% of the population who don’t believe that human activity contributes to global warming, and that peak oil is decades away. I find this optimism an ironic contrast to their pessimistic view of renewable energy technology.

We may be able to drill and mine our way to prosperity in the short-term, but eventually we’re going to have to do things differently. The longer we put it off, the harder it will be to make the transition. Once we learn to accept change, we’ll find that many opportunities for environmental progress exist throughout the country, most of which will have no adverse affect on the general population. The picture below is of Carlyle (Illinois) Lake and Dam, a good example of a renewable energy opportunity. The installation and use of hydro-electric generators here would have a positive environmental impact, with little or no negative consequences. I can’t imagine why this has not been done already.

Lake and Dam at Carlyle Illinois

John

Celebrating the First Anniversary of this Blog

If you accept the notion that “America is Addicted to Oil”, then you probably accept the high cost of gasoline as a penalty for your addiction. I find that notion unacceptable, and this blog chronicles my efforts to do something about it.

I’m learning about alternatives to fossil-fuels, and this is my way of sharing that information with others. I’ve found that it is possible to cut utility costs and do something positive for the environment on a modest budget. My renewable energy systems are growing, and my utility bills are declining. I hope to inspire others to embrace renewable energy because our combined efforts will have a significant impact upon the environment, and help to preserve natural resources for future generations. It may come as a surprise to some, but you don’t have to give up anything. In the long run your lifestyle will improve, not decline, as a result of alternative energy.

Besides saving the planet, I believe that it is important for all of us to be prepared for emergencies, and I often post ideas for doing so.

If you’re a regular reader, I’m glad to have you on board. I hope you’ll tell other like-minded people to visit as well. There is much more to learn, and much more to do. I hope to purchase a plug-in electric hybrid vehicle (PHEV) when it’s time for my next car, and to recharge it with power from my PV system. I’ll measure my overall success by how much I’m able to reduce my use of fossil fuels, including the use of electricity from coal-fired power plants.

We’re not addicted to oil, it’s just that suitable alternatives are hard to find. I suspect that bright young people will come up with solutions, just as they have with computers not so long ago. You’ll soon be “gas-free” if you choose to be, and you won’t have to settle for a car or truck that doesn’t meet your needs. The cost may be high initially, but will decline as it has with other innovative new products over the years. Additionally, the money you’ll save by not purchasing gasoline will be more than enough compensation for the high sticker price. I predict that once PHEV’s become available, the cost of gasoline will mysteriously drop significantly, perhaps below $2.00 per gallon. I don’t generally consider myself a conspiracy theorist, but in this case I am.

Please check in once in awhile to see what I’m up to, and participate by leaving comments. Let’s learn from each other.

John

Emergency Survival Ideas

Living through an emergency is challenging, but even more so for those whose don’t prepare in advance. To some, emergency survival means living in primitive conditions and eating bugs. My idea of survival is to live as comfortably after an emergency as I did before, without moving from my home, and certainly without eating bugs. Knowing that an emergency will force me to give up some conveniences, I still believe my goal is achievable, but probably in a much smaller space.

In addition to stocking up on water and food, my photovoltaic (PV) system plays a significant role in my survival strategy. But keeping even one room warm in the winter is a challenging task, since my PV system doesn’t produce nearly enough electricity to do the job using resistive heating. To deal with that problem I’ve installed a corn-burning stove. And, while the stove’s motors require a significant amount of electrical energy, the PV system is capable of providing it. It is only necessary to store a supply of corn sufficient to keep the stove going in the event of a long-term emergency. A pellet-burning stove would be another good choice for emergency heat, with the added bonus that mice are not attracted to the pellet fuel as they are with corn. A good supply of bagged pellets can easily be stored in a garage or basement. A wood-burning stove or fireplace is another alternative heating option, but you’ll need to keep an ample supply of firewood on hand. An advantage of a wood-burning stove is that it does not require electricity to operate. A disadvantage of wood is that it does not burn as clean as corn or pellets, requiring more attention to the chimney and flue lines. Electricity may also be needed in order to circulate the heat. A kerosene heater is another emergency heating option, but not a particularly attractive one since it involves storing a large quantity of an expensive and flammable liquid fuel. Additionally, the smell of kerosene burning is not something I’m particularly fond of.

Refrigeration is another thing I don’t want to do without in an emergency. Besides preserving food and making it taste better, refrigeration is a necessity for those who need to keep medicine fresh. To make sure I have enough electrical power to maintain refrigeration in the event of a long-term emergency, I’ve had to abandon the idea of using my big, energy-wasting refrigerator-freezer combination. Instead, I provide power to an efficient top-loading freezer. Even with my small photoelectric (PV) system I can keep frozen food frozen indefinitely, and I can use the freezer to produce ice for use in portable coolers. I already have several blocks of ice in the bottom of my freezer, giving me a head-start for the next power failure. A full freezer has the added advantage of operating more efficiently than a not-so-full freezer. The coolers (ice chests) can be kept outside during the winter in order to make the ice last longer, and in the coolest part of the house during the summer.

In the event of a grid power failure, I’ll do most of my cooking in a microwave oven. I’ll also consider a solar-cooker, an outdoor charcoal grill, and even a campfire in the backyard as long as firewood is available. It’s important to remember that it might be necessary to boil water for drinking, and all of these options can be used as necessary.

Electrical energy needs will be the greatest during the coldest winter months when keeping warm, cooking, and lighting place the greatest load on my solar electric system. Periods of extended cloud cover might also limit the amount of energy available during these times. My goal is to enlarge my current PV system until I’m confident that it can meet my needs under the worst-case conditions. Once that’s done, I’ll have an abundance of energy generating capacity and storage to serve me when power outages occur during mild or warm weather. My goal of living comfortably in the event of an emergency is easily achievable during those times.

In addition to the electrical requirements for lighting, heating, and refrigeration, energy will be needed for a radio, TV, and to charge cell phone batteries. These devices use only a small amount of energy, easily provided by even a small PV system. Still, they must be considered when calculating energy needs. Here is an example/summary:

Corn stove - - - - - 100-Watts - - - 12 hours per day - - 1200-Watt/hours per day
Chest freezer - - - 35-Watts(avg) - 24 hours per day - - 840-Watt/hours per day
Microwave oven - 750-Watts - - - 0.5 hours per day - - 375-Watt/hours per day
Lighting (cfl's) - - 45-Watts - - - - 3 hours per day - - - 135-Watt/hours per day
TV - - - - - - - - - - - 60-Watts - - - - 2 hours per day - - - 120-Watt/hours per day
Radio - - - - - - - - - 5-Watts - - - - - 4 hours per day - - - 20-Watt/hours per day
Cell phone charger - 25-Watts - - - 1 hour per day - - - - 25-Watt/hours per day

Total need per day: 2715-Watt/hours

These needs can be met with 700-Watts of solar panels, assuming 4 hours of sunlight per day. Installing eight 100-Watt solar panels and an appropriately sized battery bank will ensure ample power in the event of a grid power failure. Holding down the cost of the PV system was accomplished in this example by excluding devices that consume large amounts of energy. Using a microwave oven instead of an electric frying pan is much more energy efficient, and using a broom instead of a vacuum cleaner also helps. A larger system would, of course, provide even more comfort during an extended power outage by providing the power needed for additional appliances, and other substitutions are possible. A few hours of air conditioning in the summer can be substituted for the use of the corn-burning stove in the winter. However, we’re talking about a window air conditioner in this example, since the PV system described here cannot provide enough power for a central air system. Still, as I said earlier, I believe it is possible to live comfortably in the event of an emergency, but in a smaller space.

In addition to its use as an emergency backup electrical system, the PV equipment can provide a portion of your everyday electrical needs, reducing your utility bills. You might use a small system to power only a few items in your home, perhaps your refrigerator and freezer. As your PV system grows, you can add additional appliances. I hope to own a plug-in electric hybrid vehicle (PHEV) someday, and will use my PV system to charge its batteries. If all goes as planned, I’ll be driving on free power from the sun.

John