Monday, June 23, 2008

Living a Better Life - Post Oil

Did your parents ever scold you for wasting energy? Did they complain when you didn’t close a door or turn off the light when you left a room? I suspect that most of us were chastised on occasion. Some of us might recall a parent saying; “when you’re paying the electric bill, you can leave the lights on as much as you want”.

By contrast, children of the future might be chastised for NOT using electricity. That may sound odd, so let me explain. Photovoltaic (PV) panels generate electricity as long as the sun hits them, but they’re most productive during “peak” sunlight hours. Most of the United States gets peak sunlight, and therefore maximum output from solar panels, for 3 to 5 hours per day. A grid-tied system feeds this energy back into the grid, and it offsets power used at night. On the other hand, the energy produced by an off-grid system is usually stored in batteries. For several reasons, this process is far less efficient than a grid-tied system. However, if the off-grid system output is used to directly power a load, instead of storing and retrieving it, system efficiency increases dramatically. We get the most from an off-grid system by using it during peak sunlight hours, and we should exploit that whenever we can. Chores like washing and drying clothes, pumping water, and preparing food should be done during the day. Using appliances and machinery during the day, and avoiding their use at night, will be common practice in the future. The child who forgets to do his chores during peak sunlight hours may be in for a scolding.

For the past 100 years we’ve gotten used to paying for the electricity we use. It may be hard for some of us to grasp the concept of free electricity, but PV-produced electricity is indeed free. Once we’ve used all we need for charging batteries and powering devices, the rest can be considered free. We can leave lights or appliances on at no cost (except for the wear and tear on the lights and appliances).

Some people believe that civilization will decline as fossil fuels become more expensive, but I believe that we’ll adjust. Learning new habits will be part of that adjustment. The way we use electricity will not be the only change. We’ll still have transportation, but the vehicles that take us from place to place will change dramatically. We’ll still have comfortable homes, but our HVAC systems will be radically different than they are today. The equipment and systems will still be automatic and thermostatically controlled, and we’ll continue to make adjustments to ensure optimization. In other words; our equipment will be different but we’ll use it pretty much the same way we use the equipment of today.

More of us will have gardens in the future, and those who already have gardens will have bigger ones. Gardens not only help offset the rising cost of food, they can be part of our heating and cooling systems. Some already heat their homes with biofuels, and some use “green roofs” to help keep their homes cool.

You might argue that the ideas I’ve presented here represent a more labor-intensive lifestyle than we’re used to, indicating a decline in the quality of life, but I would disagree. While many of these strategies do indeed require more effort, they’ll also keep us more fit and in better health. We’ll benefit from a better quality of food, more exercise, and better air quality. Anyone who’s ever compared a store-bought tomato to one grown in a backyard garden knows what I mean. Tomatoes that have to be shipped a long distance are picked green, and “gassed” to turn them red by the time they show up in the supermarket. They’re rock-hard, and have little flavor. I can only guess that the nutritional and cancer-fighting properties are not what they should be either. And it’s wise to remember that the recent salmonella outbreak linked to tomatoes was a result of industrial agriculture. Shipping fewer vegetables not only means better food, it also means fewer trucks on the road, which reduces fossil fuel use and improves air quality.

When it comes to the future, there are three kinds of people: those who let it happen, those who make it happen, and those who wonder what happened.

John M. Richardson, Jr.

There will be bumps in the road to oil independence. We’ve overreacted to the rapid rise in the price of oil by making ethanol from corn (kernels), when we should be making it from agricultural waste (cellulosic ethanol). But we’ll adjust, and we’ll eventually be living a far better life than we do today. We’ll replace our dirty gasoline-powered cars with non-polluting electric ones. We’ll develop better ways to keep warm in the winter and cool in the summer. We’ll find better ways to heat water. We’ll generate at least a portion of our own electricity. We’ll build communities that allow us to walk or bike to the grocery store and to work. Additional chores will instill a greater sense of responsibility in our children, resulting in far fewer social problems than we have today.

What we need now is for governments to stop making war, stop promoting fossil fuels, and to begin supporting alternative energy in a substantial way and with well thought out plans. Beyond that, we need little help from them. If they’ll just get out of our way and let us use what God has given us, we’ll be fine.


Monday, June 16, 2008

Unbelievably Low Electricity Rates

Here’s something you’re not going to believe - electric rates below 1 cent per kilowatt hour (kwh). My electricity provider, Ameren, must have lost its mind! For most of the United States, electric rates are about ten cents per kwh, with many areas paying much more than that.

As a participant in the “PowerSmart Pricing” plan, my electricity rate fluctuates from hour to hour, depending on the demand at the time. Shown below are the rates for June 11th, 2008. Notice that from 2:00am until 4:00am electric rates are below 1 cent, and then slightly more than 1 cent per kwh from 4:00am until 6:00am. The highest cost for the day was just over 11 cents per kwh at 3:00pm.

Date * * * * * * * Hour * * * * Price
2008-06-11 * * * 00 - 01 * * * 0.015520
2008-06-11 * * * 01 - 02 * * * 0.012190
2008-06-11 * * * 02 - 03 * * * 0.009200
2008-06-11 * * * 03 - 04 * * * 0.009380
2008-06-11 * * * 04 - 05 * * * 0.012560
2008-06-11 * * * 05 - 06 * * * 0.013790
2008-06-11 * * * 06 - 07 * * * 0.020730
2008-06-11 * * * 07 - 08 * * * 0.030550
2008-06-11 * * * 08 - 09 * * * 0.042160
2008-06-11 * * * 09 - 10 * * * 0.060670
2008-06-11 * * * 10 - 11 * * * 0.077770
2008-06-11 * * * 11 - 12 * * * 0.091420
2008-06-11 * * * 12 - 13 * * * 0.100440
2008-06-11 * * * 13 - 14 * * * 0.108230
2008-06-11 * * * 14 - 15 * * * 0.111300
2008-06-11 * * * 15 - 16 * * * 0.111880
2008-06-11 * * * 16 - 17 * * * 0.104470
2008-06-11 * * * 17 - 18 * * * 0.095140
2008-06-11 * * * 18 - 19 * * * 0.084570
2008-06-11 * * * 19 - 20 * * * 0.070230
2008-06-11 * * * 20 - 21 * * * 0.084700
2008-06-11 * * * 21 - 22 * * * 0.073010
2008-06-11 * * * 22 - 23 * * * 0.042210
2008-06-11 * * * 23 - 24 * * * 0.027310

As unbelievable as these rates are, I was even more surprised on June 16th when my 3:00am rate dropped to .00207 (two tenths of a cent per kwh).

These low rates won’t last forever. When plug-in electric cars become available, most will be charged at night. This increased demand for electricity will drive up the rates. But for now I’m taking advantage of these exceptionally low nighttime rates by topping off the charge on my batteries while rates are at their lowest, and using the stored energy when rates are higher. My battery charger is on a timer, set to power it up from 1:00am until 5:00am. Load switching is automatic. I’ve also switched most of my laundry chores to late-night. See my previous post for additional details, or my March 15th post.

For information about the Ameren plan, visit the PowerSmart Website.


Monday, June 09, 2008

Adjusting to New Batteries and Higher Electric Rates

Every PV system upgrade has had a noticeable effect on performance, and my recent battery upgrade was no exception. The larger battery bank takes longer to charge on a sunny day, but it also powers loads for longer periods at night. Because of the battery bank upgrade, I decided that it would be wise to review system settings. My goals are:

• Prevent battery overcharging.
• Prevent battery under-charging.
• Prevent batteries from discharging too deeply.
• Get as much energy from the system as possible, reducing my electric bill.
• Maintain safety.

A charge controller prevents batteries from overcharging, and mine is adjustable via internal switches. Since my old batteries were sealed, and my new batteries have removable watering caps, I’ve readjusted charging parameters to accommodate the new batteries. I’ve adjusted the battery voltage upward a little. Some “gassing” shouldn’t be a problem, since I’ll be checking battery fluid level on a regular basis.

My batteries are in a windowed sunroom, and therefore I’ve set “Equalization” to manual instead of using the automatic equalization setting. I’ll open the windows when I equalize the batteries, allowing hydrogen gas to escape. My charge controller keeps track of the days between equalization, so I’ll know when it’s time to do it.

My automation settings help me get the most from my system, while protecting the batteries, by performing two basic functions:

• Wait until batteries are nearly fully charged before switching on loads.
• When battery voltage declines to a preset value, remove the loads.

The automation settings turn the inverter on and off, and therefore control the loads. I’ve adjusted the settings as posted below:

• Battery High Voltage Threshold = 13.85 volts (Turn inverter on)
• Battery Low Voltage Threshold = 12.25 volts (Turn inverter off)

I have a Transfer Switch, which is nothing more than a relay, wired to use AC from the inverter as the default. It switches to utility-supplied AC when the inverter is off. With this setup I can be pretty sure that my refrigerator and freezer will always be powered up.

Since I’ve just spent a great deal of money on the new batteries I’ve decided to be more conservative with the settings in order to prolong their life. I’ve adjusted the Battery Low Voltage Threshold upward, minimizing the depth of discharge. This adjustment not only prolongs the life of the battery, it means that I’ll have more reserve energy available in the event of a grid power failure. I’ve adjusted the Battery High Voltage Threshold upward, providing a little more assurance that the batteries will be fully recharged each day.

Even with these conservative settings I’ve observed a significant performance increase with the new batteries. I’ve also learned that it is beneficial to keep the load relatively high. A heavy load reduces the amount of time that the charge controller spends in the “absorption” and “float” states. In other words; more of the available sun’s energy is used to power the loads and therefore less of the sun’s energy is unused.

Adjusting to “PowerSmart Pricing”

My electricity rates vary on an hourly basis, depending on the demand at the time. I might pay as little as 1.5 cents per kwh when demand is low, and more than 17 cents per kwh when demand is high. Now that summer is here, and demand is greater, electric rates tend to be highest from about 10:00am until about 8:00pm. This has caused me to adjust my strategy somewhat. I want to make sure that I’m using electricity from the PV system as much as possible during times when rates are highest. In addition to using as much energy from the sun as possible I can take advantage of this large price differential by charging my batteries at night when rates are low, and use the stored energy during the day when rates are high.

In other words:

I sometimes buy electricity for less than 2 cents per kwh (to charge batteries), and use that stored energy when utility rates exceed 17 cents per kwh. Even with system losses considered, I suspect that I’ll come out ahead. I shift loads to the PV system when electric rates are highest, hoping to have enough energy from the sun and stored energy to last until rates drop.

To avoid manually switching things on and off in the early morning hours I use a timer. Here's a picture of my timer, charger, and battery bank.

And here's a simplified diagram of my system with the charger and timer:

I’ll have to compare this summer’s electric bill to that of last summer to see if my efforts have paid off. If so, I don’t think I’ll have any problem convincing the wife that we can benefit from a couple more panels by the end of the year.