I’ve lived in an off-grid house for the past 39 years. Since I make my own electricity, my electricity costs are much higher than those of most Americans. Because of my off-grid lifestyle, I often lack perspective when I try to help people who ask questions about ordinary energy choices. (I’ve had to compensate for my lack of relevant experience by undertaking anthropological studies of my grid-connected neighbors.)
Back in the old days, I used to haul water in a bucket from the spring, and I made whole-wheat flour with a hand-cranked mill. (Don’t ask.) So when I’m in a retrospective mood, I can be amazed by simple things.
“Look: all I have to to is turn this little knob and water flows out of the faucet!”
“If I flip this switch, the mill will make flour by itself!”
Karyn and I try to keep our batteries charged, of course. In sunny weather, we get most of our electricity from our rooftop photovoltaic (PV) array. When the weather turns cloudy, or days get short, we have to charge the batteries with a gasoline-powered Honda generator.
Since I still have vivid memories of the old days, when I did everything by hand, I’m grateful for the conveniences made possible by our Honda generator. But generators are a pain. Anyone who lives off-grid has a visceral understanding of how complicated it is to burn fossil fuels to create the rotary motion needed to power a generator or alternator. Gasoline-powered generators are noisy, require frequent maintenance, and use expensive fuel. Every kilowatt-hour we generate this way is hard-won and expensive.
One solar panel at a time
I bought my first PV module (a 33-watt Arco panel that cost $275, or $8.33/watt) in 1980. My PV array (like those of most off-grid hippies) is a collection of mismatched panels collected over several years.
When the Carizzo utility-scale solar facility in California closed down in the early 1990s, I bought three used Arco modules from the dismantled plant. Over the years, I continued to buy PV panels, usually one at a time, as I could afford them.
I didn’t keep perfect records, but I have receipts for some of my purchases. In 2002, I bought a 120-watt Kyocera module for $525. That’s only $4.37/watt — about half the price of my first module.
In 2004, I bought another 120-watt Kyocera module, this time for $477 — down to $3.98/watt.
Eventually, I accumulated 16 miscellaneous PV modules that produced about 700 watts. A few years ago, I realized that my roof was getting crowded, so I stopped buying PV modules.
Meanwhile, the cost of PV modules just kept dropping. This summer, I saw an ad for ten used 120-watt Kyocera modules for $1,000 — in other words, 83 cents a watt. So I sprang for another 1,200 watts of PV.
This latest batch of modules was an order of magnitude cheaper than the first module I purchased.
Time for a second array
Over the last few weekends, I’ve been installing a ground-mounted rack to hold my ten new PV modules. I recently flipped the breaker that sends power from the new array to my charge controller.
The array is wired for 70 volts DC. It delivers PV power to my electrical room through #6 cables in a buried conduit.
It’s hard to describe the feeling I have when the sun is shining on the new array and I read the display on my new charge controller. The system is making gobs of electricity, and I didn’t have to haul in any gasoline to make it happen. Of course, the PV array has no moving parts, and it isn’t making any noise. The 10 new panels are sitting out there in the sun, silently pumping just as many amps into my battery bank as I get when my Honda generator is running.
Isn’t that amazing? These simple slabs of glass, aluminum, and silicon are inexpensive, foolproof, durable — and fun. I fully expect my new PV array to produce power for the next 30 years, without any maintenance.
Waking up in the future
Over the last 34 years, I’ve seen the cost per watt for PV modules drop to 1/10 of the price in 1980 — or, more accurately, to 1/29 the price, if inflation is taken into account. So my $1,000 buys 29 times as many watts now as it used to.
Lots of things have gotten worse since 1980, including biodiversity and suburban sprawl. But some technical developments (including the development of inexpensive PV modules) have been so surprising that I sometimes feel that I took a short nap and woke up in the future.
Just watch: in the next two or three decades, inexpensive PV modules will change the world.
Martin Holladay’s previous blog: “Dense-Packed Cellulose and a Wrong-Side Vapor Barrier.”