Today was a gloomy day here in the Seattle region. The sky was overcast and it was nonstop raining. I happened to be driving through downtown around noontime when I saw a sign which gave the solar flux: .23 kw.
A square meter of standard photovoltaic panel generates only about 150 volts of power, max, and a kilowatt-hour per day of energy. At .23 flux, we’re talking about 35 watts per square meter max, and .23 kilowatt hour per day per square meter.
Well, I just measured my two bedroom apartment. It’s about 70 square meters. It’s in a two story building, so I have to share roof space with the people below me, but still that’s 35 square meters.
All right, then that’s 35 square meters of roof space times .23 kilowatt hours per day per square meter, which equals 8 kilowatt hours per day. That’s about half my energy usage in winter, but with better insulation, energy conservation, and above all, a smaller and more practical refrigerator, I might just be able to get to that.
Actually, I wouldn’t be allowed to put solar panels on my rooftop. The apartment complex management wouldn’t allow it. But what if my community were to build a solar array so that it didn’t have to tap off a state or national power grid?
The city of Bellevue, Washington, has a population of 122,000. Let’s say we have 100 square meters of photovoltaic paneling per person. That would require 12,000,000 square meters total, or 12 square kilometers. This would be only 14% of the land area of the city — which is surrounded by more rural areas, by the way.
For the entire United States, 300 million people would require 30 billion square meters for residential usage, or 30,000 square kilometers. This is only .3% of the surface area of the US. Total power usage for industry as well would require about one percent of US land area — about what we have paved over. And all those median strips are presently going to waste.
Back to my community of Bellevue. If we were to build enough solar panels on rooftops, on freeway median strips, and on sidewalk awnings, then we wouldn’t have to tap into state- and national- power grids.
What about snow days of complete overcast? Well, batteries do allow for a reserve of several days, but then there is also the possibility of generating auxiliary power with fossil fuels.
You see, I’m a practical shade of green. If it gets really dark and cold, then fine, let’s use fossil fuels. But the rest of the time, let’s use solar power. Okay, you might reply, but even if we only use it for a few days a year, don’t we still have to build a big giant fossil fuel plant and support all the infrastructure as well?
I thought so too, then I priced portable power generators. Not the small home ones, but the big ones. I would send you to the page for a 22,500 watt beauty, but it’s not working from yesterday. Hmm. So let’s go with this 10 kw generator at Amazon. It costs a thousand dollars and provides enough power for twenty house holds. That’s fifty dollars per household.
Imagine one of these on every street. You know, where the state-wide electric company already has a house-sized switching station. Anyhow, it would sit in a shed until needed. And it would only be needed a few days every year.
With neighborhood solar arrays and portable power generators, electrical power in Japan would have been restored in no time. I know from personal experience that there’s nothing more agonizing than waiting days for power to be restored at the whim of a large regional power authority. And in my case, that was just from a wind storm.
But what about the infrastructure cost of all this? Solar panels are nothing more than silicon wafers, just like computer chips, and so they are likely to follow the same decline in price as computer chips, and eventually cost pennies per square meter. I see that happening in the next ten years.
But what about now? What would it cost now, say, for the nation of Japan to abandon its national nuclear power initiative and embrace instead a paradigm of local solar arrays and neighborhood power generators?
Well, I haven’t done the calculations, but I suspect it would be less than the cost of replacing Japan.
Engineer Zero 