After my last post about solar power, my neighbor Tom Dickson suggested I use propane instead of the sun. For a lot less money I could bury a propane tank in the backyard and run a generator whenever the power goes out. Tom is a really smart guy, and his solution makes a lot of sense.

Normally our electric company generates just enough electricity to match demand. If demand exceeds generating capacity by even 5%, we experience a brownout. If generated electricity exceeds demand, then the extra is usually lost. The power company has to have enough capacity to run all our air conditioners and appliances on the hottest day of the year and also carefully monitor customer usage to match moment-to-moment demand.

Electricity can travel only about 300 miles with our current power lines, so it is usually generated close to the place where it will be used. When you hear someone talk about powering the whole country with wind farms in the Midwest or solar farms in New Mexico, you also hear them talk about a “smart grid.” A smart grid would be one that uses new and more expensive power lines to create a grid that would allow electricity to travel across the county. It would also balance the solar and the wind energies.

Electricity doesn’t store well. You can charge a battery, compress air, or use “pumped storage” (water is pumped up into a large storage tank when there is excess electricity, and then the water is released to power a turbine on the way down when electricity is needed). These methods are very expensive, so it’s unlikely there would always be enough stored power to make up for many cloudy days or windless nights. A wind/solar, long distance transmission, and power storage system could easily cost $3 trillion. That’s about $10,000 for every man, woman, and child in the USA.

Usually a smart grid also includes putting devices in our homes that would automatically turn up the thermostats on our air conditioners whenever demand exceeded capacity. In other words, with a $3 trillion smart grid we could all experience hot flashes.

We typically pay 8-10 cents per KWh for coal, nuclear, or natural gas-based electricity. Solar or wind power costs more like 21 cents per KWh, even after federal and local governments subsidize half the cost. Even ethanol, which makes no sense at all, is cheaper than solar or wind power. As Tom Dickson suggests, propane at about 11 cents a KWh is a no-brainer.

So, why am I still interested in solar power? I guess I am trying to figure the whole thing out.