Solar Power - Myths & Misconceptions

There are a few common myths about solar power that we've all heard, and I'd like to offer a few truths, or at least some insights about them.

Solar Power is Free. This is the first one that everyone tries to use to generate attention. While no one has yet figured out a way to charge for or to tax sunshine, it's only free if you eat it as it's coming down. The light is free but the means to collect that light into a usable asset invariably costs money.

Solar Power is too spread out to be useful. This is often put forth by the adversaries of solar, like the wind power camp, the fuel cell folks, those dam hydro-power conglomerates, and the hot rock geothermal bunch. And of course the fossil fuel and nuclear industries. With all those opponents claiming solar is too thin to be useful, how could I possible claim otherwise?

How spread out is sunshine? Well think about it in terms of agriculture, an acre of corn grosses the farmer ~$3500 per year and may net 1/2 of that yet they keep planting. The same acre of solar farm will yield electricity and RECs' worth ~$3000 with only a fraction of the O&M. And before you think it, they are not mutually exclusive; good solar land generally isn't naturally good for farmland.

Concentrating Solar Power means more energy from less area. No, actually all it means is that the active components can be made smaller. Sunlight has a flux energy density of 1350W/sq meter normal to the surface of the sun. By time is gets to the solar device it's down to less than 1000W most of the time. But we call it 1000W for simplicity. It's that simple if you want 3000W of solar watts of solar energy, you must have a collection area the size of a sheet of plywood, and it has to be pointed at the sun.

What concentrators do is to bring all the sunlight falling on that large area and bring it down to a much smaller area of collector. Concentrators can offer ratios from 2-3:1 to several thousand to 1. When the collectors are very expensive this can save a lot of $$$, but if the concentrators are expensive the benefit is reduced. Mirrors are considered to be the least expensive, while lenses are the most familiar to anyone who played with a burning glass as a kid.

The problem with concentrating PV is that the solar cell has become the leaf under the magnifying glass, when you focus that much sun in such a tiny chip. Well it doesn't take long for crackling sounds to emanate and smoke to start billowing up.

Thin-Film PV has also been distracting attention from the facts. By claiming to drop the $/Watt cost of solar cells into the low pennies range, they neglect to mention that thin films are fragile. They still need all the protection offered to the cells by the glass & aluminum frames, and they do nothing to reduce the interconnect complexity of the system.

Let's look at the ideal case for both Thin-Film and Concentrating PV as they like to put forth in their claims. Let's assume that the concentrators are so good the size and cost of the cell drops to 1 cent for 1 kilowatt of power. Compared to the current $4 to $5 per Watt that's almost zero. Same with thin film, just a wisp-o-magic.

But the frames, the glass the racks, the reflectors, the entire balance of the installation still takes up the same area and the same effort to install. When NanoSolar announced $1/W cells last December, it was shown that what that reallt did was to drop the installed price of a 1000W panel array from $7 to $6 per Watt because of the decreased efficiency and increased area required. Hardly a breakthrough, but it got a lot of ink.

CPV does increase the efficiency and decrease the net area required, but demands active tracking of the collector panels, and that means very expensive dual axis trackers. A recent article pointed out that a CPV array could pay for itself in 2 years if the price of electricity was $0.75/kWh. Connecticut was recently hit with back to back 20% increases in the price of electricity, my rate jumped to a whopping $0.167/kWh. The CPV folks want me to absorb another 450% increase to make their product look good. I don't think so.

There is an economically viable technology for capturing sunlight. Yes, no more myths. The technology exists, it has for 25+ years, it's called Concentrating Solar Power (CSP) and it's been operating in the desert south west since the 1980's and in Spain for almost as long. The concentrators consist of large mirrors, and the collectors consist of steel pipes, just like the leaf under the magnifying the pipes get very hot, but a fluid circulated inside to keep them from burning. The mirrors turn with the sun from morning to sunset. The fluid in the pipe goes to a boiler where is makes steam and that steam eventually turns a generator, just like any other power plant.

When governments throw enough money at an engineering problem, they will invariably solve it, and the plants in the southwest are testament to that, as were all of the mighty projects of the 20th century, from the Panama Canal to the International Space Station.

Only when private industry gets behind a project does the technology become affordable for the people to take advantage of it. Classified military computers once calculated firing tables for artillery tables, today you're reading this blog, maybe even on a mobile device.

The massive mirrors of the Saguaro, SEGS, & LUZ installations were developed using the finest government traditions, they're large, expensive and they function as designed. We have a new panel technology that roughly compares a WWII Army Field Radio to an iPhone(tm). It doesn't depend on magic, just 60+ years of manufacturing experience that we all share. We do exactly the same thing, we concentrate and collect the thin energy of sunlight and turn it into electricity, but we do it for less $$$, we do it faster, and we do it cheaper than the government.

The Light is Green!