Solar Power (part 4)

Written by peterkienle on January 17, 2009

(continued from part 3)

As a we are waiting to go operational I have some time to ponder the pros and cons of my $15,000 investment, alternative energies in general and solar in particular. Despite my feeling of doing something good for the environment and (maybe) for our bottom line I know that this technology is young, even though it has been around for decades, and like my computer the equipment I am installing might be outdated in a few years. Our calculations still show that we’ll break even after about 22 years. The system has a life span of 35-40 years. It is a very long term investment.

There is lots of talk these days about green energy and solar and wind are usually the first technologies mentioned. The problem with both of these is that you only get electricity when the sun shines or when the wind blows. There are really only two ways to have access to electricity when there is no sun or no wind: oversize your system and store surplus energy in batteries or a grid interconnect. Unless you don’t have access to the grid battery storage is really a bad idea. Electricity storage will have to be much more efficient than what is currently available to a homeowner. If you read Scientific American or MIT Technology Review or do a search on the internet you find many people doing great and promising research. Last summer I had a little test setup in my yard with a small solar panel electrolyzing water into oxygen and hydrogen. Nothing much came of it – maybe the plastic bag I used to collect the gases was leaky. More likely the electrodes were the wrong metal. At the same time I am not sure how safe I would feel if there was half a Hindenburg’s worth of hydrogen in a pressurized tank under my house. No storage then. But then each time the sun goes down you will draw power from the grid instead of your panels. So the power utilities can’t really scale down their power plants. Sure, if you work at home and most of your power is used during normal work hours you might be able to offset that with a solar array. But even if my whole street does what I do and nobody draws a single watt from the grid during the 4-8 hours of usable sunlight the power company still will have to keep their coal or nuclear power plant running. As far as I understand you can’t just flip a switch and turn them on or off. To my knowledge just gas power plants allow for relatively fast on/off cycling. At the same time changes in the electric infrastructure will take people like us into consideration.

Of course there are really cool proposals such as once we all have electric cars their batteries will function as energy storage while hooked up to the grid. One literally ‘cool’ idea I read about was to replace the current wires of the electric grid with superconducting material which is kept at very low temperatures by liquid hydrogen. Superconductivity means that electricity can flow through a conductor without resistance. Usually this is done by cooling certain materials to temperatures close to absolute zero. These would be pretty substantial ‘wires’ but they would function to deliver electric energy and hydrogen and could serve as giant energy storage reservoir. Not cheap, though. (September 2006  issue of Scientific American).

Then we also have the really huge stuff like solar power satellites in geosynchronous orbit around the Earth. Geosynchronous means the satellite is at such a distance from Earth that it appears to be hanging above the same point on the ground even as it is orbiting the planet at breakneck speed. Something like that could collect solar energy day and night. It would have to be huge (as in miles and miles of panels) and the energy would have to be transmitted to the ground using tightly focused microwaves or lasers. Since the US will lose manned orbital access for a few years after the Space Shuttle fleet is retired and NASA’s new rockets are not finished yet it doesn’t look too good for large cargo hauls to 36,000km orbits.

And, really why do I need to set solar panels up in my front yard if the payback is so long term that I can’t even be sure to still be alive to see it? Because it’s something that I can do now! This whole energy thing is made up of so many networked components that we can’t rely on one solution only. And we need to accept that it’s a moving target. Maybe more people would put solar panels or wind turbines up if you could buy them at Walmart. The fact that you can’t and that you have to actively make an effort to find skilled and knowledgeable people to help you with it forces you to learn about energy. I think that even if you end up not installing anything you will be much more conscious about your energy footprint and you will discover ways to waste less – or you stick your head in the sand (from what I understand ostriches don’t actually do this) and pretend that everything is fine and no change is necessary.

(to be continued)

Copyright © by Peter Kienle