ORN#12 Concentrating Solar Power

Hi friends,

It’s been a while.

We haven’t released a video for weeks now, mostly due to me spending a lot of time learning the ropes of the new job as a home energy auditor. It hasn’t left me much time to do video editing. Things seem to be going smoother now so we should be back to a more regular pace. It’s been incredibly gratifying to me in the new job though, and it’s a great feeling to spend my working hours helping people save energy. (and money!) It’s truly the kind of work I would do even if I wasn’t getting paid for it (shhhh….don’t tell my boss).

So….our latest video is ORN#12 Concentrating Solar Power, which is Carrick’s tour of Nevada Solar One, a different way of generating electricity from the sun. We’re used to seeing solar panels as a way of making electricity, but out in the desert of Nevada they are concentrating the heat from the sun using parabolic mirrors, which eventually turns a steam generator and makes electricity. This was yet another stop on our cross-country journey that was not open to the public, and we had to make special arrangements for a tour of the facility. Fortunately we sounded professional enough that they let us in!

http://www.youtube.com/watch?v=Hna-SERm1uw



Nevada Solar One is one example of concentrating solar power (CSP) to generate electricity – here they use rows and rows of parabolic trough mirrors that follow the sun throughout the day, and the mirrors focus the intense desert sun onto a small receiver tube overhead. The fluid inside the tube is heated by the sun to 750 degrees and is piped to a heat exchanger that produces steam to turn a generator, making electricity. Our guide explained that while the concentrating solar aspect is newer technology, the steam generator is of course many generations old, so the basis of the whole system is easy enough to build and operate, and is scalable. You may have seen other types of concentrating solar power technology, like the field of mirrored dishes (that look like satellite dishes) that reflect their light onto a central tower. It’s the same idea.

One of the most amazing things we found out about concentrating solar power is that 100 square miles of desert would be enough to power the entire U.S. if it was filled with concentrated solar power plants like Nevada Solar One. Considering the vast stretches of desert we drove through in the Midwest, it seems like a no-brainer. Of course, you have transmission issues delivering it to the rest of the country, etc. etc., but it still serves as an example of a kind of renewable energy that is already proven and could provide power on a massive scale. Our guide Bob told us that there is a lot of research going into developing heat storage capacity so that they could continue to generate electricity after the sun goes down.

During the interview out in the field of mirrors, Bob offered to have one of the mirrors rotated down to our level so we could see it up close. Carrick, not one to miss an opportunity to have some fun, walked right up to it and started making faces at himself in the mirror reflection. I had to leave that part in!

A big setback for companies building concentrating solar power plants like Nevada Solar One is the upfront cost of building the plant. It’s a lot more expensive to build a power plant like this, but then the fuel is free and in the Nevada desert there’s almost a guarantee that it’s going to be really sunny, every day. Natural gas and coal power plants are cheaper to build than CSP plants but then they have to deal with sources of fossil fuels that have costs that swing wildly up and down. Places like Nevada Solar One can set a price to sell electricity that doesn’t change – nice and dependable, just like the sunlight that powers it.

There are two issues that I’ve seen come up with concentrating solar power, that are worth considering. First is CSP plants can use a lot of water because of the steam generation and cooling. Water is scarce enough in the desert but is getting even more difficult an issue because cities and farming farther north are using the resources up. I’ve read that the once-mighty Colorado River is now just a trickle by the time it gets to the Gulf of Mexico. Another issue is the destruction of wildlife habitat in the desert if CSP plants really scale up. To my eyes the whole region of Nevada desert we drove through looked dead, dead, dead, but I’m sure there is a wildlife ecosystem there regardless. That is certainly an important issue to keep in mind when talking about building miles and miles of these CSP plants.

That’s all from here – enjoy the video and hopefully we can get another one out to you soon.

Be well,
Colin & Carrick