A plant will mitigate approximately 356,000t of carbon dioxide per year

[samhpes]

The Mount Signal Solar 206MW Project construction was completed in May 2014 and commercial operation is expected to begin later in the year. When operational, it will be among the largest single-axis tracker solar power plants in the world. It will produce enough energy to power 72,000 homes in the San Diego.Mount Signal3.jpg

[inetdog]

Interesting that the plant is far enough south that the single horizontal axis (north-south) tracker design apparently gives good performance.

[russ]

We would have to see the plant specifications to understand how much of that is real and how much is BS. Many of the claims of CO2 reduction are smoke and mirrors.

[J.P.M.]

Interesting that the plant is far enough south that the single horizontal axis (north-south) tracker design apparently gives good performance.

It seems that most solar plants of this type are single axis. I'd suspect the tracking philosophy/design has more to do with cost, reliability, service requirements and other factors than latitude. Basically, the plant designers probably figure that's the easiest way to get the lowest LCOE for the investment. My guess is the owners main concern with CO2 mitigation lies in its PR value.

[SunEagle]

We would have to see the plant specifications to understand how much of that is real and how much is BS. Many of the claims of CO2 reduction are smoke and mirrors.

One bit of information I have not seen is the amount of CO2 put into the atmosphere to make all of those panels and tracking system. If you are going to claim the theoretical amount of CO2 is being mitigated you should first subtract the amount of CO2 produced. That would provide a more accurate number.

Also where the panels are made will depend on how much CO2 is produced. I would suspect more CO2 is produced in countries that use coal as a fuel source like China. But that is another story.

[Sunking]

One bit of information I have not seen is the amount of CO2 put into the atmosphere to make all of those panels and tracking system. If you are going to claim the theoretical amount of CO2 is being mitigated you should first subtract the amount of CO2 produced. That would provide a more accurate number.

Also where the panels are made will depend on how much CO2 is produced. I would suspect more CO2 is produced in countries that use coal as a fuel source like China. But that is another story.

Glad to see someone thinking. Many times when you take a look at how much energy went into making the system, you discover there is a net loss of energy making the whole thing pointless. Advocates hide those facts. What is sad is th epublic is to ignorant to ask the right questions and just goes along with it.

[bcroe]

One bit of information I have not seen is the amount of CO2 put into the atmosphere to make all of those panels and tracking system. If you are going to claim the theoretical amount of CO2 is being mitigated you should first subtract the amount of CO2 produced. That would provide a more accurate number.

That is true, but then for a fair comparison, you must know the CO2 it would take to put up
a conventional generating plant instead. Bruce Roe

[KenZ71]

Glad to see someone thinking. Many times when you take a look at how much energy went into making the system, you discover there is a net loss of energy making the whole thing pointless. Advocates hide those facts. What is sad is th epublic is to ignorant to ask the right questions and just goes along with it.

Excellent points. I have often heard the net environmental impact of hybrid vehicle production outweighs the benefits of their operation. Are solar panels the same? Is it a case where government subsidies are needed to buildup interest and demand so that the process is perfected thus improving the environmental impact?

Sounds a bit too optimistic.

[bcroe]

Excellent points. I have often heard the net environmental impact of hybrid vehicle production outweighs the benefits of their operation. Are solar panels the same? Is it a case where government subsidies are needed to buildup interest and demand so that the process is perfected thus improving the environmental impact?

Yes and they said, my gasoline car took as much energy to build, as it will use in its
lifetime. Until actual numbers can be posted on both sides of the equations, its just talk.
Bruce Roe

[SunEagle]

That is true, but then for a fair comparison, you must know the CO2 it would take to put up
a conventional generating plant instead. Bruce Roe

Oh I agree that compared to a conventional generating plant (soup to nuts), a renewable energy generating system will put out far less CO2. And I support the building of those renewable generating plants.

What I don't like is when I see them claim the number of "cars eliminated from the roadways" or "tons of carbon in the atmosphere" mitigated by this "Green" energy source because it is not the whole story. They always fail to mention the part of how much carbon is produced in the first place to manufacture that Green energy generating source.

I guess the whole truth is not as glamorous as the half truth.

[pleppik]

Glad to see someone thinking. Many times when you take a look at how much energy went into making the system, you discover there is a net loss of energy making the whole thing pointless. Advocates hide those facts. What is sad is th epublic is to ignorant to ask the right questions and just goes along with it.

Back in the 1970's, photovoltaic systems took more energy to build than they would produce over their lifetime.

That's not been the case for a long time, but analysis of the EROI for PV tends to get a wide variety of answers, anywhere from 6-ish to almost 40. EROI is the ratio of the energy produced to the energy invested, so anything over 1.0 means you get more energy out than you put in.

[Some people argue that for an energy source to be viable for an industrial society you need EROI of 12 or more, but I'm skeptical of that claim since the EROI for many conventional fuels like natural gas, nuclear, and "tight" oil is often estimated to be less than 10.]

I think a lot of the variation in EROI estimates is because these things (a) are estimates, and (b) depend a lot on assumptions you make about upstream energy sources and efficiency, and (c) are sensitive to what you consider part of the energy investment.

Anyway, here's a nice overview I found from a couple years ago, from IEEE Spectrum.