Mark Mehos: Concentrating Solar Power, or what we call CSP, is a technology that takes the energy from the sun, converts that energy to thermal energy or high temperatures, and takes those high temperatures to run a typical turbine, to generate power.
Mark Mehos manages the Concentrating Solar Power Program at National Renewable Energy Laboratory in Golden, Colorado. Mehos is describing a type of solar power plant that can power thousands of homes.
Mark Mehos: The thing about CSP, is that they use concentrating optics, typically mirrors or sometimes lenses, to concentrate sunlight.
Large arrays of mirrors or lenses, he said, can be located in sun-saturated regions such as Spain, and the American Southwest. The sunlight they collect is converted to electricity through a turbine, or it can be saved in a thermal storage system.
Mark Mehos: The advantage there – and it is a significant advantage – is that if the day is cloudy, but you still want to generate electricity, you can draw from that thermal storage system and still generate electricity.
Mehos said this system can store up to six hours of solar energy. Within the storage tanks are millions of gallons of molten salt. The salt can reach up to 400 degrees Celsius, or 750 Fahrenheit as it retains the sun’s heat, to be transferred later into electricity. Mehos said scientists are still working to make this kind of solar power cheaper, and more efficient.
Mehos explained that there are three main types of Concentrated Solar Power: the parabolic trough, the solar power tower, and the parabolic dish. EarthSky asked why there is a need for so many different variations on solar power.
Mark Mehos: The reason for that is the infancy of the technologies right now. What we have is a number of different technologies that are being tried. Different companies feel a particular technology may be the technology that will win. It’s possible that one may win. It’s possible that all of the technologies might win. They’re just different approaches to generating electricity from sunlight.
Some of these plants – such as the parabolic trough – have been operating for twenty years. But the technology continues to develop. Spain has been a leader in pioneering new Concentrating Solar Power plants, and America is following.
Mark Mehos: Spain is a good example of where a lot of plants are being built. Those plants are all on the order of 50 megawatts. In the U.S. we are starting to see much, much larger installations being proposed. There are companies now proposing installations of 280 megawatts, for example.
Mehos said 100 megawatts powers 30,000 homes, on average. He said a choice of these solar technologies is available to utilities now.
Mark Mehos: So it is an option, but it is a higher cost than conventional technology with the current incentives. So what’s needed is to continue the research and development that we are doing, continue and enhance policies, to try to increase manufacturing base. Make lands available. It takes a combination of research and policy for this to happen.
I am a strong proponent of building out solar trough / turbine powered generation plants as a future piece of a multifaceted solution to our growing energy needs. Curiously, that places me at odds with many environmentalists in my neck of the woods (or desert in my case).
Here in Nevada, most solar power plant applications are stalled in the BLM amidst hot (no pun intended) environmental debate. The main issue is “Energy Sprawl.” Here is a good environmental research article that sums up the problem and concern:
Climate Policy Impacts on Natural Habitat for the United States of America – [http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006802#pone-0006802-g004]
The question I have is how are we going to transition to renewables if those, who in word, support government policy to force industry to transition are the same individuals who, in action, staunchly oppose it happening? Perhaps E&S could do a piece on this important and seemingly counterintuitive environmental debate. Specifically, an objective look at how we might balance land use issues in the pursuit of clean energy.
Hi Hank, it’s a complicated world, isn’t it? EarthSky doesn’t report on environmental debates – we interview scientists. But it sounds interesting!
I believe solar and wind harvest will unsettle the solar equillibrium. I believe therre is already present near a 30% alteration of the solar equillibrium and budget and that atmospheric aerosol content and distribution is adding earth heat, especially the aerosol matter in suspention in above cloud zones, sensing solar radaint distribution that would usually pass-through without heat intensity introduction. Aerosol masses are not only gasseous, but include synthetic matter such as microscopic tire material, and frictinal produced metal and non-metal wear of transportation sources. These materials when intact are controlled but when issolated in microscopic size are indeed a problem, a cause of much of our global temperture elevations. Aircraft a very large but not alone as a contributor of upper atmosphere polutants have not been limited but must be, along with many other contaminants producers at ground level, that produce chemical and frictional micro and macro sized, lighter than air/gas combinations we breath.
Great discussion.
Jerry,
I think your estimate of a 30% alteration might be a bit high. Most scientists agree that man’s contribution to aerosols and green house gasses, or the atmosphere’s anthropogenic constituent, amounts to approximately 1%. What is being intensely studied in climatology circles is the climate’s sensitivity is to that 1%. This is important because the climate’s sensitivity then determines how much the “radiative budget” and thus the solar equilibrium is affected by man’s activities.
Climate sensitivity is not very well understood simply because it is a chaotic system with many short term and long term natural cycles and non-linear behaviors and interactions. Before climate sensitivity to the anthropogenic content of the atmosphere can be fully nailed down we need to have a better understanding of the natural climate variations and sensitivities to factor them correctly. We’re not quite there yet but we are getting closer. From the body of more recent peer reviewed literature, there is growing evidence that climate sensitivity to anthropogenic agents is not as high as previously believed and may be closer to 1/4 that suggested in the IPCC’s 2007 AR4 report.
My point is I don’t think solar and wind harvest will unsettle the solar equilibrium simply because any effect the development of wind and solar energy has on the atmospheric constituents and solar insolation is negligible in the whole of our planet’s radiative mechanisms and their sensitivity to man’s activities. When you consider the small percentage of the earth’s total land mass solar and wind farms would take up then consider how small the contribution of earth’s land mass is to the total radiative budget, it seems that adding a few solar and wind farms here and there won’t upset the apple cart.
lets have some fun and go wild.