Energy Biz - March/April 2008 - (Page 36) tHe role of solar parT of a baLanced enerGy pLan by jeffry e. STerba I Commend the authors of the article, “A Grand Solar Plan,” for developing a thoughtprovoking concept regarding the potential of solar energy to address our energy needs, reduce our dependence on foreign oil and reduce our emissions of greenhouse gasses. I, like the authors, believe that solar energy, as well as other renewable energy sources, can and must play a significant role in our energy future. History has proven that without bold ideas, significant advancements will not occur. I also agree with the authors that small, safe incremental steps aren’t enough, and that significant subsidies are needed to move supply technologies out of the R&D phase and into demonstration projects and on into deployment. However, I respectfully disagree with the premise that this is the time to focus in on any one technology as the silver bullet. There isn’t one. I don’t know anything in the energy business that has a one-size-fits-all solution, and electric generation in a carbon-constrained world is no exception. The history of energy generation in the United States is littered with a number of expensive examples of the country being misled into believing that a single type of generation was the solution to the issue of supply. There was nuclear power, which was going to be too cheap to meter. Then, with such abundant fuel supplies, coal generation was to be the answer. Most recently, natural gas was the fuel of choice. None of these turned out to be the silver bullet. Let’s not fall into that trap again. Photovoltaics have a significant role to play in the future, but I believe a more comprehensive portfolio of solutions is needed. The following outlines some concerns I have about the plan laid out in the article, and then offers what I believe is a more compelling framework for successful CO2 emissions reductions by the electricity sector. The feasibility of the authors’ grand solar plan rests on many arguable assumptions. Let’s look at the specific assumptions in three areas: generation and storage technologies, land use, and high-voltage direct-current transmission-line infrastructure. TEChNOlOGy aNd COST CONCERNS The emphasis on thin-film technologies is understandable as one of the authors is a well-known thin-film expert previously employed at the National Renewable Energy Laboratory. However, I believe that choosing any one solar technology as the cornerstone of a future supply plan, and making that choice now, is both shortsighted and unnecessarily premature. It’s still unclear whether or not thin films will have a meaningful cost advantage, either in the short-term or the long-term, over siliconbased PV cells. For example, one of the world’s largest silicon-based PV manufacturers believes it can get the price of its PV modules down to $2 a watt by as early as 2010; if so, what can they accomplish by 2020, when the authors theorize an installed cost of thin-film cells of $1.20 a watt? As for long-term advantages, given the emerging nature of thin-film technologies, their long-term Solar, nuclear and wind power, along with energy efficiency, are crucial elements of a comprehensive portfolio of options for secure, reliable and low-emitting energy generation. © 2008 JuPiTEriMagEs cOrPOraTiOn; LighTBuLB PhOTO By WP cLiP arT durability is not fully understood. Silicon cells, however, have already proven their durability, lasting 20–25 years with limited power degradation. The total installed system costs for installations of any type of generation facility have been increasing due to the costs of raw materials, such as steel and cement, to build the balance of plants — such as structures, inverters and switchgear. So the total system cost figure of $1.20 a watt by 2020 is most likely understated. Furthermore, these costs don’t include the true costs of energy storage. Implementing compressed-air energy storage as a single technology to manage a large network of PV plants is only a partial solution; an additional flywheel/battery storage solution will likely be needed to address grid stability issues. Finally, the statement that only 10 percent of U.S. energy will come from distributed PV installations — 36 E n E rgyB i z March/April 2008
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