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Beyond Fossil Fuels: David Mills on Solar Power

The founder and chief scientific officer of Ausra weighs in on the hurdles facing his industry
solar thermal, renewable energy, solar power



COURTESY OF AUSRA, INC.

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Editor's note: This Q&A is a part of a survey conducted by Scientific American of executives at companies engaged in developing and implementing non–fossil fuel energy technologies.

What technical obstacles currently most curtail the growth of solar power (particularly solar thermal)? What are the prospects for overcoming them in the near future and the longer-term?
The biggest obstacles are ability to scale, long-term reliability and interruptibility due to clouds and the daily solar cycle. Ausra's core technology, the Compact Linear Fresnel Reflector (CLFR) system, is simple and robust. We are optimizing for the lowest cost of energy, not highest technical sophistication. This combination results in the best value to our customers and high reliability. CLFR uses an array of relatively flat mirrors that reflect sunlight to boil water in elevated tubes, producing steam that drives turbines to generate electricity. CLFR is also the most land-efficient solar technology. By using nearly flat mirrors, water/steam heat transfer, and commodity materials, we are also able to achieve significant cost savings and rapid deployment. Additionally, by using our special reflector geometry, we are able to have a greater density of reflectors in the area and use about half of the ground area of competing technologies. Our systems produce steam for stand-alone, large-scale solar power plants as well as to augment energy output and reduce emissions at existing conventional power plants. The steam can also be used for industrial applications, such as food processing and enhanced oil recovery. Unlike photovoltaic (PV) or other concentrated solar technologies, which lose output immediately when clouds come over, our technology has 20 to 30 minutes of stored capacity, so it can adjust to weather changes or other factors affecting the electric grid. CLFR hybrid plants (with natural gas boilers) can also provide firm capacity to the grid. We are currently proving our CLFR technology at our five-megawatt demonstration and test facility in Bakersfield, Calif. This is the first of its kind in the U.S. and the first large-scale solar thermal plant to go online in California in nearly 20 years.

Are there obstacles to scaling up solar power to serve a larger national or global customer base?
The biggest challenge to larger-scale solar is the ability to get project financing in today's tough credit market. We expect the upcoming year to be a challenging one, which is why we've accelerated Ausra's evolution from a project development company to a solar technology and equipment provider—expanding our customer base and reducing our capital and debt requirements.

Can the existing energy infrastructure handle growth in solar power? Or does that, too, need further modification?
Our current, aging transmission grid is built on a patchwork collection of local systems. We need to invest in a modern national transmission grid that can carry solar power to America's population centers to meet our growing demand for energy and to decrease the nation's dependence on foreign oil. Additionally, open land and superior solar radiation make the deserts of the American Southwest the best place to build large-scale solar power plants. But for those plants to provide electricity to the whole nation, we need a modern transmission grid that reaches those locations. We're encouraged that President Obama's economic stimulus package and energy plan places an emphasis on modernizing our nation's transmission infrastructure. We look forward to working with the administration and Congress to achieve that goal.

Given the current economic crisis, can your industry get the necessary capital (from public or private sources) to adequately finance its growth?
The economic downturn has left many of the financial firms that provide capital for commercial solar projects without taxable income and unable to utilize the solar investment tax credit (ITC) the way it was intended. We are encouraging Congress to monetize the ITC through mechanisms such as a long-term Department of Energy (DOE) grant. This will allow these firms to qualify for the tax credits and allow large-scale projects to be financed, built, and reach operation. But we have to be aware of the current environment, and we are very intrigued by PG&E CEO Peter Darbee's recent comments about building and owning solar power plants as opposed to purchasing solar energy from third-party providers. Utilities are now able to utilize the ITC and have the balance sheets to finance large power plants. Ausra can provide equipment to utilities to help deploy large-scale solar plants rapidly and cost-effectively. Our business model has also evolved and expanded to focus in the near-term on smaller, less capital-intensive projects that will provide power augmentation for existing coal and gas-fired power plants and provide solar-generated process steam for a number of industrial process applications. Our long-term focus will remain on providing equipment for large-scale power plants that utilities and independent power producers can own and operate. In the near-term, Ausra's evolution from a project development company to an equipment provider reduces our capital and debt requirements and allows us to increase our focus on further technology development and equipment sales.

From a strategic standpoint, which is the bigger competitor for solar: incumbent coal, oil and gas technologies or other alternative energy technologies?
We are actually seeking out coal and gas-fired power plants as potential customers. We can integrate our solar thermal technology into existing power plants to boost their energy output during peak demand with solar power and reduce their overall carbon footprint. Likewise, our direct, reliable solar steam generators can be used in a variety of industrial applications, including enhanced oil recovery, petroleum refining and food processing. We can help these types of companies lower their fuel and emissions costs. President Obama has made it clear that renewable energy will play a large role in his economic recovery efforts and in our future energy policy. Clearly a number of clean technologies will have the opportunity to thrive, but realistically, rooftop PV panels, as good as they are, will not be able to meet our energy needs on their own. We will need large-scale solar projects to meet our increasing electricity demands, and we feel that Ausra has a competitive advantage in being the most land-efficient and cost-effective form of large-scale solar.

Is there a cost target that you and others in your industry are aiming to achieve in, say, five years?
That is difficult to answer, due to the wildly fluctuating prices of oil and gas, construction materials, and the cost of capital. That being said, solar power has the benefit of a fuel source that is free—the sun. With the right tax policies, such as a mechanism for pricing the cost of carbon, there is no reason solar thermal power cannot be cost-competitive with fossil fuels in the near future.

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