At the end of last year, the Solar Energy Industries Association (SEIA) reported that 17.5 gigawatts of solar systems have been installed as of the third quarter of 2014—enough to power 3.5 million additional homes. The SEIA also indicated that this growth in solar capacity is accelerating rapidly, noting that “so far this year, solar represents 36% of the new generating capacity in the U.S., second only to natural gas,” compared with 10% in 2010. With all signs pointing to continued growth in solar energy, the innovations made possible by materials science R&D that I mentioned in Part 1 of this post will become even more critical as the industry works to meet the future demand for solar technology.
I was fortunate enough to take part in a collaborative effort that aimed to make the link between materials science R&D and a sustainable energy future clear to the media and policymakers with the power to support this important area. Composed of material scientists from five diverse technical societies*, the Advanced Materials for Our Energy Future project identified the materials R&D areas with the greatest potential for creating new energy sources or more effectively conserving current ones and captured the results in a brochure with examples from a range of power generation sources, including solar, wind, geothermal, nuclear, fossil, biofuels and hydrogen.
Because of my experience in the solar silicon photovoltaic cell industry, my work with this group addressed the variety of advanced material solar technologies that can be used to effectively capture energy from the sun, including photovoltaics (PV) and concentrating photovoltaics (CPV), among others. To continue to drive innovation in solar power energy systems, I believe the following should serve as key advanced materials research priorities in these technology areas:
Photovoltaics (PV) – Despite the growth in the market, solar power is still fairly cost-prohibitive to the average consumer. Improved materials and cell designs that increase PV cell efficiencies are needed to reduce the cost of electricity produced by solar systems. This can be achieved by:
- Closing the gap between research and commercial cell efficiencies used in modules
- Identifying or developing abundant, nontoxic and low-cost materials for thin film PV
- Developing novel nanoscale surfaces that reduce reflection and increase the full spectrum capture of sunlight
- Creating efficient, high-volume methods to recycle solar system materials at the end of their life cycle
Concentrating Solar Power (CSP) – CSP uses sunlight-concentrating reflectors to generate the high temperatures necessary to drive steam turbines that produce utility-scale electric power. The three primary CSP types are parabolic trough, dish, and power tower systems. Each makes use of reflective mirrors to focus sunlight on fluid such as oil, water, gas or molten salt. Materials research is needed to:
- Improve optical materials for reflectors with greater durability and low cost
- Enhance absorber materials and coatings with higher solar absorbance and low thermal emittance
- Develop thermal energy storage materials with improved heat capacity
- Improve corrosion resistance of materials in contact with molten salts
On-going sponsorship for the research and development needed to achieve the above priorities is being provided by the Department of Energy (DOE). For example, DOE’s SunShot Initiative actively supports PV and CSP R&D projects. The 2014 SunShot Initiative report highlights projects focused on decreasing the cost and increasing the efficiency of PV and CSP solar energy generation. Programs like these provide material scientists and engineers with the opportunity to research and develop advanced materials to advance solar technology. Continued support for these efforts will be needed to “power the future”.
*The Advanced Materials for Our Energy Future project is a collaborative initiative of the American Ceramic Society (ACerS), the Association for Iron & Steel Technology (AIST), ASM International (ASM), the Materials Research Society (MRS) and The Minerals, Metals & Materials Society (TMS).