Smart Energy Technologies & Energy Storage
Aim/Objective: While the world’s most efficiency photovoltaic (PV) cells, which utilize III-V materials, have achieved efficiencies above 30% and even 40% at concentration, these cells have been used primarily in space applications due to their expense. Prior attempts to move III-V solar into terrestrial markets have largely involved the use of concentrator PV (CPV) technology, which requires the use of external trackers, is only able to collect direct irradiance, and has not taken off in the marketplace. Additionally, traditional CPV cannot be installed on rooftops where the potential for efficiency to drive system savings is the greatest. However, there are several emerging fixed-tilt CPV concepts which can absorb some diffuse light, addressing these prior challenges and providing a potential pathway for rooftop modules with 25-40% efficiency. By examining four different fixed-tilt CPV designs, we explore the potential for these modules to drive reductions in installed system cost and influence the size of the residential PV market in the United States. While this analysis focuses on CPV, our analysis of the balance-of-system cost and the markets for high-efficiency rooftop PV is be broadly applicable to a suite of high-efficiency PV technologies.
Methods: We evaluate the value proposition of these high-efficiency, fixed-tilt CPV modules in residential rooftop applications by modeling: 1) the potential for increased efficiency to drive balance-of-system cost savings, 2) energy production and the levelized cost of energy, and 3) the influence of module efficiency and system size on adoption in residential rooftop markets across the United States. In particular, we explore how the market for high efficiency PV modules could evolve in highly electrified futures where increased electric loads could result in a large number of area-constrained rooftops. PV adoption modeling will be achieved by utilizing the National Renewable Energy Laboratory (NREL) Distributed Generation Market Demand (dGen) model. Balance-of-system cost reductions are estimated using a detailed bottom-up PV system cost model created using data collected from installers and developers.
Results: This analysis indicates that several important factors could drive customer demand for higher-efficiency solar modules in residential markets. First, high-efficiency modules drive installed cost savings, particularly in residential markets. Second, in the future, increased electrification of building and transportation loads will result in a greater number of homes with insufficient roof area to host a standard efficiency PV system large enough to offset 100% of their consumption.
Conclusion: We find that fixed-tilt CPV modules could drive reduced system costs and increased residential PV adoption in certain cases, with the market size dependent on how residential electric rate structures and solar policies evolve, the ability of the modules to achieve high energy yield in the field, and the cost of manufacturing modules at scale.