A report by Germanys Fraunhofer Institute for Solar Energy Systems ISE and the U.S. National Renewable Energy Laboratory (NREL) on the status of concentrator photovoltaics (CPV) published this week outlines the great strides the sector has made in recent months in terms of market penetration, efficiencies and lower levelized costs of electricity (LCOE).
According to the report, Fraunhofer has achieved record efficiencies of 36.7% for CPV modules and 46% efficiencies for CPV cells in laboratory conditions, but the report also states that commercially available CPV modules regularly exceed 30% efficiency.
At utility-scale, these CPV efficiencies could potentially reduce the amount of land required for a large solar plant, in turn allowing for a competitive LCOE as costs come down. The technology is most effective in sun-rich areas with Direct Normal Irradiance (DNI) greater than 2,000 kWh per square meter.
Thus far, a mere 330 MW of CPV solar power is grid-connected globally, the majority of which is in China (145 MW), the U.S. (79 MW), South Africa (42 MW), Italy (20 MW) and Spain (18MW), with Australia, Portugal, Greece and Chile each dipping their toe into the market.
The largest single CPV plant is the 80 MW Golmund installation in China, built by Suncore, which uses two-axis tracking to maximize the technologys yield. The report also added that the majority of large-scale CPV plants use high concentration PV (HCPV) modules, which boast higher efficiencies and thus can reduce the area size of these multi-MW plants.
HCPV modules, the report adds, tend to use III-V multi-junction solar cells, whereas low concentration PV (LCPV) use c-Si or other cells. In hot climates, the III-V multi-junction cells perform better and do not decline as severely as conventional c-Si modules.
Higher efficiency, but at what cost?
Installation costs for CPV have typically proven quite high in recent years, stunting the sectors growth at a time when conventional PV technology has become increasingly cheaper. However, the report finds that installed CPV prices are tumbling. Fraunhofer ISE states that a typical 10 MW CPV project would cost between 1,400/kW ($1,600/kW) and 2,200/kW ($2,500/kW) to install.
Based on these installation rates, LCOEs can be as low as 0.10/kWh to 0.15/kWh ($0.11 to $0.17) for a CPV plant located in a geographic region with DNI at 2,000 kWh. In regions with DNI at 2,500 kWh such as southern Spain, Greece and many parts of Australia, the U.S. and Latin America those costs come down to around 0.08/kWh, the study found.
If installations continue to grow at current pace through to 2030, LCOE for CPV systems could fall to as low as 0.045/kWh, states Fraunhofer at which point the technology would outperform conventional PV on cost.
Efforts are still required on numerous fronts, however. The market for CPV has suffered a series of setbacks in recent years, and R&D focus has tended to drift into other realms. Higher efficiencies are the ultimate goal for CPV researchers, and there has been encouraging progress in this field since the year 2000, with system efficiencies now reaching beyond 30% in real world conditions. If current trends are maintained, installed CPV systems could deliver efficiencies of 42% by 2035, states the report.
Much of CPVs future growth hinges on the efficiencies extracted from III-V multi-junction cells, and the availability of material required to produce these cells. Gallium, Indium and germanium are usually used to form a typical III-V multi-junction cell, and each suffer from limited global supplies a challenge that the CPV industry has to face in the coming years, the report concludes.