Solar energy conversion toward 1 terawatt

The direct conversion of solar energy to electricity by photovoltaic cells or thermal energy in concentrated solar power systems is emerging as a leading contender for next-generation green power production. The photovoltaics (PV) area is rapidly evolving based on new materials and deposition approaches. At present, PV is predominately based on crystalline and polycrystalline Si and is growing at >40% per year with production rapidly approaching 3 gigawatts/year with PV installations supplying <1 % of energy used in the world. Increased cell efficiency and reduced manufacturing expenses are critical in achieving reasonable costs for PV and solarthermal. CdTe thin-film solar cells have reported a manufactured cost of $1.25/watt. There is also the promise of increased efficiency by use of multijunction cells or hybrid devices organized at the nanoscale. This could lead to conversion efficiencies of greater than 50%. Solar energy conversion increasingly represents one of the largest new businesses currently emerging in any sector of the economy.