expand their grids to trade with neighboring countries having limited hydro. Wind power development Offshore wind is becoming more profitable Solar thermal Solar thermal energy capacity has increased from 1.3 GW in 2012 to 5.0 GW in 2017. Spain is the world leader in solar thermal power deployment with 2.3 GW deployed. The United States has 1.8 GW, most of it in California where 1.4 GW of solar thermal power projects are operational. Several power plants have been constructed in the Mojave Desert, Southwestern United States. As of 2017 only 4 other countries have deployments above 100 MW: South Africa (300 MW) India (229 MW) Morocco (180 MW) and United Arab Emirates (100 MW). The United States conducted much early research in photovoltaics and concentrated solar power. The U.S. is among the top countries in the world in electricity generated by the Sun and several of the world's largest utility-scale installations are located in the desert Southwest. The oldest solar thermal power plant in the world is the 354 megawatt (MW) SEGS thermal power plant, in California. The Ivanpah Solar Electric Generating System is a solar thermal power project in the California Mojave Desert, 40 miles (64 km) southwest of Las Vegas, with a gross capacity of 377 MW. The 280 MW Solana Generating Station is a solar power plant near Gila Bend, Arizona, about southwest of Phoenix, completed in 2013. When commissioned it was the largest parabolic trough plant in the world and the first U.S. solar plant with molten salt thermal energy storage. In developing countries, three World Bank projects for integrated solar thermal/combined-cycle gas-turbine power plants in Egypt, Mexico, and Morocco have been approved. Photovoltaic development Photovoltaics (PV) is rapidly-growing with global capacity increasing from 230 GW at the end of 2015 to 890 GW in 2021. PV uses solar cells assembled into solar panels to convert sunlight into electricity. PV systems range from small, residential and commercial rooftop or building integrated installations, to large utility-scale photovoltaic power station. The predominant PV technology is crystalline silicon, while thin-film solar cell technology accounts for about 10 percent of global photovoltaic deployment. In recent years, PV technology has improved its electricity generating efficiency, reduced the installation cost per watt as well as its energy payback time, and reached grid parity in at least 30 different markets by 2014. Building-integrated photovoltaics or "onsite" PV systems use existing land and structures