Photovoltaic devices constitute the most common form of solar energy generation. According to the Solar Energy Industries Association (SEIA),
“Photovoltaic (PV) devices generate electricity directly from sunlight via an electronic process that occurs naturally in certain types of material, called semiconductors. Electrons in these materials are freed by solar energy and can be induced to travel through an electrical circuit, powering electrical devices or sending electricity to the grid.”
PV energy shows the most promising growth, with more photovoltaic capacity added since 2010 than in the last four decades. In fact, since the turn of the century, PV has been the fastest-growing renewable in the world.
China is slated to add the most PV in the coming years, followed by the U.S. and Africa, India and the Middle-East playing a rapid game of catch up. Overall, the IEA predicts that solar photovoltaic systems will generate up to 16 percent of the world’s electricity by 2050.
Solar thermal electricity is a less common form of solar energy generation, utilizing mirrors to concentrate and direct solar rays at water to power steam turbines (e.g. the Ivanpah plant in the Mojave desert). This type of solar creates electricity that can be stored and deployed as needed, and IEA predicts that it will become more prominent as PV becomes more widely used, supplementing mid-day peaks and supplying energy during evenings and early mornings.
By 2050, IEA projects STE will provide 11 percent of the world’s electricity.
In 2008, solar energy cost about $4 per watt. Today, it’s down to $0.80 per watt and is projected to fall as low as $0.30 per watt by 2050.
According to the agency, “The take-off is around 2025 to 2030. By then the cost of solar will be $100 per megawatt/hour and will compete with fuels facing carbon prices of $50 a tonne.”