Bright Ideas in Solar Energy

Abstract

B right I deas in S olar E nergy B S J Jo Melville It’s no secret that solar power is one of the electricity directly. Though STE dates back to ancient fastest-growing subsects of the renewable energy times (such as the semi-mythological tale of Archimedes industry. In 2011, $150 billion was invested into solar at Syracuse, in which the famous Greek mathematician energy -- more than wind, biofuels, and hydroelectric allegedly defended his home city from a naval siege by combined, according to Bloomberg New Energy Finance deploying large parabolic bronze mirrors to remotely (BNEF, 2011). The reason that solar energy receives such ignite the besieging ships), it is still widely used today -- a spotlight, even among other renewable energies, is many modern solar power plants, rather than using solar because it is considered by many investors to have much panels, use mirrors to concentrate sunlight to boil water untapped potential, a belief that backed the 50% growth to spin turbines. In fact, the largest solar power plant in in investment solar energy saw in 2011. Wind energy is the world, the 354-megawatt Solar Energy Generating capricious and, like hydroelectric energy, is hugely limited Systems works by this very method (for reference, an by location; few biofuels can claim to be truly as emission- average coal power plant has an output of about 500 neutral as other alternative energy sources. Solar energy, megawatts) (Quiggin, 2012). on the other hand, can be implemented effectively in Photovoltaic solar collection techniques, on the many climates, requires little infrastructure, and can be other hand, are far more contemporary, yet have had a used effectively on a personal or an industrial scale. About much greater cultural and scientific impact than solar 4.2 quadrillion kilowatt-hours (kWh) of solar energy strike thermal energy. All modern photovoltaic research is the earth every day, of which about 2.1 quadrillion kWh based on the photovoltaic effect, discovered in 1839 by make it to the surface (Quiggin, 2012). As much energy Henri Becquerel, that details how light can induce an strikes the Earth in 24 hours as is contained in all the electric current in certain materials by exciting electrons petroleum reserves on Earth! The solar power industry with rays of incident light. The first photovoltaic cell was is growing exponentially created in 1954 at Bell Labs, -- more megawatts of solar and was able to convert 4% power have been installed of incoming solar energy in the last 18 months than into electrical power (this in the 30 years before that! is known as the cell’s Why is solar power conversion efficiency). growing so rapidly, and is it In 1958, Vanguard I destined to last? became the first solar- To answer those powered satellite, a field questions -- and to in which solar continues understand what lies in to dominate to this day the future for solar energy (almost all satellites, -- we have to understand including the International the current state of the Space Station and Hubble solar energy industry, the Telescope, extract power Solar cells have been the dominant method for powering satellites bottlenecks holding it from their photovoltaic and space stations since the 1960s. back, and how advances arrays). Since then, in synthetic materials are advances in technology, helping to overcome those materials, and methods barriers. It is by these innovations that widespread solar have each improved the viability and versatility of solar power will live or die. power. Currently, the largest photovoltaic power station Most types of solar energy collection can be is the partially-completed Topaz Solar Farm in San Luis divided up into two broad fields: photovoltaic (PV) and Obispo, with a power output of 300 megawatts, though Solar Thermal Energy (STE). Solar Thermal Energy is solar it is expected to reach 550 megawatts once it is complete in its most fundamental form -- collection of heat energy (SEIA, 2013). from sunlight -- and contrasts with the stereotypical While traditional photovoltaic cells use crystalline photovoltaic notion of turning energy from the sun into structures (often of silicon, because it is easy to work with), 13 • B erkeley S cientific J ournal • S ynthetics • S pring 2014 • V olume 18 • I ssue 2