Solar energy production
Solar radiation can be converted directly into electricity by solar cells (photovoltaic cells). Inside, a small electrical voltage is generated when light hits the junction between a metal and a semiconductor (such as silicon), or the junction between two different semiconductors.
The power generated by a single photovoltaic cell is typically around two watts. However, by connecting large numbers of individual cells, as in solar panel arrays, hundreds or even thousands of kilowatts of electrical energy can be generated in a solar power plant or in a large home network.
Solar energy in practice
The energy efficiency of most current photovoltaic cells is only about 15-20% and, because the intensity of solar radiation is low to begin with, large, expensive assemblies are required to produce even quantities moderate energy.
Small photovoltaic cells operating on sunlight or artificial light have been widely used in low-power applications.
Larger units were used to power water pumps and communications systems in remote areas, as well as for weather or telecommunications satellites. Conventional crystalline silicon panels and emerging technologies using thin-film solar cells, including building-integrated photovoltaic systems, can be installed on the roofs of homeowners and businesses to replace or augment conventional electrical power.
Concentrated solar power plants use concentrating collectors to channel sunlight received from a wide area onto a small, blackened receiver, greatly increasing the intensity of the light, to produce high temperatures. Arrays of carefully aligned mirrors or lenses can concentrate enough sunlight to heat a target to temperatures of 2000°C or more.
This heat can then be used to operate a boiler, which in turn generates steam for a turbine or steam power plant. To produce steam directly, moving mirrors can be arranged to concentrate large amounts of solar radiation onto blackened pipes.
Other applications
Solar energy is also used on a small scale for purposes other than those described above. In some countries, solar energy is used to produce salt from seawater through evaporation. Similarly, solar-powered desalination units transform salt water into drinking water, by converting the sun’s energy into heat, directly or indirectly, to drive the desalination process.
Solar technology has also emerged for the clean, renewable production of hydrogen as an alternative energy source. Mimicking the process of photosynthesis, artificial leaves are silicon-based devices that use solar energy to split water into hydrogen and oxygen, leaving behind virtually no pollutants. Further work is needed to improve the efficiency and cost-effectiveness of these devices for industrial use.
US solar energy production
Solar energy production in the United States has experienced a remarkable surge in recent years, emerging as a pivotal player in the nation’s quest for sustainable energy sources. With abundant sunlight resources across various regions, America has witnessed a substantial increase in solar installations, both at residential and utility scales.
The adoption of solar power has been facilitated by declining costs of photovoltaic (PV) technology, coupled with supportive federal and state policies, tax incentives, and renewable energy targets. Furthermore, advancements in solar panel efficiency and energy storage technologies have enhanced the reliability and affordability of solar energy systems, all this helped by the decrease in the cost of solar panels and equipment.
As a result, the USA has become one of the global leaders in solar energy production, with numerous utility-scale solar farms and rooftop installations contributing to the diversification of the energy portfolio. Solar power not only reduces greenhouse gas emissions and mitigates climate change but also creates job opportunities, drives economic growth, and strengthens energy security.
Moving forward, continued investments in solar infrastructure, research, and development are vital to developing the full potential of solar energy and transitioning towards a more sustainable and resilient energy future, with less pollution and CO2 gas emissions.
