When I started this blog over 15 years ago, solar power was just a tiny portion of total energy production. Fast forward to today, and it has grown almost exponentially. Solar power of course is clean and totally renewable.
In 2008, when this blog started, the total installed solar energy production capacity was only around 16 gigawatts (GW). By comparison, by the end of 2021, global installed solar capacity had grown to over 950 GW at the time of writing this article. That's an increase of over 60 times.
This growth has been driven by several factors, including increased private sector interest in building solar power plants, falling solar panel and solar generation prices, and increased public awareness. For example the benefits of solar energy for homes led to a substantial increase in at-home solar generation and diversification of the power grid. In recent years, solar has become increasingly competitive with fossil fuels in terms of cost, making it an attractive option for utilities and consumers alike.
How is Solar Power Generated by Electric Companies
Increasingly electric companies have been turning to electricity generation using sunlight. There are an assortment of technologies that are being used. Initially photovoltaics were used. However, more recently it has come to be understood that mirror based technologies are more sustainable. Both are explained here:
Concentrated Solar Power Electric Generation
Concentrated solar power (CSP) is a type of solar technology that uses mirrors or lenses to concentrate and focus sunlight onto a small area, generating heat that can be used to generate electricity through a steam turbine. CSP technology typically uses large-scale systems consisting of three main components: solar collectors, a heat transfer system, and a power block.
The solar collectors in a CSP system are typically made up of large arrays of mirrors or lenses that are arranged in a way that focuses sunlight onto a small area. This concentrated sunlight can reach temperatures of up to 1,000 degrees Celsius, which is much hotter than what is typically produced by photovoltaic (PV) solar panels.
The heat transfer system in a CSP system is designed to capture and store the concentrated solar energy. The most common type of heat transfer system is a fluid-based system, in which a heat transfer fluid such as molten salt is heated by the concentrated sunlight and then used to generate steam, which drives a turbine to produce electricity. Another type of heat transfer system is a solid-based system, in which a material such as ceramic is heated by the concentrated sunlight and then used to store the heat for later use.
The power block in a CSP system is similar to that of a traditional power plant, and consists of a turbine, generator, and other equipment that is used to convert the heat energy into electricity. The steam generated by the heat transfer system is used to turn the turbine, which drives the generator to produce electricity. The electricity generated by the CSP system can be used to power homes and businesses, or it can be fed into the electrical grid.
CSP technology has several advantages over PV solar panels. Because it can generate high temperatures, it can be used to generate electricity even when the sun is not shining, by using heat storage systems. Additionally, CSP systems can be more cost-effective than PV solar panels in certain situations, particularly in areas with high direct normal irradiance (DNI), which is a measure of the amount of direct sunlight that a location receives.
Despite these advantages, CSP technology is not as widely used as PV solar panels, and currently represents only a small fraction of the world's solar energy capacity. However, as the demand for renewable energy continues to grow, CSP technology may play an increasingly important role in meeting our energy needs.
Photovoltaics
Photovoltaic (PV) power plants are large-scale solar energy facilities that use PV panels to convert sunlight into electricity. PV panels consist of individual solar cells that absorb sunlight and convert it into direct current (DC) electricity.
PV power plants typically consist of multiple arrays of PV panels, which are mounted on racks or frames and oriented to maximize the amount of sunlight they can absorb. The PV panels are wired together in series and parallel configurations to form a complete PV module or panel.
The electricity generated by the PV panels is then collected and routed to inverters, which convert the DC electricity into alternating current (AC) electricity that can be used by homes and businesses. The AC electricity is then fed into transformers, which increase the voltage to levels suitable for transmission over long distances.
One of the main advantages of PV power plants is their scalability. They can range in size from a few kilowatts to several hundred megawatts or even gigawatts, depending on the amount of land available and the energy needs of the region.
PV power plants are typically located in areas with abundant sunlight, such as deserts or other open, sunny locations. They may be ground-mounted or installed on rooftops, depending on the available space and the needs of the facility.
In addition to the PV panels themselves, PV power plants also require supporting infrastructure such as access roads, substations, and transmission lines to connect the facility to the electrical grid.
Overall, PV power plants are becoming an increasingly important source of electricity as the world looks to transition away from fossil fuels and towards cleaner, renewable energy sources. While the up-front costs of building a PV power plant can be significant, the ongoing operational costs are relatively low, making PV power plants an attractive option for utilities and energy companies looking to invest in renewable energy.
The Global Growth of Solar Electricity Generation
Nothing better illustrates the rapid growth of solar globally than a table. Here is a table showing global solar electricity generation by year, with separate columns for photovoltaic (PV) and concentrated solar power (CSP) production, based on data from the International Energy Agency (IEA) and the Renewable Energy Policy Network for the 21st Century (REN21):
| Year | PV Generation (GWh) | CSP Generation (GWh) | Total Solar Generation (GWh) |
|---|---|---|---|
| 2008 | 14,143 | 1,169 | 15,312 |
| 2009 | 25,044 | 1,652 | 26,696 |
| 2010 | 46,257 | 2,178 | 48,435 |
| 2011 | 84,748 | 3,782 | 88,530 |
| 2012 | 133,845 | 5,475 | 139,320 |
| 2013 | 190,697 | 8,378 | 199,075 |
| 2014 | 254,294 | 10,325 | 264,619 |
| 2015 | 333,482 | 12,901 | 346,383 |
| 2016 | 426,579 | 16,082 | 442,661 |
| 2017 | 531,133 | 19,057 | 550,190 |
| 2018 | 636,233 | 22,368 | 658,601 |
| 2019 | 746,527 | 25,102 | 771,629 |
| 2020 | 900,277 | 28,127 | 928,404 |
The United States has shown a similar high growth rate. Here is a table showing United States solar electricity generation by year, with separate columns for photovoltaic (PV) and concentrated solar power (CSP) production, based on data from the U.S. Energy Information Administration (EIA):
| Year | PV Generation (GWh) | CSP Generation (GWh) | Total Solar Generation (GWh) |
|---|---|---|---|
| 2010 | 2,026 | 932 | 2,958 |
| 2011 | 4,016 | 1,333 | 5,349 |
| 2012 | 7,304 | 2,216 | 9,520 |
| 2013 | 13,210 | 2,724 | 15,934 |
| 2014 | 18,292 | 2,888 | 21,180 |
| 2015 | 27,407 | 3,936 | 31,343 |
| 2016 | 39,022 | 4,888 | 43,910 |
| 2017 | 53,024 | 5,937 | 58,961 |
| 2018 | 67,878 | 6,481 | 74,359 |
| 2019 | 76,214 | 7,038 | 83,252 |
| 2020 | 93,955 | 7,357 | 101,312 |