What is concentrated solar energy (CSP)?
Concentrated solar power (CSP) is a method of generating electricity using mirrors. Mirrors are used to reflect, concentrate, and focus sunlight on a point. This heat is then converted into electricity. The heat is used to make steam, which can drive a turbine to produce electrical power. CSP technology allows for the continuous production of heat. You can use it on days when there is no sunlight, before sunrise, and after sunset.
The International Energy Agency (IEA) estimates that CSP production increased by 34% in 2019. This is a remarkable increase, but CSP still needs to reach its Sustainable Development Goals. (SDGs) requires an average growth rate of 24% between 2019 and 2030.
What is concentrated solar power?
CSP technologies employ a mirror structure that concentrates sunlight’s energy onto a receiver. The receiver then converts it into heat. The heat is converted to steam, which drives a turbine that generates electrical power. CSP plants can use thermal energy storage systems to store power until it is needed. This is useful for when there is little sunlight. CSP is a flexible source of renewable energy because it can store energy.
CSP systems can be combined with other power sources to create a hybrid power plant. CSP systems can also be combined with thermal-fired power stations that burn coal, natural gas, and biofuel.
There are four types of CSP technologies.
- Parabolic-trough systems This system concentrates solar energy using curved, trough-shaped reflectors directed onto a receiver tube. The pipe is usually filled with thermal oil. This oil is heated and used to produce electricity in a steam generator.
- The power tower system employs Heliostats, which track the sun’s energy and direct it onto a receiver located at the top of a tower. The receiver heats a fluid, often molten salts, and it is used to create steam that drives a turbine generator.
- Linear Fresnel Systems Large numbers of collectors are arranged in rows. Mirrors are placed flat on the ground to reflect the sun onto the receiver pipes above. Fresnel, similar to tower and trough systems, can be integrated into a power block or directly generate steam.
- Parabolic dishes systems A parabolic dish acts as a concentrator and reflects solar energy onto the receiver mounted on a structure with a tracking system that tracks the sun. A heat engine then generates the heat from the collected heat. This dish can reach very high temperatures, making it suitable for solar reactors.
CSP’s greatest advantage is its renewable nature. CSP’s unlimited supply means that it can be used continuously and not run out. This makes it a renewable energy source. It reduces the carbon footprint. CSP is more friendly to the environment than fossil fuels that emit carbon dioxide. It can increase the quality of the air and slow down climate change.
CSP provides electricity in a steady source, unlike solar photovoltaics and wind power which only provide intermittent supply. CSP plants can store solar energy as molten salts. This makes the electricity generated predictable and reliable.
CSP can easily be integrated into existing steam-based power stations. CSP can be used even in power plants that run on fossil fuels. Because of the simplicity of operations and maintenance, CSP plants are also less expensive than nuclear or hydrocarbon-based fuels.
You can combine concentrated solar power with other energy sources to create a safer grid. CSP can be used in the electricity mix to meet future electricity demands. CSP can also be used to aid in oil recovery. The steam it produces can then be used to concentrate heavy oils, making it easier to pump.
It can also be used for transportable energy. Ecofys, a renewable energy consultancy, published a study to examine the feasibility of CSP as a technology for producing cost-effective hydrogen that could be used to power transportation.
Concentrated solar power has its disadvantages.
CSP has its flaws, despite the many benefits. It is heavily dependent on the location. CSP plants, like solar PV or wind power, require large land areas to function. This makes them uneconomical in densely populated areas.
Concentrated solar power requires a lot of water to run steam turbines and cool thermochemical reactors. Seawater could be a solution, but it can cause solar radiation problems for the landscape. CSP plants are also able to attract animals with their light. Some species can even die from the heat.
CSP plants can also be expensive to operate. It isn’t easy to find thermal energy storage materials that can withstand high temperatures. Molten salt is one example. It solidifies at low temperatures and breaks down at high temperatures.
CSP cannot always compete with other energy sources such as solar PV or fission-based nuclear power. Concentrated solar power is at risk of being obsolete as other breakthroughs are made.