Concentrated Solar Power (CSP), Explained

CSP technologies use a mirror configuration that concentrates the sun’s solar energy onto a receiver, which converts it to heat. The heat is then converted into steam to drive a turbine that produces electrical power. CSP plants can use thermal energy storage systems to store the power until it’s needed, for example during periods of minimal sunlight. The ability to store energy is what makes CSP a flexible source of renewable energy.

CSP systems can also be combined with other power sources to create hybrid power plants. For example, CSP can be integrated with thermal-fired power plants that use fuels like coal, natural gas and biofuel.

There are four types of CSP technologies:

1. Parabolic trough systems – Through this system, solar energy is concentrated by curved, trough-shaped reflectors, which are focused onto a receiver pipe. The pipe usually contains thermal oil, which is heated and then used in the thermal power block to generate electricity in a steam generator.
2. Power tower systems – These systems use mirrors called heliostats that track the sun and focus its energy onto a receiver at the top of a tower. A fluid (often, molten salts) is heated inside the receiver and is used to generate steam, which drives a turbine generator.
3. Linear fresnel systems – A large number of collectors are set out in rows. The mirrors are laid flat on the ground and reflect the sun on to the receiver pipe above. Similar to trough and tower systems, fresnel can integrate storage in a power block or generate steam directly.
4. Parabolic dish systems – A parabolic-shaped dish acts a concentrator that reflects solar energy onto a receiver mounted on a structure with a tracking system that follows the sun. The collected heat is then generated by a heat engine. The dish can attain very high temperatures, which makes the system potentially well-suited for use in solar reactors.

Perhaps the most obvious advantage of CSP is that it’s renewable. Its supply will never be exhausted and be can used continually, so it’s a sustainable energy source. It also reduces carbon footprint. Unlike fossil fuels, which emit carbon dioxide when burned, CSP uses the earth’s natural resources, which is kinder to the environment. It can improve the quality of air and reduce the rate of climate change.

CSP also provides a relatively continuous source of electricity, particularly in comparison to solar photovoltaics (PV) and wind power, which provide intermittent supplies. Because CSP plants can store solar energy in the form of molten salts, the electricity generated is predictable and reliable.

CSP can be easily integrated into existing steam-based power plants. Even those running on fossil fuels can be used for CSP systems. The operating cost of a CSP plant is also lower than nuclear and hydrocarbon-based plants because the operations and maintenance is simpler.

Concentrated solar power can be used in combination with other energy sources, providing a more secure energy grid. When used in the energy mix, CSP can help meet future electricity demand. It can also aid oil recovery as the steam it produces can be used to concentrate heavy oil so it’s easier to pump.

It also has potential to be used as a transportable form of energy. For example, renewable energy consultancy Ecofys published a study to assess the feasibility of CSP being used as a technology to produce cost-effective hydrogen that could act as an energy carrier to power transportation.