Widespread adoption of solar power has been hampered due to a lack of electrical storage capacities. The solar industry is still some way from a comprehensive storage solution, but there is a glimmer of hope on the horizon. A relatively new solar energy technology called concentrated solar power (CSP) is beginning to be developed for commercial electricity production. CSP is a niche solar market that holds great promise for the advancement of the solar industry and also the renewable energy sector. In this article, we will find out how Concentrated Solar Power (CSP) works; the benefits it brings, and why it is important to proponents of solar and renewable energy.
concentrating solar power
A CSP power plant uses mirrors to focus sunlight onto pipes or plates containing a heat transfer fluid. This fluid then passes through a heat exchanger creating steam to power the turbines for power generation. This technology can be used with or without thermal energy storage. Most new plants are incorporating thermal storage due to the flexibility benefits this offers.
Solar Thermal Storage
Molten salt is the heat transfer fluid of choice. The salt used is a mixture of sodium nitrate and potassium nitrate. This material is abundant and relatively cheap. In the dry state, the powder resembles table salt. When heated to over 200 degrees C, it turns into a clear liquid. The liquid is stored in two tanks. The hot tank is 595 degrees C and the cold tank is 295 degrees C, to keep the salts in a liquid state. The size and insulating properties of the tanks, together with the electrical charges and the amount of sunlight directed at the plates determine the storage capacities. This will be relatively short-term neighborhood storage from 6 to 24 hours. This storage capacity is very advantageous for the operation of the electrical network.
Advantages for the electrical network
Peak electricity demand is typically 4-8 pm The sun is not shining or is at an inappropriate angle for solar power production at these times. This is when solar storage becomes very advantageous for the electrical grid. CSP with thermal storage can smooth out these demand spikes where other solar sources fail. The more wind and solar power sources available to the grid, the more difficult it will be to balance it. CSP with solar thermal storage helps balance this profile and becomes a symbiotic relationship with other renewable energy sources. Everyone wins!
Several projects are beginning to bear fruit. In the US, major CSP projects are being built in the Southwest as we speak. A CSP project in Spain recently announced that it had supplied power for 24 hours. Its normal production time is 20 hours, but even this becomes a great advantage over electricity supplied by photovoltaics. Although energy storage is relatively short term, this is a great benefit for CSP and PV. This will allow more PV production during the day, while CSP heats liquids for evening and night use.
These are exciting times for solar and renewable energy proposals. Concentrating solar power with thermal storage will be of great help for all intermittent sources of renewable energy. Storage capacities make this a game changer. This really is a marriage of solar energy technology.