Supporters of renewable energy have been dreaming of the day when solar power would finally be able to provide 24/7 baseload energy year-round. Well it seems that their dreams may have come to fruition, with the construction of the Gemasolar power plant in the Spanish province of Andalucia.
Gemasolar is a sleekly designed, 19.9-MW solar power plant with an expected production of 110,000 MWh per year, or enough energy to power 25,000 homes. But the real gem of the plant is a 15 hour battery to ensure that electricity may still be provided even when solar power is inaccessible.
This is a huge step forward in the solar industry.
Previously, the biggest problem with solar power was the inability to generate electricity when solar energy was absent; solar power plants could generate electricity when the sun was in the sky (and shining), but after nightfall you were fresh out of luck and would have to rely on other forms of energy for power. Other attempts to incorporate batteries for solar energy were ineffective in providing baseload power.
But Gemasolar solves this problem by incorporating two tanks of salt thermal energy storage. These tanks are filled 60% with potassium nitrate and 40% with sodium nitrate. Environmentalists would be pleased to note that both compounds are environmentally safer and cheaper than their chemical-based counterparts. These “salt” batteries can retain heat generated from the plant for up to 24 hours.
Part of the success of the plant can be attributed to its utilization of Concentrating Solar Power (CSP) or thermal solar technology. Gemasolar uses 2,650 large reflective mirrors called heliostats which reflect sunlight to a single point on a tower. This tower contains a fluid which heats up several hundred degrees Celsius, generating enough steam to drive a turbine to produce electricity. To ensure they are properly angled for optimal solar concentration, the heliostats move with the sun using two motors and built in programmable logic controllers.
Gemasolar collects and generates power when sunlight is abundant during the daytime, and then releases stored power as needed at night-time when the sun goes down.
Admittedly, 19.9-MW is not a ton of electricity. But it is the first solar energy power plant of its kind and technology can only go up from here. I’m sure as technology improves and innovations are introduced to this brand new system, we will start to see more solar power plants provide 24/7 baseload energy around the world. China certainly has big plans for solar power integration by 2015.
They should pay a summer visit to Spain.
Image credit: Torresol Energy