Thermal Energy Storage

The World's First Baseload (24/7) Solar Power Plant

In the future solar power plants will be as plentiful as personal computers or cell phones are today and they will generate energy on demand. Today I have witnessed the future of energy: a solar power plant capable of generating solar electricity around the clock.

Located in the Spanish province of Andalucia, Torresol Energy’s Gemasolar is the world’s first utility-scale commercial baseload solar power plant.

Torresol Energy, the company that built Gemasolar is a joint venture between Spanish infrastructure giant Sener and Masdar – Abu Dhabi’s Future Energy Company.   During my visit to Gemasolar I met with Santiago Arias, Torresol’s Chief Infrastructure Officer and one of the co-founders of the company.

Solar Salt Batteries

Gemasolar, which officially launched last month (May 2011), is a 19.9-MW plant with a 15-hour ‘battery’. Gemasolar’s expected production is 110,000 MWh per year—or about enough to fully power 25,000 households. Because it can store energy, this 19.9 MW generates the equivalent of a 50 MW solar power plant without storage, according to Mr. Arias.

Gemasolar’s battery consists of two tanks of molten salt thermal energy storage that allows the solar plant to generate on-demand electricity: during the evening, during cloud cover or rain, or even days or weeks later. Molten salt energy storage (MSES) or ‘solar salt’ batteries are thermal not chemistry-based batteries like Lithium-ion which power electric vehicles like Tesla’s (Nasdaq: TSLA) Roadsters.

MSES uses a combination 60% potassium nitrate and 40% sodium nitrate which retains 99% of the heat for up to 24 hours. Another way to put this number: this battery loses just 1% of the heat energy per day.(1)

Potassium nitrate happens to be environmentally safer and cheaper than most chemical-based battery alternatives.   In the Middle Ages, this ingredient was used to preserve food and it is still used in the production of corned beef.(2)  Potassium nitrate is also used in toothpaste (for sensitive teeth) as well as in garden fertilizers.  MSES capital costs are also relatively low, clocking in at $50 to $100 per kWh, compared to about ten times that for a Li-on battery that powers a personal computer or electric vehicle.

Gemasolar is not the world’s first commercial solar plant with MSES.  If I had driven another 300 Km (186 miles) due south-east on Andalucia’s A94 highway I would have seen Andasol-1, a 50 MW CSP plant that has been operating with a 7.5-hour battery since July 2009.  Gemasolar basically doubled the battery availability to 15 hours.

Pressure Imbalance in Thermal Energy Storage Tank? | Applied science

During charging operation, the suction header of the primary chilled water pump will accommodate the water coming from the return line at 150Psi and the water from the tank at around 10 Psi. the pump selection’s NPSHr is 1.9 meter and Available from tank is 11 m. Does this scenario lead up to the event where the chilled water from the primary line go into the lower pressure side which is the tank, thus preventing the mixing of the two chilled water return source?

The pipe from the tank has PRV which will prevent the back flow, but does the pressure difference of 150 and 10 psi be a cause of stagnation of water in the tank?

Thermal Energy Storage, Systems and Applications

Thermal energy storage, basics-design-applications to power generation and heat supply

Solar thermal energy storage

Thermal Energy Storage, Energy Storage, Solar Collector, Seasonal Thermal Store, Molten Salt, Peaking Power Plant, Capital Cost, Enthalpy of Fusion, Air Conditioning, Coefficient of Performance

Thermal energy storage