Commercial testing has shown that the 280-megawatt Solana solar power plant situated near Gila Bend in the Arizona desert is capable of generating power even in the absence of sunlight through the use of thermal energy storage.

During the day, the Solana plant makes use of 2,700 parabolic trough mirrors to transfer the sun’s energy onto pipes containing a synthetic oil, which serves as a heat transfer medium.

The synthetic oil subsequently flows to boilers where it heats water for conversion into steam, which in turn powers 140-megawatt turbines for the generation of electricity.

Abengoa, the Spanish engineering firm responsible for building the $2 billion plant, claims that this thermal storage method means Solana is capable of generating clean energy at maximum power for as long as six hours without exposure to sunlight, providing electricity to around 70,000 homes.

The Solana plant could well be a landmark development for the renewable energy industry as it proves that thermal storage is a viable means of remedying the intermittent nature of solar power generation.

While solar and wind power are two of the most widespread forms of renewable energy, they continue to suffer from the fatal flaw of dependance upon fickle weather conditions, which do not necessarily coincide with fluctuating patterns of consumption.

In Germany, for example, the government’s laudable efforts to increase usage of renewable energy have led to the problem of surplus generation at certain times, occasioning negative wholesale prices for electricity, as well as the converse problem of insufficient generation during bouts of inclement weather, bringing with it the risk of blackouts.

The thermal storage system deployed by Abengoa serves to remedy this problem, greatly heightening the reliability of climate-dependent clean energy.

Abengoa claims that the ability of the plant to generate power for six hours under conditions of darkness means it is capable of meeting peak electricity demand in the area during the early evening.

“Dispatchability also eliminates intermittency issues that other renewables, such as wind and photovoltaics, contend with, providing stability to the grid and thus increasing the value of the energy generated by CSP,” said the company in an official statement.

Abengoa commenced construction of the plant in 2010 and has executed a power purchase agreement with Arizona Public Service (APS), the state’s largest electricity utility, for all of the plant’s output.

The Solana plant is just one of four solar power facilities approved for the area, with APS pushing hard to take advantage of the Arizona’s climate resources and transform it into the solar capital of America.