Solar Power with Molten Salt

One of the drawbacks for Solar power was it couldn’t generate electricity during the night and now thanks to a new technology involving molten salt, Solar power can be generated even during cloudy days and nights.

Solar power critics complain that it can’t generate electricity during night or under cloudy skies, SolarReserve wants to change that view with their unique technology involving molten salt. Their technology will store the captured solar energy in molten salt and use that energy during the day and at night also because of high heat retaining capacity of the salt.

A solar plant made by SolarReserve will be able to produce up to 500 megawatts of peak power comparable to a regular coal power plant without harmful greenhouse gas emissions. A typical one megawatt energy will be able to supply more than 1,000 households.

The concept used by SolarReserve is similar to the one in Seville, where its solar power tower gathers the heat generated by hundreds of solar panels and heats the water inside the tower. This steam then passes through a series of turbines to generate electricity. Instead of the water, SolarReserve uses commonly available salt in the towers.

The hundreds of arrays of mirrors around the tower will focus the heat onto the tower and will heat the salt inside. At, 1000 degree Fahrenheit, the molten salt is then pumped into a steam generator that will turn a turbine to make electricity. After the process is complete, the cooled salt is sent back to the tower again for reheating by the solar arrays.

Lee Bailey, managing director of US Renewables Group, SolarReserve parent company said to Inhabitat:

Due to the unique ability of the product to store the energy it captures, this system will function like a conventional hydroelectric power plant, but with several advantages…This product is more predictable than water reserves, the supply is free and inexhaustible, and the environmental impact is essentially zero.”

The reason they are using molten salt (mixture of sodium and potassium nitrate) instead of water is because molten salt stores the heat efficiently for a longer time without loss of heat compared to water and other liquids.

The National Solar Thermal Test Facility conducted several studies and concluded that molten salt is the most efficient fluid when it comes to transporting sun’s heat. The study states, “molten salt is used in solar power tower systems because it is liquid at atmosphere pressure, it provides an efficient, low-cost medium in which to store thermal energy, its operating temperatures are compatible with today’s high-pressure and high-temperature steam turbines, and it is non-flammable and nontoxic.”

We will hear more about this technology in the coming years and now the critics can’t complain too much about solar power. It offers considerable advantages compared to coal power. SolarReserve hopes to build 10 plants over the next 10 to 15 years.