Thursday, September 1, 2016

Solar and Storage - A Match Made in Heaven

Storing the sun's energy is the holy grail of solar power. Despite solar's vast potential it still suffers from intermittency. Simply put, solar's biggest weakness is the fact that the sun is not always shinning. This increases the need for some form of energy storage system. One that can dole out electricity at night or when the sun is obscured by clouds.

Renewable energy has shown strong growth and the COP21 agreement signals accelerated growth.  Driven by market forces clean energy keeps growing. The costs of energy storage are declining and solar is now the least expensive form of power on earth.

There are also a growing number of efforts to harness and store the sun's energy. There is already a commercially available product that combines solar energy collection and storage solutions in one plug and play unit. It is called Powerstation 247.  According to Cleantechnica, it has the storage capacity of 17.28 kWh which is more energy than the Tesla Powerwall.

Some solar plants store the sun's energy by converting it to heat. As reported in the Review Journal, a project called Crescent Dunes is the world's first and only utility-scale solar power thermal plant with fully integrated energy storage technology. The 110 megawatt solar project is located on a 1,600-acre facility a couple hundred miles northwest of Las Vegas. It employs 10,000 mirrored heliostats that focus sunlight on a 640-foot-tall central tower, heating the molten salt inside to more than 1,000 degrees. The heat stored in the molten salt is then used to convert water to steam and drive generators to produce electricity.

A recent Science Daily, article shows how even the desert sand can be used to store the sun's energy. Researchers have used concentrated solar power to heat desert sand to store thermal energy up to 1000°C. Sand is less expensive and more efficient than molten salts.

While these storage efforts show promise, none of these designs are perfect. There is as yet no truly revolutionary commercial scale option available for solar energy storage. But there will be. Innovation will be driven by the value and convenience that comes from marrying solar power production to energy storage.

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