Effectively, GE hopes to use the CO2 as an enormous battery whose chief purpose would be to store solar energy. Although the sun is a great source of energy, it’s rather undependable — after all, the sun has to be out in order for us to capture its rays. “That’s the grand challenge,” Stephen Sanborn, senior engineer at GE Global Research said in a statement. “We need to make renewable energy available to the grid when it is needed.”
And that’ll happen with the help of the significant CO2 reserves scientists have been storing for ages. The process would work in two stages — first, solar energy would be captured and kept in a liquid of molten salt. Then, extra energy from the power grid would cool CO2 into dry ice. When power is needed, the salt would turn the dry ice CO2 into what is known as a “supercritical” fluid, which is matter that does not have specific liquid or gas phases. The supercritical fluid would in turn flow into a CO2 turbine called a sunrotor, whereupon energy would be disseminated as needed.
It sounds plenty complicated, but according to Sanborn, it’ll actually be incredibly cost-effective. “It is so cheap because you are not making the energy, you are taking the energy from the sun or the turbine exhaust, storing it and transferring it,” he says. The scientist claims that sunrotors could operate with 68 percent efficiency, which is significantly better than today’s most effective gas power plants, which are only 61 percent effective. “The result is a high-efficiency, high-performance renewable energy system that will reduce the use of fossil fuels for power generation,” Sanborn says.
We’re still around five to ten years away from seeing these babies in action, but don’t despair, environmental activists — there is a way to fight greenhouse gasses. And in a way, it’s with greenhouse gases themselves.
