Fighting CO2

We all know that we have a bit of a problem with greenhouse gasses. Ultimately, carbon dioxide causes an estimated 60% of the enhanced greenhouse effect, and sadly, even if we decrease our CO2 production, it will only help so much, as this gas stays in the atmosphere around 100 years.

To solve this problem, General Electric (GE) has developed a technology that can create a solar battery using carbon dioxide, so we will be using the leftover CO2.

Their design follows a two-part process. The first part requires collecting heat energy from the Sun and storing it in molten salt. To do this, the team would use a large array of mirrors that is connected to the salt. The second part uses surplus electricity from the grid to cool a pool of liquid CO2 to the point that it becomes dry ice.

To break this down, when extra electricity is needed, the heated salt can be used to warm up the solid CO2 to a "supercritical" state between a gas and solid. This is then fed into the "sunrotor," a CO2 turbine based on a GE steam design. The compact but powerful turbine is estimated to generate as much as 100 megawatts of “fast electricity” per installed unit, or enough to power 100,000 U.S. homes.

The sunrotor design (a prototype is shown below) also offers an alternative solution to the issue of how power plants can make use of stored gas and the CO2 they're legally required to not release back into the atmosphere.

Image credit GE

“We’re not talking about three car batteries here,” says Stephen Sanborn, senior engineer and principal investigator at GE's GRC. “The result is a high-efficiency, high-performance renewable energy system that will reduce the use of fossil fuels for power generation.”

GE's solar battery can also lower the cost of electricity from $250 to $100 per megawatt-hour. “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,” says Sanborn.

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