Everyone knows the world has to transition from fossil fuels to renewables like solar and wind as our main source of electrical energy. But the problem is, renewable sources only function some of the time. Solar only works when there’s sunlight. Wind only works when there’s a breeze. Tidal only works when the ocean is ebbing or flowing. What we need is a way to take all that free energy and store it somehow until we need it. Then and only then will renewable energy replace traditional technology.
Researchers at MIT think they have found the solution. Donald Sadoway, the John F. Elliott Professor of Materials Chemistry, and several colleagues have already formed a company to produce and market a liquid battery large enough to handle the needs of an electrical grid. That battery uses two layers of molten metal, separated by a layer of molten salt that acts as the battery’s electrolyte (the layer that charged particles pass through as the battery is charged or discharged). Because each of the three materials has a different density, they naturally separate into layers, like oil floating on water.
The problem is that keeping all those components in a molten state requires the device to operate at 700 degrees Celsius and it takes a fair amount of energy to reach and maintain that temperature. New research has allowed the scientists to lower the operating to between 450 and 500 degrees Celsius, meaning less power is needed to heat the battery so more is available for the grid.
Until now, the best solution for large scale electrical storage has been to use excess electricity to pump water uphill into an elevated storage tank. When needed, that stored water is released to power turbines as it flows back downhill. The new, MIT-developed liquid battery concept eliminates the need for all those pumps, towers and turbines.
As exciting as the news from MIT is, I think renewable energy geeks like myself should be even more charged up (pun intended) about the water battery that scientists at USC are working on. Why? Because it uses no metals or other potentially hazardous materials. It relies exclusively on quinones, organic compounds found in nature as part of the photosynthesis process. And it operates at room temperature, so no power is need to keep the battery heated.
Ultimately, which system finds widespread commercial acceptance will come down to cost, longevity and environmental considerations. But the day when batteries will absorb all the electrical power renewable sources can produce and store it for later use is coming. In fact, it’s almost here. When we can uncouple our need for electrical energy from our dependence on fossil fuels, mankind will have truly achieved a milestone.
Source | Images: MIT.