Renewable power has the potential to transform our energy consumption, but like most innovations, it has a downside. One of the biggest stumbling blocks to a renewable-powered society is the intermittent nature of its generation. In other words, wind power works when the wind is blowing, and solar power works when the sun is shining. But what do we do when the sky is dark and the winds are calm?
Innovation and its cousin, indefatigable optimism, are two hallmarks of the renewable age. Channeling both, scientists at the Massachusetts Institute of Technology (MIT) believe they have developed a solution. In February, the university announced new results from an ongoing research program, showing a promising technology that could level the load from power generated by renewables. The technology is longer lasting and more affordable than previous methods.
The system uses high-temperature batteries, which feature liquid components that settle naturally into distinct layers because of their densities. The three molten materials form the positive and negative poles of the battery and a layer of electrolyte in between. Abundant and inexpensive materials make up all three layers.
The scientists borrowed from their work on the electrochemistry of aluminum smelting, which is conducted in cells that operate at high temperatures. By essentially running the smelter in reverse, they produced a battery, which, when plugged into an electrical source, drives magnesium out of an alloy and across the electrolyte to join negative electrodes for a stored charge. The battery delivers current when the magnesium atoms lose electrons and travel back across the electrolyte to form the alloy again. The scientists used a salt mixture containing magnesium chloride for the electrolyte and antimony for the positive electrode. The batteries operate at 1,292°F.
According to Donald Sadoway, the lead researcher on the project, “if this technology succeeds, it could be a game changer [for renewables].”