Renewable energy – such as photovoltaics and wind power – is rapidly moving into the mainstream, with global solar capacity set to outproduce nuclear energy capacity for the first time. But a major holdup has been how to store the electricity produced by renewables; consequently, good, cheap, long-lasting battery storage has been the Holy Grail of R&D in this area. But how close are we in reaching this goal? To track progress, the authors have introduced a new, “two-factor” model of analyzing innovations in energy storage that accounts not only for total sales of a particular technology but also for the degree of investment in innovation, measured by looking at the number of new patents issued in energy storage technology. Read this new article in the January/February issue of our digital Journal.