Rarely has such a crucial enterprise for the future of human civilization led to such little commercial success.
Long-duration energy storage holds great potential for a world in which wind and solar power dominate new power plant additions and gradually overtake other sources of electricity. Wind and solar only produce at certain times, so they need a complementary technology to help fill the gaps. And the lithium-ion batteries that supply 99 percent of new storage capacity today get very expensive if you try to stretch them out over many hours.
The problem is, no clear winner has emerged to play that long-duration role. Here at Greentech Media, we've spent years covering the contenders, which range from quixotic defiers of the laws of physics to understated, scientifically minded strivers. The makeup of this roster has fluctuated to the rhythm of bankruptcies and new investments.