<i>&quot;Desalination plants need to run 24 hours a day, requiring expensive battery packs to supplement solar power when the sun’s not shining.&quot;</i><p>Why? Electricity is hard to store cheaply. However, we&#x27;ve known how to store water for millennia. Is there something about reverse osmosis that makes it impossible to stop? Why not just turn off the pumps and let the pipes drain?