Renewable energy sources are all around us, but harnessing and storing them has been a great challenge. Recent innovations like solar microgrids are changing that. They’re able to capture energy from the sun and store it in massive batteries that can distribute power during outages. This allows critical services — like those in hospitals, warming stations and water treatment facilities — to run during blackouts. Several towns, including Highland Park and Caldwell, are building these solar grids through a state-run pilot program.