One of my neighbors at the lake set up a stand alone solar system for his pier. He bought a complete kit from Costco and had it connected to a box that held several golf cart batteries. It ran two boatlifts, switched led lights and two trickle chargers for the boats. Also had a few outlets - was a nice setup except for the price - think he said including the batteries the setup was around 4k. I think your best bet on seeing a return would be a solar assist hot water system.