I've had the solar water heater on my roof for years, but I've recently installed photovoltaic panels to offset my electrical usage. Excess electricity is sent back into the grid for my neighbors to use (until they install the panels on their own roofs...) How many homes and buildings could be outfitted for the price of just one new power plant (hydro, nuke, etc.)? And my greenhouse provides space heat for the whole house in the most low-tech way imaginable.

I've had the solar water heater on my roof for years, but I've recently installed photovoltaic panels to offset my electrical usage. Excess electricity is sent back into the grid for my neighbors to use (until they install the panels on their own roofs...) How many homes and buildings could be outfitted for the price of just one new power plant (hydro, nuke, etc.)? And my greenhouse provides space heat for the whole house in the most low-tech way imaginable.