Off-grid electricity is really expensive (but still cheaper than paying the power company), whether it's the investing into solar and other "green" energy or simply running a generator! Here is what we use for our showers during the warmer months/sunny days! Heck, even if you're suburban/city, build one and have it ready for just a mid-afternoon rinse or what have you! If you want detailed instructions on how to build this, let me know in the comments!