Renewable energy is plentiful and cheap, but not always available when it's needed most. Traditional batteries are improving, but often contain toxic chemicals that can harm the environment. The Gravity Battery concept aims to change that by storing excess energy as potential energy that can be released via gravity. http://gravitybattery.info/
Dres landing! After returning to the Odyssey 2, I calculated the fuel required to return to Kerbin. I'm 3km/s dV short of acquiring SOI. New mini-project? Build a refueling station in Kerban orbit to act as a launch post for an Odyssey 2 refueling mission.