Depending on how organised you are, and how much soup/boiled root veg you eat, soaking your rice over night and steaming it over soup/veg you're boiling the next day, is going to be much more energy efficient than probably all other methods.

I think brown rice only takes about ten minutes to steam once it's been soaked overnight, but I have never actually tried this method myself as I don't eat that much soup or boiled root veg, and I have a bad habit of forgetting things if they're not in my direct line of sight.

I cook all the rice I eat in an enamelled cast iron pot, on an induction stove hotplate.

(I am hella poor these days and have metered electricity, this has been the cheapest way I've found so far that works for me.)

• Add 1 part washed brown rice into the pot

• Add 1.5 parts cold water into the pot

• Add salt or stock cube/seasoning if desired

• Bring to a rolling boil for 2 to 3 minutes

• Cover pot with foil and lid to trap heat and steam

• Reduce heat to the lowest it can go while simmering continously

• Simmer for 15 minutes

• Turn off heat but do not touch or move the pot.

• Wait 15 to 20 minutes for the rice to steam cook the rest of the way.

This method works great, unless it is the dead of winter and cold enough in my kitchen that the pot cools too quickly to finish steaming the rice through. In which case I add a little more water and bring it to a boil again, and cover, lower the heat and steam it again for ten minutes, while hovering over the pot shivering and debating whether or not to just eat it as is, or wait for it to be both mushy and crunchy.