[yongjik]

Your exercise is already useful to you (and those around you): it keeps you healthier and reduces future medical cost expected by the society.

It sounds like a fun project, so I'm not arguing against that, but I don't expect it to "help the Earth" in any meaningful way. Considering the fossil fuel usage by modern agriculture (and all the energy spent on delivering the food to our mouths), the net climate impact of using "human energy" is probably worse than an electric kettle.