If you don't mind a completely centralised cryptocurrency, https://solarcoin.org https://solarcoin.org distributes coins based on how much solar energy you prod

If you don't mind a completely centralised cryptocurrency, https://solarcoin.org https://solarcoin.org distributes coins based on how much solar energy you produce. That's great, but doesn't really compete with Bitcoin and others, which aim for censorship-resistance through decentralisation.