PoW blockchains are often criticised for using a lot of energy. Energy usage is a requirement for Nakamoto Consensus to work. It is precisely this that makes PoW chains objectively identifiable, verifiable and valuable.
In a competitive system, miners are incentivised to use the maximum amount of energy that is economically viable to mine digital coins they can sell for a profit, whilst securing the chain as a bonus.
In a cooperative system, users can use the minimum amount of energy required to secure the chain, as there are no incentives to use more.
Decentralized energy is far more sustainable than centralized energy. Sustainable energy scales in time. Since users have only to do small amounts of work, rather than large mining operations doing large amounts of work, the users themselves can generate all the energy required, by using whatever means at hand to simply charge their mobile phones as usual.
Minima is compatible with the concept of Free Energy. Energy you do not even pay for, since you generate it yourself (solar probably). If you give Free Energy to a single competitive miner he will be very happy, as he can now use even more energy to try and mine even more coins. Give Free Energy to all the miners, and the effect is nullified, mining is a zero-sum game after all, and they will continue to use the same amount of centralized power as well as the Free Energy.