Is there an intrinsic reason why cryptocurrencies currently take a lot of energy to keep working? Is there a way to make a cryptocurrency still widely used but make it energy efficient?
As another post says, we currently rely on PoW. This needs energy. Maybe other consensus algorithms (like PoW), also need (more) energy. BUT: There are also consensus algorithms, we need less energy. Its that simple. The only thing here is: coins e.g. BTC need to switch to another one which needs less energy.
It would seem so.
Ethereum has partly switched from Proof of Work to Proof of Stake: https://en.wikipedia.org/wiki/Proof_of_stake
... and we may well look back on energy expenditure of Proof of Work as almost all total waste: https://stuart-reynolds.medium.com/is-bitcoins-energy-consumption-a-problem-for-the-world-ff213cc2136a