Mining cryptocurrencies like Bitcoin is a little more complicated than creating value out of thin air: It actually takes time, energy, and electricity to create the coins. (That’s what limits supply.) So, even if it’s not ripping metal out of the ground directly, it’s still a sort of old-fashioned, limited-resource-using idea.

If you’re looking for a more sustainable cryptocurrency, we suggest you check out SolarCoins. To earn installments of this newly created currency, you actually need to produce energy through solar panels. New Scientist:

People with solar panels on their house will receive solar renewable energy certificates from their energy company in return for feeding a megawatt-hour of electricity back into the grid. These certificates are already traded for cash, but present one to SolarCoin’s organizers and you’ll receive one coin — they expect to start distribution in a matter of weeks.

True, the coins are worthless at the moment, but if people start using the currency to support solar energy, it should acquire value. SolarCoin Foundation spokesman Nick Gogerty says the initiative is aiming for $20 to $30 per SolarCoin, effectively providing solar panel owners with a crowdfunded feed-in tariff and encouraging more people to take part.

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If you’ve already got the solar panels … well, why not? You could feed energy back into the grid AND have untraceable money for buying your drugs! (We have no idea what cryptocurrency is for now that Silk Road is gone.)

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