One of the worst features of blockchain technologies like cryptocurrency and NFTs is their horrific energy use. When we should be wringing every bit of efficiency out of our electricity use, most blockchains require computers to perform pointless calculations repeatedly.

The obvious solution is to base blockchains on useful calculations—something we might need to do anyway. Unfortunately, the math involved in a blockchain has to have a very specific property: The solution must be difficult to calculate but easy to verify. Nevertheless, a number of useful calculations have been identified as possible replacements for the ones currently being used in many systems.

A paper released this week adds another option to this list. Optimization problems are notoriously expensive in terms of computations, but the quality of a solution is relatively easy to evaluate. And in this case, the systems being optimized are small energy grids, meaning that this approach could partly offset some of a blockchain’s horrific energy usage.