Proof-of-Useful Work
Discussion
"Sirer's team at Cornell is developing a green blockchain algorithm called Proof-of-Useful Work, in which the next computer to validate a block and collect new coins is chosen based on energy expended performing a useful function in the real world.
"For example they might be trying to do protein folding. 'Look, I worked for 10 minutes and solved so many protein fold efforts and that should entitle me to add a block to the end of the blockchain,'" Sirer said.
His team faces competition from MIT professor of engineering Silvio Micali. Launching its currency in May, his startup Algorand developed a public blockchain that runs on a version of proof-of-stake, which drives electricity consumption to almost zero, Micali said. The blockchain can process thousands of transactions every few seconds, he said." (https://www.cnbc.com/2018/02/23/bitcoin-blockchain-consumes-a-lot-of-energy-engineers-changing-that.html)
More information
See also: Proof-of-Work-by-Renewable-Energy
Directory at Blockchain Proofs