Proof of work is the most secure way we have by far of running a decentralized currency.  I am hopeful that a better, more energy-efficient method will be developed, but until then, I think advancing the state of the art is worth the energy cost.<p>It&#x27;s not obscene to me that a truly global currency, that is decentralized and not controlled by any government, would cost a tenth of the energy output of a modest-sized power plant.