Energy-currency as in "petro-dollar" there could be an "energy-cryptocurrency". Cryptocurrencies are decentralized forms of banking thus a threat to central and private banks. Today there are many examples of this type of cryptocurrencies, e.x.., https://solarcoin.org/en/node/6 The use of cryptocurrencies wouldn't be gambling anymore as it is today. Additionally, cryptocurrencies would have a very nice fit into the idea of worker coops. Why? Having a decentralized banking infrastructure underneath this new way of organizing society is a must.