Energy for blockchain products is one of the main topics of discussion for the development process of the cryptocurrency industry. As Bitcoin mining is very demanding in terms of energy usage and has become even harder to do over time, Bitcoin’s proof-of-work algorithm has been altered in other, less consuming algorithms for new cryptocurrencies. Bitcoin’s influence on the energy sector is hard to overestimate. Bitcoin energy consumption is currently taking more energy than most countries on the planet. This is not just the reason for the large profits in the energy industry but also a warning for the environment, as it is a threat to the climate with an amount of 20 megatons of CO2 emission per year. The reduction of the energy consumption for cryptocurrencies is also an important task as government environmental policies may become an obstacle for the blockchain industry.