Electricity is necessary for cryptocurrency mining because it powers the computers and hardware used to solve complex mathematical equations needed to create blocks on a blockchain. These equations verify transactions, and miners are rewarded for verifying a certain number of transactions, which requires a lot of computational power. The more powerful the hardware, the faster the calculations can be done and the higher the reward for the miner. Without electricity, there would be no way to power the computers or do the calculations needed to mine cryptocurrency.