On the Bitcoin network, a block is mined every ten minutes. The exact time frame depends on the efficiency of the global network of mining nodes. Bitcoin uses the Hashcash proof-of-work function, and the more nodes are working toward finding the solution to the cryptographic puzzle, the faster a solution will be found. To maintain the normal 10-minute block time the hashing difficulty algorithm is adjusted every two weeks.
The Bitcoin proof-of-work system is using a lot of energy, and the electric consumption increases with the usage of the network. Bitcoin detractors are using this argument to explain why Bitcoin won’t be able to scale and be used as a global currency. Although this is a valid argument, Bitcoin’s proponents argue that the electricity used is mostly coming from renewable energy and are betting on a second-layer solution like the lightning network to solve both the transaction speed and energy cost limitations.