The Bitcoin blockchain requires a “proof of work” to codify all the transactions that have been sent to the network every 10 minutes.

Many blockchains use a proof of work to do this and it is usually performed by a computer or circuit which applies a mathematical formula to obtain a result. In simple laymans terms a formula can be as simple as A + B = C

If A = 1 and B = 2, then C will equal 3

Whilst this is a good way to secure a blockchain to prove that the information the blockchain contains has not been tampered with it comes at an environment cost of using electricity to power the computers which in turn secure the blockchain.