The amount of energy required to power the Bitcoin blockchain has been a heated topic of discussion lately brought up by groups who are concerned about the carbon footprint of the cryptocurrency.

In response to these growing concerns, many altcoins have now been structured following an eco-friendlier protocol called proof-of-stake (PoS), which reduces the amount of energy consumed when validating the transactions that need to be recorded within the blockchain.

Some of these cryptocurrencies include Cardano (ADA), Polkadot (DOT), and more recently Ethereum (ETH) now that the protocol will be migrating from a proof-of-work (PoW) protocol to PoS.

The following article takes a closer look at these "greener" crypto tokens while explaining the reasons why the PoS protocol is considered more energy-efficient.

Proof-of-Work vs. Proof-of-Stake

The proof-of-work protocol was conceived by Satoshi Nakamoto, the anonymous creator of Bitcoin. Random mathematical puzzles need to be solved by "miners" - which are the nodes that power the Bitcoin blockchain - and they are compensated accordingly for every block mined.

As the level of difficulty for solving these mathematical puzzles increases as a result of how the Bitcoin blockchain is designed, the amount of energy used by the computers that are used nowadays for mining increases as well.

According to data from the Cambridge Bitcoin Electricity Consumption Index, the amount of energy consumed by the Bitcoin blockchain per year is 69.63 TWh, which is higher than the residential electricity consumption of the United States as a whole.

In response to the energy-intensive nature of the PoW protocol, blockchain developers came up with the proof-of-stake (PoS) protocol, which only allows validating nodes that have staked a certain number of tokens to participate in the network.

Why is PoS eco-friendlier?

Under the PoW protocol, miners are competing to see who solves the complex mathematical puzzles needed to generate the correct hash for validating a transaction made within the Bitcoin blockchain or any other PoW-powered network for that matter.

This results in a big number of computers around the world using a lot of electricity to perform the many iterations needed until the puzzle is solved, which means that the energy consumed by those who don't get the puzzle right ends up being wasted.

Meanwhile, the PoS protocol seeks to reduce the number of nodes competing at the same time by only allowing those who have a stake in the blockchain - in the form of a certain percentage of tokens in relation to the total - to participate in the process of validating new records. Additionally, only one node is randomly selected by the network's algorithm to validate the next transaction in line.

Moreover, the PoS protocol also reduces the difficulty of the validation process as computers only need to check if the hash that identifies the last block recorded on the blockchain matches the one embedded in the new transaction hash.

After that piece of data is validated, the new block is propagated and validated by the rest of the network's nodes and the original validator is compensated accordingly.

A lower number of active nodes, the fact that only one node is assigned to validate each pending transaction, and the simplicity of the validation process makes PoS an eco-friendlier protocol compared to PoW.

Which blockchains have already adopted PoS?

Cardano is an infrastructure blockchain that aims to become the go-to platform on which decentralized applications (dApps) will be built in the future as it has already fully embraced the PoS protocol.

According to Cardano's founder, Charles Hoskinson, his project is 1.6 million times more energy-efficient than the bitcoin blockchain.

Cardano primarily aims to become a place in which developers can build ID-verification and tracing dApps, with its Ouroboros technology being the first peer-reviewed PoS crypto protocol in the history of the entire ecosystem.

Meanwhile, the Polkadot blockchain is another "green" crypto project that was developed by one of Ethereum's co-founders in response to the scalability issues faced by the Ethereum blockchain.

Finally, Ethereum itself will be launching an eco-friendly update of its blockchain soon. This update is known as the "London hard fork" and it will replace the current PoW-powered version of the blockchain for a brand new PoS version.

This update is expected to occur on August 4 and market participants are fairly optimistic about the impact that this change in the underlying protocol that powers the blockchain could have on the continuation of Ethereum's widespread adoption as the favorite platform for dApps.