# PoS Blockchains

PoS consensus blockchains have experienced considerable growth in 2020/2021. According to the Q2 2021 Staked review, there are now 26 PoS coins in the top 100 cryptocurrencies with a combined market cap of over **$450B**, a 150% increase from Q1 2021. Many other PoS projects also entered maturity or obtained significant milestones in 2020/2021. 

The PoS growing popularity is related to environmental and scalability issues surrounding PoW. PoS blockchains require significantly less energy than PoW. The mining of new coins doesn’t require solving energy-demanding computational puzzles like PoW. It happens through staking native coins to validator nodes at no cost. The non-reliance on large amounts of cheap energy and specialized equipment makes PoS less likely to be geopolitically centralized.

![BTC and ETH PoW vs. PoS energy consumption. Source](https://1815433019-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FWNvyNUMwIxg7MJFRxs0N%2Fuploads%2Ft0DRxnZcOZgIuFCWz7ux%2Fimage.png?alt=media\&token=88052d69-0ba9-403a-ab41-d231ed9bb7c7)

There are currently multiple different PoS consensus solutions that differ in their on-chain governance. For example, PoS blockchains require validator nodes to stake specific amounts of native tokens to vote on protocol proposals. In contrast, DPOS and NPOS (delegated and nominated proof-of-stake) allow native token holders to choose validators by delegating coins to their nodes. Only the ‘nominated’ validators can vote on structural changes.

![Popular types of PoS governance protocols. Source](https://1815433019-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FWNvyNUMwIxg7MJFRxs0N%2Fuploads%2FEWzziilr90ef2gcgjfRU%2Fimage.png?alt=media\&token=ccff7d23-c6dd-49d9-bf04-2fecf1e0b941)