Tesla CEO Elon Musk surprised many last week when he tweeted that the electric car company would not be using bitcoin (BTC) as payment due to the environmental impact of cryptocurrency mining.

In some ways, it was also surprising that Musk is seen as a crypto enthusiast, that the company only began accepting BTC in February, and that there is a huge established energy demand for bitcoin.

According to Digiconomist, the overall carbon footprint of the bitcoin mining industry is comparable to that of Singapore due to the enormous energy consumption of the powerful rigs that solve the complex equations needed to generate new blocks. Some proponents, such as Twitter CEO Jack Dorsey, have suggested that bitcoin mining "incentivizes renewable energy," and Musk previously agreed.

Now, however, Musk says Tesla is "concerned about the rapidly increasing use of fossil fuels" for mining. According to his tweet, the company is considering alternative cryptocurrencies that use much less power than the Bitcoin network. The price of bitcoin fell more than 13% on the news.

However, not all cryptocurrencies use a similar resource-intensive model to generate blocks and validate transactions. For example, Ethereum 2.0 is reported to be 99.95% more environmentally friendly than the current version. For example, Ethereum 2.0 is reported to be 99.95% more environmentally friendly than the current version.

Here is a look at five other popular cryptocurrencies that take a greener approach than Bitcoin.

Nano, an explicitly eco-friendly currency, does not "mine, mint, or print," uses a lightweight proof-of-work model, and reportedly takes only seconds to process a transaction on a typical consumer PC.

With no need for heavy-duty mining rigs or top-end GPUs, NANO has been touted as a clean alternative to Bitcoin and Ethereum; NANO's price nearly doubled in the wake of Tesla's announcement, but like many other cryptos, has since fell and is now back to its end-April level.

Chia, newly launched by BitTorrent inventor Bram Cohen, puts a twist on the familiar proof-of-work method. Its "proof of space and time" model uses storage space on a computer to establish "plots" of cryptographic numbers and "farms" them during network runs.

One of the hottest mining coins because you don't need an expensive, high-performance GPU to participate, Chia mining can exhaust entry-level consumer SSDs in a matter of weeks.

Created by Ethereum co-founder Charles Hoskinson, Cardano has skyrocketed in value in 2021, rising more than tenfold in price since the beginning of the year, hitting an all-time high of $2.44 last week (May 16) According to CoinMarketCap, market cap ranking, it is currently the sixth most valuable cryptocurrency.

The blockchain network is based on peer-reviewed research and relies on a proof-of-stake consensus model in which participants hold ADA coins within the network and receive compensation as a result. Hoskinson claims that the entire network uses only 6 GWh of electricity per year, a small fraction of what Bitcoin consumes. Cardano is now actively lobbying Tesla to adopt ADA over BTC.

Like Cardano, Polkadot also comes from the co-founder of Ethereum (Gavin Wood), who decided to try a different approach; Polkadot has also skyrocketed in value since the beginning of this year and has increased in price over 200% since the beginning of 2021, making it one of the top 10 cryptocurrency performers by market cap and is in the top 10 cryptocurrency performers by market capitalization.

Polkadot is designed as a multi-chain network that can bridge the gap between different blockchains and is based on a Nominated Proof-of-Stake (NPoS) model that is based on holding coins within the network rather than energy-intensive mining. (NPoS) model.

Stellar Lumens (XLM) is another well-established cryptocurrency that has benefited from a market-wide rise in 2021, increasing in value by about 300% since the beginning of the year.

XLM's unique consensus model for verifying transactions is energy efficient, requiring only a small number of distributed nodes to verify each transaction. Therefore, XLM does not require huge amounts of energy like some blockchain networks, which may be why it has been adopted for large projects.