There’s been a lot of attention on Bitcoin’s shocking environmental impact in recent months, and while efforts are being made to minimize the carbon footprint of the cryptocurrency, some investors are jumping ship in favor of greener options. With more than 4,500 mineable coins and tokens in existence, which, if any, are the most sustainable cryptocurrencies?
UPDATE: Following immense interest in this topic and great leads on other green cryptocurrencies, I’ve added six new tokens/networks below. Any of the coins listed here would be a good choice for Tesla as the company searches for digital currency with a much smaller carbon footprint than Bitcoin. Keep the suggestions coming, ideally with solid leads/info on why a token deserves attention from investors who care about sustainability, and I’ll do my best to take a look. Are you a Dogecoin fan? See why everyone’s favorite canine inspired cryptocurrency didn’t make this list. here.
How we compiled this list
Truth be told, it’s incredibly difficult to point to any one currency as being ‘greener’ than others. This is because there are so many parameters at play. Many much smaller cryptocurrencies, for instance, naturally have a far lower energy footprint because they involve far fewer daily transactions compared to Bitcoin. Scale them up, however, and they may be just as bad, if not worse than the cryptocurrency we currently love to hate.
That said, some cryptocurrencies are inherently more energy efficient than Bitcoin. Why? Because Bitcoin relies on a ‘Proof of Work’ system that involves huge amounts of calculations (and, thus, processing power) to produce a single token. Cryptocurrencies that instead use a ‘Proof of Storage’ or ‘Proof of Stake’ system use far less energy, as do currencies using a technology called block lattice, which doesn’t require mining.
Even among ‘Proof of Work’ cryptocurrencies, however, some are more energy intensive than others. This is primarily because these currencies use ASIC-resistant algorithms that consume significantly more energy than should be expected relative to how much of the cryptocurrency market they represent. A good example of this is RavenCoin which, by one calculation, accounts for 4.32% of the total rated power of the top 20 cryptocurrencies but has a market capitalization of just 0.06%. Interestingly, Bitcoin uses an algorithm that does allow for mining ASIC-based devices, and these devices are considerably more energy efficient than conventional graphic processing units (GPUs).
As Bitcoin rises in value, the climate suffers
Market dynamics also play a big role in the energy consumption of cryptocurrencies. In numerous cases, market slides or crashes that drop the price of Bitcoin, Ethereum, or other big players in this area lead to miners slowing down or turning off their devices as it’s no longer profitable to run the machines at that price.
In November 2018, for instance, the Digiconomist estimates that Ethereum’s miners more than halved their energy consumption (from around 20 TWh to 10 TWh) in under 20 days because the price tanked. As the price of Ethereum has once again risen in 2021, so too has the energy consumption associated with the cryptocurrency. As of March 31st, 2021, Digiconomist estimates Ethereum as using more than 31 TWh annually, an all-time high.
So, which cryptocurrencies have a shot at being more sustainable than Bitcoin? Here are a few of the main contenders, in no particular order, presented with the caveat that this is absolutely not investment advice. At the time of writing, I have no investments in or ties to these or any other cryptocurrencies.
#1. SolarCoin (SLR)
SolarCoin is global, decentralized, and independent of any government. You can spend and trade SolarCoin just like other cryptocurrencies, but the key difference is that the platform aims to incentivize real-world environmental activity: verifiably produced solar energy.
How it works
SolarCoin has a novel approach to cryptocurrency, creating 1 Solarcoin for every Megawatt hour generated from solar technology. Currently, this network mostly relies on users uploading documentation to prove energy generation, but the Internet of Things may one day streamline this process with automatic updates from solar arrays.
Consider SolarCoin as a helpful way to more quickly offset the cost of installing a solar array!
#2. BitGreen (BITG)
BitGreen was founded in late 2017 as a response to the environmental impact of Bitcoin. It is a community-driven initiative and energy-efficient alternative to Proof of Work consensus cryptocurrencies. The company created a non-profit foundation to oversee the maintenance of the BitGreen project.
BitGreen is intended to incentivize eco-friendly actions, with users able to earn BITG by, for example, carpooling on a ride-hailing app, buying sustainable coffee, and volunteering. You can also earn BITG by ‘staking’, using a desktop wallet or building a masternode.
How it works
BitGreen uses a low-energy Proof of Stake algorithm with segwit and deterministic masternodes as part of their proprietary protocol
BitGreen can be spent on goods and services through BitGreen’s partners or traded on ProBit Exchange, Mercatox, STEX, and Crex24 exchanges.
#3. Cardano (ADA)
Cardano was developed by the co-founder of Ethereum, Charles Hoskinson, and was tested by academics and scientists as the world’s first peer-reviewed blockchain. It functions mainly as a digital currency but can also be used for digital contracts, DApps, and other purposes. Compared to Bitcoin’s 7 transactions a second, Cardano can achieve 1000 per second.
How it works
Cardano is inherently more energy efficient than Bitcoin as it uses a ‘Proof of Stake’ consensus mechanism where those participating in the currency buy tokens to join the network. This helps save a staggering amount of energy, with the founder of Cardano claiming that the cryptocurrency network consumes only 6 GWh of power.
Cardano is similar in some ways to Ethereum, but without a lot of the bloat associated with the latter token. This enables Cardano to scale up to meet increased demands for the cryptocurrency, without compromising on speed or efficiency.
#4. Stellar (XLM)
The Stellar network was released in 2014 (forking off from Ripple) with the goal of bridging the gap between traditional financial institutions and digital currencies. Stellar doesn’t charge institutions or individuals for using the network and is increasingly seen as a serious alternative to PayPal as it enables faster, easier, and more cost-effective cross-asset and cross-border transactions.
Stellar is operated by the Stellar Development Foundation, a non-profit organization. It got its start with funding from Stripe (the payments startup), along with donations from BlackRock, Google, and FastForward. Tax-deductible public donations fund the network’s operating costs and the hard market cap for Lumens and removal of an inflation standard demonstrates that the SDF is looking to maintain a network that enables easy, accessible, low-cost cross-border payments rather than to make a quick buck with massive gains in the price of Lumen.
The network has also attracted serious engagement from IBM and Deloitte, as well as banking institutions in Nigeria, the Philippines, India, France, the South Pacific, and most recently the Ukraine. This brings to life the SDF’s vision to “unlock the world’s economic potential by making money more fluid, markets more open, and people more empowered.” Stellar was the first distributed technology ledger to receive certification as Shariah compliant.
How it works
Through the Stellar network, you can exchange US Dollars, Bitcoin, Pesos, Yen, and pretty much any currency traditional or crypto. The network’s token, Lumens, are used to facilitate these trades on the blockchain-based distributed ledger at a fraction of a cent and with great efficiency (which also translates to a lower carbon footprint). The network also allows individuals and institutions to create tokens for use on the network, which has inspired some to use the network for sustainability initiatives such as investing in renewable energy.
The key distinguishing feature of the Stellar network is its consensus protocol. This SCP is open-source and relies on authentication of transactions occurring through a set of trustworthy nodes rather than running through the whole network as a proof-of-work or even proof-of-stake algorithm. The cycle for authentication is thus much shorter and faster, keeping costs low and energy use to a minimum. The algorithm behind this is known as a federated byzantine agreement and is an energy-efficient alternative to the Bitcoin style traditional mining network.
Stellar’s token, Lumens (XLM), can be bought and sold on most exchanges, including Binance, Coinbase, Kraken, Bittrex, Bitfinex, Upbit and Huobi.
#5. Nano (NANO)
Nano is free, fast, and uses considerably less energy than Bitcoin and many other cryptocurrencies. It has been around since the end of 2015 and has a relatively small carbon footprint even now. It is also scalable and lightweight as it doesn’t rely on mining.
How it works
Nano uses block lattice technology, which is energy efficient. It is still reliant on a Proof of Work mechanism, but the block lattice goes beyond blockchain to create an account-chain for each user on the network. The Nano platform uses a system called Open Representative Voting (ORV), where account holders vote for their chosen representative, who then work to securely confirm blocks of transactions.
On the Nano platform, user accounts can be updated asynchronously, rather than needing to involve an entire linear blockchain as is the case with Bitcoin and others. Instead of competition and delays, then, Nano involves just the sender and receiver account-chains and can handle as many as 125 transactions per second.
#6. IOTA (MIOTA)
As a cryptocurrency, IOTA has not proven as volatile in terms of price as many other tokens. While good news for those looking for more stability in the market and greater financial sustaianability, this has proven disappointing for those investors looking for the same pay-off as with early investments in Bitcoin, Ethereum, or other altcoins.
In terms of energy sustainability, because IOTA uses Fast Probabilistic Consensus for consensus and only relies on Proof of Work in part, the overall energy consumption of the network is very small. The best figures available for IOTA’s energy consumption come from a PhD student called Amir Abbaszadeh Sori. Writing before the algorithm update, Abbaszadeh Sori calculated the average ECPT (energy consumption per transaction) for IOTA and found that each transaction used just 0.11 Watt hours.
This is very low, even compared to more established financial networks such as VISA and Mastercard. And, like many cryptocurrencies, IOTA blows Bitcoin out of the water in terms of energy use. With the new updates set to make Atomic Transactions the norm for IOTA, this could reduce the transaction size from 1.7kb to less than 100 bytes, presumably reducing the energy consumption accordingly.
Indeed, IOTA released figures in May 2021 outlining a possible 33-95% reduction in energy consumption associated with the Chrysalis upgrade, reducing the energy requirement to just over a millionth of a kWh per transaction.
To calculate the ECPT under the current algorithm though, Abbaszadeh Sori used three smartphones with different processors and versions of Android (but no iPhones) and sent an iota token 25 times with each device. The measure of energy used included approval of the transaction, complete proof of work, preparing inputs and outputs, validating the receive address, synching the account, and final validation.
While the results were very clearly in favor of IOTA as a much more eco-friendly cryptocurrency, Abbaszadeh Sori himself acknowledges some limits to his study. For instance, there’s no accounting for IOTA nodes and IOTA Coordinator energy consumption. And now we have an updated IOTA 1.5, which no longer has the Coordinator Node, these calculations are less relevant.
That said, if we take the above figure for EPCT and multiply it by the 1000-1500 transactions per second that the current IOTA system is said to be able to handle, this amounts to annual energy consumption for IOTA of:
1000-1500 TPS = 31536000000-47304000000 transactions per year
0.11 wH per transaction = 3.47-5.2 Gigawatt hours per year
At the low end, this amounts to around the equivalent of 2,459 metric tons of greenhouse gas emissions annually. That’s 535 passenger vehicles on the road for a year, or the energy used by 296 homes for a year. At the higher end, with 1500 TPS, the numbers rise to 3,687 metric tons of GHG CO2-eq. That’s 802 cars on the road for a year, and 444 houses powered.
#7. EOSIO (EOS)
EOSIO is a public blockchain beloved by developers because it is simple to set up and write applications in several programming languages, is highly scalable, and costs nothing.
How it works
EOSIO is another ‘Proof of Stake’ platform that uses pre-mined EOS tokens that can be traded on standard cryptocurrency exchanges such as Coinbase, Binance, and Kraken.
#8. TRON (TRX)
Based in Singapore, TRON is a non-profit organization and public blockchain supporting almost every programming language. The peer-to-peer platform allows creators to share applications directly on the blockchain, making the whole process more energy efficient.
How it works
TRON operates using decentralized governance based on a two-tier model of Super Representatives (SR) and Super Representative Partners, with every account able to become an SR and able to vote for SRs.
The TRON currency, Tronix, is pre-mined and can be traded on Binance and other exchanges, with big plans afoot for TRON’s future, including using it to create decentralized gaming platforms.
#9. Burstcoin (BURST)
Burstcoin was possibly the first blockchain to use Turing-complete smart contracts which allow for the creation of non-fungible tokens (NFTs) and use in on-chain games. It is also likely one of the most environmentally friendly, sustainable cryptocurrencies as it has been using ‘Proof of Capacity’ rather than ‘Proof of Work’ since 2014.
How it works
With Burstcoin, ‘miners’ are rewarded for using storage space for ‘mining’. Meaning that a computer with a 1 terabyte harddrive barely uses more energy to mine Burst than an idling computer. This makes it far more efficient than ASIC mining or GPU mining on a ‘Proof of Work’ algorithm.
The network is driven by volunteers and you can trade Burst on Bittrex, STEX, and other cryptocurrency exchanges.
#10. Holochain/HoloTokens (HOT)
Holo is still in development, but 2021 is expected to be a big year for the network. An Initial Community Offering of Holo revolved around a pre-sale of cloud-hosting services as transferable ERC20 tokens called HOT on the Ethereum public blockchain. Again, this makes Holo different to other cryptocurrencies in that it is backed by a tangible asset (cloud-hosting services). Holo charges a fee on transactions using the P2P network, meaning that revenue is tied directly to the number of apps and hosts on the network.
In theory, transaction speed is limitless on Holochain, and energy expenditure is very low. In practice, I’ve seen no clear data on how much energy Holochain consumes, though it is bound to be many orders of magnitude lower than Bitcoin, Ethereum, and almost every other cryptocurrency.
How it works
Holochain is an open-source framework for peer-to-peer applications and its token HoloTokens (HOT) requires no mining. This means that you don’t need any specialized processors, nor is there excessive energy use involved in generating this cryptocurrency. Anyone who hosts hApps on their computer or device can receive HOT in return.
Holochain is immediate and efficient, does not rely on proof-of-work or proof-of-stake, but still enables scalable crypto-accounting. Each user provides a small amount of computing and storage, allowing P2P web applications to function, in theory, at a massive scale without need for centralized data centers or infrastructure. This depends largely on how many users sign up, however.
The cool thing about Holochain is that it can operate through a regular browser, without Holo Hosts needing to install any software. This makes it much more accessible to new, curious, and perhaps hesitant users. Holochain provides a bridge from the decentralized, P2P developer world to existing payment systems.
Because Holochain is a ‘pragmatic compromise,’ as noted by the company itself, some parts of this network are centralized. This makes it rather unique among cryptocurrency projects which typically aim to be entirely decentralized and rely fully on blockchain technology. In essence, Holo acts as a bridge between a fully decentralized network and traditional, familiar internet browsers, helping to expand the ecosystem and marketplace for DApps.
DEVVIO’s initial community offering may occur in June 2021, though details are scarce. In the meantime, this looks like a good ‘green’ cryptocurrency to keep on your radar.
According to DEVVIO founders, the DEVVIO network uses one millionth of the energy usage of Bitcoin and generates far less in terms of greenhouse gases. It was designed specifically to reduce energy expenditure and be a ‘greener’ cryptocurrency. This is clear from the founders’ commitment to creating DEVVIO as a blockchain ecosystem that can support multiparty collaboration and trust across stakeholders working in the field of environment and sustainability.
The DEVVIO system can be used to authenticate green certifications, enable markets for carbon credits, and facilitate financing for sustainability projects. And it does this without creating inefficiencies and massive energy requirements as projects scale ever upward. This isn’t a proof-of-work blockchain like Bitcoin. Instead, individual nodes talk to each other, creating an energy efficient system. It is also time efficient in that a web developer can quickly hook into DEVVIO’s blockchain.
DEVVIO’s current partners include Avnet and Panduit, which help companies embrace carbon neutrality in part by connecting big corporations to companies generating carbon credits through specific actions such as tree-planting, installing solar power infrastructure, and so forth.
How it works
DEVVIO is a distributed accounting protocol based on sharding, layer 2 protocols, and an efficient consensus mechanism. It can currently execute up to 8 million transactions per second (TPS). Each shard represents a blockchain ledger and thousands of these shards can be added to eventually enable tens of millions of TPS. This is an example of horizontal scaling, meaning that because each shard is independent, every transactions doesn’t have to go through the entire network to be authenticated; it just has to go through one independent blockchain.
To create the necessary complexity for security, DEVVIO has transactions move between shards, but each wallet is only assigned one shard. Payment happens on one shard (as part of Tier 1) and settlement on another (the Tier 2 network).
#12. Hedera Hashgraph (HBAR)
Hedera Hashgraph passed the number of Ethereum (ETH) transactions on May 6th, 2021, making it one of the world’s biggest cryptocurrency networks. In theory, Hedera Hashgraph could process more than 100,000 TPS, which would allow it to easily rival Visa and other mainstream payment systems. Thankfully, this cryptocurrency (HBAR) is a proof-of-stake token, meaning it uses far less energy than proof-of-work tokens like Bitcoin.
HBAR has a current supply of around 8 billion hbars and a fixed supply of 50 billion hbars. It is a decentralized public network used for in-app payments, micropayments, and transaction fees, as well as for network protection. Developers can use Hedera to build secure applications with near real-time consensus. This is because instead of being a block ‘chain’, Hedera is more of a graph. In fact, it’s based on technology called a Directed Acyclic Graph (DAG) which means that the speed of transaction verifications increases as more transactions are added to the network.
The list of owners and the governing council of Hedera is impressive, including Avery Dennison, Boeing, Deutsche Telekom, DLA Piper, FIS (WorldPay), Google, IBM, LG Electronics, Magalu, Nomura, Swirlds, Tata Communications, University College London (UCL), Wipro, and Zain Group.
Hedera Hashgraph consists of four main services, including HBAR, the cryptocurrency that allows for low-fee, highly customizable transactions. The other services include smart contracts, file service, and consensus service.
How it works
Hedera Hashgraph works through a system called asynchronous byzantine fault tolerance (aBFT). This allows for high-level security even if there are malicious actors on the network. It is faster than Bitcoin or Ethereum because transactions are processed in parallel, rather than having to go through the whole blockchain in a serial manner.
The network reaches consensus through ‘gossip,’ with nodes on the Hashgraph talking to each other and comparing notes on the network’s transactions, instead of mining. Select transactions are deemed ‘famous’ by the nodes because they are communicated early in the gossip process and are then verified by multiple nodes across the network.
Hedera Hashgraph plans for more upgrades to the network in the second half of 2021, including introducing sharding. This will split the network into multiple shards to enable an increase in transactions.
One of the cool things about Hedera Hashgraph is that it is already being used to facilitate sustainability projects. This includes through Power Transition, a software system backed by Hedera Hashgraph. This highly scalable digital energy platform allows people and companies to control energy use from micro grids to national grids. It can help to reduce costs and make the move to a zero-carbon economy by dramatically improving communication between players in networks of any size, making for greater energy efficiency.
Power Transition estimates that the Hedera Hashgraph platform is 250,000 times more energy efficient than Bitcoin, using just 0.001 kilowatt hours per transaction, compared to 250 kWh for Bitcoin (Digiconomist puts it at 950 kWh), 55 kWh for Ethereum, and 0.003 for Visa.
#13. Chia (XCH)
Chia is another interesting cryptocurrency in that it can be mined on Amazon Web Services cloud computing platform. Setting this up takes just a few minutes, with chia ‘farming’ simple and straightforward compared to ‘mining’ of many other currencies.
Unlike many cryptocurrencies, Chia was created by a familiar name: Bram Cohen, the founder of BitTorrent. When the platform was launched, it reportedly led to a shortage of hard drives in China as people scrambled to acquire more storage space on which to farm XCH.
How it works
The Chia Network is a blockchain and smart transaction platform that allows users to take advantage of available hard drive space to run the decentralized network. Instead of proof-of-work, the Chia Network relies on proof-of-space-time. So, storing a certain amount of data over a certain amount of time can earn you XCH, Chia’s token. XCH was created in 2017 in response to the excessive energy use involved in mining crypto.
Chia farming was designed to be accessible, with no specialized equipment needed, nor massive amounts of power. The network’s blockchain transaction platform is called Mainnet and can be downloaded at chia.net. After downloading the software, you can choose to dedicate a portion of your uncommitted hard drive space to the network and this will then tick along nicely while your computer is running, without significantly affecting your machine’s performance or requiring vastly more energy.
#14. Algorand (ALGO)
Algorand is a proof-of-stake blockchain that gets its value because it supports smart contracts. The influence of each user on the network is proportional to their stake in the system, and Algorand’s blockchain is scalable and secure, as well as free from forks and other potential governance issues.
Released in late 2019, Algorand is also relatively new to the crypto scene but was able to manage almost one million transactions per day by December 2020. One of the founders of Algorand, Silvio Micali, is a profession of computer science at the Massachusetts Institute of Technology and a recipient of the Turing Award in 2012, in part for his contributions to cryptocurrencies and blockchain protocols, all of which inspires quite a bit of confidence when compared to other newer crytpos.
The speed of transactions on the Algorand platform and its low transaction fees, in addition to being a permissionless pure proof-of-stake blockchain protocol, all mean that the network is more accessible, scalable, and uses far less energy than Bitcoin and its ilk.
How it works
The pure proof-of-stake approach of Algorand means that all validating nodes are known to each other and have to agree to create a new block each time.
Algorand does not involve mining, and the network is trying to lead the way in blockchain sustainability by creating a carbon-negative network. It was designed to be energy efficient from the get-go and has committed to offsetting any emission gaps to reduce its environmental impact further. Micali himself has said, “I care about the planet” and that the proof-of-stake algorithm “drives electricity consumption to almost zero.”
On April 22, 2021, Algorand announced that its blockchain is fully carbon neutral, thanks in part to its partnership with ClimateTrade. This organization is a leader in carbon emissions transparency and traceability and the partnership with Algorand allows CimateTrade to enhance its sustainability efforts with corporations worldwide.
The Algorand Foundation is a not-for-profit organization behind this development. The Foundation also envisions bringing on board a whole community of blockchain and mainstream developers including those wanting to use the platform to support sustainable endeavors.
Algorand and ClimateTrade plan to implement a system whereby Algorand’s carbon footprint on-chain for a specific number of blocks will be notarized, allowing the equivalent amount of carbon credit to be calculated. This Algorand Standard Asset (ASA) will then be locked into a green treasury and the protocol will continue running as carbon-negative by carefully tracing and offsetting these amounts.
The Algorand blockchain currently has 10 billion ALGO, with distribution continuing to roll out up until 2030. ALGO is currently able to be bought and sold on Coinbase, Binance, OKEx, Kraken, and Huobi.
#15. MetaHash (MHC)
MetaHash offers a fast, efficient decentralized network with zero fees and the ability to mine/forge MHC using fairly low-key hardware. MHC is just one of four parts of the MetaHash project, the others being TraceChain, MetaApps, and MetaGate. TraceChain is an algorithm for routing traffic over the network. MetaApps allows users to write stand-alone decentralized applications using C++, PHP, and Solidity, among other programming languages. MetaGate is an open source user interface for third-party developers.
How it works
Metahash is another proof-of-stake protocol that is far more efficient than its pure proof-of-work counterparts. It originally operated using a delegated PoS mechanism but has transitioned to a multiple PoS mechanism to address issues that compromised decentralization of the network. In this system, “multi-layered validation provides the basis for protecting a network against corruption. In cases when the central
network entities, which generate blocks, appear to be corrupted, the rest of the network may vote to rebuild the network and to re-distribute the roles, thus, neutralizing the threat.” This model also allows validation and block distribution to run in parallel, decreasing consensus time and improving efficiency.
#Special mention – Ethereum (ETH)
Ethereum has been making a big song and dance about going green for many years, but there’s been little follow through on all that promise. The cryptocurrency still uses enough energy every year to power a major country and as much electricity per transaction as could power an average U.S. household for a day. Still, Ethereum is more energy efficient than Bitcoin and they’re at least trying to make things better.
The founder of Ethereum has long admitted the wastefulness of the bloated cryptocurrency and in 2014 began a lofty project to overhaul Ethereum’s code with the help of the open-source movement. The plan is to replace the current Proof of Work model with a Proof of Stake mechanism, but progress has been slow. As of 2019, the developers scrapped their original strategy of rebuilding the plane while it is in the air and instead adopted a two-chain approach where Proof of Work and Proof of Stake temporarily run alongside each other. They dubbed this Ethereum 2.0.
In December 2020, Ethereum launched Beacon Chain as the first step in this shift of the network. Under Beacon Chain, Ethereum 2.0 stores and manages the registry of validators and deploys the Proof of Stake consensus mechanism. It is currently running alongside the original chain, however, with full implementation not planned until 2022. This means that the touted one hundredfold reduction in energy per transaction is yet to be realized.
(Not so) Final thoughts
With more than 4,500 tokens out there, I’m sure I’ve missed a few excellent options for sustainable cryptocurrencies. Given the exponential growth in this area of digital finance, chances are the best is yet to come anyway. If you know of an eco-friendly cryptocurrency, please leave a comment or send us an email and we’ll take a look. Feel free to check out our environmental analysis of the Dogecoin as well.
In the meantime, if you’re an investor who has already reapportioned your assets from fossil fuel companies and so forth into more sustainable investments, consider doing the same with any cryptocurrencies you hold. And if you already have a solar array set up, or are living a sustainable lifestyle, there’s basically nothing to lose by signing up to SolarCoin and/or BitGreen.