An Analysis of The Energy Consumption of Different Mining Algorithms


Mining algorithms are complex mathematical equations miners must solve to add new transaction blocks on a blockchain and get mining rewards. The algorithm used for a cryptocurrency determines the minimum hash rate (computing power) miners must have to have a chance of mining the cryptocurrency.

The higher the minimum hash rate, the more the blockchain energy consumption. This is also significant because crypto mining largely relies on fossil fuels with harmful environmental impacts.

blockchain energy consumption

There are many algorithms, ranging from Bitcoin’s SHA-256 to Ethereum’s Ethash, and Equihash, the latest algorithm. These algorithms have different energy computation ratings and outputs.

In this article, miners will gain an in-depth analysis of the energy consumption of various mining algorithms used to mine cryptocurrencies today.

How do Mining Algorithms Work?

Crypto mining is the process of adding new data blocks to a blockchain and earning rewards. Crypto mining is energy-intensive due to the required minimum computing power for successful mining. Mining requires computer hardware and software, which may be expensive depending on the mining process.

Crypto mining began in 2009 with the release of Bitcoin, the first cryptocurrency. Since then, hundreds of cryptocurrencies and thousands of miners have existed globally.

How it works:

Mining algorithms randomly choose a miner to add transaction blocks and earn mining rewards. But the chosen miners are picked from a pool of miners with enough computing power to solve the complex algorithm. Therefore, miners with more computing power have more chances of mining cryptocurrencies.

Mining algorithms adjust the mining difficulty to meet the conditions and ensure stable mining processes.

Although crypto mining is energy-intensive, the energy consumption of mining algorithms depends on the cryptocurrency being mined. Bitcoin’s SHA-256 is the most energy-intensive algorithm today.

With crypto mining using more electricity than in some countries, the environmental impact is problematic, considering the amount of greenhouse gasses released. The energy wasted on clustering algorithms in mining may increase the energy consumption of mining algorithms and the environmental impact.

Common Mining Algorithms Used in Cryptocurrency Mining

Here are some of the mining algorithms used today:

1. SHA-256

SHA-256 is a cryptographic hash function that uses any length of data input to produce an output of 256 bits. It uses a one-way function, so miners find it difficult (nearly impossible) to reverse the hash function to the original data input. This feature is key to its stability and security.

The basic principle of operation of SHA-256:

  1. The input data is padded to a multiple of 512 bits.
  2. The padded data is divided into 64 blocks of 512 bits each.
  3. For each block, a series of calculations are performed using a 64-bit state variable.
  4. The state variable is updated after each block, and the final state variable is the hash of the input data.
  • Examples: SHA-256 is used by Bitcoin.
  • Pros: SHA-256 is a secure hash function.
  • Cons: SHA-256 is a computationally intensive function with huge energy consumption.

Extensive testing proves that the SHA-256 algorithm is stable and secure but energy-intensive. It works best for Bitcoin mining and maintains the blockchain's stability.

2. Ethash

Ethash is a proof-of-work (PoW) algorithm designed specifically for the Ethereum blockchain. Ethash is based on the Keccak-256 cryptographic hash function and is considered the second most-stable algorithm after SHA-256. It was initially designed to improve mining efficiency.

Basic working principle: 

  1. The block header is hashed using the Keccak-256 hash function.
  2. The resulting hash is used as a seed for a pseudorandom number generator.
  3. The pseudorandom number generator is used to generate several nonces.
  4. Each nonce is used to try to find a hash that satisfies the Ethereum difficulty target.
  5. The first miner to find a hash that satisfies the difficulty target wins the block reward
  • Examples: Ethash is used by the Ethereum blockchain, Expanse, and Ethereum Classic.
  • Pros: Ethash is a very secure and stable algorithm. It is also relatively energy efficient, which makes it a good choice for mining cryptocurrencies using renewable energy sources.
  • Cons: Ethash is a computationally intensive algorithm. This means that it requires a lot of processing power to mine cryptocurrencies using Ethash.

3. Scrypt

Scrypt is a memory-hard function designed to make it more difficult to mine cryptocurrencies using ASICs. It is based on combining the bcrypt and PBKDF2 password hashing functions.

The basic principle of operation of Scrypt:

  1. The input data is hashed using the bcrypt or PBKDF2 password hashing function.
  2. The resulting hash is used as a seed for a pseudorandom number generator.
  3. The pseudorandom number generator is used to generate several nonces.
  4. Each nonce is used to find a hash that satisfies the Scrypt difficulty target.
  5. The first miner to find a hash that satisfies the difficulty target wins the block reward
  • Examples: Scrypt is used by Litecoin, Dogecoin, and several other cryptocurrencies.
  • Pros: Scrypt is a secure algorithm. It is also ASIC-resistant.
  • Cons: Scrypt is a computationally intensive algorithm. This means that it requires a lot of memory and processing power to mine cryptocurrencies using Scrypt.

The classification algorithms in mining consider algorithms based on their mining specificity. Scrypt’s ASIC-resistant features make it great for mining cryptocurrencies other than Bitcoin and Ethereum.

4. X11

X11 is a proof-of-work algorithm that combines 11 different cryptographic hash functions. This makes it more difficult to develop ASICs that can mine X11-based cryptocurrencies.

Here’s how it works:

  1. The block header is hashed using each of the 11 cryptographic hash functions.
  2. The resulting hashes are combined to form a single hash.
  3. The hash is used as a seed for a pseudorandom number generator.
  4. The pseudorandom number generator generates several nonces.
  5. Each nonce is used to try to find a hash that satisfies the X11 difficulty target.
  6. The first miner to find a hash that satisfies the difficulty target wins the block reward.
  • Examples: X11 is used by Dash, Monero, and several other cryptocurrencies.
  • Pros: X11 is stable, secure, and ASIC-resistant.
  • Cons: X11 is a computationally intensive algorithm. This means that it requires a lot of processing power to mine cryptocurrencies using X11.

The X11 algorithm is more suited to non-ASIC miners, thanks to the hash complex functions it runs.

Mining Algorithms and Energy Consumption

clustering algorithms in mining

Here’s how the SHA-256, Ethash, Scrypt, and X11 algorithms compare for energy consumption and mining efficiency.

Mining Algorithm

Energy Consumption (Watts)

Mining Efficiency (hashes/watt)


1,000 - 1,500

0.3 - 0.5


500 - 1,000

0.5 - 1


200 - 500

1 - 2


100 - 200

2 - 3

Significantly, the SHA-256 is less efficient than Ethash despite consuming more energy. This is one of the factors in the blockchain energy consumption problem. Besides the energy consumed by mining algorithms, computer hardware such as GPUs, CPUs, ASICs, monitors, and cooling systems also increase the total energy consumption in mining rigs.

Some factors affecting crypto mining energy consumption are

  • Mining hardware and software: ASICs and GPUs use more energy than CPUs, and the SHA-256 algorithm consumes more energy than others.
  • Efficiency: The mining efficiency determines the work output; higher output consumes more energy.
  • Cost of electricity: higher electricity costs may impact the energy consumption of mining rigs.

Crypto miners typically choose areas with affordable electricity and climate to reduce the total mining costs.

Environmental Impact of Mining Algorithms

As an energy-intensive process, crypto mining impacts the environment in different ways, most harmful. Bitcoin mining alone consumes an estimated 70 terawatt-hours of electricity annually and releases around 1.2 million metric tons of carbon dioxide annually, more than some small countries consume or release.

Crypto mining also consumes huge volumes of water used in cooling systems. The wastewater is often heated and can increase the environment's temperature when released. They may also contain chemicals taken off the devices when direct contact occurs. Lastly, mining equipment may become obsolete and form e-waste, which may be unrecyclable.

Bitcoin’s environmental impact is one reason many countries, such as China and the UK, have strict mining regulations or energy consumption caps for mining rigs.

Proposed solutions involve the classification algorithms in mining so miners can identify energy-intensive machines and software, switch to renewable energy, and adopt hybrid algorithms that consume less energy.

Regulatory Considerations

The regulatory policies for crypto mining vary from country to country. While many countries have regulations, many others still need to create policies to regulate mining. Crypto mining policies mostly fall into two categories; strict policies to regulate mining and soft policies to attract miners.

Some countries implement these policies to combat the environmental impact of crypto mining:

  • Taxes on energy consumption: crypto mining taxes bring in government revenue and discourage mining activities. This increases the mining costs and decreases revenue for commercial miners.
  • Quotas on energy consumption: energy quotas cap the energy consumption of mining rigs.
  • Outright bans on crypto mining: some countries ban crypto mining as an illegal activity to protect the environment and combat money laundering.

Countries looking to attract crypto miners often create policies like tax breaks, mining free zones, and tariff exemptions for blockchain and energy consumption.

Miners must comply with local regulations to prevent legal actions such as fines and penalties and protect the environment. This is possible through recycling hardware, renewable energy, and using energy-efficient rigs.

Future of Mining Algorithms and Energy Consumption

classification algorithms in mining

Cryptocurrency mining is poised to increase as the blockchain and cryptocurrency industries increase. The future of mining algorithms will shape how miners interact with blockchains.

Proof-of-Stake (PoS)

PoS mining algorithms allow miners to add data blocks to blockchains based on the funds they have locked in the blockchain. This algorithm is better than the PoW because it does not use brute computing force to solve complex equations but relies on the funds locked on the network.

Proof-of-Work (PoW)

Although the PoW algorithm may never be retired, future trends involve using renewable energy, such as solar, wind turbines, and energy-efficient mining systems. PoW miners can also set up their rigs in areas with low energy costs to save costs.

Hybrid systems

Some blockchains use a hybrid PoW/PoS algorithm to mine cryptocurrencies. The PoW system may take on the most work while the PoS is used to reduce the energy consumption and increase network speed.

Current and future trends like hosting for mining will see more energy-efficient algorithms used with energy-efficient hardware for mining cryptocurrency. Miners may see increased profits with favorable policies enacted in countries.


Cryptocurrency mining is currently energy-intensive and expensive to set up and maintain. Mining algorithms have various energy consumption capacities but generally consume much energy. Cryptocurrency miners are now turning to renewable energy to reduce mining costs. Other options they explore include using hybrid systems and operating in countries with low energy costs.

It is crucial for miners to reduce their energy consumption for two reasons; improving their profit margins and reducing the harmful environmental impact of mining. Miners, mining equipment manufacturers, and governments have important roles to play in reducing the amount of energy consumed by mining globally.

The creation and implementation of favorable policies will impact the future of mining, attracting miners to such countries.


Bitcoin’s SHA-256, Ethereum’s Ethash, Scrypt, and X11 are some of the most used algorithms in crypto mining. Some mining algorithms are ASIC-resistant, while others work with ASIC, CPU, and GPU miners.
The X11 and Scrypt are more energy-efficient (hashes/watt) than Ethash and SHA-256. The efficiency of crypto mining algorithms is an important factor to consider when setting up commercial mining rigs.
Crypto mining is an energy-intensive activity that’s largely dependent on fossil fuels. The impact of crypto mining includes the release of carbon dioxide and other greenhouse gasses, e-waste, and heating.
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