As great as it was for introducing the world to the idea of decentralized currency, Proof-of-Work is an extremely energy inefficient algorithm. Let's face it, Proof-of-Work is specifically designed to measure how much "Work" miners have done, where 90% to 95% of the cost of mining is electricity (source).
This work simply involves picking and hashing random numbers. In order to reduce or eliminate transaction fees while maintaining security as well as fighting CO2 pollution, the cryptocurrency movement must find a more energy efficient alternative.
This blog post is dedicated to calculating the difference in energy usage between Proof-of-Work and Proof-of-Person. Whether using Proof-of-Person, or Proof-of-Work for our calculations we assume every user is running a mobile wallet on their phone. On top of this, every system has its own mining system which uses further energy.
How much energy does Frink use per user?
Frink mining is so optimized that it barely requires more energy than required by an SPV wallet which must verify the block headers. We tested the energy usage of a SPV Bitcoin wallet for Android. For our testing we used the wallet recommended by bitcoin.org simply called “Bitcoin Wallet”. We also used AccuBattery to measure the energy usage of the application running on the mobile phone. We found that this SPV wallet uses an average of about 26.6mAh to run. Assuming an average 3.8V battery, this means it takes 0.0988Wh per per user to run the wallet. This makes it fair to estimate that POW, and POP all use roughly 0.1 Wh per user to run a wallet.
We can estimate that 99% of the time the average Frink miner only needs to expend as much energy as an SPV wallet to keep up to date with the network. With Frink at any point in time only 1% of the network needs to be monitoring all transactions as Frink miners will know in advance when it is their turn to mine and can smartly bring phone miners online on briefly then put them back to sleep when not being used. Only during this time do they need to be checking transactions to validate the fork they intend to mine off of.
How Much Extra Energy to Mine?
Now let's calculate the amount of energy required to mine above and beyond the energy required to run the smartphone wallet.
Let’s estimate the average number of transactions per second Frink has to support. Frink subdivides the network into connected communities each having a size of 1 million members at the high end. Bitcoin currently has roughly 30 million users and is maintaining roughly 3 transactions per second. This means that 18 times less users, who would make 1 transaction every 6 seconds on average.
Assume we have 10 second blocks meaning roughly 2 transactions per block and this means that the size of a block is roughly equivalent to the size of a transaction.
Also assume that the amount of energy used while mining is roughly linear with the number of transactions being processed. This means that users are using roughly 3 times more energy 1% of the time. Or in other words Frink uses roughly 3% more energy to mine than to run the smartphone wallets. This estimate means that Proof-of-Person uses a negligible 3% more energy to mine vs simply running a smartphone wallet..
How much energy does Proof-of-Work use per user?
The Bitcoin network miners are currently using an estimated annual 78 TWh to support the previously mentioned 30 million users according to Digiconomist.net This works out to 2.6 MWh per user used by Proof-of-Work currencies. On top of this, every user uses the negligible 0.1MWh per user.
How much more efficient is Proof-of-Person?
As we've calculated:
Proof of Person uses 0.1 Wh per user to mine
Proof of Work uses 2.6 MWh per user to mine
2.6 MWh/ 0.1 Wh = 26,000,000
In other words, if Bitcoin were to use Proof-of-Person rather than Proof-of-Work it would currently be consuming roughly 26 million times less energy!