With Proof of Work (PoW) blockchains becoming a hot topic for discussion as far as carbon footprint and eco-friendliness go, where does Polygon — with its Proof of Stake (PoS) consensus mechanism — rank in terms of its ecological footprint?

As per estimates, the biggest PoW blockchains can consume a yearly quota of anywhere between 35–140 TWh of electricity, with a continuous draw of anywhere between 3–15 GW of electricity. Just the two biggest PoW blockchains would be ranked 27th in yearly energy consumption if it were a country — above the likes of Sweden, Vietnam and Argentina.

It is clear that PoW eats away a huge chunk of the global sustainable energy budget every year.

By contrast, Polygon’s validators approximately consume 0.00079TWh of electricity yearly with an approximate continuous draw of 0.00009GW, orders of magnitude below the energy consumption by the major PoW blockchain networks.

Comparison between PoW blockchains and Polygon

Energy consumption

Hourly Electricity Draw comparison

To put Polygon’s eco-friendliness in perspective, Polygon’s yearly energy consumption is equivalent to:

The sheer amount of computing power required to mine transactions/blocks on the blockchain in PoW blockchains is enormous. Ultimately, it all boils down to the cost of computation of transactions on the blockchain and not just the computation itself, hence even though we are seeing improvements in the efficiency of mining devices, it translates very little into energy consumption savings.

With Polygon deploying a PoS mechanism, instead of having to deploy large computational resources to mine/verify each transaction on the blockchain, validators can instead stake a certain amount of cryptocurrency on to a smart contract which then delegates the responsibility to validate/verify transactions based on smart contract regulations and amount of cryptocurrency staked. Thus, validators move from a more computationally competitive verifying mechanism (PoW) to one where it’s not a race towards the end, ultimately depending on smart contract execution.

Calculation of Polygon’s energy consumption

While it may not be entirely possible to calculate the energy consumption of Polygon validators right down to a t, however, we can reasonably estimate the energy consumption of our 90 current validators.

Polygon’s validators use two types of nodes: validator and sentry nodes. Our validators typically use AWS EC2 instances, the specs of which are given below:

Each of these nodes has a draw of about 350W at normal utilisation levels, however, they can reach up to a maximum of 500W, hence we have taken a more conservative approach and taken the maximum draw for our calculations. Hence, per validator, total draw would be 500 + 500 = 1000W. For a total of 90 validators globally, the total draw can be calculated to be 90,000W or 0.00009GW.

Going by the same 1000W draw per validator, for 90 validators and 8760 hours per year, total year energy consumption turns out to be 788,400 KWh or 0.00079TWh

Thus, Polygon’s PoS validators consume electricity energy which is multiple orders of magnitude below PoW-based blockchain miners and that translates to more eco-friendliness and considerably fewer carbon emissions. Unlike PoW systems, over time, it can be reasonably predicted that with technical improvements in node technology, our validators will become more efficient in both validating transactions and consuming electricity accordingly.