With the halving scheduled to happen in just under four hours, unprofitable miners have already begun shutting down their equipment, Alejandro De La Torre — the vice president of major mining pool Poolin — said in a Monday interview with Cointelegraph. Per his estimations, these miners account for “15–30%” of the entire Bitcoin (BTC) hash rate.

“Mining farm personnel are shutting [their units] off as we speak since they will not want to do it after the halving — because then they're losing money,” De La Torre told Cointelegraph. 

The miners that are now fleeing will likely never come back online if they don’t upgrade their equipment or find extremely cheap electricity sources, as the mining reward will be halved once the event occurs:

“All older machines will no longer be profitable unless they are mining on nearly free electricity or if the price shoots up by 2x or more.” 

According to De La Torre, unprofitable mining operations based in China will be the first to switch off. The halving will take place in the early morning local time, which is why Chinese operators are now shutting down profitless units before punching the clock. 

Hash rate to decrease post-halving, bouncing back afterward?

This shutdown will affect the total hash rate, De La Torre added, since the soon-to-be unprofitable units generate “about 15–30%” of that number. 

As previously reported by Cointelegraph, Bitcoin’s mining hash rate has seen major volatility ahead of the halving and is likely to fall soon after it takes place — but could then start to bounce back as the new generation of mining machines gets shipped out.