Mining bitcoin is intensely competitive. Mining operations that do not proportionally scale their hashrate experience a decrease in expected bitcoin outcomes as the aggregate hashrate of the network increases. Miners are forced to continuously increase their hashrate in order to remain competitive, which results in an arms race for the most powerful and effective ASICs.
Miners can either use more energy-efficient mining hardwares that maximizes hashrate per unit of energy consumed to power their mining devices or power them with the cheapest energy that is available to maintain profit margins in the face of these competitive forces.
The early days of industrial-scale bitcoin mining were characterized by miners competing to utilize the most energy-efficient ASICs in order to achieve the highest possible hashrate. This competition was fueled by rapid advancements in semiconductor technology, as ASICs saw exponential increases in hashrate efficiency in a short period of time. Today's ASICs are 36 times more energy efficient than their 2014 counterparts, as measured by the joules required to produce 1 gigahash (or 1 billion hashes) of computing power. However, the efficiency gains in ASIC technology are becoming increasingly marginal.
Miners are encouraged to operate in areas where the cheapest and easiest-to-access energy is available. A compelling option is to expand operations in locations that are suitable for wind and solar farms. The bitcoin miners are taking advantage of the cost advantages of renewable energy, irrespective of the fact that these energy sources currently have limitations. However, solar and wind energy have become more affordable than fossil fuel sources. A number of leading miners in the industry have recently begun moving away from energy derived from fossil fuels. The Bitcoin Mining Council (BMC) estimated that in Q4 2022, renewable energy sources accounted for 58.9% of the electricity used to mine bitcoin, a significant improvement compared to 36.8% estimated in Q1 2021.
Bitcoin halving has the potential to spur miners' adoption of green energy and increase competition. Halvings happen every 210,000 blocks, roughly every four years. As the name implies, halvings diminish bitcoin block rewards  by half, which brings down incomes procured by miners by practically a similar sum in the event that there is no adjustment of the cost of bitcoin. The next halving, anticipated in 2024, will reduce block rewards from 6.25 BTC to 3.125 BTC issued per block. Miners of bitcoin are discovering that environmentally sustainable practices may be the next frontier to explore, as competition and halvings press miners to seek efficiency gains wherever possible.


https://www.globalxetfs.com.au/bitcoin-mining-is-set-to-turn-greener/