This is the best question of the day. I am glad that you have asked which one is environment friendly. Saying environment friendly does not only refer to energy consumption rather other environmental impacts and footprints should also be analyzed to conclude which one is more environment friendly.
The similarity between Gold and Bitcoin is that both of them do not have inherent inflation, means one can not print it freely like the paper currency.
The global energy consumption for Bitcoin network stands at 22 tetrawatt hours per year where as the same figure for Gold stands at 132 tetrawatt hours per year.
Environmental impact & other footprints
Transportation of Gold is really a costly affair and tremendous energy is required in order to transport precious metal like gold where as in case of Bitcoin, being a digital currency it does not require any physical means to make a transaction of bitcoin and it can be transacted to another user across the globe by an ease and the transaction time is also very very less or negligible as compared to transportation time of precious metal like gold. Transportation of Gold has also got significant carbon footprint as compared to Bitcoin.
To sum up, it can be said that Bitcoin is far more environment friendly when we compare it with precious metal like Gold. However the futuristic version of Bitcoin mining should be green. The renewable source of energy such as wind energy, solar energy, bio gas etc should be used so that Green Bitcoin mining can be a vast possibility.
When talking between gold and bitcoin who is more environmentally friendly, the answer from me is that both of these mines are not friendly. Currently 58% of Bitcoin mining facilities are located in China, which means that China is the largest bitcoin mining country in the world. Countries whose energy consumption is still dominated by coal power plants are cheap, but bad for the environment given the large amount of carbon dioxide emissions. In one hour, 1 kilogram of CO2 can be produced by a coal-fired power plant.
Whereas the biggest gold mining is currently in Indonesia or more precisely in Papua, and now almost all areas close to the gold mine have a very bad impact because of the presence of harmful substances they breathe every day as a result of gold mining near their homes . In fact, the result of this gold mining not only affects residents living in the gold mining area, but also affects the environment that has been damaged due to the expansion of the land for the gold mining.
Not only mining, in terms of Bitcoin transactions it is also claimed to be inefficient in energy consumption compared to other transaction methods such as Visa or Ethereum (other types of digital currency). Bitcoin is estimated to consume as much as 200 kilowatt-hours of electricity per transaction compared to Visa, which only uses 0.1 kWh and Etng requires 37 kWh. Whereas gold mining, the development of mercury-free technology is part of the national action plan (RAN) for the elimination of mercury at ASGM where Indonesia targets mercury-free in the sector in 2018. Director of Hazardous and Toxic Materials Directorate of Hazardous and Toxic Materials Ministry of Environment and Forestry (KLHK).
Bitcoin is structured and requires quite complex computing power. This makes bitcoin need special computer devices with fast and expensive processors, which are made specifically for the mining mechanism. To be able to provide incentives in the mining process that are needed as network operations, Proof of Work (POW) is used in mining.
These incentives are given to miners as an appreciation for the contribution of miners to maintaining the network. Automatically, it is not only the cost to have hardware to be able to mine, but also the huge cost of electricity needed.
When the price of bitcoin soared in the previous year (up to 2300%), new miners sprang up like mushrooms. Many people set up new mining farms, to compete in mining new gold in the form of digital.
Based on the results of a study conducted by Cambridge University, it was explained that almost 59% of bitcoin mining was carried out in China, especially in northern China. Bitmain Technologies, is a leading mining hardware manufacturer based in the region. The mining equipment manufacturer also operates its own mining farm located in northern China, as well as Mongolia. In the region, it has an abundant supply of coal-fired power plants, and has electricity subsidies from the state. As a result, the electricity tariff per one KWh is only worth about four cents. So that the area becomes economical enough to be used as a good mining location.
Because of the large amount of energy needed, it has special consequences for the environment. And indirectly, the transaction also seems to be less efficient amid a high price surge. Because of the lack of balance towards the environment that makes it reap a lot of criticism.
Digiconomist, the crypto-analytics platform states that energy costs for a single bitcoin transaction require approximately 215 KWh of power. Energy is enough to supply the average US household energy in a full week, or call it to run refrigerator electricity for a full year.
With the increase in the production of Bitcoin units and the scarcity of distribution increasing, along with the increasing complexity in the computational process, and that is also accompanied by the increasing power consumption of electricity needed.
At present, 0.12 percent of the world's energy consumption has been used to produce new bitcoin units. According to estimates, energy consumption for bitcoin in July 2019 will be equivalent to the total amount of the entire US today. In 2020, energy consumption for bitcoin will be the same as the energy needs of the entire world today. This is considered to be an inefficiency in developing a system that is less acceptable.