If you take the energy that is being used (wasted) today by the highly inefficient banking system and compare it to the energy
consumed during the process of mining bitcoins, you will quickly find out that the energy spent in the mining process is not that large.
So I think articles like the one you've linked are misleading. Before blaming Bitcoin, the journalist should start by analyzing the current energy
costs in the highly bloated financial sector (which is something we accept as normal, but it is far from normal).
For the sake of counter argument, the energy consumed by the inefficient banking system and gold mining can be compared with that of Bitcoin mining, there is a substantial difference. There was an article published on Hackernoon, The Bitcoin vs Visa Electricity Consumption Fallacy:
Let’s add to the mix the electricity consumption of the branches. According to the World Bank there are 12.5 branches per 100,000 adults in the world so if the world population is 7.6 billion people and we have around 70% adults, this means a total of 665,000 branches. Only in the US they appear to be close to 100,000 branches and assuming US is around 15% or less of the entire banking system worldwide you get to around the same number.
So total consumption for banks during a year only on those three metrics is around (I am rounding) 26Twh on servers, 58Twh on branches and 13Twh on ATMs for a total of close to a 100 Twh a year.
According to the article that trigger this discussion, Bitcoin annual Twh consumption is 28.67 , so currently more than 3 times more efficient than a very conservative calculation of the cost of the global banking system. Of course you will argue that the banking systems does more than handling a currency which is true but the difference is large enough that I do not think is that relevant. Even if only 30% of banks electricity consumption was the comparable part to Bitcoin, that will still make Bitcoin more efficient.
Rough estimates, Bitcoin adoption is still around 1%, comparing the current energy consumption of Bitcoin with that of global banking system doesn't make much sense and if I go by the figures in this article, 28.67 Twh with around 1% adoption and as adoption increases, I don't think it would be wrong to assume that with about 10 to 15% adoption, the Bitcoin energy consumption would be more than that of the global banking system.
Bitcoin does have an energy efficiency problem. Don't know how effective a solution LN would be, but as Andreas Antonopoulos points out in a YouTube video, the solution lies in a significant growth in renewable/alternative energy sector/establishing mining operations on locations with surplus energy.
Proof-of-work mining is contributing to massive investment and subsidy in renewables / alternative energy and efficiency improvements in processing. It is driving the decentralization of energy production.
https://hackernoon.com/the-bitcoin-vs-visa-electricity-consumption-fallacy-8cf194987a50https://youtu.be/2T0OUIW89II