Perspective is important. Let's use our old friend here, basic arithmetic. Average cost of electricity in the U.S. is $120/MWH. So let's assume we replace all currency with crypto currency and ignore how much extra electricity that's going to take. And let's assume that allows that $900M budget you cite to drop to $0. If you divide $900,000,000 by $120, you get 7,500,000 MWH, or 7.5 TWH. Back to basic math again, that's 16.7% of the 45 TWH used currently for bitcoin. Again, that ignores that if we replaced our currency with bitcoin we'd need orders of magnitude more electricity.Hey Muppet!
How much energy do you think is necessary to run the USD currency system? The FED is spending ~900M USD in 2020 (https://www.federalreserve.gov/faqs/currency_12771.htm) just to print currency and coins. Not counting all the office rooms, the 6.3m people working in this industry and transport that waste a huge amount of electricity and gas.
How many million homes do you think can you power with all this effort.
Jesus...people don't have any perspective
So to answer the question in your last sentence, the $900M used to print currency and coins could power about 16.7% of the homes that could be powered by current bitcoin mining, which in turn represents a tiny fraction of the currency the FED system represents. So what exactly was your point was again? Maybe you didn't do the math and just assumed $900M was a big number and didn't have an intuitive grasp of how big a number 45 TWH was? Or didn't think about how much electricity would be required to replace all currency with crypto currency? Because really, as we just demonstrated, the facts you presented actually all speak against your position.
