Here's one key difference between many if not most large scale industrial processes and Bitcoin mining.
Admittedly I don't know much about battery efficiency, so there may be other more efficient uses. Hydroponics lighting?
Where "waste energy" is difficult to access and available only in trickles, it's surely very unsuitable for bitcoin mining, which is energy intensive.
Frankly, there are far more pressing issues than making more bitcoin.
Sure, there’s conceivably times of low demand when some energy would otherwise go unused. But a “ hydroelectric dam 1000s of km from civilisation”? Heat extractors in Vegas hotels? You’re imagining a fantasy world.
Further, what you’re ignoring is that none of this is “waste”. It’s already being stored or used. Finding new demand for it simply makes it more expensive for existing users.
Turned off wind turbines at times of surplus. They tell us that nope, it is not (yet) being used or stored.
> Finding new demand for it simply makes it more expensive for existing users.
It's not that simple. It could very well be the case that selling a portion of energy that otherwise has no demand to a buyer of last resort enables the business to be profitable. Not selling this portion of energy would mean that the operator would have to charge their other customers more in order to be profitable.
So it could in fact make things less expensive indeed.
> Either way, we're going to need Fusion to run it in the future.
In my understanding, the economics of Bitcoin mean that eventually mining will be performed with predominantly waste energy, which is by definition that which has no other practical use. The existence of a practical use for the energy other than for mining will push its price higher than is economical to use for Bitcoin mining, because other miners using waste energy will be able to pay less to mine the next block. It's likely that energy for Bitcoin mining will come from sources like heat from flare gas, currently just burned at oil refineries and released as photons into the night sky, leaving Earth forever. Or energy from wind turbines or solar panels during periods of low demand. Or a hydroelectric dam 1000s of km from civilisation willing to pay the transmission costs to use it. Or, heck, even heat extracted from sewage in Vegas hotels, if it's enough to run a steam turbine. Basically anywhere where otherwise useless energy can be extracted in quantities sufficient for mining. I don't think, given the costs of the infrastructure likely required for fusion, we'll be seeing it employed for Bitcoin mining long term.
This is one of the aspects of Bitcoin I find most beautiful - it monetises waste.