Ever met a diesel mechanic? Every one I've ever come across has a very distinctive diesel cologne. I worry how this plays out in the field when combined with a 10,000psi gas which is explosive is almost any mixture including oxygen.
The greatest tonnages are dug out with bench mining excavators. These work 24/7/365 round the clock to fill trucks from bench faces and empty into trains.
An area such as the Pilbara region moves a billion tonne of raw material a year and ships most of that.
These excavators are electric with cables that drag behind them .. they move very slowly across bench faces and then move back across the face again, it's not like they are very mobile (aside from swinging, dipping, lifting, dumping, returning, etc.)
If you could solve the problem of running electrical cables to mobile equipment that is used in farming, road building, forestry etc. then you'd change the world and put entire industries out of business.
Your example is not very different from how they did mining at the beginning of the industrial revolution: the equipment is tethered to the mine. Electric railways have been thing for almost 150 years now, but the vehicles are still tethered to the rails.
If we could start from scratch we probably would choose your solution and not worry about mobile energy storage at all. We'd just build stuff around that constraint that equipment has to be tethered. But unfortunately a world has already been built that involves mobile equipment and you won't find much support for tearing it all down and starting again (alas). Greenfield development is engineering on easy mode. The real challenge is figuring out how to move forward given the current world.
I've got a mixed old school capital 'E' Engineering and applied math bachground coupled with a lot of exposure to mining, cattle stations, and wheat farms.
For forty odd years I've been involved in or tangential to projects related to exploration, cost cutting, new technology, optimised processing, etc.
> If we could start from scratch we probably would choose your solution
Not my solution, I first saw electric powered heavy earth moving equipment in th early 1970s.
The greatest savings to companies and greatest benefits to the environment (aside from somehow getting people across the globe to consume less) come from making the greatest consumption areas more efficient.
Mining equipment runs 24/7/365 continuosly, idealy every hour of every day of the year at near maximum capacity allowing for maintainance.
It's a sector that consumes extremely large amounts of transport energy, more than agriculture.
It's open to innovations such as "infinity trains" and massive dedicated solar farms to generate direct power in sunlight and generate on site hydrogen derivitives for generating power at night.
Farming equipment works "hard" (heavy earth turning plowing, harvesting) for a few weeks a year. Other farm activities (seeding, spraying) happens at other times in the year and doesn't require quite the same horsepower.
There's scope to split ag activity between heavy high horsepower peak usage and lighter continuous pass work.
Already we see consumer ready (but not yet widespread) Agri-bots for weeding and spraying - solar charged, battery powered, no human on board, vision enabled self driving devices that can run near continuously (half the night on battery charged during day) that can minimise spraying to "just the weeds".
I don't think a tractor is necessary a bad use case for batteries. They just need battery packs which can do the equivalent of a days work. Electric motors are almost better suited to the use case due to the torque. I'm sure some of the US mega farms have tractors which run all night (and the emissions of those are the least of their environmental issues) but this isn't common elsewhere.
I believe the problem is that a tractor runs for much of the workday at a very high load. Pulling a plough is constant hard work, not like a car that is only using a lot of power while accellerating hard. If you had your foot to the floor in a Tesla constantly you would run your battery flat in a lot less than 8 hours. I have read that the batteries for this application would therefore be infeasibly large.
Yes your example is extremely niche. It only works where you are going to work on one specific application for many years in the same place. It doesn't generalise to building a house, a supermarket or a road. It doesn't generalise to ploughing the Mid-West.
Even in your example it only works if you are taking all of the material to one destination, like an ore refinery. If it was road stone, the rock would get loaded onto a diesel truck for the final part of the journey. So again, the tractor, the excavator on a job site, the lorry, will all stay on diesel or hydrogen ICE
