A Norwegian distributor of CAT heavy machinery has converted a CAT excavator to electric power using 3.4 tons of batteries. This was 300 kWh of batteries.
A Tesla 85 kWh battery pack weighs 1,200 lb (540 kg) and contains 7,104 lithium-ion battery cells in 16 modules wired in series. 340kWh of Tesla batteries would weigh 2.16 tons.
Battery powered heavy machinery has a minor contribution to reducing air pollution. 2500 excavators have the air pollution of 60,000 cars.
Electric heavy machinery will be useful for space missions and for underground tunnel and mining work. Underground the electric machines will not require ventilation to remove air pollution, gas emissions, carbon dioxide and carbon monoxide.
If Boring Company radically reduces the cost of tunneling then we can head towards underground cities.
In space on asteroids and the moon, it would be far better to have electric vehicles for construction in airless environments.