E-quipment highlight: 4,400 hp Wabtec FLXDrive electric locomotive [update]

This is a mining industry story, not a homeowner project, but it's worth knowing about as a sign of where battery technology is headed. Wabtec, a rail equipment maker, has built battery-electric locomotives for BHP, a mining company, that haul iron ore in Australia. Two of these trains have been running for nearly a year on a dedicated track at the Jimblebar mine, and BHP just announced plans to add more, including a second set from a different manufacturer for side-by-side testing.

The technology is notable mainly for its battery size and how it recharges. Each locomotive carries a 7 megawatt-hour battery pack, far larger than anything in a home or car, and uses regenerative braking to capture energy on downhill runs with a loaded train. On long enough downhill stretches, that captured energy can be enough to send the empty train back uphill without ever plugging in again.

None of this changes what's available for home energy upgrades. But it's a useful data point on how quickly battery and regenerative-energy technology is scaling up in heavy industry, which often points to where costs and engineering improvements eventually trickle down to smaller-scale uses like home batteries and electric vehicles.