ELECTRIC commercial vehicles were once a common sight in Britain’s towns and cities. A fleet of 25,000 battery-powered milk floats roved the early-morning streets delivering a crucial part of the nation’s breakfast. Short ranges and low top speed were unimportant for a milk round but near-silent running meant customers could sleep. Their demise came as supermarkets expanded, but electrification of business vehicles is gathering pace anew.

Just as better battery technology is bringing down the cost and boosting the range of passenger electric vehicles (EVs), those advances are making electrification of commercial vehicles more appealing. The purchase price is still far higher than a comparable vehicle with an internal combustion engine (ICE). But businesses are more focused than ordinary motorists on the total costs of ownership, and on other reasons to shift to electric power.

Much attention has been paid to battery-powered juggernauts. Tesla has 500 orders for a heavy-duty electric lorry (pictured). Promised (with the usual wild optimism) to hit roads in 2019, Tesla says a version with a range of 800km (500 miles) will cost $180,000—50% more than an ICE equivalent. Daimler, Cummins, an engine-maker, and others are developing similar vehicles. Yet the chances that batteries will rapidly displace diesel in trucking are slim. Haulage businesses run on slender margins and the economics do not appear to add up. As UBS, a bank, notes, American lorries can take 40 tonnes laden weight and typically 22.5 tonnes of that is given over to cargo. Even by 2022 a comparable electric system will weigh between four and nine tonnes depending on range; a diesel power-train weighs two tonnes.

Displacing valuable cargo is bad enough. Further questions remain over the durability of Tesla’s powertrain (ICEs typically last 1m miles, but batteries degrade quickly and an expensive replacement may be required after half this distance) and also over the lack of a charging infrastructure along intercity routes. Lower fuel costs and maintenance of electric motors will not outweigh the upfront expense and inconvenience for some time.

Electrification is arriving far more swiftly for other types of large vehicle. Buses run on short fixed routes and their batteries, which can be rapidly recharged at either end, can be considerably smaller than in long-haul lorries. Electric buses are expensive but that could change quickly because of the speed of adoption in China.

Generous government subsidies both to clean up filthy city air and to help China become a global EV leader are having an effect. In December Shenzhen completed a switch to make its fleet of 16,500 buses electric. China is pushing other cities to do the same and, as more buy buses, battery and manufacturing costs are sure to fall. Peter Harrop of IDTechEX, a consultancy, reckons Chinese electric buses are on course to undercut diesel versions just on purchase price, and could soon flood the world.

The business case for smaller lorries and vans for local deliveries is also starting to stack up. These require smaller, cheaper batteries for shorter urban journeys and can be recharged at central depots. Britain’s Royal Mail is testing larger trucks made by Arrival, a small British firm, and has a big fleet of electric vans. Daimler has begun delivering a few “eCanter” medium-sized trucks with a range of 100km to UPS, an express-package firm, and will make 500 more in the next two years. Delivery companies and mail services are also testing or deploying electric scooters, three-wheelers and other smaller vehicles.

Electricity could also find its way to other sorts of vehicle. Mr Harrop anticipates strong growth in electric construction, agriculture and mining equipment as costs fall and emissions regulations tighten. There are other benefits. Construction vehicles that are silent could work around the clock. Even ride-on lawnmowers could become quieter and more reliable with batteries. Quiet refuse lorries would be just as welcomed by sleeping residents as the floats that used to deliver milk across Britain.