Sales of fully electric cars, which have no fuel tank and no internal combustion engine, remain very modest. There are two other types, genuine hybrids which have two power sources, a battery and an internal combustion engine, and the controversial “self-charging” variety, which never import electricity and are entirely powered from the tank.

Government subsidy for the latter type has been withdrawn and there have been complaints that they should not really be described as electric at all. Ultimately, the twin-powered variety will have to be replaced with fully electric models if the switchover is to be achieved and the car fleet truly decarbonised. This will take several decades – the capacity to produce enough fully electric cars does not exist and will take, on some estimates, at least another decade to create, after which point the pre-existing fleet of petrol, diesel and hybrid cars will have to be given another decade or more to wear out.

Along the way, replacing petrol and diesel power with electric propulsion does not decarbonise until the electricity generation industry moves decisively to carbon-free technology, renewables or nuclear.

Car dealers have been reporting that sales of electric cars of all types, still quite limited in Ireland, are largely confined to urban purchasers. This is unfortunate for several reasons. Car ownership in Ireland is lowest in cities – the 2016 census shows that the lowest car ownership rates in Ireland are in the central areas and inner suburbs of Dublin, and car-owning Dubs also do the lowest annual mileage. Every electric car sold to a rural dweller is worth much more, in decarbonisation value, than a sale to an urban dweller.

It is not too difficult to figure out why rural folk are slower to buy electric vehicles. They are expensive, even with substantial Government subsidy, and it will take time for prices to come down. Incomes in rural Ireland are below urban levels and the car manufacturers are not promising price cuts until serious volume production gets going, and that is several years away.

Car manufacturing is an economies-of-scale business and it will take years to scale up battery manufacturing and assembly plants. This means that it will take time for all-electric vehicles to become affordable without Government subsidies. The Exchequer can afford these subsidies only so long as the take-up is limited.

There is a second reason to be sceptical about high Government targets for the switch to electric – there was ambitious pre-election talk about up to one million electric cars on the road within 10 years. It has to do with the availability of fast-charge points. Exclusive reliance on overnight charging, or slow charges lasting hours, will not cut it with the motoring public. Nobody will risk running out of power in some remote spot and the reassurance of over-tanking is not available within the range limitations of even the latest electric cars.

A standard tank holding 50 litres of petrol or diesel offers a potential range up to 1,000km, but batteries offering this range would add so much to the vehicle weight that it would be self-defeating, worsening fuel consumption.

As a practical matter the attractions of electric cars will be limited, especially for rural dwellers, unless a big nationwide network of fast-charging points is available, and not just on the motorways. Who wants to get stuck in the middle of nowhere with no juice? You cannot phone somebody to ferry out a can full of electricity.

The auto-fuel distribution industry is organised by private enterprise. Shell, Exxon and the other fuel companies distribute petrol and diesel to forecourts all around Europe and the retailers, some of them national chains, some individual enterprises, sell on to motorists.

The system works well, and fuel is available throughout the country, sometimes a little dearer in the locations most expensive to supply.

The network of fast charge points required to replicate this level of service will need to be at least as extensive, possibly more so given the likelihood that range limitations will be with us until battery technology (reduced weight per unit energy) improves further.

In Ireland, the decision has been taken to rely on the same, competitive private enterprise model to deliver the required network and the ESB’s pioneering efforts, and subsidies, have been scaled back.

The private companies will try to deliver on the motorways and in busier urban areas but there must be doubts that they will be keen to pay high-capital costs to install capacity at the low-volume and more remote locations.

An alternative would be a socialised model, where the ESB installed the network and spread the losses across everyone’s electricity charges.

There is a further headache: who is to maintain diesel and petrol supplies in rural Ireland for the legacy fleet as demand dwindles?