An Ohme charging point detects when overall demand for electricity has dropped before it activates, avoiding demand surges at key times and giving customers the benefit of lower night-time power rates. Photograph: Miki Barlok

When we talk about making improvements to Ireland’s electric car charging infrastructure, we generally mean the network of public fast chargers. The ability to top your electric vehicle (EV) up with juice from a high-power charger – the most powerful can pump in electricity at up to 350kW – seems to be the most important thing when it comes to convincing people to switch to electric motoring.

If that is the case, then we’re thinking about it all wrong. At least that’s the opinion of David Watson. A native of Cork, Watson made the switch from working in hedge funds to working in the field of EV charging in 2017 when, along with business partner Gerry Guy, he founded Ohme (pronounced oh-me), a maker and supplier of car chargers.

“If you’d started off with an energy system that distributed power to every home and business in the country, and you wanted to lay a transport system over the top of that, you wouldn’t centralise the distribution of that power,” Watson tells The Irish Times. “This whole idea of centralised distribution of energy comes from that legacy of a liquid-based system that you can’t get the liquid to everyone’s house so we create these depots that you go to. So it’s old-fashioned thinking to think that we need to create all these hubs where you can charge really quickly.”

Ohme’s ambition is to get people charging smarter, not faster. According to the company’s research, which encompasses both the UK and Irish markets, most people’s cars are parked for around eight hours per day. In that time, assuming an 11kW charging speed, you could add 88kWh of energy to a car’s battery – that’s more energy than an average electric car battery pack can hold. The thing is, people aren’t actually charging for eight hours per day. Apparently, the average EV driver charges for three hours, between two and three times per week.

“So if you’re then driving to work five days a week, and the facilities are there, you can plug in and you will get 95 per cent of all your charging done, and there’s no massive public upgrades of systems required,” says Watson.

Of course, that then creates something of a concern over spikes in the supply of electricity. If everyone is arriving and work and plugging in, or is coming home from work and doing the same, then we’re going to have surges of demand for power at a time when we’re trying to wean ourselves off fossil-fuel electricity and on to renewables.

Wind power is arguably Ireland’s best renewable solution, because on average we have a lot of wind. Indeed, at times in 2021, the amount of wind power entering the national grid was up to 75 per cent of the total demand. The problem, as everyone points out, is that wind (and solar) fluctuates, so it can’t be depended upon to supply sudden peaks of demand.

Hitherto, the theory around electric cars has been that their batteries could soak up excess wind power overnight, and then through a complex inverter system, return that energy to the grid when needed. Effectively, everyone’s car would become a power sponge. That, though, is not what Watson’s talking about. His plan is much simpler – just by making car chargers smart, instead of just a plug in a wall, he reckons that charging EVs could even out the demand on the grid without the need to draw on their spare energy stores at all.

Regular charging points at workplaces and at home risk creating giant surges in demand at peak times, when drivers arrive in work and arrive home. Photograph: John Walton/PA

“There’s lots of behavioural stuff that you need to make that kind of reverse-charging viable,” Watson says. “There’s also a need for understanding how much you degrade the battery, because every time you cycle the battery, you damage the cells. And you damage the cells more by charging from 80 per cent to 100 per cent. You do five times as much damage cycling from 80 to 100 that you do cycling from 40 per cent to 50 per cent. In fact, just simply charging in a smart way and using the demand sensibly can help balance the grid and actually provide most of the benefit.”

So, by using smart chargers, Watson reckons that the benefit is two-fold. When everyone rocks up at work or home and plugs in, the car doesn’t have to start charging right away. Via one of Ohme’s smart chargers, it can work out when the overall demand drops, which helps to reduce sudden spikes in demand.

With fewer spikes, the grid is put under less pressure and there’s less of a need to fire up additional fossil fuel plants, which is obviously of benefit to the planet. For the individual consumer, the benefit is that the car and charger can wait until the night rate kicks in to charge, which lowers your energy costs.

There’s a fringe benefit, too – if, via smart charging, we can do away with the need for cars to be able to return battery energy to the grid, in what is known as a vehicle-to-grid (V2G) system, then we’re saving both money and efficiency. Money, because the inverters needed for a V2G set-up are expensive, and efficiency because those inverters are also heavy and add to the mass of an EV at a time when vehicle weights are already skyrocketing.

The cost of energy is suddenly a major issue and there have been worries raised in some quarters that a mass shift to electric vehicles will trigger more rises in the cost of electricity. While electric cars are generally very efficient, they do need a lot of juice, more or less doubling the current average 3,500kWh you go through in a family house.

However, Watson wants to make clear that there’s a direct and simple financial benefit to going electric. “You average fuel bill to cover 10,000km is now something like €2,000,″ he say. “If you switch to an electric car, even without any special electricity tariffs, you’re going to cut that to €850 straight away. In Ireland, if you have a day/night tariff and you charge mostly at night, you’re cutting it to about €450. So not only is there a direct benefit to you, but if you’re smart-charging you’re not contributing to peaks in the system, and you’re displacing the fossil fuel that would otherwise have to have been bought and imported.”

There’s a further benefit. While wind power is (sort of) free, the cost of wind-generated electricity is quite high, because there’s a major capital investment needed to build wind turbines and wind farms. That built-in price is made worse by the fact that, frequently, those farms have to be idled because there’s more wind power available than there is demand for it to be used – a process known as curtailment. In theory, with lots of people charging their electric cars overnight, much of that curtailment can be wiped out, as there will always be a demand for the power being generated.

“I think we can turn this energy crisis into a positive by making people more aware of energy, more aware of the value of Irish-generated or locally generated energy, and the value of technology that can help manage all of that,” says Watson.

Since 2017, Ohme has grown rapidly and is already the official EV charging supplier to the vast Motability network in the UK, which helps to provide adapted vehicles to disabled drivers. In Ireland, Ohme has been working with Iarnród Éireann, the AA, the Bright motor dealer group and Donegal County Council.

Iarnród Éireann’s experience provides an insight into how people charge and how driving an EV changes the way we work. The State-owned transport company initially installed a rank of charging points at its head office, so employees using one of its fleet of EVs could charge at work. However, it turned out that work was being mildly disrupted, as people were constantly checking the chargers to see if one was free so that they could plug-in.

As a solution, Iarnród Éireann decided to get chargers installed at employee’s homes, reducing the demand on the work chargers and making sure that people weren’t staring out the window all day, checking for a free charger.