Why the UK's buildings must plan for electric vehicles

The UK government’s announcement that “it intends to ban the sale of conventional cars and vans by 2040” has generated much debate around the infrastructure and generation upgrades needed to meet growing vehicle demand. We may need 8 Gigawatts of additional power generation by 2030 to charge our cars, coupled with large-scale electrical distribution upgrades. To put this into perspective, the amount of time it will take us to get this additional 8GW capacity is the equivalent of building around 2.6 Hinckley Point C power stations – hardly quick.

As the speed of introduction of plug in electric vehicles (EVs) gains pace, the way we refuel our vehicles will fundamentally change. No longer will the local petrol station be the only choice to refuel vehicles. In the future we will look to charge our vehicles where we work, rest and play. This is recognised by the UK Government within their recently issued Road to Zero Strategy which states that they “expect that as EVs go mainstream, charging at home overnight, or at workplaces, will continue to be the most attractive options.” The new petrol station is likely to be in buildings. BP recognised this with their recent purchase of one of the UK’s largest EV charging companies. It is therefore key as building services engineers that we understand how to allocate incoming power and provide charging networks within buildings.

If, in December at around 6pm, when the UK’s electricity load can peak at roughly 56GW, we connect all of our electric vehicles to local electrical networks, we could cause a severe overload. This unmanaged load may have the knock-on effect of creating brown-outs or even black-outs for significant parts of the power network. As building services engineers, through smart design and creative thinking we can look to reduce the impact our vehicles will have on the UK power network. By advising our clients on the most appropriate capacity of charging point to be installed, overlaid with load management and potential battery storage, we can look to avoid a nightmare situation on the national grid. To lead the way in smart charging, the UK Government has committed that by “2019 all government supported charge point installations will have to have smart functionality.”

During the 7 hours we sleep at night, we could charge our vehicles at home. Even on peak consumption days, from midnight to 7am our electrical demand stays stable at around 35GW. There is significant spare generating capacity at night to reduce the requirements for additional generation capacity for charging vehicles. The Road to Zero Strategy acknowledges this and states “the current electricity system has been designed to meet a peak in demand between 17:00 and 20:30. For the rest of the day there can be large amounts of underused generation and network capacity. Generation during these off-peak periods is usually cleaner and cheaper.”

If we installed a 3.7kW charger we could provide up to 84 miles of range every night, more than enough for the average commute. Furthermore, a 7.4kW charging station could give us 140 to 280 miles of range. However, dependant on the incoming cut out, plugging in to a number of 7.4kW charging stations at home could overload the incoming supply to the house or overload the local supply transformer.

The roughly 20GW of night time reserve could serve around 5.4 million vehicles, assuming they each have a 3.7kW connection. However, if as building service engineers we design 7.4kW connections we can only serve 2.7 million vehicles of night time reserve. It is our design of electric vehicle charging in buildings that will affect the load growth on the UK Grid by 2030.

By the time the ban on pure combustion vehicles comes into force by 2040, we may have shifted the way in which we use our vehicles. If Elon Musk’s predictions are correct, we may have more autonomous vehicles on the road. We could find that the building charging infrastructure is obsolete, because it’s not in the right place. Thus we would have spent time and money on the wrong solution. It is therefore recommendable to mitigate large increases in loads within buildings due to EV charging.

At some point over the next 20 years most buildings that we “work, rest and play” in will require some form of EV charging. The Road to Zero Strategy confirms this intent. In this report, the government states that they will provide “a grant scheme to support charging infrastructure at workplaces”. At home “the houses we are building over the coming years are EV ready. It is our intention that all new homes should have a charge point available.” Through taxation incentives for destination charging they will provide “first year allowances (FYA) to businesses installing EV infrastructure”. 

As most buildings and their infrastructure and incoming supplies last for these durations and longer, we need to think about the impact of EV on all new developments. It would therefore be recommendable for an assessment to be undertaken to this end. This could become part of each planning application, and could show how the building will mitigate its impact on the electrical infrastructure as EV load growth occurs over the next 20 years. This is relatively easy – by right-sizing charging points, installing load management and using battery storage technology, some of the peak load impact on both the UK grid and local network can be reduced. This can all be done without installing charging points until they are truly needed.

The UK needs to confront these questions sooner rather than later – as our vehicle refuelling habits change, our buildings must adapt.