Will the network be able to cope when EVs go mainstream? National Grid has a plan
24 Jan 2020 | 4595 Views | By Jesse Crosse, Autocar UK
In a few years, EVs will be taking to UK roads in much greater numbers than they are today. But will the UK’s electricity-generating network be able to keep up?
Although there has been widespread concern that it won’t, the current assessment by National Grid plc (which also manages ...
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In a few years, EVs will be taking to UK roads in much greater numbers than they are today. But will the UK’s electricity-generating network be able to keep up?
Although there has been widespread concern that it won’t, the current assessment by National Grid plc (which also manages the UK’s natural gas supply) is far more optimistic. If the right steps are taken, then far from overloading the network, EVs could actually contribute to reducing energy consumption by 2050.
Thanks partly to the 2019 Climate Change Act, which aims for net zero CO2 emissions by 2050 across the board, energy supply for EVs will form part of a massive UK decarbonisation strategy. In its annual Future Energy Scenarios report (FES), National Grid lists four possible ways in which the UK’s energy model will shape up. Two of those will achieve net zero emissions by 2050.
National Grid’s electricity network is split into two main parts: the high-voltage three-phase network and the local, low-voltage single-phase networks, carrying electricity from substations to properties.
If nothing is done, it is expected that demand on both networks will double at peak periods once the mass roll-out of EVs begins, causing serious problems.
National Grid predicts that 50 percent of all new cars will be plug-in hybrid or fully electric by 2030 and that there will be 35 million EVs on UK roads by 2050.
In the short to medium term, it is predicted that overloading the network in peak periods can be avoided by smart charging. Smart chargers fall under the control of network operators and each charger can be told when to begin charging to spread the load on the networks into low-peak times. Successful trials over the past few years have established that consumers have no concerns with the time of day their EV gets charged, particularly because it usually happens overnight.
The time shift can be overridden for urgent use and chargers potentially controlled by the consumer via an app.
The Automated and Electric Vehicles (AEV) Act of 2018 mandates the transition to a smart domestic charging infrastructure. As of 1 July last year, all new domestic chargers must be smart to qualify for support from the government’s Electric Vehicle Homecharge Scheme.
The overall balance of energy use in the UK is expected to change, leading eventually to a reduction in consumption due to increased efficiency. One key example is a dramatic shift in the way homes are heated, raising the efficiency of homes to EPC (Energy Performance Certificate) class C or higher, and the rolling out of at least 2.5 million domestic heat pump systems by 2030.
Hydrogen is expected to play a big part, mainly in heating. The idea is that electricity is used to reform natural gas to produce hydrogen in conjunction with CCUS (carbon capture, usage and storage) to neutralise CO2 from the hydrogen manufacturing process. All household and industrial boilers would eventually need to switch to hydrogen, emitting no CO2 and minimising the use of electricity.
Even with smart charging, demand for electricity will increase again as EV numbers grow, but that is expected to be offset by the roll-out of vehicle-to-grid charging. This will allow vehicles charged at low-peak prices to transfer energy to the home during more expensive peak periods, reducing the load on power generation stations during those times.
Ultra-rapid public chargers should help quell fears of range anxiety and lack of convenience for prospective EV buyers. BP Chargemaster has already begun the roll-out of 400 ultra-fast 150kW chargers planned by next year. These are capable of delivering a 100-mile range top-up in 10 minutes. National Grid also proposes the creation of ultra-rapid charger clusters (150kW-350kW) at motorway service areas. According to its 2019 FES, National Grid has already identified 54 sites that, it says, would put 99% of EV drivers within 50 miles of a cluster at any time.
National Grid says those sites can be linked cost effectively to the high-voltage transmission network directly. It also recommends that this happens before price parity with petrol and diesel cars is reached in around 2025, to avoid range anxiety being a barrier to EV uptake. It warns that this will work only with government intervention under the AEV Act, saying that a market-led approach would lead to a postcode lottery.
What's needed
UK consultancy Capital Economics forecasts that to meet 2050’s ‘net zero’ targets, the UK will need: 25 million EV charging points, 22 million home heat pumps, and £240 billion total outlay.
Making the most of what's there
A rapid-charging project called DC Share is under way with Western Power Distribution, Electricity North West and Ricardo. Its aim is to boost the capability of local networks to power rapid chargers.
Although local AC distribution networks can be protected from mass EV plug-in at peak times by smart charging, that doesn’t allow for attaching power-hungry rapid charger clusters to the same networks. For that, expensive ‘network reinforcement’ may be needed, such as increasing the capacity of transformers, overhead lines and cables.
The DC Share project will tap into surrounding networks, drawing unused power to drive rapid-charging hubs. The project will lay a DC equalisation cable network between transformers, so those experiencing heavy demand can be supported by others that are lightly loaded.
If successful, this approach would be cheaper and more efficient than implementing the usual network upgrades and enable greater numbers of rapid chargers without the need to generate extra power.