Will EVs Overload the Grid? EV Charging Concerns Explored

February 21, 2023

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The UK has committed to ban the sale of new petrol and diesel cars, and vans by 2030 in line with its climate goal of net zero emissions by 2050.

The move to electric vehicles is unfaltering, but what kind of strain to the electrical grid will be created by at least 10 million more EVs in the next decade? Can the grid cope? How can there possibly be any synergy between climate goals and the need to charge millions of new electric vehicles?

These are prudent questions given that in 2022 the Russia-Ukraine conflict quickly resulted in energy supply concerns so severe that three-hour planned power cuts were expected during the winter.

11 Million EVs Won’t be Charging at the Same Time

There are currently over 660,000 battery-electric vehicles (BEVs) in the UK and an additional 445,000 plug-in hybrids (PHEVs). Per LGV and the Energy Savings Trust (EST), it’s estimated there will be between 8 and 11 million electric or hybrid cars on UK roads by 2030. By 2040, this number could reach 25.5 million. This is gargantuan growth but moving to vehicles with net zero emissions is a critical part of the UK’s overall net zero goal. Similar transitions are planned elsewhere around the globe, the US aims for half of all new vehicle sales to be electric by 2030.

Imagine the demand on the grid as 10 million more electric vehicles hit the road. What happens to the power grid if all those vehicles are plugged in to charge at the same time? Overload, right?

If the 32 million cars currently in the UK were electric, the demand for charging them, if they were all plugged in at the same time, would equate to 229GW. The capacity of the National Grid in 2020 was 75.8GW.

In reality, the chances of every EV charging at the same time are extremely slim though not impossible. Some will be driven, parked, or used once in a while and charged much less often. Others will be charged at work, at the supermarket, or at home overnight. In the near future, EVs may charge from renewable energy sources, serve as battery stores and sell their power back to the grid when energy demand peaks.

A Constantly Evolving Power Grid

Experts are not expecting electric vehicle charging to overload the grid and there are number of reasons for this confidence. In August 2022, the National Grid described the issue of the grid not being “able to handle the increase in EVs,” as a myth. The National Grid reiterated earlier commentary that the shift is to EVs is gradual, renewable energy sources are being developed, and “we’re constantly evolving the electricity grid.” The issue of developing the grid, nationally and locally, is critical though. Local substations, transformers, and power distribution networks will all require significant updating.

According to the National Grid, electricity demand peaked in the UK at 62GW in 2002 and has fallen by around 16% since, because energy efficiency has improved. It estimates that a complete shift to EVs would only increase demand by around 10%, putting consumption still well below the 2002 peak.

There is another reasonable calculation, as per Forbes. This puts average EV consumption at 3.5 miles per kWh and an average user distance per annum of 7,400 miles, so each car will consume an average of 2,114kWh of energy per year. Multiplied by 32,697,408 vehicles gives total EV consumption of 69TWh. The UK produced 323TWh of power in 2019. EVs won’t draw all the grids power but they may require additional capacity which could come from further energy efficiencies elsewhere or from renewables.

An additional problem for the power grid is that EV chargers are designed to deliver a controlled current to lithium-ion batteries. EV charge current isn’t flexed when demand to the grid is high, EV chargers continue to pull power at the same rate. This contrasts with traditional domestic high-energy appliances like ovens and kettles, which will reduce power draw in times of grid stress.

Balancing Demand to the Grid – Smart Charge Control and Charge Timing

Energy stakeholders are well aware of the theoretical strain on the grid should many EVs be charging concurrently, so regulations are being built in to prevent such a problem.

The UK government has introduced its Electric Vehicle Smart Charge Points Regulations for 2022 and beyond. The regulations cover private EV charge points and smart cables for EV charging, and they ensure EV charge points have smart functionality. This functionality allows for EV charging to happen when there is less demand on the power grid, and for charging to pause when demand is high. The US has its Smart Chargers and Time of Use Rate programs to achieve similar results.

On January 17, 2023, the UK government and Ofgem published the Electric Vehicle Smart Charging Action Plan. The plan’s goal is to make smart charging the “preferred method of long duration charging by 2025.” The plan is supported by further investment of £16 million in funding from the Net Zero Innovation Portfolio (NZIP) for smart charging technologies. Based on the plan’s release:

“The government and Ofgem will seek to remove the barriers that currently prevent the full development of a diverse and competitive smart charging market, while making sure the energy system is ready to respond to the upturn in energy demand that electric vehicles will bring.”

We may be some way from an entirely smart grid scenario where the electricity grid communicates fluently with smart chargers to automatically manage charging times. A scenario where charging switches off when demand is high or supply low, and charging is enabled off-peak or when there is excess energy to the grid but this will certainly be the ultimate goal.

Governments, and energy stakeholders, want to avoid high volumes of EV charging at peak times. In the UK, energy usage peaks between 5pm and 8pm as it gets dark and people return home from work, cook, and finish household tasks or plug in additional devices. Outside of EV regulations, energy companies are already rewarding households that can cut energy use during peak times.

UK electricity tariffs are cheaper at night, which will encourage off-peak charging and there are likely to be further incentives for off-peak charging as EV numbers grow. Peak charging could also be discouraged by the implementation of higher electricity tariffs during this time.

Overcoming EV charging problems, developing EV charging infrastructure, improving grid efficiency and local power infrastructure, and balancing charging demand to power grids are all important components to EV adoption and development. The UK has committed £1.3 billion to developing public and private charge points and has pegged up to £1 billion for the development and production of EV batteries. Ofgem plans to reinforce the UK power distribution network.

Using Off-Peak Renewable Power Sources

The proportion of energy generated by renewable sources is growing quickly. Some of these sources can generate additional grid capacity at certain points in time. Solar energy can pick up some slack from daytime demand. Windy periods, or windy nights, may be able to meet additional demand, or night-time demand from EV charging.

Effectively co-ordinating peaks in both energy supply and demand could be key to meeting EV charging requirements whilst balancing climate goals and without overloading the grid.

Powering Your Home and Giving Back to the Grid - The Potential of V2H and V2G

Vehicle-to-home (V2H)

Battery capacity must be substantial for EVs to “go the distance,” with petrol and diesel vehicles and innovation in battery technology is pushing this capacity upwards.

This capacity means an EV battery has the potential to be used as a flexible energy storage device or home battery system that can help off-set power supply and demand fluctuations. When there is excess or cheap power, EVs can be charged. When power demand is high, or expensive, EV batteries can give power back to homes and even back to the grid.

In a V2H scenario, an EV can be charged with excess solar power generated by the home. When it’s dark, or cloudy, the EV can give the stored power back saving the household from purchasing electricity.

Vehicle-to-grid (V2G)

In 2018, OVO Energy and Imperial College London declared V2G could have the potential to save the UK energy network £3.5 billion per year. OVO Energy and Nissan conducted a three-year trial after installing 330 bidirectional chargers in UK homes. They concluded the homes could save up to £725 annually on their electricity bills if they gave (or sold) stored power from their EVs back to the grid during peak hours.

There are several barriers to V2H and V2G. Bidirectional chargers are large, unsightly, and costly. The number of homes generating their own power is still relatively few, and few current EV models support bidirectional charging technology. Plus, given the complexity of power networks and the number of EV makers, the diversity of EV charging, and the number of electricity companies involved, co-ordinating energy price and exchange is an incredibly complicated operation.

A Smart Energy Future

Virtual power plants are pitched as a solution to managing grid pressure and would form part of a smart distribution network. The Power Potential R&D, project run by UK Power Networks and National Grid ESO, plans for renewable power operators within a region to be able to produce energy but also to be able to contribute to correcting problems with supply or voltage that occur within a network.

Virtual power plants can also consist of groups of EV chargers and enable V2G EV energy is trialling such systems that shift loads away from evening peaks, or that prioritize charging when renewables are creating a surplus.

Our net-zero emissions future and shift to EVs may rely predominantly on the strength of the technology supporting this societal change. Energy distribution networks, entire power grids, must become fully smart.

Eliminating energy waste, channelling surplus energy, and adjusting supply when demand is high can all be controlled automatically by integrated smart technologies.

This smart future is immediately possible. Bringing it to fruition, however, will rely on all stakeholders developing and implementing technologies that share the same design principles. Technologies must be able to easily communicate and work with one another, right from power plants down to EVs, chargers, and other devices at home.