Electric cars and grid power capacity

Question

The UK has a target to be carbon-neutral by 2050:

As we can see in the image large cuts across all type of CO2 emissions are required. This article by the BBC suggests a number of ways in which this could be achieved.

One particular claim is that the UK "won't need to overhaul [its] motoring habits" but will need to use electric cars. While in itself this seems reasonable, the electricity capacity in the UK is already described by some as stretched with the possibility of blackouts in the future.

Given that electric cars will require a significant amount of electricity (possibly exceeding on their own the current capacity of the grid):

1. How is the UK planning to accommodate this level of demand whilst also reducing supply from CO2 producing sources?
2. Are there any estimates of how large the increase in demand will be to power wide spread use of electric cars?

Answer 1

National Grid supplies the energy for the UK, and also manages the high voltage power transmission system. Each year, they prepare a Future Energy Scenarios report looking at energy needs across the UK and the different alternatives for how those needs can be met. The most recent FES was published in July 2018, and is the source for the figures and quotes below.

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Widespread adoption of electric vehicles will increase energy consumption by 30%

The FES includes two possible future scenarios with heavy EV adoption -- "Community Renewables" (envisioning widespread energy decentralization) and "Two Degrees" (focused on a centralized model for limiting global warming to 2C). In these two scenarios, the UK meets the goal of ending sales of gas and diesel powered vehicles by 2040.

This table shows 2017 demand (for all sectors) and expected growth in the transport sector by scenario:

An interesting aspect of the model is that early, aggressive adoption of EVs reduces the total peak demand, because of smart charging and vehicle-to-grid (V2G) technology:

In all our scenarios, peak demand from EVs is managed through smart charging. This behaviour is more evident in our two 2050 compliant scenarios, reducing peak demand by 8 GW in 2030. By 2040 this saving would stabilise at 32 GW.

The increase in electricity demand from EVs will be met mostly with wind power

This figure shows how the generation mix is expected to change in the "Community Renewables" scenario:

You can see that the greatest growth comes in the form of wind (on- and off-shore) and solar capacity, with coal generation eliminated by 2025, and natural gas diminishing to a fraction of its current capacity by 2035. The description in the text reads (emphasis added):

Figure 5.2 shows the annual electricity output of different generation technologies and their carbon intensity in the Community Renewables scenario. Here, the electrification of transport and heat increases demand, leading to higher generation output being produced to meet demand.

By 2030, renewable generation, particularly wind and to a lesser extent solar, makes up more than 75 per cent of generation output. By 2030, the carbon intensity of electricity has fallen to 75 grams of CO2/kWh, and then continues to fall to reach 32 grams of CO2/kWh by 2050.

In the "Two Degrees" scenario, off-shore wind and nuclear make up a larger share, with on-shore wind supplying less, and solar about the same.

Answer 2

It has been previously suggested that large numbers of electric-vehicles can charge overnight without overloading the power-grid.

Then within the context of charging overnight, the current trend of charging-stations-everywhere seems goofy.

Also, hydrogen fuel-cell electric-vehicles can be expected to become popular. Fuel-cell vehicles with nickel-metal hydride batteries are less risk of fire than lithium-battery electric-vehicles. And fuel-cell vehicles are quick fueling and have long driving ranges. Fuel-cell vehicles can weigh less since they have fewer batteries.

Then production of hydrogen can be by electrolysis of water which requires electricity or production of hydrogen can be by steam-reforming of natural-gas which requires heat. However, steam-reforming of natural-gas does release some amount of carbon.

Consider ethanol derived from sorghum and reformed into hydrogen and that could be carbon neutral. Of course the growing of sorghum requires land-use but sorghum only requires 25 inches of annual rainfall.

The question arises that since we keep finding oil then what is gasoline going to be used for ? Maybe gasoline will be run in gas-turbines at 60% efficiency to produce electricity ? Of course hydrogen could be run in fuel-cells to produce electricity at 85% efficiency. These efficiencies are based on using waste heat in an additional process and that is what a vehicle does not do.