Electric Vehicles – Driving Instability on the UK Electricity Grid?

With a drive to, and incentivization, for UK drivers to move towards electric vehicles, questions may be asked as to how stable the UK electricity supply is and what these increases on the electrical grid may mean for UK residents and businesses.

The UK new car market has been undergoing turbulent shifts with registrations of diesel vehicles down for the 28th consecutive month in August 2019 with a decline of -22.1% upon August 2018. Whilst hybrid electric car registrations increased by a substantial 34.2% with 7,758 joining UK roads in August 2018, the demand for battery electric vehicles rose an impressive 158.1%. The rise of consumer confidence in electric vehicles is likely to continue into 2020, according to the Society of Motor Manufacturers and Traders (SMMT), who predict that battery electric vehicles will double their market share and see 51,000 registrations next year (SMMT, 2019).

With seismic changes to the transportation industry in the UK, how will this affect the UK electricity supply?

McKinsey & Company, the worldwide management consultancy firm, carried out research into the impact of electric vehicles in 2018 which identified that “the uptake in electric vehicles is unlikely to cause a significant increase in total power demand, however, it will likely reshape the electricity load curve” (Engel et al, 2018) with a rise in electricity consumption in the evening when people plug their electric vehicles in to charge upon returning home from work/ or after their day’s errands.

Although electric vehicle adoption is forecast to increase the changing load curve, it is likely to be extremely regionalised with high concentrations occurring in cities and suburban areas – reflective of residential areas and “other concentration points of EV charging such as public EV-fast-charging stations and commercial-vehicle depots” (Engel, et al, 2018).

McKinsey and Company performed an analysis on how residential adoption would affect a typical residential feeder circuit of 150 homes with 25% local electric vehicle penetration resulting in an increase of approximately 30% on the local peak load. This research also additionally identified that “beyond peak-load increases, the highly volatile and spiky load profiles of public fast-charging stations will also require additional system balancing” (Engel, et al, 2018). If not managed, substation peak-load increases from EV-charging power demand will potentially push local transformers beyond their capacity and as such will require upgrading to cope with fluctuations and poor power supplies.

Changes to the load curve will ultimately result in voltage sags and swells, which will almost certainly cause power quality problems for many users, particularly those at the end of the power line.

In recent years, the UK has already undergone major changes in its generation of electricity with increases in renewable energies such as solar and wind energy. By harnessing the volatility of these generation methods, the UK could look to address the potential fluctuations which may be caused by the increase in electric vehicle charging through partnering the charging patterns in accordance with weather conditions i.e. reducing charging opportunities through incentives in times of minimum electricity generation such as in the early evenings in the winter when there is no sun present. This could look to address instabilities and reduce peak loads which could cause problems on the power network.

Additionally, as the UK starts to address climate change goals with initiatives including the replacement of gas boilers with electric ones – a move to address the 14% of greenhouse gases that come from our homes (Harrabin, 2019) – further instability will be added to the UK power network.

For now, whilst the new UK car market continues its overall decline due to continuing economic uncertainty it appears that the biggest threat to the stability of the UK power networks lies within the renewable energies which already cause fluctuations on the line and not an increase in electric vehicles. Despite this, it appears apparent that the once relatively-stable UK electricity supply will become more and more erratic and as such increasing numbers of voltage stabilizers will be required in businesses, and possibly remote and rural homes, to cope with these unpredictable fluctuations.

References
Engel, H., Hensley, R., Knupfer, S. and Sahdev, S. (2018). The potential impact of electric vehicles on global energy systems. [online] McKinsey & Company. Available at: https://www.mckinsey.com/industries/automotive-and-assembly/our-insights/the-potential-impact-of-electric-vehicles-on-global-energy-systems [Accessed 31 Oct. 2019].

Harrabin, R. (2019). Central heating boilers ‘threaten climate goals’. [online] BBC News. Available at: https://www.bbc.co.uk/news/business-50041077 [Accessed 4 Nov. 2019].

SMMT. (2019). New car market declines in July but pure EV registrations almost triple – SMMT. [online] Available at: https://www.smmt.co.uk/2019/08/new-car-market-declines-in-july-but-pure-ev-registrations-almost-triple/ [Accessed 31 Oct. 2019].