Battery strategy goes flat: Net-zero target at risk Contents

Chapter 1: Introduction


1.Batteries and fuel cells are expected to play an important role in decarbonisation in many countries, including contributing to the UK’s goal of reaching net-zero greenhouse gas emissions by 2050. These two technologies would contribute to this objective by facilitating the use of low-carbon energy sources and improving the efficiency of energy systems. Batteries are used to store electrical energy for use at later times or on the move. They will allow low-carbon electricity to be used in more applications and with less waste. Fuel cells are devices that use a chemical fuel to generate electricity (and heat), more efficiently than many alternatives. They will allow wider use of fuels that can be manufactured by low-carbon processes; for example, hydrogen can be produced by electrolysis using renewable electricity (essentially the opposite process to a fuel cell), or in future by advanced nuclear reactors.1 Fuel cells coupled with electrolysers are already available as a scalable method of storing energy as hydrogen for the generation of electricity at a later time.

2.The focus in the UK and comparator countries has been on batteries for light road transport: for cars, and for vans to a lesser extent. A wider array of applications is envisaged for batteries and fuel cells in other modes of transport (heavy-duty road, rail, shipping and aviation, as well as off-road and industrial robots). The technologies can also be used in non-transport sectors (so-called ‘stationary applications’), for example to store and supply energy on networks and in buildings.

3.Changing from our current dependence on fossil fuels will be a significant undertaking. It has been made more urgent by the introduction of the targets to reduce emission by 78% by 2035 (compared to 1990 levels) and to reach net-zero emissions by 2050.2 The electricity generation mix must be decarbonised by 2035, and the supply of electricity must at least double by 2050. Following analysis by the Committee on Climate Change,3 the Government has decided that all new cars and vans sold from 2030 onwards will be powered by electricity or hydrogen, rising from 5% of sales today.4 For heavy transport and stationary applications, batteries and fuel cells are starting to be used, but further development is needed for solutions that can make sufficient impact. Shipping and aviation are yet further behind due to onerous technical requirements. Once solutions are identified for these sectors, they will have to be deployed at great pace to contribute to the UK’s 2050 net-zero target.

4.Transitioning to the use of batteries and fuel cells offers opportunities for countries that are developing these technologies. Research and innovation can be translated into commercial products, and industrial-scale manufacture can be expanded to meet domestic demand and potentially to allow export to other markets. Countries such as the UK are seeking to expand their industries in order to achieve these economic gains and avoid becoming reliant on imported technologies.

Structure of report

5.Chapter 2 of this report introduces batteries, fuel cells and their applications, and outlines the expectations of the people who use them. Chapter 3 delves into the detail of the technologies, examining likely future developments and their ability to meet users’ expectations. Chapter 4 examines the UK’s battery and fuel cell sectors to understand their requirements at all stages from research to manufacturing, and sets out global strategic issues that will affect these sectors’ ability to grow and to contribute to the UK’s decarbonisation ambitions.

6.We are grateful to all those who gave evidence to our inquiry. We also thank our specialist adviser, Professor Clare Grey FRS of the University of Cambridge.

Technical terms and useful data

7.This report discuses a number of technical matters. Terms are explained when first used, and a glossary is included at the end of the report. Some common terms and helpful data are presented in table 1.

Table 1: Technical terms and useful data

Term or data



A device that uses chemicals to store energy that can be released as electrical energy

Fuel cell

A device that reacts a chemical fuel (such as hydrogen) with another chemical (such as oxygen) without causing combustion, to produce electricity and heat


A device that uses electricity to break down chemicals, for example water into oxygen and hydrogen (the opposite of a fuel cell)

Orders of magnitude

Refers to quantities being 10, 100, 1,000, etc times larger or smaller. Prefixes are put in front of units: kilo (k) = thousand; mega (M) = million, giga (G) = billion, tera (T) = trillion i.e. 1 with 12 zeros, etc.


The total amount of work that can be done, such as lighting a light or turning a motor. The greater the energy available, the more work that can be done. The basic unit of energy in electrical engineering is the watt-hour (Wh). Larger amounts of energy are measured in units such as kilowatt-hours (kWh) i.e. one thousand watt-hours, megawatt-hours (MWh) i.e. one million watt-hours, etc.


How quickly work can be done: that is, power is the ‘energy per unit time’. The greater the power, the more rapidly work is being done. The basic unit of power is the watt (W). Larger amounts of power are measured in units such as kilowatt (kW) i.e. one thousand watts, megawatts (MW) i.e. one million watts, etc.

UK energy demand

In 2019, the UK used around 2,100 terawatt-hours (TWh) of energy. This includes all of the different sources and uses of energy. The biggest contributions to energy supply were from oil (44%, used mostly for transport) and natural gas (29%, used for heating and electricity generation).5

UK electricity demand

In 2019, total UK electricity demand was around 300 terawatt-hours (TWh). This electricity was supplied mainly by natural gas (40%), renewables (37%) and nuclear (17%). The use of electricity was split roughly into thirds between industry, homes and ‘other uses’.6

Household energy consumption

Based on data for 2018 and 2019, average annual household consumption was 3.1MWh for electricity and 12MWh for gas, for a household with ‘medium’ consumption and a single tariff electricity meter.7 For homes that do not have electrical heating, electricity demand equates to about 8–10 kWh per day, with some seasonal variation. Gas demand varies more significantly by season.

1 Hydrogen can be produced in several different ways. Currently the most common method is steam methane reforming (SMR) which uses heat to break up methane gas into hydrogen and carbon dioxide. The most widely available low-carbon method is electrolysis, whereby electricity is used to split water into hydrogen and oxygen. If the electricity is generated by low-carbon sources, then the hydrogen would be considered to be low-carbon. Hydrogen can also be produced via processes such as the ‘sulfur-iodine cycle’, the heat for which could be provided by some designs of advanced nuclear reactor. Some fuel cells use other chemicals such as ammonia or methane, which are produced by processes that could be decarbonised to some extent.

2 HM Government, ‘UK enshrines new target in law to slash emissions by 78% by 2035’ (20 April 2021): [accessed 14 July 2021]

3 The Committee on Climate Change (CCC) is an independent, statutory body established under the Climate Change Act 2008. Its purpose is to advise the UK and devolved governments on emissions targets, and to report to Parliament on progress made in reducing greenhouse gas emissions and preparing for and adapting to the impacts of climate change.

4 The Committee on Climate Change has forecast that the number of battery-electric vehicles in the UK will need to increase from around 5% of current sales to almost 100% by 2030. See Committee on Climate Change, The Sixth Carbon Budget: The UK’s path to Net Zero (9 December 2020) p 98: [accessed 2 July 2021]

5 Department for Business, Energy and Industrial Strategy, UK Energy Statistics, 2019 & Q4 2019 (26 March 2020): [accessed 7 July 2021]

6 Department for Business, Energy and Industrial Strategy, UK Energy Statistics, 2019 & Q4 2019 (26 March 2020): [accessed 7 July 2021]

7 Ofgem, Decision on revised Typical Domestic Consumption Values for gas and electricity and Economy 7 consumption split (6 January 2020): [accessed 8 July 2021]

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