Performance – environmental sustainability

Our responsible business strategy covers 5 key areas – environment, community, people, economy and governance. Our environmental responsibilities build on previous commitments outlined in Our Contribution, our previous Environmental Sustainability strategy.

The metrics on this page help us monitor and evaluate our performance across a range of different environmental matters. 

We independently assure our greenhouse gas emissions against the international standard ISO 14064-3 greenhouse gas assurance protocol. Read the verification of our 2019/20 Greenhouse Gas Emissions.

Climate Change

We know that by working together and sharing resources, National Grid can enable a fair and affordable transition to a clean energy economy and reduce our own emissions.

We consider climate change risks and opportunities in terms of physical and transition risks. Our third disclosure against the recommendations of the Task Force on Climate-related Financial Disclosures (TCFD) in full and our disclosure is available in our 2019/20 Annual Report on pages 57 to 62.

In the short term, physical risks are most relevant and we are principally focused on the risks from weather-related events in the US, and flooding events (in both the UK and US). We will actively update our understanding of potential risks by drawing on the UK Climate Projections 18 and are investigating other potential risks such as the impact of rising temperatures and widening temperature ranges on the performance and operation of the equipment on our networks. The ongoing monitoring and appropriate mitigation of the risks from a changing climate is part of day-to-day business risk management processes. We have previously responded to the UK government climate adaption reporting process, with our most recent response in 2016. We will be providing an updated response in 2021. 

Scope 1 and 2 greenhouse gas emissions

Having outperformed our 2020 target by 25%, we have redefined our targets to reflect the greater ambition of the company. We now aim to achieve net zero by 2050, with new interim reduction targets of 80% by 2030 and 90% by 2040, from a 1990 baseline. Our Scope 1 and 2 target aligns to a well-below two degrees pathway consistent with the ambition requirements of the Paris Agreement and Science Based Targets initiative (SBTi).

Our Scope 1 and 2 greenhouse gas emissions are reported in line with the WRI/WBCSD Greenhouse Gas Protocol Corporate Standard for all six Kyoto gases and using the operational control approach for emissions accounting. These Scope 1 and 2 emissions are independently assured against the international standard ISO14064-3 Greenhouse Gas Assurance Protocol.

Our total Scope 1 and 2 emissions (including line losses) for 2019/20 were around 6.5 million tonnes of carbon dioxide equivalent (CO2e). This represents a 70% reduction on our 1990 baseline. 

Greenhouse gas emissions (Scope 1 and 2 million tonnes of carbon dioxide equivalent)
Greenhouse emissions - graph 1

Breakdown of emissions 2019/20
Emissions - graph 2
Scope 3 greenhouse gas emissions

Our Scope 3 greenhouse gas emissions are reported in line with the WRI/WBCSD Greenhouse Gas Protocol Corporate Value Chain (Scope 3) Standard. We independently verify all our Scope 3 emissions. 

Our Scope 3 emissions for 2019/20 were 29.8 million tonnes carbon dioxide equivalent (2018/19: 30.1 million tonnes), and consisted of: 

  • around 5.4 million tonnes associated with the procurement of goods and services 

  • around 24.3 million tonnes associated with sold product (gas and electricity) 

  • other Scope 3 emissions of around 0.0804 million tonnes, including business travel using third party carriers, employee commuting and waste 

Changes to some Scope 3 emissions can be attributed to modifications in the emissions factor used, as well as further improvements to collection of Scope 3 data. Our historic data has not been re-baselined to reflect these changes.

Most of our Scope 3 emissions are emitted from two key business activities - the sale of gas and electricity to customers in the US (82%) and the purchase of goods and services (18%).  Business travel, employee commuting and waste in comparison account for 0.3%.

In the US, our energy efficiency programmes are making a real difference in helping our customers reduce their energy use. The American Council for an Energy-Efficient Economy (ACEEE) scored all three states that we operate in among the top five for energy efficiency, with Massachusetts ranked at number one.

Scope 3 emissions customer use (bottom data) supply chain use (top data) (million tonnes CO2e)
Scope 3 graph

Scope 3 emissions other (million tonnes CO2e)

Other scope emissions graph 2
Sulphur hexafluoride (SF6)

SF6 is an extremely effective electrical insulator and has significant advantages over alternative materials. It's non-flammable – a critical requirement in the high-voltage applications where we use it – and because of its effectiveness takes up less volume than an equivalent insulating volume of an oil alternative.

However, SF6 is a greenhouse gas – one tonne is equivalent to approximately 22,800 tonnes of carbon dioxide. It does leak in very small volumes from our assets. Therefore, we’re exploring new initiatives and SF6 alternatives that will facilitate a net zero transmission system. 

Sulphur hexafluoride losses (tonnes) 
Global SF6 losses graph 1



Energy use

Our energy use is primarily gas and oil consumption in our US generation facilities.

Our generation facilities on Long Island used approximately 12.3 million MWh of natural gas and 0.6 million MWh of fuel oil during 2019/20.

Our non-generation energy is used mainly by our gas-fuelled compressors at the Isle of Grain LNG import terminal.

In 2019/20 we used approximately 1.6 million MWh of gas and 0.7 million MWh of electricity in our non-generation activities.


Fuel used for transport 

As part of our commitment to reduce our fleet emissions, the UK Electricity Transmission business has purchased its first electric vehicles (EVs). This is the start of an ongoing programme to replace our conventional internal combustion engine (ICE) fleet with alternative fuel vehicles (AFVs). 

During 2019/20, we used 42.9 million litres (2018/19: 35.5 million litres) of petrol and diesel for our commercial fleet.

The reduction seen in 2017/18 is predominantly due to the sale of our UK Gas Distribution business. This meant our fleet inventory reduced by 7,000 vehicles. Previous years data have not been adjusted to reflect the sale of our Gas Distribution business.

Fuel used by transport (million litres)
Fuel used by transport graph 1
Water use

Most of the water we use is for cooling at our generation facilities in the US and electricity cables in the UK. This water is returned to source after use, so equates to zero consumption. Our water data is reported on a calendar year basis.

Water consumed 

During 2019, we consumed approximately 1.76 million cubic metres (mcm) of fresh water for both operational and non-operational purposes across our operations, compared with 1.74 mcm in 2018. This equates to some 121.02 cubic metres per £ million of revenue (2018/19: 116.52 cubic metres per £ million of revenue).

Cooling water

During 2019, we extracted and returned to source around 1,226 mcm of sea water (2018: 1,1315 mcm) used as cooling water at our US generation facilities. We also extracted and returned to source 2.76 mcm of surface water at our UK operational sites.

Water consumption
Water consumption graph 1







Water used for cooling (million cubic metres) 
Water used for cooling- graph 2
ISO 14001

We have environmental management systems certified to the international standard ISO 14001.

100% of our material regulated operations are covered by ISO 14001 environmental management systems.

NOx & SOx emissions

Our material emissions of NOx are from our generating facilities in the US, which are also our only material source of SOx.

In 2019/20, we emitted around 1,958 tonnes of NOx and 305 tonnes of SOx, compared with 2,565 and 1,602 tonnes respectively in 2018/19.

NOx emissions (tonnes)
NOx emissions graph 1





SOx emissions (tonnes)
SOx emissions - graph 2
Customer energy efficiency

National Grid offers many electricity and natural gas energy-efficiency programmes for residential and business customers. For residential customers, the programmes offer various incentives and assistance to make homes more energy efficient; through lighting, appliances, high-efficiency heating equipment and water heaters, boiler controls, and insulating and sealing measures. For business customers, our electricity and natural gas energy efficiency programmes can help improve efficiency at existing or new facilities; by lowering operation and maintenance costs through efficient lighting and controls, heating systems, heating, ventilation and air conditioning (HVAC), windows and insulation instalments, and by participating in other industry-specific efficiency installations and programmes.

During the 2019 calendar year, participation in National Grid’s gas energy efficiency programmes had a 25% decrease over 2018 with 1.3 million participants.  In 2019, there were 6.7 million participants in the Company’s electric energy efficiency programmes, which was a 72% increase from 2018 (mainly due to the large number of residential lighting measures which do not count unique participants but use a proxy of number of bulbs per participant).  Combined, this resulted in 8 million participants in the gas and electric programmes. 

Through participation in these programmes, during the 2019 calendar year customers saved over 43 million annual therms of gas and over 1.4 million annual megawatt-hours of electricity.  These equate to 256,794 tonnes and 634,164 tonnes CO2e respectively using state-specific conversion factors.   

More information on our US energy efficiency programmes can be found via the energy service and regions links on our US website.

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