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Environment and Energy



Facts and figures

We have compiled these Facts & Figures to help you find out how much energy you can save from simple actions such as switching off lights and equipment

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Energy at the University of Cambridge


Total electricity consumption by the University was 136.9 GWh in 2017/18...

  • That's equivalent to 36,614 homes or 78% of the whole of Cambridge’s domestic electricity demand (there are 46700 homes in Cambridge according to the last census), or 0.043% of UK power demand (the UK consumed 319 TWh of electricity in 2017).
  • The tour de France peloton would need to ride continuously for 183.7 years to produce this amount of power. (Average pro-cyclist output of 429Watts, 198 riders in tour)
  • Approximately 57% of electricity is used during the day, 18% at weekday night and 18% at weekend day and 7% weekend night.  
  • The biggest single building electricity user is West Cambridge Data Centre, using 9 GWh elec
  • The 10 largest electricity supplies within the University account for 71.3GWh (52% of total consumption). The two largest are Chemistry and Physics.
  • The University produces 595,219 kWh of energy from solar power across the estate. This is enough electricity to power the Department of Pharmacology (Building E030 Tennis Court Road) for a year!


Total gas consumption by the University was 99.6GWh in 2017/18...

  • That's equivalent to 7,476 homes.
  • The 8.94million m3 of gas consumed is nearly the volume of Kings College chapel each day! (Or it's enough to 3192 hot air balloons).
  • 53% of gas is used during week days. 22% on week day nights, 17% weekend days and 8% weekend nights.
  • The largest single gas supply is CRUK with 9GWh.
  • The 10 largest gas users account for 47% of total use.

Electrical devices and appliances

View our template Lighting and Resources Responsibility Plan, and identify who has responsibility for ensuring which equipment is switched off:

 Download 'Lighting and Equipment Responsibility Plan (template)'


Mobile phone chargers, laptop docking stations and some desktop printers use energy regardless of whether they are charging or not because the voltage transformers on the plug consume energy. This is known as electrical leakage.


Reducing your PC monitor brightness from 100% to 70% can save up to 20% of the energy the monitor uses. (Harvard)

By setting all University staff PC monitors to go to sleep after 10 minutes instead of 30, we could save over £3000 each year.

By setting all University PC monitors to go to sleep after 10 minutes instead of 30, each year we could:

  • save more CO2 than is produced by a plane flying from London to Paris.
  • save enough energy to run all streetlights in Cambridge for four nights.
A third of a PC’s energy is used by the monitor.

A PC monitor left on overnight can waste enough electricity to laser print over 500 pages. (Energy Saving Trust)

Energy from devices such as computers left on standby account for 5-10% of the total electricity used in residential homes and accounts for about 1% of the world’s carbon dioxide emissions. (Lawrence Berkeley National Laboratory)

Leaving a computer on overnight for a year creates enough CO2 to fill a double-decker bus. (The Carbon Trust)

Old CRT monitors use more than three time as much energy as LCD monitors.

Mythbuster: "Screensavers save energy"


If everyone boiled only the water they needed every time they used the kettle, we could save enough electricity in a year to power the UK’s street lights for nearly seven months. (Energy Saving Trust)

If all staff at Cambridge only filled their kettles to the amount needed:

  • we could avoid the equivalent in greenhouse gas emissions of four London–Paris flights each year.
  • we could save £20,000 on electricity bills.

If all students at Cambridge only filled their kettles to the amount needed:

  • we could avoid the equivalent in greenhouse gas emissions of 16 London–Paris flights each year.
  • it could save the University £80,000 on electricity bills.

Photocopiers and printers

Turning your photocopiers and printers from standby to off overnight can save enough energy to power both your LCD TV and your refrigerator at once.

Leaving your photocopier on standby overnight:

  • releases as much greenhouse gas over a year as driving from Cambridge to Paris and back again.
  • wastes enough energy to make 30 cups of tea. (The Carbon Trust)

A photocopier left on overnight uses enough energy to produce over 1500 copies. (The Carbon Trust)

If a photocopier is left on all day and used for 20% of that time, it will account for about £350 of energy each year. Switch it off overnight and at the weekends when possible.

Try to source photocopiers which use a low melting point toner. These can save up to 40% of the energy used by reducing the warm up time, which also reduces staff waiting time because copying and printing have a faster recovery time from stand-by mode.

Heating and cooling


Air conditioning an office for one extra hour a day uses enough energy in a month to power a TV for over a year. (The Carbon Trust)

Air conditioned buildings use roughly twice as much energy as naturally ventilated ones. (Royal Institute of British Architects)

Electric heaters

Electric heaters can significantly interfere with the building’s main heating system – depending on locations, using an electric heater can send a message to the thermostat that the building/ that part of the building is at temperature or too warm, meaning that the central heating gets turned off! This makes the user of the heater and their colleagues feel even colder.

This is the main reason that Maintenance do not want staff using these heaters – not just because they are energy intensive!

Electric heaters can produce twice as much greenhouse gas as central heating.

Electric heaters can be up to three times as expensive as central heating.


Leaving your fan running overnight over the summer wastes enough energy to:

  • run an LCD TV over the same period.
  • power your iPhone for 25 years.
  • power your laptop for a year.

It would take a tree more than a year to absorb all the CO2 emitted by a single fan left on overnight over a summer.


Facts from The Carbon Trust

Turning the thermostat down 1°C saves 8% in heating costs, not to mention the CO2 emissions spared.

A 2°C increase in office temperature creates enough CO2 in a year to fill a hot air balloon.

Nearly 50% of the CO2 emissions produced by the UK come from heating and cooling in buildings.

A typical window left open overnight in winter will waste enough energy to drive a small car over 35 miles.

The University's Thermal Comfort Policy sets out our expectations for temperatures within University buildings. It gives suggestions of how to monitor and adapt your environment, as well as contact details to report any issues.


Each light left on overnight over a year costs your department £24.

A single light left on overnight over a year accounts for as much greenhouse gas as a car drive from Cambridge to Paris.

A small department can save over £1,000 each year by ensuring that lights are not left on overnight.

If you ensure that just 4 lights around your workspace are switched off every night, each year you could:

  • save as much CO2 as produced by 20 car trips from London to Paris.
  • reduce your carbon footprint by the same amount as cutting out 10 flights from London to Paris.

If you ensure that 10 lights around your workspace are switched off every night, each year you could:

  • save as much CO2 as would be produced by a car trip from Cambridge to Moscow and back.
  • save as much CO2 as would be produced by 50 car journeys from Cambridge to London.
  • reduce your carbon footprint by as much as you would by cutting out two flights from London to New York.
  • reduce your carbon footprint by the same amount as cutting out 25 flights from London to Paris.

Lighting a typical office overnight wastes enough energy to heat water for 1,000 cups of tea. (The Carbon Trust)

Office lights left on overnight use enough energy in a year to heat a home for almost 5 months. (Energy Saving Trust)

The UK wastes £170 million a year by leaving lights on unnecessarily. (Energy Saving Trust)

Turning off unneeded lights could remove 171 kg (376 lb) of CO2 emissions per year. (Energy Saving Trust)

FALSE: "Leaving fluorescent lights on saves energy"

If you would find stickers or posters helpful in encouraging building users to switch on to switching off, we have these available:

Lab equipment


Check your freezers for efficiency, temperature setting, and age: work with us to help replace outdated equipment and make sure that everything else is running at peak efficiency.

 Download 'Ultra Low Freezer Management Guide'

Chilling up your ultra-low freezer from -80°C to -70°C can reduce energy consumption by 30% and prolong freezer life.

Fifteen years ago all ultra-low freezers were set to -65°C or -70°C. The drive to continually lower freezer temperatures has more to do with marketing and selling freezers than it has to do with science. (My Green Lab)

When new, ultra-low freezers consume approximately 16 to 22 kWh per day – about as much as the average family household. After years of service, they typically consume 30 kWh per day.

Outdated Ultra Low Temperature freezers guzzle two to four times as much energy as a normal freezer to do so.

Poor maintenance of freezers can increase condensing temperature or reduce evaporating temperature by several degrees, resulting in an increase in energy use of up to 10%.

Increasing the temperature of your Ultra Low Freezer by 10°C can save you the amount of energy used by one standard freezer.

Other lab equipment: top tips

Remember that the cheapest and greenest piece of equipment is one that you don’t need to buy:

  • Can you run a lab space efficiency audit before authorising purchases?
  • Can enough space be made in existing fridges or freezers by removing out-of-date or unknown samples to avoid a new purchase?

Declutter fridges and freezers: dispose of redundant samples and make sure those that are left aren’t being stored at temperatures colder than they need.

Share lab equipment if practical – try to avoid having a single sample in each shaker, stirrer or centrifuge.

Don’t make excessive use of glassware – it takes energy to heat and treat water to wash it.

Only use drying ovens for already-dry glassware. Initially drying in a drying cabinet makes the drying ovens more efficient for everyone, as there is reduced evaporated moisture for the oven to deal with.

Fit timers to your drying ovens so that they don't run overnight and at weekends if not needed. Consider replacing with modern versions that heat to temperature quickly.

Labs and water saving

Labs can consume significant amounts of water, and there is potential for wastage through leakage, oversight or choice of equipment. Often savings can be made at very little additional cost. LabRATS demonstrate that poor sample rinsing practices can lead to significant water waste, as well as dirty samples. Read more:

Climate Change

Every National Academy of Science of every major country in the world confirms that human activities are the main source of climate change and that the burning of fossil fuels is largely responsible for driving this change. One of the priority areas in The University of Cambridge’s Sustainability Vision, Policy and Strategy is to reduce carbon emissions, therefore helping to reduce its contribution to climate change. As well as this, the University carries out significant research activity around climate change and sustainability, through academic centres and networks, industry-facing research, and programmes of student activity. Read more about the University of Cambridge's academic activity around energy efficiency and sustainability.

(Facts from Global Action Plan)

Our responsibility

The UK produces around 2% of global greenhouse gas emissions – it’s the 8th largest emitter in the world.
Per year, the average person in the UK emits 9.8 tonnes of CO2 – that’s double the global average.
Developing countries are only a part of the problem. China, for example, produces less emissions per person than the USA, the UK and Australia.

Climate change in the UK

2014 was the warmest year on record for UK land and coastal waters.
2014 was the fourth wettest year on record for the UK.
8 of the 10 warmest years for the UK have occurred since 2002 and all the top ten warmest years have occurred since 1990.
7 of the 10 wettest years for the UK have occurred since 1998.
Mean sea level around the UK rose by 1.4 millimetres per year (mm/yr) in the 20th Century, when corrected for land movement.

Source: Met Office

Waste and Recycling

From 2014 to 2015, 2,482 tonnes of waste was collected from bins on University sites. That’s the weight of the London Eye, or to give it some Cambridge perspective.

If our waste was collected by punts on the Cam, we would need 6,128 punts to collect it all!

It would be enough waste to fill King’s College chapel 37 feet deep!

Fortunately, 903 tonnes of this was recycled, that’s equivalent to the weight of all of the University of Cambridge’s 12,000 undergraduate students put together!

The UK produces more than 100 million tonnes of waste every year.

In less than two hours, waste produced in the UK would fill the Albert Hall in London!

Compared to virgin paper, each ton (1000kg) of recycled paper can save 17 trees, 380 gallons of oil, three cubic yards of landfill space, 4000 kilowatts of energy, and 7000 gallons of water.

Find out more about waste and recycling at the University by visiting our Waste and Recycling page.


A 15-second lift journey consumes as much energy as a 60W light bulb does in an hour.