Means for calculating the carbon footprint
1.Introduction
The prospect of calculating your organisation’s carbon footprint can be a daunting one and this document sets out a definition of, and means for,organisations to calculate their carbon footprint.
In most instances establishing a value for one element of your emissions will be a relatively straightforward task, in other cases in will not be so straightforward.
In an effort to standardise calculations all sources of energy are converted into, and displayed as, their equivalent quantity in Carbon Dioxide (CO2) and expressed as CO2e.
2.Baseline year
2.1Where the differences lie
With different baseline years to work to it would not appear possible to align the requirements of the CCA with the CRS. However the update to the CRS[1] shows a graph of NHS CO2e since 1990. Funding in the NHS was still in decline until the mid 1990s after which the trend reversed. Emissions followed a similar pattern and emissions in 2007 were the same as 1990. It should be pointed out this trend is only applicable to the NHS; other organisations should remove 1% for each year before the baseline year back to 1990. This is because energy consumption increases by an average of 1% each year but does not take into consideration any expansion in the Trust, i.e. increasing staff and activity levels that in turn lead to increased building space.
2.2Establishing the baseline figures.
The means for tackling the time gap between the 1990 baseline and the baseline your Trust chooses as their baseline year you should add 1% of the calculated carbon footprint for each year back to 2007. So if you choose to use 2008 as your baseline year then you must remove 1% from your calculated carbon footprint for 2008.
The Sustainable Development Unit (SDU) has recommended using 2007 as a baseline year.
The targets for the CCA are to reduce CO2eemissions by 34% based on the 1990 baseline year by 2020 and by 80% by 2050. This means that to meet the first target of the CCA you will have to reduce your Trust’s emissions by 52% by 2020.
3.What is a carbon footprint
From The Carbon Trust website:
A ‘carbon footprint’ measures the total greenhouse gas emissions caused directly and indirectly by a person, organisation, event or product.
The footprint considers all six of the Kyoto Protocol greenhouse gases:
Carbon dioxide (CO2),
Methane (CH4),
Nitrous oxide (N2O),
Hydrofluorocarbons (HFCs),
Perfluorocarbons (PFCs),
Sulphur hexafluoride (SF6).
The six GHG are referred to as the GHG basket.
The carbon footprint is expressed in tonnes of carbon dioxideequivalent (CO2e).CO2e means the emissions from combustion or leakage of a gas, liquid or fuel expressed as an equivalent measure of CO2. Methane is 23 times more damaging as a Greenhouse Gas (GHG) than CO2; therefore a tonne of methane equals 23 tonnes of CO2e.
Below is a table that lists the GHG basket along with the CO2 equivalence.
Greenhouse gas / Chemical symbol / EquivalenceCarbon Dioxide / CO2 / 1
Methane / CH4 / 23
Nitrous Oxide / N20 / 310
Hydrofluorocarbons / HFC / 140 - 11,700
Perflurorocarbons / PFC / 6,500 - 9,200
Sulphur hexafluoride / SF6 / 23,900
In practical terms it is unlikely that Trust’s emit significant quantities of GHG other than CO2 though air conditioning systems as well as some clinical procedures should be checked for the gases they use.
4.What needs to be calculated?
4.1Buildings
The Trust estate is the easiest direct source to calculate but some definition is required. It is recommended only buildings that are occupied or used by the Trust should be included in the calculation. If you have a building in your estate that is not occupied by your staff and not consuming any energy, or not wholly used by your Trust then this building should not be included in the calculation for your carbon footprint.
Most of the data is available on ERIC but I would only use this if you are confident the data is accurate.
4.1.1Fully occupied buildings
Use the utility bills for each building. From the utility bills extract the consumption data and use the table in Annex A to convert your consumption into CO2e.
4.1.2 Partially occupied buildings
A partially occupied building is one where two or more organisations share the building and the emissions are needed to be calculated for each organisation. For this situation it is recommended the heated volume is used as a means of determining how much carbon yourorganisationis responsible for.
Calculate the occupied volume for the entire building and proportion the utility cost according to the volume your organisation occupies. If a building has a heated volume of 2000m3 and your organisation occupies 500m3 then your organisation is responsible for 25% of the emissions. Where there are shared areas such as reception and hallways it is recommended that this volume is split equally between the occupying organisations.
If the area your organisation occupies is metered separately then use the utility bills generated for that area. Add on any shared areas, calculated using the method described above.
It is suggested that as long as healthcare services are being contracted directly or indirectly by the NHS then the proportion of the footprint allocated to the Trust should be included in the Trust’s footprint.
If for example a non-NHS organisation is contracted to deliver health services to the Trust and the Trust only accounts for 25% of the contracting organisations CO2e, then the 25% is added to the Trust footprint.
4.1.3Empty or Void buildings
If you have a building in your estate that is empty and not consuming neither energy nor water then this building should not be included in your footprint calculation. If the building is empty and consuming energy and/or water then it does need to be included.
4.1.4Air conditioning
Air conditioning units leak refrigerants and are measured Ozone Depleting Potential (ODP) not CO2e. If you know what family of gases the refrigerants live then the volume leaked from a system can be calculated. The amount of source energy an air conditioning unit uses can be measured.
4.2Vehicles
Calculating emissions from the fleet operated within your organisation relies on knowing how many miles are being drivenand the vehicles being usedor volumes of fuel consumed.
It also relies on being able to distinguish between vehicles used daily for commercial activities, such as delivering goods and vehicles used for mixed business and private use. In the main, mixed use is satisfied by leased vehicles and mileage allowances. To distinguish between the fleet types they are referred to as Commercial and Grey.
A reliable source of emissions data is available from Carfueldata.org.uk website[2] or the Travelfootprint.org website[3]. Both these websites quote current production models. The emissions figures are quoted in grams of CO2emitted per kilometre.
Quoted emissions figures for a given vehicle reflect an average emission and not one that accurately reflects the actual emissions. If a vehicle is quoted as having an emission of 165 g/CO2/Km that is an average calculated under test conditions and do not represent real life. In a bid to compensate for this DEFRA, in their publication ‘Guidelines to Defra/DECC’s GHG Conversion Factors for Company Reporting: Methodology Paper for Emission Factors’[4] recommends, on page 25, adding 15.5% to published emissions figures to reflect the real world situation.
4.2.1Commercial Fleet
The most accurate measure of emissions from your fleet is by calculating the emissions from the amount of fuel you use. Each litre of diesel burnt produces 2.38 Kg of CO2 and each litre of petrol burned produces 2.3 Kg of CO2.
To establish the total CO2 emissions from your commercial fleet multiply the quantity of fuel used by the conversion factor; 2.38 for each litre of diesel and 2.3 for each litre of petrol.
4.2.2Grey Fleet
Unless you have access to figures that reflect the amount of fuel used, i.e. fuel card or receipts, you will have to use the manufacturers quoted emissions figure and multiply it by the distance driven. Once you have done this multiply the result by 1.155 to add the recommended 15.5% weighting. This only applies to business related mileage.
4.3Travel
4.3.1Staff travel
Calculating the emissions created by staff travelling to and from work will require some work to be carried out. In order to get an accurate picture you will need to know.
- The postcode of the usual residential address. There are a number of websites that offer a free distance calculator based on two postcodes. Click HERE[5], HERE[6] or HERE[7] for three of them.
- The journeys made to and from work in a year. This will require removing holiday allocation and ideally and absenteeism.
- If using a car to travel to work then the make, model and fuel type. Please note that the Department of Transport does not currently require exhaust emissions to be published for motorbikes and should therefore be exempt. Cyclists can be exempt but not those who travel by public transport or use electrically powered vehicles. These are included below. It will also be necessary to take into consideration any car sharing schemes as two people using one car represent a reduction in emissions.
It is impractical to get involved in trying to calculate complex journeys involving more than one form of transport and accordingly this has been discounted, from this exercise. However, if a significant number of your staff have complex journeys then you may consider including them in the calculation.
4.3.1.1Electric vehicles
For staff using electrically powered vehicles, take the power consumed in charging the vehicle and multiply the kilowatt hour by the conversion factor in the table in Annex A. It is accepted that currently few members of staff will be using electric vehicles; however, this method applies to any electrically powered vehicle used by your organisation.
4.3.1.2Public transport
Bus – Table 2 in Annex A quotes figures for three types of travel. A local bus is a single decked vehicle with seating for less than 30 passengers. A coach would be a vehicle with one or more decks that has been designed to travel between towns rather than within a town. All other buses are considered as London buses.
Train – Rable 4 in Annex A details the four main train types used on the UK rail network.
Boat – Table 5 in Annex A details the emissions for both foot and car passenger. The distinction here is that being on foot is considerably less polluting.
Plane–Table 3 in Annex A lists the emission per passenger Km for the three most common flight types.
4.3.2Visitor travel
There are three types of visitors to hospitals, out and inpatients, relatives visiting patients and business visitors.
Surveying business visitors is a matter of asking each visitor to supply the postcode they travelled from and the form of transport they took. If a car then ask for the make and model.
It is not feasible to consider constant monitoring of patient visitor travel so it is recommended that a quarterly survey is carried out to determine how far visitors have travelled to your organisation.
It is envisaged that most patient visitors will arrive in a private car or a taxi, though some will have used public transport. Some sensitivity needs to be employed in conducting a survey as visitors will potentially be in an uncomfortable frame of mind, being concerned for their relatives and in and outpatients may be concerned about the reason or outcome of visiting a specialist or clinic.
4.4Waste
Waste is problematic as there are many variables and there is a debate surrounding the net value of emissions. In general it is recommended that all aspects of waste are not included.
Waste does need to be approached holistically as a separate subject. Food waste can be used to feed bio digesters, producing methane which is burned and used to produce electricity, which is a benefit. But if more emissions are released transporting the food waste to the bio-digester then clearly the benefit is lost.
The same arguments apply to recyclable waste too. The benefit then is not in reducing emissions but in reducing landfill and using the resource productively.
It should be pointed out that any contractor providing a waste collection service will be under contract and that contract should include carbon emission monitoring performance data. The contractors should also be required to calculate their carbon footprint, ideally based on this calculation model.
4.5Equipment and plant
All equipment that uses a fuel that is a piece of equipment or an item of plant needs to be included in the footprint calculation. For these items it is recommended that the volumes of fuel consumed is recorded and the volumes converted to CO2e using the conversion factors of 1 litre of diesel = 2.38 Kg of CO2e and 1 litre of petrol = 2.3 Kg of CO2e.
4.6Procurement chain
According to the NHS CRS 60% of carbon emissions resides in the procurement chain. The SDU have displayed a breakdown of procurement emissions on page 5 of their publication ‘NHS England Carbon Emissions: Carbon Footprint Modelling to 2020’. For a copy click HERE[8].
The potential savings make this section of the carbon footprint an obvious target and some consideration needs to be given how gains can be achieved. Before savings can be made it will be necessary to calculate the carbon footprint of each provider and then proportion the result among each of the provider’s clients.
As providers are under contract to your organisation the easiest means of achieving this goal is to add the requirement for calculating and reporting details of the carbon footprint into all your contracts. Care should be taken not to make the requirements too onerous as this may have an impact on the cost of the contracts.
So that a standard can be established it is recommended the method of calculation outlined in this paper is used by your providers to calculate their footprint. This way a consensus will be achieved.
Some consideration should be given to encouraging providers to maintain their own carbon footprint. This will encourage providers to introduce measures to reduce emissions thereby encouraging a wider reduction in emissions.
4.7Reduction of footprint
Reduction of the footprint is allowable if energy is being produced within your estate using a renewable source. All the power from solar Photovoltaic (PV) cells, wind turbines or water driven turbine will be counted as a CO2e credit on your footprint. A meter will be attached to any device you have showing the supply. Biomass generators are not included because although energy is being produced from food waste the act of burning produces an exhaust, which includes CO2. A cubic metre of methane when burned will produce one cubic metre of CO2 and 2 cubic metres of water vapour.
Some offset is allowable if you include the CO2e from the combustion of the methane and credit the amount of electricity generated from the generator.
Annex A conversion factors
Table 1Sources of energy to CO2e
Energy source / Units / Kg of CO2e per unitElectricity from national grid / Kilowatt hour / 0.537
Natural gas / Kilowatt hour / 0.185
Liquid petroleum gas / Kilowatt hour / 0.214
Liquid petroleum gas / Litre / 1.495
Gas oil (red diesel) / Kilowatt hour / 0.252
Gas oil (red diesel) / Litre / 2.674
Fuel oil / Kilowatt hour / 0.268
Fuel oil / Litre / 3.179
Diesel / Kilowatt hour / 0.250
Diesel / Litre / 2.630
Petrol / Kilowatt hour / 0.240
Petrol / Litre / 2.315
Industrial coal / Kilowatt hour / 0.330
Industrial coal / Tonnes / 2,457
Wood pellets / Kilowatt hour / 0.025
Wood pellets / Tonnes / 132
Drinking water* / Kilolitre / 0.276
Foul water* / Kilolitre / 0.693
Diesel** / Litre / 2.63
Petrol** / Litre / 2.30
Biodiesel (ME)*** / MegaJoule / 86.4
Biodiesel (HVO) / MegaJoule / 86.4
Bioethanol / MegaJoule / 84.8
BioETBE (refinery) / MegaJoule / 84.8
BioETBE (non-refinery) / MegaJoule / 84.8
Biomethane / MegaJoule / 62
Biomethane / Litre / 0.001977
Biomethane / m3 / 1.977
Biodiesel (ME)*** / Litre / 2.8605
Biodiesel (HVO) / Litre / 2.9652
Bioethanol / Litre / 1.8045
BioETBE (refinery) / Litre / 2.3087
BioETBE (non-refinery) / Litre / 2.3087
Biomethane / Kg / 3.038
Source: The Carbon Trust, last accessed 24 February 2009
* - Water (2008)available at
** -
*** - Biodiesel (Methyl Ester), biodiesel produced from oils using conventional esterification
Processes
**** - Biodiesel (Hydrotreated Vegetable Oil), biodiesel produced from vegetable oils using
hydroprocessing.
Table 2 2009 GHG Conversion Factors for buses
Bus Type / gCO2e per passenger kmLocal bus / 111.5
London bus / 83.8
Coach / 30.6
Source: 2009 Guidelines to a DEfRA / DECC’s GHG Conversion factors for Company Reporting: methodology paper for emission factors[9].
Table 3 2009 GHG Conversion Factors for flights
Flight type / gCO2e per passenger kmDomestic / 171.0
Short haul / 98.3
Long haul / 112.2
Source: 2009 Guidelines to a DEfRA / DECC’s GHG Conversion factors for Company Reporting: methodology paper for emission factors[10].
Table 4 2009 GHG Conversion Factors for rail travel
Rail type / gCO2e per passenger kmInternational rail / 17.7
National rail / 57.7
Light rail and tram / 83.4
London underground / 78.0
Source: 2009 Guidelines to a DEfRA / DECC’s GHG Conversion factors for Company Reporting: methodology paper for emission factors[11].
Table 5 2009 GHG Conversion Factors for passenger ferries
Travel type / gCO2e per passenger kmFoot passenger / 19.3
Car passenger / 133.2
Source: 2009 Guidelines to a DEfRA / DECC’s GHG Conversion factors for Company Reporting: methodology paper for emission factors[12].
Annex B Glossary
CCA – 2008 Climate Change Act
CRS – NHS Carbon Reduction Strategy
For Further information please contact:
Ian Pauley,
Mark Marshall,
Annex CReferences
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