OU Carbon Calculator FAQs

Saving, opening and deleting calculator files

On the Summary screen follow the instructions at the bottom. For example:

• To save your existing footprint file. Select the upper box, type the name of the file you want to keep (eg, ExistingFootprint1). Select ‘Save’
• To open ExistingFootprint1 (or any other file that you’ve named). Select the down arrow in the lower box, select the file and select ‘Open’
• To delete a file, select it and select ‘Delete’.

Why does the calculator not ask for real data?

Some calculators ask users for ‘real data’ such as annual gas and electricity use, car mileage, flight distances, etc. However, many users have found these difficult to access, and they only account for ‘direct emissions’, around 20% of the total consumption-based footprint. This calculator uses national statistics for the most typical cases, then refines this level with further questions. The result is usually close to that obtained from real data.

Your household

Why count both adults and children in the household?

The calculator gives its results in terms of your individual or personal emissions, both direct and indirect.

However, household income and a much consumption (eg, heating, vehicle use, the house itself, services like mortgage payments, and hence responsibility for their emissions) is usually shared. The result is emissions per person are lower with more people in the household. The calculator asks you to enter all persons, including children, on the Your household screen. This is because children are all part of the population, and their households can be considered responsible for their impact.

Is it worth increasing home occupancy. The effect of extra children?

A very effective way of reducing your personal carbon footprint is to have more people living in your household (eg, by taking in a lodger).  But having (more) children is not a good way of reducing your personal footprint. This is because it has been calculated that having a child probably adds more to your carbon footprint than any other decision you might make, even ignoring the cumulative impact of their descendants.

Room heating

Have I got cavity or solid walls? Has a cavity wall been filled?

For details go to http://www.energysavingtrust.org.uk/cavity-wall-insulation

Is your electricity from a 100% renewable electricity supplier?

Some electricity companies offer genuine 100% renewable electricity, meaning that the amount of power they buy to match what they supply to customers from the grid comes from direct contracts with renewable generators. However, renewable generators can sell excess ‘REGO’ certificates (issued for each megawatt hour of renewable energy generated) created at times of surplus to non-renewable energy generators. So, many so-called 100% green electricity tariffs are a mix of fossil fuel, nuclear and renewables purchased on the wholesale market and then ‘labelled’ green by buying REGO certificates. Other ‘greenwashing’ electricity suppliers, including some who claim to supply 100% renewable energy, do so simply by buying up excess REGO certificates which are for renewable electricity that was generated anyway and so doesn’t increase its supply. 

For more information see: https://energysavingtrust.org.uk/advice/switching-your-energy-supplier/

The calculator takes into account that a few 100% renewable suppliers (eg, Ecotricity, Good Energy) do invest in further renewable capacity, and some also supply green gas containing a proportion of biogas. In the calculator 100% renewable electricity is assumed to produce lower emissions than normal grid electricity. Furthermore, consumer financial preferences for renewable energy act as a signal to the government and industry to increase investment in renewables

Travel

Business travel by car and public transport is excluded because it is counted as a business activity included in Infrastructure.

How to estimate car use?

You probably know the type and typical annual mileage of household vehicles, but car club and other people’s car details for lifts may be more difficult to identify. For Car clubs and Lifts with others, you have to estimate occupancy (ie, the number of people normally in the vehicle). Count taxi trips as lifts.

How to estimate public transport use?

Journeys by Public transport are not shared, so are allocated to the individual. The calculator does not distinguish between different modes of public transport but takes averaged official emissions data.

How many hours a MONTH do you routinely travel on public transport?

Your regular weekly trips by train could be 10 miles to work and back five days a week and visiting relatives 50 miles every weekend, the total is about 22 days/month x 10 miles+ 4 weekends/month x 50 miles = 420 miles per month by train. At an average train speed of 60 to 80, say 70 mph = 6 hours per month. The UK average is about four and a half hours per month.

Approximately how many hours per YEAR do you travel by train, bus, coach or ship?

For some people it is a low number, but for others it can be high (e.g. two train trips from London to Edinburgh and back, 2 × 14 hours = 28 and quarterly to Bath 4 × 3 hours = 12; train and ferry to Brittany = 16 hours, various bus and coach trips = 40 hours; Eurostar to Paris 8 hours; total = 104 hours per year.

Flying

Why not use accurate flight distances?

There are many online calculators that provide flight distances between airports. We have decided to use the quick and easy method of choosing flying from the UK to an area on a world map. Typical journeys to the different regions are provided in popups.  If you fly to a particular destination less than once per year, use a decimal fraction, eg, if you fly to New York (Eastern North America) about every three years to visit relatives, enter = 0.33.

Income

Why is household income so important?

In the calculator income is only used to estimate emissions from Goods and Services, because there is no other way without a detailed questionnaire on spending. Goods and Services is the largest single category of household spending and the largest category of emissions, so inevitably income makes an important contribution to the total carbon footprint.

What if I or we save or invest some household income?

Some people manage to save some money rather than spending it. This money does not disappear but is used by financial institutions to invest in other activities which produce emissions. Eventually you might claim all that money back and spend it. Nevertheless, the calculator assumes that not spending directly tends to somewhat reduce your emissions. 

Goods

How is 'green' or 'non-green' consumption considered?

Emissions from goods and services consumption depend not only how much income you have to spend, but how the money is spent.

That is the function of the pairs of opposite broadly ‘green’ and ‘non-green’ consumption behaviours offered in the Goods section.  For example, if you spend a lot on clothes and frequently throw away old ones you might select the far-right button on the ‘Keeping things repaired and maintained’ vs ‘Replace often with new things’. If you are the opposite type of consumer and rarely replace your clothes you might select the far- left button. In you are in the middle or tend towards one or other behaviour you select the relevant button.

Infrastructure

What is 'infrastructure' and why is it such a large component?

In principle the entire UK economy, including all its imports (plus international aviation and shipping) exists for the benefit of the whole UK population. From this perspective the population is collectively responsible for the emissions generated by the economy. 

But there are some emissions that cannot be directly controlled by consumers. An important part of this is all the goods and services provided by the government and paid for through taxes. This component is allocated almost equally to each personal footprint.

The other component of Infrastructure covers emissions not directly controlled by consumers or by the central government. It includes universities, cities and local authorities, non-profit organisations, and business activities that are unaffected by consumer choices.

The calculator takes the consumption perspective as far as it can, but there are many corporate choices beyond the control of consumers, so the calculator takes the view that some ‘effective responsibility’ should be allocated to the businesses themselves and other non-state suppliers of goods and services. This is calculated in the Infrastructure section.

Summary

The summary screen shows your personal and the UK average carbon footprints and their components.

Target

The calculator provides two types of carbon footprint reduction targets: Government and Personal. The Target screen tells you how to set a Personal or Government reduction target. 

The Personal target is a percentage reduction on your existing footprint and can be set at any level. Don’t forget to click the ‘Accept footprint’ button before setting your Personal reduction target.

The three Government targets of 30%, 46% and 54% are the percentage reductions required in the average 2016–17 UK consumption-based carbon footprint per person. These reductions are approximately equivalent to percentage reductions of 35%, 50% and 57% in 1990 territorial GHG emissions set in UK government’s carbon budget on the way for the UK to reduce its emissions by 2050. 

Decarbonisation

What is decarbonisation?

‘Decarbonisation’ means reducing or removing GHG emissions from the economy. This is usually done through actions by government or industry, such as replacing fossil fuels by renewables or nuclear power; removing CO₂ from the atmosphere by carbon capture and storage; increasing industrial energy efficiency and producing, and perhaps subsidising, low carbon goods such as electric cars. You could say that some of the individual and household level actions in the calculator (eg, home insulation) also achieve decarbonisation, but the term is usually reserved for larger-scale, non-household emission reduction measures.

The Decarbonisation screen provides some options that can contribute towards reducing your personal footprint by decarbonising the national or global economy. This is done via emission reduction measures by government paid by you through taxes and/or carbon offsets voluntarily paid for by you but undertaken by others, often projects in developing countries.

Decarbonisation is given a separate line in the Summary and deducted from your personal footprint total. You could end up with a negative footprint and can claim to be doing something worthwhile to tackle the climate emergency.