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How does Loop’s green journey calculate my carbon emissions?

Find out more about how our green journey calculator works

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How does Loop's green journey calculate my carbon emissions?

In June each year, the Department for Business, Energy & Industrial Strategy (BEIS) publishes emission conversion factors for use by UK and international organisations to report on greenhouse gas emissions. We use the latest version of these figures to convert your electricity, gas, oil and LPG usage to carbon emissions in our green journey calculator.


Transport emissions

If you enter your car registration number (number plate), we get its emissions per kilometre from the Driver and Vehicle Licensing Agency (DVLA). 

If not, emissions for an average car are in the data set that we use for electricity, gas, oil and LPG usage, and we use those.

If you have an electric car, we can identify this from the number plate you enter. Electric cars have none of the 'tail-pipe emissions' of a petrol or diesel car. However, generating the electricity required to charge the car does lead to emissions and we reflect this in the calculator. As the grid decarbonises these emissions will fall.


image-44Calculating solar

For solar panels, we use data from the Photovoltaic Geographic Information System (PVGIS) for a 4 kW array on a south-facing roof in the middle of the country to estimate solar generation.

According to the Sixth Carbon Budget, the UK is aiming to phase out fossil-fuelled electricity generation by 2035, so we assume that up until then, solar generation will displace fossil-fuelled generation as part of this process.

BEIS also publishes estimates of annual greenhouse emissions for the UK as a whole, broken down into different components. We take the latest estimate for emissions from fossil-fuelled generation from there and calculate the emissions reduced by solar generation using this factor.


How should I interpret the net-zero journey if I already have solar installed?
If you have solar installed, it’s unlikely that the net-zero journey will perfectly reflect your emissions. We assume a 4kW south-facing array in Oxford and only a very small minority of people satisfy these conditions! However, you’ll have a good idea how big your array is, which direction it faces, and whether you’re north or south of Oxford, so make an adjustment to get an idea of the impact of your array. The other steps of moving to an electric car and moving to low carbon heat should all be reflective of your circumstances.


Insulation and efficiency

We assume a 10% reduction in energy use. Loop customers have on average reduced their electricity usage by 10% and we expect this will increase over time.

When we simulate switching your fossil-fuelled car to an electric car, we again use figures for an average electric car from the BEIS emissions conversion factors.


Low carbon heatingHeat pumps - will they replace gas in peoples homes 1

For low-carbon heat, we are modelling the switch to an electric heat pump.

Different heat pumps and boilers vary significantly in performance, so we use central estimates that normal electric heaters are:

  • 100% efficient,
  • oil and gas boilers that are 90% efficient,
  • and electric heat pumps produce around three times as much heat energy as they consume (since they extract heat energy from the air or ground outside) - effectively 300% efficient.

Depending on your current heating method, we use these figures to estimate your electricity consumption for heating with an electric heat pump, and use the BEIS conversion factors to convert that to carbon emissions.

Finally, we use the Sixth Carbon Budget estimates for grid emissions to calculate future emissions from your now all-electric home.


What if I’m on a green tariff?
Green tariffs are controversial and are currently under investigation by the government.

 This article from consumer choice champion Which? provides a great introduction to the many different shades of green tariffs. Two energy companies can define a green tariff in totally different ways.

At a basic level, your electricity comes from the grid and will be supplied by a mix of generators connected to the grid. What is interesting is that this mix of supply doesn’t change if you switch to a green tariff so there is no way to link your home’s supply directly to a specific generator.

This is really important to understand as if you are on a green tariff and reduce how much energy you use, you will still reduce the amount of carbon being emitted by our power stations.

It’s also often misunderstood that green tariffs lead directly to more renewables such as wind and solar being built. Although green tariffs may have a marginal impact, it’s in fact a government-backed scheme called ‘contracts for difference’ that has the biggest impact on how much renewable generation gets built.

Some green tariffs offer genuine environmental benefits but it’s really hard to quantify and rate the different suppliers. We’ve considered the pros and cons carefully when building our net-zero journey. We’ve chosen not to take green tariffs into account, so if you’re on a green tariff, please take a look at how "green" the tariff is and treat this as an additional benefit which is not currently captured in Loop’s journey.