carbon

Carbon.scot
As we start 2025, we are still gathering current data, but until we have a few weeks worth of data it's not really worth showing the current data on the charts below. Some charts have been "frozen" at the end of 2024 so that you can still review them. It's also an opportunity to make some major updates and improve the site. In the meantime we'll have some new articles looking back at 2024 in the Opinions section. The realtime info on the home page will still update every half hour. Please check back at the end of January for the new updated charts and the initial 2025 data.

Before diving into the charts ... click for more context.

Context

It's really important to understand this data in the wider context of Scotland's greenhouse gas emissions. The charts generally show that electricity in Scotland's 2 grid areas (North and South) is very low carbon and more often that not in the North, zero emission. That's amazing and still improving. But, electricity only accounts for 4-5% of Scotland's emissions.

What about the other 95% of emissions? Domestic transport (28%), buildings (18%) and fuel supply (9%) make up more than 50% of the emissions. These 3 sectors are ripe for electrification. In fact fuel supply could almost be eliminated if we relegate hydrogen to edge cases that industry can handle themselves rather than continuing to view it as a domestic heating and transport solution. It's not. That is the most urgent phase of Scotland's energy transition.

Further electrification as the primary route to decarbonisation means quite simply that we'll need to produce more electricity. That electricity should be generated by fuelless means; wind, solar, hydro, marine, geothermal. When surpluses exist, that electricity should be stored so that it can easily be dispatched back to the grid using battery storage e.g. conventional battery storage, compressed air and pumped hydro.

Using the charts ...

Carbon.scot is in a pre-launch phase at the moment, but we wanted to get some charts and explanations out as soon as possible.

These early versions of the charts do not allow you to interact with the data to hone in on specific regions, time periods or generation types, but that's coming.

A picture of a chart legend showing some values switched on and some switched off. A picture of a chart legend showing some values switched on and some switched off.

When some charts load, not all of the information is shown. This is to enhance clarity and readability. However, there is a legend underneath or on the right-hand side of each chart that enables you to toggle values on and off. A line through a data segment on the legend indicates that it is not on the chart and can be switched back on. Just click on segment in the legend to toggle it.

To fully decarbonise the grid by 2030, carbon intensity goals are reduced every year.

Carbon intensity has 5 classifications; very low, low, moderate, high and very high. In 2025, a very low classification is from 0 to 29 grammes CO2 / kWh. When the upper limit of a classification is exceeded the carbon intensity for that grid area moves into the classification above.

As the share of wind and solar supplying electricity to the grid increases at any given time, the classification moves towards one of the lower bands. Conversely, when more fossil fuel gas is used, the classification moves into the higher bands.

Carbon intensity classifications up to 2030

  • < 30 gCO2 / kWh
    Very low
  • 30-99 gCO2 / kWh
    Low
  • 100-179 gCO2 / kWh
    Moderate
  • 180-250 gCO2 / kWh
    High
  • 250+ gCO2 / kWh
    Very high

Historical and future targets for carbon intensity

Carbon Intensity Over Time

Average annual carbon intensity - 2019 to 2024

Summary

Key takeaways

Average carbon intensity each month - 2022 to 2024

Summary

In this chart we see the average carbon intensity of the grid in 6 different areas. Scotland - North, Scotland - South, North East England, South West England, England and Wales. The values on the chart indicates the number of grammes of CO2 emitted to generate a unit (1kWh) of electricity. The intensity target for 2024 is 35 gCO2/kWh. The lower the numbers the better. National Grid aims to have the entire grid at 0 grammes of CO2 per kWh by 2030.

Key takeaways

  • Since September 2022, South Scotland has had an average of less than 50 grammes every month.
  • The past 2 years also been good for North Scotland with zero CO2 emissions for over half of the year, but we see peaks and troughs. The peaks are mostly in summer months and show that there are gaps in wind production that need to be filled. Mature generation methods - solar, hydro, geothermal and battery storage - have a massive role to play here.
  • Wales often has a high carbon intensity. Although wind production in North Wales helps, South Wales is heavily reliant on gas for electricity production.
  • South West England is one of the leaders in solar and gets about 20% of its electricity from solar. But it has peaks and troughs and some of the highest carbon intensity values across the year because it relies on gas for electricity production when the sun goes down.

Carbon intensity over the past 28 days - The rollercoaster

Summary

In this chart we see the carbon intensity of the grid in 3 different areas over the last 28 days; Scotland - North, Scotland - South and Great Britain overall. The values on the chart indicates the number of grammes of CO2 emitted to generate a unit (1kWh) of electricity.

Moving the cursor over the chart will show the precise time and date and carbon intensity in the 3 different areas at the time.

Key takeaways

This is not a chart to be looked at in minute details. The intention here is to show the degree of variability over a sustained period. In any 28 day period there are 1344 data points per grid area.

  • The variability in North Scotland is incredible. The area is on target to have over 200 emission free days this year, but when the wind drops there aren't many fossil fuel free options deployed there to take up the slack. The carbon intensity figures shoot up as we can see from the spikes on the North Scotland data. Pumped hydro storage, battery storage, solar, hydro and marine have to be expanded here.
  • In South Scotland, the peaks and troughs are much shallower, rarely going above 100 grammes which is still considered low carbon intensity. A concerted drive by farmers, businesses and local authorities could deliver a huge solar boost to the region and coupled with storage, many of the worst peaks could be flattened.

Glimpses of Zero Emissions from the Grid

Number of full days with no CO2 emissions. A carbon intensity of 0

Summary

The chart above shows the number of days per year that each grid area produces electricity with zero carbon emissions.

Please note that carbon intensity is measured every half hour. We calculate a full day by summing the number of half hour segments at zero in the year divided by 48 to give the number of days. Therefore the days are not contiguous, but a collection of 48 half hour periods at any time in the year.

Key takeaways

  • 2024 data is of course not yet complete, but we have already seen another record breaking year for North Scotland with over 200 full days of zero carbon electricity so far.
  • Zero emissions is amazing. As we can clearly see, it has been very difficult to achieve for all 14 grid areas except North Scotland which now does this for more than half the year.
  • Only 5 of the 14 areas have ever achieved a day at zero.
  • Carbon intensities of 10, 20, and 30 are also excellent, and many more areas would show up in this chart if that was the criteria, but we wanted to highlight the stark difference between North of Scotland and the rest of the National Grid.

Even though the North Scotland grid area has by far and away the most time with zero emissions, it does not automatically follow that North Scotland will a) have the most number of days in the target range of 35gms of CO2 emitted per kWh or b) have the lowest average carbon intensity over the year. Most days on target will probably be North East England and lowest average carbon intensity may end up being South Scotland.

This shows how nuanced the picture is. It's not just about a single snapshot in time showing really good or really bad carbon intensities. It's not about showing one single carbon intensity figure for all 14 regions rolled up into one.

Understanding this helps us make more accurate statements. For example, some people attack electric cars by saying that the car doesn't have emissions, but the electricity that they charge from does have emissions. That's true, but we see that in North of Scotland, over 60% of the time, you'll be able to get a zero emission charge, and in North East England, you'll get a very low carbon charge for nearly 320 days a year.

One thing is clear, the figures get better every year and the trend towards zero or very low carbon is set.

Number of days on or below the 2024 target of 35gms of CO2 emitted per kWh generated

Summary

The chart above shows which grid area produces electricity on or below the carbon intensity target for that year (35 grammes in 2024).

Please note that carbon intensity is measured every half hour. We calculate a full day by summing the number of half hour segments at zero in the year divided by 48 to give the number of days. Therefore the days are not contiguous, but a collection of 48 half hour periods at any time in the year.

Key takeaways

  • 2024 data is of course not yet complete but we can see that all 14 regions do hit targets to varying degrees.
  • 3 grid regions are zero carbon for over half the year.
  • Yorkshire is included with a score of zero because it did have a few periods on target, but less that the 48 required to complete a full day and get a score of 1
  • The target for 2025 will be reduced to 30 grammes of CO2 / kWh

Share of Electricity by Source

Electricity source by year - North Scotland grid area

Summary

This chart shows the percentage breakdown of electricity by source in the North Scotland grid area.

Key takeaways

  • It's clear that wind is dominant generation source in the North of Scotland making it the true powerhouse of the country and helping reduce the average carbon intensity across all 14 regions of grid GB.
  • It would be good to see solar, hydro, geothermal and marine of all scales taking up more of the other 25% needed.
  • Solar plays a negligible role on the grid in the region, however it could have a crucial role in helping to fill the gaps and feed storage batteries. This could be crucial on those crisp, windless winter days that often occur in Scotland and during the peak summer months when wind is highly variable in the North.

Electricity source by year - South Scotland grid area

Summary

This chart shows the percentage breakdown of electricity by generation source in the South Scotland grid area.

Key takeaways

  • Like the North of Scotland, the South produces and consumes mainly wind and has done since 2022.
  • Wind production is heading towards 60%.
  • The interplay between wind and nuclear is almost mirrored.
  • Although solar still hasn't broken the 2% mark there is a lot of potential for it to catch up to the more usual 5-6% contribution. Much could be achieved through the promotion and support of agrivoltaics to farmers and small crop growers.
  • Councils and NHS Scotland have a critical role here in increasing solar production on their own property and land portfolios.

Electricity source by year - North East England grid area

Summary

This chart shows the share of electricity by source in the North East England grid area.

Key takeaways

  • While North East England grid area clearly has a substantial proportion of electricity coming from wind, nuclear is the largest provider. The combination of the two is what enables the region to have consistently low-carbon electricity. North East England is currently the region which has the most number of days on or below the 2024 target of 35 gCO2/kWh
  • North East England - as well as being one of the leading renewables areas - shares features with Scotland other than a high proportion of electricity from wind. It is also has a very low reliance on gas and under utilises solar.

Electricity source by year - All 10 grid areas in England

Summary

This chart shows the share of electricity by source in England's 10 varied grid areas.

Key takeaways

  • England crossed the threshold of using more wind than gas for the first time in Summer this year, but a long 'Dunkelflaute' at the beginning of November reverted the situation so that gas is now once again the dominant energy source for generating electricity in England as a whole. This situation should eventually change and improve with a new government commitment to promote more wind development in England.
  • European imports of electricity are very high this year probably reflecting the increase in interconnecters with European countries (France, The Netherlands, Belgium, Norway, Denmark) and the fact that electricity prices are lower in EU countries. It may be a seasonal and strategic effect. We'll know by the end of the year. It should also be remembered that hidden multiple generation sources are within the term "import" so gas and wind will be part of that import mix skewing the real figures.
  • Solar is playing an increasing role and coal is breathing is final gasps as a generation fuel.
  • Hydro remains the least important source which is a lost opportunity.

The evolution of solar and wind in a few key areas

Summary

The chart above begins by showing us the percentage of electricity derived from solar panels in 4 region in England and Scotland.

The same is available for wind by toggling on the same regions in the legend of the chart on the right. Wind and solar are the same colour for each region.

Key takeaways

  • South West England is clearly a solar leader.
  • The 3 wind rich regions lack solar developments.
  • South Scotland has more solar than North West England.
  • North West England has good wind potential, but we can see the lack of growth in wind during the period of the de facto ban on new onshore developments in England.
  • Both grid regions of Scotland show steady growth in wind and this is why we now have such a highly decarbonised grid.

3 points about solar PV

Myths: Moaning about weather and absent summers is culturally ingrained into day to day discourse and this translates into a mistaken belief that solar becomes less of an option the further north you go.

Solar PV requires light, but we tend to associate that with hot, sunny days. A crisp, clear day in winter can actully be better than a hot summer day as the efficiency of some solar panels degrades as it gets very hot.

Profits: If your sole motivation is to maximise profits then you'll probably situate your solar array in South West England as it has a higher solar irradiance that other parts of the country. This is why we see such a disparity in the figure for South West England and the other regions in the chart above. However, the amount of electricity produced from a 500kW solar installation in Cornwall doesn't vary that much from the same installation in Fife. It varies by a couple of percent. That might be a huge factor for an investor looking to maximise profits. But to a local authority looking to defray electricity costs or a farmer looking embark on an agrivoltaics project it shouldn't be front of mind.

BTM: Some solar PV is connected to the grid and generates and income for the owner. This is highly quantifiable. But, solar PV doesn't have to reach the grid to be used. This is called behind-the-meter (BTM). It is estimated that BTM solar PV installations in the UK generate approximately 4-5 TWh (terawatt-hours) of electricity per annum. That isn't included in the above data. However, it still contributes to decarbonisation by reducing the demand for electricity from the grid.

Coal's demise

Summary

Coal was used to generate electricity for the last time in the UK at 3pm on tht 30th of September 2024. This chart shows the extent to which coal was used in England, Scotland and Wales in the final years.

N.B. Northern Ireland is not included in the figures. The dataset used covers Great Britain only. The last coal-fired power station closed in Northern Ireland in 2023.

Key takeaways

  • Scotland quit coal in 2016 which is why it appears as blue line at zero all along the axis. Wales got off coal in 2020, Northern Ireland in 2023 and England in September 2024.
  • For the past few years coal usage in the UK has been around the 1% mark and therefore not a significant part of the electricity generation mix.
  • While not the first country to phase out coal, having the UK, a G7 economy quit coal is highly symbolic.
  • Other countries can do this. Other countries need to do this.