Methodology the source data from National Grid and Elexon is translated into figures: EIR release

Information requested

For both of the below data sets, sourced from Scot Gov’s Scottish Energy Statistics Hub, please provide the methodology by which the source data from National Grid and Elexon is translated into the figures reported by Scot Gov.

1. Proportion of electricity consumption by fuel (https://scotland.shinyapps.io/sg-energy/? Section=RenLowCarbon&Subsection=RenElec&Chart=ElecConsumptionFuel)
2. Scottish generation meeting demand (https://scotland.shinyapps.io/sg-energy/? Section=SystemSecurity&Chart=ScotGenDemand)

As the information you have requested is 'environmental information' for the purposes of the Environmental Information (Scotland) Regulations 2004 (EIRs), we are required to deal with your request under those Regulations. We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA. This exemption is subject to the 'public interest test'. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption. We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes. This is essentially a technical point and has no material effect on the outcome of your request.

Response

1. The proportion of electricity consumption by fuel percentages are sourced using the National Grid Carbon intensity API (https://api.carbonintensity.org.uk/). The data is an estimate of the amount of CO2 emitted per kilowatt hour of electricity consumed by fuel type. This is provided on a half hourly basis and we then summarise and group the data to show this on a quarterly basis.
   
   Wind, Hydro, Bioenergy and Waste, and Solar fuel sources are grouped together in the “renewables” category. The “Low Carbon” category includes all those included in “renewables” with the addition of Nuclear.
   
   The half hourly data is summed up to give a total for each technology by quarter and year and is then divided by the total for all technologies to give us the percentages presented on the hub.

Quarter	Biomass	Coal	Gas	Hydro	Imports	Nuclear	Solar	Wind	Renewables	Low carbon	Total
2022 Q1	123062	3465	1118605	1039687	251966	1950690	69035	7626151	8857935	10808625	12182918
2022 Q2	142029	142	2368811	670827	228753	2101879	167314	5725728	6705899	8807778	11405761
2022 Q3	183971	1011	2573496	537368	165502	1770041	177972	5463547	6362858	8132898	10872826
2022 Q4	152320	1320	1308317	1123518	317737	2170880	33170	7627734	8936742	11107622	12735366
2022 Q1-Q4	601382	5938	7369229	3371400	963958	7993490	447490	26443160	30863434	38856923	47196870
Proportion of CO2 consumption	1.3%	0.0%	15.6%	7.1%	2.0%	16.9%	0.9%	56.0%	65.4%	82.3%	100.0%

2. There is a license agreement in place between Strathclyde University and Elexon, providing access to their data feeds on an annual subscription basis.
   
   We receive the Elexon generation data from Strathclyde University, the data includes the amount of electricity generated every half hour in MW by fuel type. We get historic half hourly demand data from the National Grid data portal (https://data.nationalgrideso.com/demand/historic-demand-data). The generation data and the demand data are then grouped by quarter and year.
   
   To calculate the proportion of time the total demand is met by electricity generated by fuel type for the year, the number of half hourly periods where electricity generation exceeds demand is divided by the total number of half hourly periods in the year:
   
   Percentage of time where generation > demand = (number of periods where generation > demand) / (total number of periods).

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