Energy saving per capita: 50% Electricity demand: 560 TWh
The core MARKAL run was created using the UK MARKAL model. Further information on the assumptions and modelling structure supporting the core MARKAL (described as run ‘DECC-1A’) can be found at: www.decc.gov.uk/assets/decc/11/cutting-emissions/carbon-budgets/2290-pathwaysto-2050-key-results.pdf
These outputs were produced with a number of underlying assumptions imposed on the model. The results below should be interpreted in the light of these assumptions.
- The UK MARKAL model covers CO2 emissions from energy use and does not model non-CO2 greenhouse gases (GHGs), land use, land use change and forestry (LULUCF) and international aviation and shipping sectors. As a consequence, the 80% 2050 target covering all GHGs on the net UK carbon account was translated to a ‘MARKAL equivalent’ of a 90% reduction for the core MARKAL run
- The core MARKAL run included the impact of the draft Carbon Plan3 commitments to 2020 on the basis that policy and initiatives are already in place to achieve them. For key technologies and policies this representation is explicit; actual penetrations of specific technologies and targets were included. For other policies the representation is indirect, and a UK-wide CO2 emissions constraint in 2020 was imposed to mimic the assumed impact.
- The core MARKAL run was based on central estimates of fossil fuel prices and central estimates of service demands.
What is the sectoral picture in 2050?
Electricity generation capacity is split between carbon capture and storage (CCS) (29 gigawatts (GW)), nuclear (32 GW) and renewables (52 GW). Wind power is installed earlier as part of the Carbon Plan commitments, with 28 GW in place by 2020. In terms of electricity supplied, nuclear and CCS together deliver the majority (72%). Unabated gas plays a significant back-up role in 2050 to balance the system, but largely fades out as a baseload technology from 2030 onwards. Electricity imports and small-scale combined heat and power (CHP) also contribute. CCS with power generation is an important technology from 2020 onwards, generating more than a third of all electricity. The MARKAL run uses this technology to achieve negative emissions rates for electricity by sequestering the CO2 associated with the biomass share (20 % of fuel input to these generators in 2050 is biomass).
In buildings, a reduction in space and water heating demand is accompanied by a large reduction in final energy consumption. Natural gas disappears from heating almost entirely, while electricity consumption increases significantly. Heat pumps, which draw heat from the surrounding environment with the help of some electricity, serve a larger proportion of heating service demand than any other technology.
The chemicals, iron and steel, and nonferrous metals sectors all exhibit the maximum allowable demand reductions of 25% from the central estimate of service demand, driven by MARKAL’s demand-response assumptions. This central estimate does not reflect the Updated Energy and Emissions Projections that the Government has used in this report, and posits a higher baseline level of demand. The MARKAL model suggests that some industries might scale back operations significantly. Industry also benefits from the ability to adopt CCS in the MARKAL model. By 2050, 65 million tonnes carbon dioxide equivalent (MtCO2e) a year is sequestered from industrial processes.
Of all the end-use sectors, transport shows the lowest demand response in the core MARKAL run, with approximately 5% reductions for most service demand categories. The mix of end-use technologies is extremely varied in 2050 when compared with today. Battery electric, biomass-to liquids and hydrogen fuelled vehicles are all used. However, conventionally fuelled vehicles are not expected to be significantly used by 2050 under this optimised pathway.
As the MARKAL model does not account for non-CO2 emissions, much of agriculture’s GHG impact is not explicitly accounted for (other than as part of the overall 90% decarbonisation constraint). LULUCF emissions and removals are also not considered. If domestic forestry were to make a significant contribution to bioenergy feedstock supplies, carbon sequestration associated with land use change would deliver additional abatement. The core MARKAL run demands 350 terawatt hours (TWh) of bioenergy a year by 2050.
What does this scenario imply for security of supply and wider impacts?
A balanced generation mix with a relatively high deployment of intermittent renewable generation technologies such as wind and marine power means that the back-up requirements of this run are significant. An additional 38 GW of gas plant is needed to meet the system balancing requirements imposed by the model.
Per capita energy demand falls by 50% compared with 2007, while total electricity demand increases by 50% from 2007 levels.
In order to meet the demands of CCS and system back-up generation, natural gas remains an important part of the fuel mix in 2050, with 344 TWh of imports. Oil plays a much smaller role than it does today, with the UK importing roughly a sixth of what was brought into the country in 2000, despite declining natural reserves.
History of changes to this pathway
The "Analogous to MARKAL 3.26" pathway was first published on the web tool in December 2011. We subsequently noticed that we had not specified this MARKAL run as accurately as possible, so in May 2012 we released version 3.1.0 of the Calculator (spreadsheet and web tool) correcting this. The main change we made here was to increase the generation capacity of renewables (from 45 GW to 52 GW in 2050); this leads to an increase in back up gas power stations and an increase in imported gas (gas imports rise from 264 TWh to 344 TWh).