Carbon and Environmental Footprinting of Low Carbon UK Electricity Futures to 2050

What is it about?

Carbon and environmental footprint analysis has been employed to estimate the environmental impacts associated with UK power generation based on historic data and alternative energy scenarios out to 2050. Methodologies were established for the present study to calculate the environmental and carbon footprints of the UK electricity industry on both a historic timescale and in accordance with the HDPS scenarios. These were consistent with that developed by the Global Footprint Network and related bodies. The environmental footprint was broken down respectively into carbon (effectively cf), embodied energy, transport, built land, water, and waste components. Annual environmental footprint per GWh of electricity produced (ef) was then calculated over the time-frame of 1950-2050. It was found that the current total environmental footprint (EF) as a result of UK electricity supply and demand is 41 Mgha, with an estimated uncertainty of 4%. If future trends follow the HDPS BAU scenario this footprint in 2050 is projected to fall to about 25 Mgha (3%), whereas both the LC and DG scenarios lead to footprints of less than 4 Mgha (5%). The latter two scenarios were found to give rise to quite similar trajectories out to 2050. It is argued that the latter two scenarios are more likely to reflect an effective transition pathway in terms of meeting the 2050 CO2 reduction targets for electricity generation, with the ‘Deep Green’ scenario proving the preferred choice if complete decarbonisation of UK power generation were deemed desirable.

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Why is it important?

Electricity generation contributes a large proportion of the total greenhouse gas emissions in the UK, due to the predominant use of fossil fuel (coal and natural gas) combustion for this purpose. The British Government has set a legally binding target of reducing the nation’s CO2 emissions by 80% over this timescale in comparison to a 1990 baseline. It is recognised that in order to achieve this target, the UK Electricity Supply Industry (ESI) needs to be decarbonised over this period. In order to determine future trends in the power sector footprints, a range of future energy scenarios were adopted that had previously been developed for the UK SUPERGEN Consortium on ‘Highly Distributed Power Systems’ (HDPS). They were developed from a synthesis of those that had been earlier devised for future network technologies on the one hand, and domestic energy demands on the other. Three resulting scenarios were characterised as ‘Business As Usual’ (BAU), ‘Low Carbon’ (LC) and ‘Deep Green’ (DG) futures, and yielded possible future electricity demands to 2050. The BAU scenario is based on incremental change over time with a continuation of near-term trends in technologies, and energy policy responses to the climate change and energy security challenges. Growth in the take-up of decentralised energy resources (DERs) is assumed to be consumer-led, rather than stimulated by an act of government policy intervention. In contrast, the LC scenario implies an extensive penetration of micro-generators in the home to satisfy heat and power demands (the former not displayed in the present work). However, these energy requirements are minimised by way of improved insulation of the building fabric and other demand reduction measures. Under this scenario, DERs contributes 44% of UK electricity supply by 2050, and residential dwellings are significant net exporter of power. Finally, the DG scenario presupposes a network where centralised renewable energy technologies e mainly large-scale onshore and offshore wind turbines - have an important role in the power generation. Demand reduction again plays an important role (in a similar manner to that with the LC scenario), but fossil fuel power generation is effectively eliminated.

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