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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Assessing the Impact of UK Clock-Change Policy upon Energy Usage and Carbon Emissions

Yu-Foong Chong

Assessing the Impact of UK Clock-Change Policy upon Energy Usage and Carbon Emissions

With Kyoto, EU and national targets of reducing carbon emissions, the UK is committed to cutting its impact on global warming. Combined with concerns over energy security and hydrocarbon scarcity, there is pressure to review current practices and policies in the search for ‘quick win’ methods in which to improve the UK’s energy efficiency, and in doing so reduce its carbon emissions.

The UK currently follows Daylight Saving Time (DST), better known as British Summer Time (BST) within Britain, during which the clocks are put forward by one hour to make use of available daylight in the bid to conserve electricity. Originally established in 1916 during the First World War, the premise was that in the summer sunrise occurred before the majority of the population were awake, and as a result wasting several hours of daylight, whilst in the evening after sunset the population would still be awake and require the use of additional energy to provide illumination and heating. Thus by moving the clocks forward during the summer, energy could be saved by maximising use of the extra daylight available.

The UK currently follows a clock policy on Greenwich mean time (GMT) for 5 months from November to March, and GMT+1 for 7 months over the summer from April to October.

During World War II, Britain switched to using GMT+1 in the winter and GMT+2 in the summer, and from 1969 to 1972 there was a 3 year experiment in operating GMT+1 all year round. Since then there have been several attempts to re-implement either of these clock-policies. However, due to a lack of conclusive data, these have failed to pass through Parliament.

Despite the fact that DST is common in Europe and America, surprisingly little research has been done on the impact of this policy. This report aims to find out how to assess the best time-zone which is optimal for the UK in reducing energy usage and therefore carbon emissions. This is done via a detailed study of Britain’s electricity demand since 2001, assessing different methods for estimating the savings to be made during peak hours and their impact on carbon emissions.

Different modelling techniques are discussed and explained, which allow for the seasonal effects on demand and address the way in which electricity is generated in order to meet this. Relevant social and political implications are considered.

The report concludes that the UK clock-change policy is not currently optimal, and that by extending BST or switching to Central European Time, significant energy and carbon savings can be made. However, for conclusive data, an experimental period on CET is required.


Course Overview


The need to engage in better problem definition through careful dialogue with all stakeholder groups and a proper recognition of context.


An ability to work with specialists from other disciplines and professional groups acknowledging that technical innovation and business skills also must be understood, nurtured and combined as precursors to the successful implementation of sustainable solutions.


An understanding of mechanisms for managing change in organisations so future engineers are equipped to play a leadership role.


An awareness of a range of assessment frameworks, sustainability metrics and methodologies such as Life Cycle Analysis, Systems Dynamics, Multi-Criteria Decision making and Impact Assessment.