Introduction
This paper examines the present sources and distribution of electrical power in the United Kingdom and looks at the possible / likely changes in the future. Since April 2005, the electricity generating and supply industries of England & Wales and Scotland have been integrated, as a result of the Energy Act 2004.
According to the Department of Energy and Climate Change (DECC) The Current British Electricity Network can be summarized as electricity generators (all sources including renewable sources) connected to a transmission grid, which comprises:
The National Grid (circa 25,000km of high voltage overhead lines, and
Regional Distribution Networks (circa 800,000km of overhead lines and/or underground cabling).
National grid lines operate at 275,000 volts in England & Wales, and 132,000 volts in Scotland and offshore, whereas the regional distribution networks interconnecting lines or cables operate at different voltages which may be at 11, 33, 66 or 132kV.
The transmission systems are owned by the National Grid (England & Wales), Scottish Power Transmission (SPT) and Scottish Hydro Electric Transmission Limited (SHETL) in Scotland. Northern Ireland Electricity owns the Northern Ireland grid. Transmission network interconnections between England and Scotland & Northern Ireland, and between England, France and the Netherlands, facilitate electricity import and/or export.
UK-based generation of electricity fell in 2011 compared with the previous year, due to a number of factors, which included a fall in exported electricity and a rise in the amount of power imported from France and the Netherlands. Those factors also included extended shutdown of power stations for maintenance.
At present, Britain’s power generation picture shows a diverse range of fuels used to generate electricity, with gas, coal and nuclear energy being the three major contributors. However, with some existing power stations approaching their end of life dates, and a number of gas-fired power stations facing closure by the operators due to poor economics caused by the increased cost of gas, the UK generating capacity may soon face a shortfall. An article: UK facing 4GW electricity generation capacity loss from April 2013 on the ICIS Heren website predicts that the shortfall could be experienced by April 2013.
Also, with renewable energy sources still providing only a small percentage of total power required, future strategy is a major concern. This paper looks at how the UK electricity generation may develop in the coming decades, especially how the desired low-carbon solution may be achieved.
Background Literature
Literature used as sources for this research is listed on the Works Cited page at the end of this paper.
Data
Data used in this research paper has been derived from the literature referenced in the Works Cited page, primarily from:
1. “The Current British Electricity Network”. Department of Energy and Climate Change. Web. 14 April 2012, and
2. “UK Electricity Scenarios for 2050”. Dr Jim Watson (2003). Tyndall Centre for Climate Change Research and SPRU – Science and Technology Policy Research, Freeman Centre, University of Sussex, Brighton BN1 9QE.
This Research
Sources of UK-generated electricity in 2011 (see Charts 1, 2 and 3 obtained from The Current British Electricity Network, a DECC publication dated March 2012) were – in order of percentage share – Gas (39.8%), Coal (29.7%), Nuclear (18.9%), Renewables (9.5%), Other (1.3%) and Oil (0.8%).
Chart 2 shows the fuel types used to generate the UK’s power in the years 2008-2011. Taking the most recent period (2011), there was an overall 4.2% drop in UK-generated electricity, which included a small increase from 2010 in electricity generated from coal but a more significant fall (16.9%) in that produced from gas, mainly due to high gas prices, resulting in some gas-powered power stations producing little or no electricity. Nuclear power generated electricity increased by 11% from the previous year, mainly due to the effects of nuclear power station closures for maintenance in 2010. One notable increase in 2011 was from wind power up over 54% from the previous year. This was due in part to increased capacity but also because the wind speeds were higher in 2011. Similarly, due to 84% higher rainfall in 2011, hydroelectric power sources provided a 58% increase.
In addition to these fluctuations in the UK domestic power generation scene, the levels of electricity imports and exports vary year by year according to the situation in respect of demand and generating capability. Chart 3 shows the year-by-year fluctuations in imports and exports between 2008 and 2011. Generally, the UK imports more electricity than it exports, although in the third quarter of 2009 and the first quarter of 2010 that situation was reversed when the UK was a net exporter to France, the Netherlands and to Ireland.
In 2011,overall consumption of electricity fell to its lowest level since 1998, perhaps due to higher average temperatures reducing demand for heating purposes.
Having summarized the present UK electricity generation picture, what does the future hold?
In his paper UK Electricity Scenarios for 2050, Watson (2003) makes the point that in order to achieve 60% reduction in UK carbon emissions by the year 2050 to which the UK is committed, there will have to be major changes to the UK electricity system, including less use of fossil fuels and more extensive use of renewable energy sources and other low carbon sources, such as fuel cells, and perhaps greater use of nuclear energy. Actions and policies needed to achieve that required 60% reduction in carbon emissions are dependent upon the nature of the electricity demand that will need to be met. Watson’s paper was based on four future scenarios developed by the Royal Commission on Environmental Pollution (RCEP), which can be summarized as follows:
Scenario 1: Energy demand increase zero. Combined supply sources: Renewables, Nuclear or fossil fuel power stations where carbon emissions are trapped and disposed of;
Scenario 2: Reduced demand (50% reduction of heat demand plus 25% reduction in other uses). All renewable energy sources – no nuclear of fossil fuel power sources;
Scenario 3: Reduced demand as Scenario 2, but using a combination of energy sources comprising renewable and either nuclear power or fossil fuel power where carbon emissions have been prevented;
Scenario 4: Large reductions in demand (66% reduction for heat and 33% reduction for other energy uses). Energy supplied almost entirely from renewable sources.
Based on this scenario modelling, the RCEP produced data as summarized in Table 1, based on the annual average energy supply levels in Gigawatts (GW). Because the data in Table 1 are based on measures of annual average rates, the figures require conversion to obtain meaningful values for the capacities and outputs of different generating technology types so that for each scenario the numbers and types of the various power plants can be estimated. The results are shown in Table 2.
The numbers in Table 2 are based on presumed values for sizes of different types of power plants (based on present sizes) and on estimated load factors for the different types of plants. These estimated load factors are given in Table 3 and the consequent capacities of generating plants (all technologies) are detailed in Gigawatts-electric (GWe) in Table 4.
Note: 1 Terawatt-hour = 1012 watt-hours.
The RCEP scenarios and associated electricity generating output and capacity values used in Watson’s paper are based on annual averages, derived from a set of simple rules, and assumptions about forecast demand levels. Table 6 shows – for each of the four scenarios – the TWh values for supply and demand. Note that in some cases (e.g. 1998) the larger value for supply compared with demand can be explained in part by generation, transmission and distribution losses. However, large differences in indicated values for supply and demand, (e.g. in Scenario 1) are due because not all electricity generated from fossil fuel sources is consumed as electricity but is used for purposes such as providing high or low grade heat.
Summary and Conclusions
Bearing in mind the target of reduced carbon emissions by 2050, it is apparent that extensive changes are required to the current heavy preponderance of fossil fuel sources of UK electricity. It would also make economic sense to avoid being a net importer of electricity if practicable; i.e. by having sufficient domestic generating capacity including reserves.
Regarding the RCEP scenarios for UK electricity in 2050 as described in Watson’s paper, they are all based on the target of 60% reduction in carbon emissions (against 1990 levels) to which the UK is committed under the 2008 Climate Change Act. To achieve this reduction, it is clear that the UK electricity system must undergo major change from the system we have at present. In all of the four RCEP scenarios considered, the UK system has to feature a much higher percentage of electricity generated from renewable sources, and become more de-centralized with greater capacity in the generation sector. Note also that in all the four scenarios the demand is either no greater than it was in 1998 or has been reduced. Key elements of the projected scenarios are:
Using fossil fuel generated power much less in a primary role and more to provide a backup source for renewable sources that may be intermittent;
Expansion of nuclear power (in two of the scenarios) or fossil fuel power sources with carbon emissions removed;
Improved energy efficiency resulting in zero or negative demand growth;
Use of generated electricity as a source of heat (high or low grade) in scenarios where generation significantly exceeds demand.
Of course the four RCEP scenarios may not provide a sufficiently wide range. For example, it may transpire that many households may have micro-CHP (micro Combined Heat and Power) systems installed. According to an article entitled Micro-CHP on the Energy Saving Trust website, “The main output of a micro-CHP system is heat, with some electricity generation, at a typical ratio of about 6:1 for domestic appliances”. The same article explains that a typical household installation can generate about 1KW of electricity and that surplus electricity generated can be sold to the National Grid. If a huge number of homes have micro-CHP installations by 2050, the scenarios would be affected, as they also would by larger than anticipated contributions from renewable sources such as wave, wind or solar power.
It is to be hoped that the desired emissions reduction targets are reached by 2050, giving the UK a much “greener” electricity generation and supply system.
Chart 1 – UK Power Generation 2011: Fuel Sources by Percentage
Chart 2 – UK Power Generation: Fuel Sources 2008-2011
Chart 3 – UK Trade in Electricity
Notes:
1. Table 1: Fossil fuel figures allow for all end uses of the generated energy [Source: RCEP, 2000].
2. In Tables 1 to 5, Nuclear power stations could be substituted by fossil-fuel power stations with carbon emissions capture and disposal.
3. Tables 1-6 are sourced from the Watson (2003) paper referenced earlier.
Table 1 – Output from Energy Sources in 2050 under four RCEP Scenarios
(Annual Average Rate, GW)
Table 2 – Numbers of Generating Plants in the Four RCEP Scenarios
Table 3 – UK Generating Plants Load Factors in the Four RCEP Scenarios
Note: Calculations used in creating this Table derived from RCEP, 2000 and DTI, 1999.
Table 4 – UK Generating Plants Capacities in the Four RCEP Scenarios
Table 5 – UK Electricity Generation (TWh) in the Four RCEP Scenarios
Table 6 – UK Electricity Supply and Demand (TWh) in the Four RCEP Scenarios
Works Cited
“Micro-CHP (micro combined heat and power)”. Energy Saving Trust. Web. 15 April 2012.
“The Current British Electricity Network”. Department of Energy and Climate Change. Web. 14 April 2012.
“UK Electricity Scenarios for 2050”. Dr Jim Watson (2003). Tyndall Centre for Climate Change Research and SPRU – Science and Technology Policy Research, Freeman Centre, University of Sussex, Brighton BN1 9QE. Tyndall Centre Working Paper No. 41. November 2003. Web. 14 April 2012.
“UK facing 4GW electricity generation capacity loss from April 2013”. ICS Heren. Web. 14 April 2012.
