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Electricity usage in UK
The UK with around 65,0000 MW of conventional energy generating capacity sources its conventional energy primarily from coal, gas, and nuclear sources. The contributions of the three sources are widely unequal with less than a third of the total electricity coming from coal based plants, over a third coming from natural gas, while nuclear sources contribute around 25% of the domestic electricity. However, the contribution of nuclear sources is expected to gradually decline with older plants reaching the end of their operating life, and unlikelihood of any new nuclear plant commissioning in the UK with the privatisation of the bulk of the nuclear industry.
While there is a natural correlation in the UK between the availability of wind and wave power and the electricity demand at a monthly time scale, this degee of aggregation removes the interday variability that is present in both supply and demand. In the UK wind and wave power deliver more energy during times of high electricity demands, with periods of low electricity demand typically associated with significantly lower wind power output. Wave power shows higher average energy production during peak demand periods than does wind power, however, this energy production tends to drop quickly in hours with lower demand. Average energy production from tidal stream power is uniform across all demand hours.
While the long term availability of wind and wave power is broadly correlated to changes in electricity demand, output variability from these resources, together with tidal stream power will affect the net electricity demand pattern to be met by conventional generators. The impact varies both with the size of the renewable resource development and with composition of the renewable capacity: where renewables deliver 5% or less of total energy to the electricity network over a year, there is little impact on net demand variability.
It may be of some interest to note that the electricity demand in the UK has fallen substantially in the last few years and surprisingly there is no sign of recovery. It is however not known the origins of the slump in electricity demand. It could be recession, improved energy efficiency or simply demand reduction because of soaring prices. Should the cause lie in economic recession, one might expect soaring demand with recovery. On the other hand if it is efficient use of energy, the reduced electricity demand might persist. Energy use admittedly is thought to be insensitive to price rise. If the cause lies in soaring energy price, we might have arrived at a formula to check rising electricity use and the carbon emissions. However, the fact as it turns out is that the reduced energy consumption can be attributed to big commercial and industrial users that have slashed their consumption, while the household demands have remained stable as evident from the data published by the National grid for every half hour period. In other words it is the fall in economic activity that has led to electricity cuts. An analysis of the demand reductions between 2008 and 2009 was made by guardian.co.uk dated June1, 2009. The analysis covers the latest available data covering the period January – March 2009 as shown in the table below:
Month Reduction between 2008 and 2009
January 2009 -1.50%
February 2009 -1.50%
March 2009 -6.90%
Total for the period -3.20%
The table shows an accelerating decline but that doesn’t appear to be the valid conclusion because electricity demand is known to be dependent on temperature which was unusually low in the months of January and February but high in March. Another table below compares the mean England temperatures in 2009 and 2008:
Mean England 2009 Mean England 2008
temperature (degrees C) temperature (degrees C)
January 2.8 6.3
February 3.9 5.2
March 6.7 5.9
The analysis attributes the steep fall in March 2009 to the relatively high temperature in this particular month while understating the reductions in the first two months of 2009. The question raised here is what factors are forcing the reductions? The comparison was made for the pattern of reductions for each part, each day ensuring 2008 and 2009 data contained the same number of days and week days for a fair comparison. The average reduction in use each half-hour point in aday was calculated. For instance, a figure for the average electricity use at 4.30 a.m was obtained for March days in each of the two years in study. The result showed that the electricity use reduction varied between 10% and less than 6% during fixed hours in the morning and evening. It was also noticed that periods of least reductions from 2008 to 2009 coincided with the periods of highest electricity demand from domestic consumers. This could probably mean that the UK domestic demand remains unchanged while industrial demand has sharply declined. This could be corroborated with the help of Environmental Change Institute's report “The 40% House”. The report offers domestic and non-domestic daily winter demand for the year 2002, according to which demand peaks at about 7.30 am and 6pm. In the March 2008 and 2009 data as well these periods were marked by least reduction in electricity demand.
In the UK, home, industry, and commerce consume approximately one-third each of total electricity consumption. However, the available data shows domestic proportion is much higher in morning and early evening. This goes on to show that the domestic demand remains largely unchanged as expected. On the otherhand, at 4 a.m, while domestic demand is 20% of the total, the aggregate demand is down 10% when big industries are expected to be using electricity for making plastic, steel, or anything else. Perhaps the reason for this cut is attributed to slowed down economic activities combined with energy use reduction plans put in place by the industries. While reduced electricity consumption should be hailed, it is also a matter of concern because the combined impact of income squeeze, fuel price hike and energy efficient appliances has made no dent on domestic energy consumption. Moreover, it is also doubtful whether energy reduction programmes in some industries have really reduced energy use. This hypothesis might be corroborated by the evidence offered by the latest UK data (Index of Production for Q1 2009, published 12 May). According to this data, the industrial output was down 12.1% compared to 2008. The rough analysis of data shows the actual reason for the fall in electricity use is economic recession, and neither improved energy efficiency, nor reduction in electricty waste. Therefore, in all likelihood, electricity use will shoot up once economic recession is over, whatever that may mean to the implications for carbon emissions.