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2 Trends in Scottish Energy: 1990 - 2002
2.1 HEADLINE DATA
This section compares and contrasts:
1. The AHS Emstar 1990 figures (including the revisions made in this report to the domestic sector) with
2. The 2002 Scottish Energy Study (with adjustments made to enable comparison with 1990, e.g. adjusting for exported electricity).
Total energy consumption is similar for the two years:
- In 1990, Scotland:
- Consumed nearly 166 TWh of delivered energy across its main demand sectors, plus nearly 14 TWh for oil refining and coking. Hence, total consumption in 1990 was almost 180 TWh.
- To provide the 180 TWh of energy consumed, this study calculates that 236 TWh of primary energy was required in Scotland in 1990, most of the losses between primary energy and energy consumption were associated with electricity generation.
- Was responsible for 46.5 Mt of CO 2 emissions. - In 2002, Scotland:
- Consumed 165 TWh of delivered energy across its main demand sectors, plus nearly 11 TWh for oil refining. Hence, total consumption in 2002 was 176 TWh.
- To provide the 176 TWh of energy consumed, the primary energy required in Scotland was 230 TWh , as found in 1990, most of the losses were associated with electricity generation.
- Was responsible for 44.0 Mt of CO 2 emissions.
However, these similar headline figures hide many important differences within the total envelope of fuel use and CO 2 emissions.
The following sections summarise the main facts, for fuel use, electricity generation, energy demand and CO 2 emissions.
Details of the interpretation and adjustment of the reported 1990 dataset, to enable comparison with the 2002 dataset, are provided in Appendix 1.
2.2 ENERGY USE
Figure 1 shows energy use in Scotland split by the main fuels used in 1990 and 2002:
Figure 1: Energy use in Scotland - 1990 & 2002
Solid fuel: Direct consumption of solid fuels fell substantially across the demand sectors, from 20 TWh of direct use (plus 3.6 TWh for coke production) in 1990, to only 4 TWh of direct use in 2002. This is largely due to the closure of the Ravenscraig steelworks although fuel switching across all sectors has also made a large contribution.
Oil: 1990 consumption was nearly 71 TWh (plus 10 TWh of refinery losses). Overall, oil-based fuel consumption had fallen 15% to 61 TWh by 2002. This was made up from a combination of a large decline in industry and service consumption, partially counterbalanced by increases in transport and domestic consumption. Refinery losses showed a small increase (10.6 TWh).
Natural gas: Consumption of gas has risen considerably, from 49 TWh (revised 1990 figure) to over 63 TWh in 2002. Demand has grown across all non-transport sectors, with the domestic sector being the largest consumer in both 1990 and 2002.
Electricity demand: Consumption within Scotland rose from 26 TWh in 1990 to 32 TWh in 2002, i.e. an increase of nearly 20%. Electricity demand rose across all three non-transport demand sectors: domestic (9.7 TWh to 12.3 TWh), industry (8.3 TWh to 10.2 TWh) and services (7.2 TWh to 11.3 TWh) 1.
Renewable energy: In 1990, renewable energy only registered in the AHS report for hydro-electricity generation: input of 4.4 TWh, saleable energy from this estimated to be 3.8 TWh. By 2002, total primary energy for electricity had increased to 5.46 TWh, with the contribution from hydro being similar to that in 1990 2. The increase was made up from generation by wind and thermal renewable sources.
The 1990 AHS report did not register any direct use of renewable energy, although it will have been present (for example, wood-burning fires and boilers). The 2002 study has estimated a small contribution of direct renewable consumption ( e.g. wood-burning), although, given the nature of this fuel, figures are difficult to track.
2.3 ELECTRICITY GENERATION
Figure 2 shows the fuels used for electricity generation in Scotland in 1990 and 2002.
Figure 2: Fuel for electricity generation in Scotland - 1990 & 2002
The nature of electricity generation changed considerably, with:
- Consumption of solid fuel for generating electricity rose (from 27 to 40 TWh), although some of this additional consumption will be associated with electricity exports. The result was more output from the coal-fired generation at Longannet and Cockenzie power stations, from an estimated 7.5 TWh to 13.2 TWh saleable electricity (a 76% increase on a like-for-like basis). Both facilities are now 40(+) years old.
- Gas consumption for electricity generation rose (from a reported zero TWh in 1990 to 21 TWh in 2002), although some of this will be associated with electricity exports. The main reason is the inclusion of additional gas-fired generation at Peterhead. Initially, generation at Peterhead was by conventional steam cycle, more recently augmented with CCGT generators. The 1990 reported figure was 0 TWh, 2002 = 7.8 TWh (on a like-for-like basis).
- Nuclear fuel is used solely for electricity generation. Consumption of nuclear fuels fell from 50 TWh in 1990 to 42 TWh in 2002, largely because of the loss of some installed generating capacity between these dates 3. Overall generating efficiencies are unlikely to have changed significantly. This is mirrored in the decrease in nuclear generation from approximately 14 to 13.5 TWh of saleable electricity (taking into account that nuclear generation consumes more than average self-consumption).
- Virtual elimination of oil-fired generation, from 1.2 to > 0.2 TWh. Oil generation is now predominantly used for nuclear stand-by and small-scale generation.
- Saleable electricity from renewable sources increased by 13%, from 3.8 TWh to estimated 4.5 TWh of saleable electricity.
2.4 DEMAND BY SECTOR
Figure 3 shows energy demand in Scotland for each of the main sectors, for 1990 and 2002:
Figure 3: Energy demand in Scotland - 1990 & 2002
Domestic: Consumption rose by 15% over the 12 years (using a revision to the AHS figures), from 48.5 to 56.0 TWh. The 2002 figures are dominated by gas, used mainly for heating. Electricity consumption rose by over 25%, due to an increased demand for electrical consumer goods/domestic appliances/ PCs etc. Solid fuel consumption was reduced to almost half its 1990 consumption figure.
All of the above trends are broadly in line with UK domestic trends over the same period.
Industry: Consumption fell from 50 TWh to 35 TWh, down 31%. This reflects the UK trend away from 'heavy', energy-intensive industries. It would appear that, across the UK, new jobs have been created in the less energy-intensive sectors, e.g. engineering, or in service industries. Scotland was part of this UK trend, for example, with closures at Ravenscraig Steel, Burntisland Alumina and others.
The fuel mix has moved away from coal and oil (combined use in 1990 = 58%, 2002 = 18%) towards much greater use of gas and electricity. Again, this in part reflects changes to the structure of the industry and its sub-sectors. However, it also shows the impact of simple economics (gas was relatively cheap in the mid to late 1990s), combined with increasing demand for 'cleaner' fuels as environmental legislation obliged either cleaner production or end-of-pipe abatement.
Transport: Appeared to reflect the general UK trend, where energy consumption for transport has risen by approximately 10%. This may be an underestimation, but it is difficult to say by how much given some of the uncertainties of both the 1990 and 2002 transport energy figures.
The principal fuel use was, is, and is likely to remain dominated by oil.
Services: Figures indicate a 10% increase from 24.4 to 26.8 TWh. Gas and electricity have grown at the expense of oil and coal (which was quite small to start with). Gas has replaced the other fossil fuels for space and water heating, in fact, the total non-electricity consumption has, if anything, fallen slightly. The increase in electricity is likely to reflect the changing nature of services, for example, more refrigeration (shops and warehouses), additional office equipment ( PCs, faxes, printers, photocopiers) and air-conditioning (although this is not a large element of energy use in Scotland).
2.5 CO 2 EMISSIONS
Two factors influence the level of CO 2 emissions, i.e. the amount of fuel used and the carbon emissions factors for those fuels. As shown earlier, the total fuel use in 1990 and 2002 is very similar. However, total CO 2 emissions fell from 46.5 to 44.0 Mt ( i.e. 5.4%), mainly as a result of changes to the fuel mix 4. The most significant changes to fuel mix included:
- Direct use of solid fuel for heating in industry, services and homes has been largely replaced by use of gas, or oil, i.e. fuels with lower CO 2 emissions.
- Coal use for electricity generation increased significantly.
- Gas use for electricity generation increased significantly.
In addition to the energy-related CO 2 emissions, there are significant non-energy sources, particularly land-use emissions. A short comparison of these wider CO 2 sources is included at the end of Appendix 1.
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