THE DIFFERENT FUEL TYPES
The contribution of different fuels to the overall picture in 2002 is shown in Figure 3. This includes the fuels used to generate electricity. The importance of oil and gas can be seen. Further commentary on each fuel is presented below. Some of this fuel use is directed at generating electricity; separate consideration is therefore given to this.
Figure 3: Distribution of all fuels used in Scotland in 2002
Gas
Gas is used directly for heating in the domestic, industry and service sectors. Demand has grown in all sectors. Domestic users were the largest consumers in both 1990 and 2002. Gas is also used to generate electricity at Peterhead power station. A large volume of gas (almost 400 TWh in 2002, compared to Scotland's total energy consumption, in 2002, across all sectors of 175 TWh) is extracted and transported through Scotland each year. Most of this export goes to England, with some going to Ireland.
Between 1990 and 2002, consumption of gas for electricity generation has grown markedly; it was essentially zero in 1990. Direct consumption for heating has risen by over 22%.
Oil
A large quantity of oil (around 1,150 TWh) is produced in Scotland each year. Most of this is exported as crude oil but almost 10% is refined at Grangemouth. The majority of the energy products from oil ( e.g. petrol) used in Scotland is consumed for transport purposes, although some are used for heating in the industry, domestic and service sectors.
Oil-based fuel consumption fell by around 15% between 1990 and 2002. This reflects a large decline in the use of oil in the industry and service sectors, which outweighs the significant increase associated with transport.
Coal
The majority of coal consumption in Scotland is related to electricity generation at Longannet and Cockenzie. Scotland exports much of its coal production to England and Ireland.
Coal use for electricity generation rose by just over 50% between 1990 and 2002. Some of this electricity is, however, exported. On the other hand, the direct use of coal dropped substantially (by around 75%). This is largely due to the closure of Ravenscraig in the early 1990s, although energy users switching from coal to gas also had an effect.
Nuclear fuel
In 2002, there were three nuclear power station sites in Scotland, at Torness, Hunterston and Chapelcross. The latter has now closed.
Consumption of energy derived from nuclear fuels fell by around 16% between 1990 and 2002, essentially reflecting the loss of generating capacity over that period.
Renewables
The main sources of renewable energy in Scotland are the hydroelectric generators built in the mid-20 th century. There are, however, increasing contributions from wind, newer small-scale hydro schemes and thermal renewable sources.
Over the 12-year period since 1990, the contribution from renewables has increased by around 13%. The contribution from hydro schemes is similar to the level in 1990. The overall increase reflects newer schemes for wind and thermal sources.
Electricity
In 2002, Scotland had six major power plants: two fuelled by coal, one by gas and three from nuclear fuel. These generated the majority of the electricity. In addition, Scotland has a number of hydro schemes, along with wind and thermal schemes, two pumped-hydro storage facilities and many small-scale generators (including combined heat and power ( CHP) systems).
Of the total fuel used in Scotland over 43% is used in the generation of electricity. The distribution between the fuels used in the major power plants 3 is shown in Figure 4.
Figure 4: Fuels for electricity generation in Scotland in 2002
The process of generating electricity entails energy losses due to the thermal efficiency of the different types of power station. For example the coal fired plant is estimated to have a thermal efficiency of 37%. The average efficiency of electricity generation in Scotland is 41%.
The share of generation output by fuel used in the major power plants is shown in Figure 5. Those forms of electricity generation which have a higher than average efficiency have a higher share of the electricity output, e.g. renewables which has 5% of fuel input yet 11% of output. Of the electricity generated in Scotland, 70% is used in Scotland, the remainder is accounted for by losses in the electricity grid and exports to the rest of the UK.
Figure 5: Electricity output in Scotland in 2002 by fuel type
In 2002, Scotland exported about 20% of electricity generated to England and Ireland. According to current plans many of the major power plants are, however, expected to stop generation in the next 10-20 years. If these plans were implemented, in 15 years' time, only two of Scotland's existing large plants would be in operation: Peterhead (gas-fired) and Torness (nuclear).
By 2020, Scotland aims to generate 40% of its electricity needs from renewable sources. While future plans for some of Scotland's major power stations have been made known, these may change in response to market conditions. Similarly, plans for new power stations are commercial decisions for the electricity generation sector. Their decisions will take into account factors such as: future energy prices, electricity demands, the regulatory environment and new technical developments.
Over the 1990 to 2002 period, the nature of electricity generation changed considerably. This is characterised by:
- More coal-fired generation at Longannet and Cockenzie; an increase of around 66%.
- New additional gas-fired generation at Peterhead, from a very low level in 1990.
- Less nuclear generation; a decrease of around 16%.
- Virtual elimination of oil-fired generation.
- More use of renewable sources; an increase of around 13% in saleable electricity.
Energy Use by End Consumers
The distribution of energy sources consumed by end consumer is shown in Figure 6.
Figure 6: Energy use by end consumers in 2002
The distribution of energy sources used by each of the main groups of end consumers is shown in Figure 7, this is shown as the percentage of the total energy use by all end consumers.
Figure 7: Distribution of energy use by end consumer in Scotland in 2002
This shows a number of key features:
- The largest use of gas is in the domestic sector, with significant use in industry and services.
- The dominant use of oil in the transport sector.
- Electricity use split evenly across the domestic, industry and service sectors.
- A small share for solid fuel, with the most significant use in the domestic sector, for those homes without access to other energy supplies.