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Renewable electricity

In 2001, just over 1% of electricity consumed in the South West was generated from renewable sources. The UK Climate Change Programme expresses an aim for renewables to supply 10% of UK electricity by 2010. The government's Renewables Obligation also includes a target of 15.4% of renewable electricity by 2015 (DTI, 2004b ). The Energy White Paper also emphasises the importance of real progress by 2020, highlighting an aspiration to achieve double the 10% 2010 target for renewables by 2020 (DTI, 2003b).

The South West should be able to achieve 11-15% of electricity generated from renewable sources by 2010. This target was specified in the REvision 2010 project, which aimed to identify sub-regional renewable electricity generation targets for the South West (GOSW & SWRA, 2004). A more detailed breakdown of the electricity targets set, information on the regional renewable energy strategy, and assessments of resources available for renewables in the South West, can be found in Additional Information.

The scenarios below examine different technology mixes to meet a target of 15% of electricity supplied by renewables by 2015. Three factors have been assessed in reviewing the potential benefits of the different renewable technology mixes in the South West:

  • Job creation (overall and within the region).
  • Investment levels.
  • Land requirement for energy crops and onshore wind turbines.

General renewable electricity assumptions

  • All of the scenarios have been designed to meet the UK Climate Change Programme 10% renewable electricity target in 2010, which is then assumed to continue to the Renewables Obligation target of 15% by 2015 (DTI, 2004b).
    • At the time of writing the REvision 2010 report, official regional electricity consumption data was unavailable. However, detailed consumption figures have since been produced by the Department of Trade and Industry and have been used in this analysis (DTI, 2004).
  • Between marker years in the calculation (2001, 2004, 2010, 2015), all renewable energy penetration was assumed to grow on a straight line basis.
  • It is assumed that the Oldbury Magnox station will close in 2013 (HMNI, 2002), and that the Langage combined cycle gas–fired power station will be commissioned in 2008, with completion in 2010 (National Grid, 2004).
  • Consistent with the ecological footprinting methodology, the net operating emissions of all electricity sector renewable technologies are assumed to be zero.
  • The South West employment calculations are based upon estimates of the benefits accruing to the region as a proportion of the total employment benefits arising from renewable energy installation and operation. For this analysis, the assumed local benefits are 5% for renewable technology installation, 10% for operation and maintenance, and 80%-100% for biomass/waste fuel supply (ESD, 2004).

Further assumptions are discussed in Additional Information.

Scenario 1: REvision 2010 renewable electricity mix

What would be the effect of extending the REvision 2010 proposed renewable electricity mix for 2010 (GOSW & SWRA, 2004) to a 15% renewable electricity target by 2015?

Table 10
REvision 2010 electricity technology mix
 
Renewable technology Installed capacity (MW)
Total 563-665
of which…  
Shoreline wave 1
Offshore wave 5
Tidal barrage 0
Tidal stream 1
Small-scale hydro 9
Solar Photovoltaic 2
Energy crops/Forest residues 73
Straw 0
Anaerobic digestion 15
Poultry litter 10
Landfill gas 46
Energy from waste (EFW) 32-38
Onshore wind 319-415
Offshore wind 50
 
  • Because the projected electricity consumption figure used in the analysis (DTI, 2004) is higher than the earlier projection used for REvision 2010, the REvision 2010 capacities are insufficient to meet the current 10% target (3,600 GWh) in 2010.
  • For the development of the 2015 capacity forecasts to meet the 15% target (5,700 GWh), the maximum resource figures for each technology option were met, and then selected technologies increased further to meet the target.

Table 11 summarises the findings of Scenario 1 for renewable electricity.

Table 11
Estimated renewable electricity, and associated employment estimates, based on REvision 2010 renewable electricity mixes, in 2015
 
Installed capacity:  
Total (MW) 6,320
Renewable (MW) 1,590
Total cumulative investment (£ million) 1,200
Land requirement:  
Energy crops ('000ha) 50
Onshore wind ('000ha) 6
Employment:  
2015 total (fte) 5,900
South West 2015 total (fte) 2,000
South West cumulative 2001-2015 (fte) 14,200
South West jobs per unit of investment (fte/£m) 12
South West jobs per MW installed (fte/MW) 9
fte = full time equivalent
1. Energy crops and onshore wind turbines can share the same land to reduce the total requirement.
2. The net capacity figure for electricity imports was derived by equating it to a plant running for 100% of operation time.

Scenario 2: Individual technology strategies

How would other individual renewable technologies meet the extended 15% renewable energy target by 2015?

Four technology scenario options were analysed, each of which focussed on a different technology. These options were: biomass and waste; wind; photovoltaics; and wave and tidal.

Starting from base case energy consumption, scenarios were developed in two stages.

  1. The 2010 10% target was achieved by increasing the penetration of the individual technology or group of technologies for each option.
  2. After 2010, the same technologies are increased to meet the 2015 15% target. Where feasible, some capacities specified in REvision 2010 (GOSW & SWRA, 2004) have been increased.

Table 12 summarises the findings of the renewable electricity technologies analysed in Scenario 2.

Table 12
Estimated renewable electricity, and associated employment estimates, based on individual technology strategies, in 2015
 
  Biomass & waste Wind Photovoltaics Wave & Tidal
Installed capacity:  
Total (MW) 6,320 6,650 8,620 6,030
Renewable (MW) 1,590 1,930 3,890 1,300
Total cumulative investment (£ million) 1,200 1,100 10,400 1,500
Land requirement:  
Energy crops ('000ha) 51 37 37 37
Onshore wind ('000ha) 6 9 3 3
Employment:  
2015 total (fte) 6,500 4,500 19,500 2,600
South West 2015 total (fte) 3,600 1,300 2,200 1,200
South West cumulative 2001-2015 (fte) 23,000 12,500 19,300 11,800
South West jobs per unit of investment (fte/£m) 16 11 2 8
South West jobs per MW installed (fte/MW) 23 7 5 10
fte = full time equivalent
Note: Energy crops and onshore wind turbines can share the same land to reduce the total requirement

Renewable electricity Total Carbon Audit/Total Energy Audit

Measuring the ecological footprint of any technology or process involves taking its whole lifetime environmental impact into account. In addition to the operating impact of the technology, this will include the impact arising from manufacture, assembly, installation, commissioning, decommissioning and disposal. For energy technologies, the lifetime assessment can take two forms: a Total Carbon Audit (TCA), or a Total Energy Audit (TEA). The TCA covers all aspects of the environmental impact of a technology, while the TEA focuses on the technology's net energy consumption during its lifetime.

TCA is very country specific, and can have high levels of variability. Firstly, the comparison with other technologies depends, for example, on where the renewable technology is manufactured, and where the biomass or fossil fuels are produced. The examples below are for renewable energy produced in Denmark, which has its own wind manufacturing capacity, has an organised biomass infrastructure and imports all of its fossil fuels, which is not the case in the South West. Secondly, variability arises from the difficulty in determining the boundaries of the analysis. For example, when calculating the impact of wind turbines, should the assessment include the manufacture of the plant to produce and install the wind turbines?

Owing to this variability, and the lack of definite TCA numbers in the UK, let alone the South West, it was not possible to perform a full TCA analysis for the renewable electricity sector in the region.

Example 1: Total Carbon Audit for biomass fuels

It has been questioned whether biomass fuels are CO2 neutral. A study carried out in Denmark showed that the emissions from the procurement of biomass fuels are equivalent to, or less than, those for fossil fuels, as shown in Figure 2 (Fock & Christiansen, 1997). If this graph also showed the emissions from fuel combustion, the emissions factors for fossil fuels would increase by 55-95 kg CO2/GJ, against a zero increase for the biomass fuels.

Figure 2
CO2 emissions for fuel procurement (kg CO2/GJ)

fig 2

Source: Fock & Christiansen, 1997

Example 2: Total Energy Audit for Vestas Wind Systems

The Danish wind turbine manufacturer Vestas has performed a TEA, from the extraction of raw materials to final disposal, of two versions of its 2 MW V80 wind turbine (for onshore and offshore applications). Taking into account the total energy consumption of the wind turbines over their lifetime, and their anticipated electricity production, Vestas has calculated (from two installed wind farms) that the net energy payback takes 7.7 to 9 months out of a 20-year lifetime, as shown in Table 13.

Table 13
Energy balance of two versions of the V80 (2 MW) wind turbine
 
Turbine Total electricity consumption (MWh) Annual electricity generated (MWh) Energy Balance (months)
Manufacturing & dismantling Operation Transport Total
Onshore 3,280 330 20 3,640 5,640 7.7
Offshore 5,450 570 50 6,080 8,090 9
Note: Totals may differ due to rounding
Source: Vestas, 2004

Scenario 3: One planet lifestyle

What is required to achieve a one planet lifestyle level of CO2 emissions by 2015, from electricity supplied in the South West?

The following variables were assumed:

  • The renewable electricity Scenario 2 was taken as the starting point, and the penetrations achieved in all four Scenario 2 options were applied for 2010 and 2015.
  • Any shortfalls for 2015 were met by assuming an increased penetration speed for renewable technologies, by using the 2015 penetrations from Scenario 2, with any additional required capacity being provided by photovoltaic panels, either as standalone systems or connected to fuel cell storage systems.
  • Seabank CCGT gas-fired and Indian Queens oil-fired power stations will be decommissioned between 2010 and 2015. Langage reduces its electricity output by approximately 20%.
  • A hydrogen economy was not considered, as it was assumed that the required infrastructure will not in place by 2015.

For a detailed breakdown of the installed capacity for each technology, see Additional Information. Table 14 summarises the findings of renewable electricity Scenario 3.

Table 14
Estimated renewable electricity and associated employment estimates, based on one planet lifestyle assumptions, in 2015
 
Installed capacity:  
Total (MW) 14,640
Renewable (MW) 12,310
Total cumulative investment (£ million) 29,100
Land requirement:  
Energy crops ('000ha) 124
Onshore wind ('000ha) 10
Employment:  
2015 total (fte) 74,900
South West 2015 total (fte) 8,300
South West cumulative 2001-2015 (fte) 48,300
South West jobs per unit of investment (fte/£m) 2
South West jobs per MW installed (fte/MW) 4
fte = full time equivalent
Note: Energy crops and onshore wind turbines can share the same land to reduce the total requirement

Cumulative investment

Renewable electricity scenarios 1 and 2 above, show that one option clearly requires much more investment than the others: photovoltaic technology (PV) dominated Scenario 2, and was nearly 10 times more expensive than others. PV is expensive per MW installed and even assuming a reduction in price as the technology matures, it is still more expensive than other renewable energy options. In addition, PV produces less electricity per MW installed than other technologies – this means that more capacity must be installed to produce the same amount of electricity. The difference in cost between the remaining scenarios is small. For Scenario 3: One planet lifestyle, maintaining current levels of electricity consumption to 2015 greatly decreases the requirement for renewable plant, thereby reducing the amount of investment required by 45% to £16 million.

Figure 3
Cumulative investment in the South West due to renewable energy, 2001-2015

fig 3

Employment

The local employment benefits for new renewable electricity plant in 2015 can be assessed in three different ways: absolute employment growth, employment per unit of investment and employment per unit of installed plant. For Scenario 1: REvision 2010 renewable electricity mix and Scenario 2: Individual technology strategies, the biomass and waste scenario was the best option for all three measures, owing to the significant employment generated in the agricultural and fuel supply sectors. For the other scenarios, the PV scenario had the best total employment (10,400 cumulative full-time equivalent (fte)) owing to the large number of panels that need to be installed. Scenario 1 was the best per unit investment (12 FTE/£m) and the wave and tidal scenario the best per unit of new capacity (10 FTE/MW). Scenario 3: One planet lifestyle achieves the most employment in the South West, but is the worst scenario under the other employment criteria.

Figure 4
Cumulative employment in the South West due to renewable energy, 2001-2015

fig 4

Land requirements

Land is required for energy crops and onshore wind turbines. Total arable and horticultural land area in the South West is just over 500,000 hectares. The renewable electricity scenarios suggest that between 40,000 and 93,000 hectares of land would be needed for energy crops and wind turbines. This number could be reduced by up to 9,000 hectares by using the same land for both purposes, by planting crops around wind turbines. For Scenario 3: One planet lifestyle, the land requirements are higher at almost 100,000 hectares, which is 20% of all agricultural land in the region. However, as the location for wind turbines is not constrained to agricultural land, the impact could again be reduced slightly.

CO2 emissions

Increasing renewable energy penetration reduces the total CO2 emissions arising from the electricity sector in the South West.

In all scenarios except for Scenario 3: One planet lifestyle, the net reduction in 2015 emissions from 2001 is 6%, compared with a 2010 reduction of 13%. The main cause of the increase of emissions between 2010 and 2015 is the assumed closure of Oldbury Magnox station in 2013, whose output is replaced by imported electricity. This closure reverses the trend of reduction in emissions up to 2010, leaving a net reduction at 2015 of 6% from 2001 levels (see Figure 5).

The second key cause is the effect of electricity consumption growth in the South West. As consumption grows, an increasing proportion of new renewable growth is used to match this growth instead of reducing total emissions. However, if electricity consumption remained static at the 2001 figure, the net effect of increasing renewable energy penetration would be a 21% reduction in emissions by 2015.

For Scenario 3: One planet lifestyle, to achieve a 73% reduction in emissions, it was necessary to close the Seabank CCGT and Indian Queens oil fired power stations and decrease the output from the (new) Langage CCGT. Table 15 shows the CO2 emissions with the renewable electricity scenarios, by technology.

Table 15
Emissions by technology for renewable electricity scenarios ('000 tonnes)
 
  Base case: 2001 Scenarios to 2015
Scenario 1 & Scenario 2 Scenario 3
Renewables 0 0 0
Nuclear 0 0 0
Combined cycle gas turbine* 1,930 4,990 2,360
Open cycle gas turbine** 220 220 0
Coal 0 0 0
Oil 0 0 0
Imported 7,260 3,710 140
Total 9,420 8,920 2,500
* A gas fired plant.
** Usually oil-fired plant designed to supply peak demand.
 

Figure 5
South West electricity sector air emissions as a proportion of the 2001 base case

fig 5

Reduction of the ecological footprint

Figure 6 illustrates the effect of an increase in renewable energy on the total direct energy ecological footprint for the South West, for the scenarios discussed above.

Figure 6
Total direct energy base case and scenario ecological footprints for the South West

fig 6

Note: Renewable energy has a 0 gha footprint, so electricity consumption could increase without increasing the footprint, if the increase in consumption is supplied from renewable energy sources.