Delivered cost estimates for new grid

and wind farms

For onshore wind farms, the range of costs is taken from the European Wind Energy Association (EWEA, 2004, Figure 2.3, p99). These costs range from €900 to €1150 per kilowatt installed, including grid connection. For the purposes of this analysis, the figure of €1000 is used. For offshore, a cost of €1500 per kilowatt installed is used. In the light of recent reports, this offshore cost is low.

The cost of transmission has been estimated assuming the use of direct current (DC) technology. For power levels of 500MW+ and distances of 100km+, this is the only viable technology. Due to the absence of a synchronous source, it has been assumed that it would be necessary to use voltage source converters at the wind farm end. Although, to date, this technology has not been used at these power levels, there are no obvious technical reasons why this could not be done (PB Power, 2002). At the load end, conventional converter technology would be employed with transmission voltages in the region of +450 kilovolts (kV).

Costs have been estimated using averages of those quoted by several internal and external sources, including PB Power (2002). Capital costs and losses split between fixed costs (per megawatt) and variable costs (per megawatt kilometre) have been assumed as in Table 10.4.

Table 10.4 Capital costs

Capital costs

DC

DC

Fixed cost

Variable cost

Cost (€ million/MW)

0.378

Offshore cost (€/MWkm)

630

Onshore cost (€/MWkm)

200

Losses

DC

DC

Fixed cost

Variable cost

Percentage

2%

Percentage/100km

0.33%

Source: Hughes and Hurley (2005b)

Source: Hughes and Hurley (2005b)

It has been assumed that annualized costs are equivalent to 10 per cent of capital costs. This results in transmission costs, excluding losses, ranging from under €0.02/kWh to around €0.06/kWh as distances range from 500km to 3000km, depending upon the offshore-onshore balance. This compares with average costs paid for grid capacity of €0.006/kWh from England to France and €0.019/kWh from Germany to The Netherlands in 2003.

While there is likely to be a charge for connecting to the alternating current (AC) grid at the load end, this may be a negative charge if the wind farm output has, as is assumed above, been transported to a major load centre. Therefore, a zero charge has been assumed here as a conservative assumption.

Table 10.5 Transmission cases and costs

Transmission cases (1000 MW)

Transmission cases (1000 MW)

Table 10.5 Transmission cases and costs

Distance onshore (km)

Offshore (km)

Total

Total capital costs (€ million)

Scotland to Dublin

175

55

230

448

Dublin to French Alps

1355

45

1400

678

North-West Africa to mid Germany

1500

1

1501

679

Northern Norway to mid Germany

500

1500

2000

1424

Northern Russia to mid Germany

2000

0

2000

778

Greater Gabbard to Köln

290

160

450

537

Baltic to mid Germany

200

200

400

544

Greater Gabbard to The Netherlands

50

200

250

514

South Irish Sea to Köln

800

240

1040

689

North Sea north to mid Germany

300

500

800

753

North Sea south to mid Germany

350

250

600

606

Irish Sea to France

1

500

501

693

Celtic Sea to mid Spain

300

1000

1300

1068

Source: Hughes and Hurley (2005b)

Source: Hughes and Hurley (2005b)

To calculate the cost of transmission of a quantity of electrical energy (in megawatt hours) from a wind farm to a load centre, the utilization factor of the wind farm was set equal to the capacity factor of the wind farm. This is a worst case assumption as the likely utilization factor of parts, if not all, of the transmission line could be much higher since other power could also be transmitted. The capital cost of production per megawatt hour at the wind farm site is calculated using a capacity factor derived from the estimated wind speed at the site (Dowling et al, 2004).

Table 10.6 Total capital costs at load centres per megawatt hour

Case

Wind speed (m s-1)

Capital cost generation (per MWh)

Capital cost transmission (per MWh)

Total capital cost at load centres (per MWh)

High wind area (onshore)**

7.07m s-1 at 60m*

379

0

379

Medium wind area (onshore)**

6.45m s-1 at 60m*

450

0

450

Low wind area (onshore)**

5.53m s-1 at 60m*

633

0

633

South Irish Sea to French coast

8.5m s-1 at 100m

512

237

749

South Irish Sea to French coast

10m s-1 at 100m

414

192

606

North Sea South to Germany

8.5m s-1 at 100m

510

206

716

North Sea South to Germany

10m s-1 at 100m

413

167

580

North Sea north to mid Germany

>10m s-1 at 100m

<413

<167

<580

Baltic to mid Germany

8.5m s-1 at 100m

510

185

695

Baltic to mid Germany

10m s-1 at 100m

419

21 0

629

Thames Estuary

~9m s-1 at 100m

467

160

627

** Mean annual wind speed at 10m; the rest of wind speeds at hub height. Source: Hughes and Hurley (2005b)

** Mean annual wind speed at 10m; the rest of wind speeds at hub height. Source: Hughes and Hurley (2005b)

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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