Cardiff-Weston vs Shoots – a comparison of the barrage schemes
|
Cardiff-Weston barrage |
The Shoots barrage |
Length of barrage |
15.9m |
6.5m (approx) |
Turbine No x runner dia. |
216 x 9m |
30 x 7.6m |
Type of turbine |
Bulb, fixed distributor, |
Straflo or rim generator, |
No of turbines/Caisson |
4 |
2 |
Generator capacity |
40MW |
35MW |
Total installed capacity |
8,640MW |
1,050MW |
Annual energy output |
|
|
with reverse pumping |
17TWh (Approx) |
2.75TWh |
Annual energy, ebb |
|
|
generation only |
16.5TWh(approx) |
2.75TWh |
Contribution to UK |
|
|
electricity supply |
|
|
(2006 data) |
4.40% |
0.70% |
Capital cost (2006) |
£15B |
£1.4B-£1.8B |
Annual O&m costs |
£115M |
£22M-£27M |
Unit cost of electricity |
3.6-22.3 p/kWh |
3-15.4 p/kWh |
Annual saving in CO2 |
|
|
based on 0.43kg/kWh |
7.3M tonnes |
1.2M tonnes |
Lifetime carbon saving |
877M tonnes |
142M tonnes |
Environmental aspects |
Both schemes need to |
fish passes and injury |
|
look at sedimentation; |
injury passing through |
|