Curtailment

1
Curtailment

• Richard Ford
• UK Grid Connections Manager
• Renewable Energy Systems

2
Definitions

• Constraint
• Not enough network
• Location specific
• Winter evenings?
• Compensation
• Requires
• Network investment

• Curtailment
• Not enough demand
• System-wide
• Summer nights?
• No compensation
• Requires
• Interconnectors
• Storage

3
Need for curtailment?

• Min System Demand 600MW
• Min thermal generation 200MW
• Maximum un-curtailed wind 400MW
• Over 400MW wind will have accepted connection
  offers by Summer 2007!

4
Any curtailment proposal should

• Be simple
• Allow generators to estimate the risk and impact
  of curtailment before accepting connection offer
• Protect the rights of generators once connection
  offer accepted
• Avoid the need for system operator
  despatch/intervention

5
One wind farm
Increasing wind speed
lt4 m/s
12 m/s
gt15 m/s
6
Two wind farms
Assumes wind conditions are similar
7
Many wind farms
8
Curtailing wind to 400MW?
9
Curtailing wind to 400MWcapping option
Impact of curtailment increases as capacity of
wind on network increases
10
Curtailing wind to 400MWsimplest option
11
Unecessary loss of production at lower wind speeds
170 MW
12
RES proposal
13
Curtailing wind to 600MW
14
Last on First off
86 W/S 14.3m/s
15
Curtailing wind to 500MW
16
83 W/S 14.1m/s
71 W/S 13.4m/s
17
Curtailing wind to 400MW
18
80 W/S 13.9m/s
66 W/S 13m/s
57 W/S 12.4m/s
19
More MWh from wind than the simplest option
80 W/S 13.9m/s
66 W/S 13m/s
57 W/S 12.4m/s
170 MW
20
Conclusions

• Minimises lost wind energy
• Simple
• Predictable
• Protected rights from acceptance of connection
  offer
• Bankable
• Self dispatch