Balancing challenges and
actions related to wind
production, example from
Twenties.
Nina Detlefsen, Energinet.dk
Outline
Why wind power is a challenge
Balancing in Denmark
Example from Twenties
Why is wind power a challenge?
Variability
-
Wind power is a variable source of production
Predictability
-
Forecasts improve – but will always be uncertain
-
Balancing is needed because of forecast errors
Wind power is traded day-ahead at Nordpool Spot
-
Uses statistical models to predict wind power
- Based on several meteorological weather predictions
- Continuously tuned and updated
The day ahead forecast determines the spot price.
The day ahead forecast error determines the regulating costs.
DK 1
DK2
Ramping of wind turbines ~ variability
Largest ramp at HR1 is 78%
In DK1 it varies up to 10%
Ramping of wind turbines ~ variability
Largest ramp in DK1 is 14%
At HR1 it varies up to 35%
Challenges with wind
Variability – needs another production that is as variable as
wind
Predictability – even though forecasts improve they will never
be perfect
How do we manage the balance?
• Normal use of reserves
1. Primary reserves (frequency reserves)
2. Secondary reserves
3. Tertiary reserves
• Use reserves in the opposite direction
1. Tertiary reserves
2. Secondary reserves
3. Primary reserves (frequency reserves)
Balance
Predicted Balance
Balance
Regulation
Balance
Balance
Balancing in the Danish system
Detailed power schedules for all units
Power schedules for wind power is based on short term wind
power predictions
Order regulating power based on predicted imbalance
Twenties project: Demo 4 STORM MANAGEMENT
Main objective
• Demonstrate shut down of wind farms
under stormy conditions without
jeopardizing safety of the system
Horns Rev 2 (200MW)
Flexible turbine control
Storm front forecasts
Investigate cost of changed production
associated with the planned down
regulation
• Coordinate wind farm control with
HVDC interconnector control and with
hydro power plant operation
www.twenties-project.eu
28/01/2011
Water power
•
•
•
•
Wind power
Approach
Strategies
Two possible strategies:
- Controlled action
- Automatic control
Controlled action involves:
-
Based on wind speed forecasts
Calculate wind power forecasts
Predict system imbalance
Trade regulating power – hydro from Norway
HVDC is regulated accordingly
Automatic control involves:
- New controller in the turbines will reduce power more gradually
- Automatic imbalance control
Cases
Forecast storm:
- Can perform a controlled action
No storm forecast:
- automatic more gradual reduction of power
Forecast storm:
- Define storm in terms of meteorological forecast
- Decide threshold for when to invoke the controlled action
- Based on skill score
Work to be done
Analyze storm forecasting
Different strategies for managing the storm
Study system impact
- Imbalances
- Regulating power and reserves
Case study – Storm November 11th 2010
Summing up
Why wind power is a challenge:
- Variability
- Predictability
Balancing in Denmark
- Predict system imbalance – based on detailed power schedules
- Order regulating power accordingly
Example from Twenties
- Storm – most variable wind situation
- Expected to danger system safety in the future