SINTEF Energy Research 1 Planning And Operation Of Large Wind Farms In Areas With Limited Power Transfer Capacity by M. Korpås, J. O. Tande, K. Uhlen, E. S. Huse, T. Gjengedal

SINTEF Energy Research 2 Introduction: Wind integration in constrained grids Case study specification Description of simulation model Smoothing of wind generation within a large area Simulation results Conclusions Outline

SINTEF Energy Research 3 At many locations with excellent wind conditions the development of wind farms are hindered by grid issues. The limit for wind power capacity is not easy to establish. Conservative assumptions are often applied that unnecessarily limits the wind power installation. This presentation shows that significantly more wind power can be allowed by: taking account for the wind power characteristics facilitating coordinated power system operation. The combination of wind and hydro (with storage) is of particular interest, and used as a case for this presentation. Introduction

SINTEF Energy Research 4 Case study specifications Hydro power plants 380 MW w 760 GWh reservoir Wind farms (115 MW - ??) Local loads 420 kV main transmission 132 kV corridor Max transfer capacity 420 MW AGC Automatic Generation Control or manual by System Operator Hydro inflow (MWh/h) 2110 GWh/y 1940 GWh/y Load (MW)

SINTEF Energy Research 5 Simulate 30 years operation on an hour-by-hour basis Model inputs include: 30-year time series with inflow to hydro reservoir and wind power Statistical variations in consumer load and electricity price from the EMPS-model (Multi-area Power-market Simulator). Specification of the power system components, including: hydro storage capacity rated power of hydropower plant thermal limits of 132 kV transmission lines Assumed AGC strategy: The AGC operates to avoid line overloading Control hydro: control the hydropower first and secondary the wind power (if needed) Control wind: control the wind power only Simulation model

SINTEF Energy Research 6 Long-term wind and inflow variations

SINTEF Energy Research 7 Hour by hour wind power variations

SINTEF Energy Research 8 Hour by hour wind power variations

SINTEF Energy Research 9 Control wind Simulation of 3x200 MW wind farms

SINTEF Energy Research 10 Control hydro Simulation of 3x200 MW wind farms

SINTEF Energy Research 11 Simulation of 3x200 MW wind farms summation of three wind farms simple scaling of wind production congested wind hydro

SINTEF Energy Research 12 Income vs. wind capacity control hydro Year with lowest income reduction control wind Year with highest income reduction

SINTEF Energy Research 13 Simplified and conservative assumptions allow less than 200 MW of wind power Significantly more is possible by: assuming coordinated control taking account for the geographical wind smoothing effect Installation of 600 MW of wind power results in: no significant reduction in income from energy sales if adjusting hydro generation only 1-5 % reduction of income if constraining wind power and leaving hydro according to schedule (all compared to the non- congested case) Summary results from case study

SINTEF Energy Research 14 Power system coordination allows for surprisingly large amounts of wind power. It is essential to take account for the power system flexibility and the stochastic and dispersed nature of wind power. The presented methodology facilitates this and represents a rational approach for power system integration of wind farms in areas with limited transfer capacity. Conclusion