Energy Curtailment Regulation Impact on Distributed Generation Integration

This paper investigates the relationship between energy curtailment regulation and investments in distribution networks in a deregulated electric power system with distributed generation. Curtailment due to the network constraints is the interest of the paper. The network investment can be based on accommodating the energy produced from distributed generation without curtailment; however, a part of these investments is only relevant for a few hours annually when the generation is too high compared to the demand. Therefore, energy curtailment is generally allowed. The curtailed generation owners are compensated according to the curtailment regulation. In this paper, the optimal curtailment and investment are obtained by a proposed method under different energy curtailment regulations. The method is based on a network investment optimization model including fluctuating load and generation, investment timing, curtailment and regulatory impact. Case studies of German and Swedish energy curtailment regulations are performed. All the costs are obtained by a network investment model, which considers network constraints, fluctuations of generation and load and regulatory settings. The reference total social cost is assumed to be the minimum of the combined grid investment and energy curtailment costs. Results show that deep connection charge scheme for DG sends out strong locational signals for the DG connection and which reduces the total social cost compared to shallow connection charge scheme. Also the pre-agreed maximum curtailment level and high compensation price can lead to high total social cost.