Options for allocating and releasing distribution system capacity: Deciding between interruptible connections and firm DG connections

• A cost benefit analysis of DG connection options in a constrained area is undertaken.
• The smart connection option is by far the best option when comparing with Business as Usual (BAU) connections.
• We find that small and large generators can prefer different connection arrangements.
• Lower curtailment levels tend to reduce the value of firm connections.

The aim of this study is to quantify the trade-off between selecting a distributed generation (DG) smarter connection with limited export capacity and a more expensive firm DG connection with a guarantee of full export capacity. The study is part of the analysis of a customer funded network innovation project in the UK. A cost-benefit analysis of the different connection options for connecting DG customers in a specific constrained area in the UK is performed. The study not only requires the identification of the main cost drivers and revenues (including embedded benefits and those allowed by regulation) for getting a new DG connection but also illustrates the interaction (operational and contractual) between the different parties involved (generators, distribution network operators, electricity suppliers, and demand). This study provides empirical evidence, under a number of scenarios, of the potential savings when a smart connection option is available. The results suggest that in general small wind DG customers will always have an advantage in selecting a smarter connection over large ones. We also examine the type of connection that would be preferred by solar PV DG customers and Anaerobic Digestion (AD) DG customers. The study shows that lower curtailment levels tend to substantially reduce the value of firm connections.