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NETWORK / 10 / MAY 2019 DISTRIBUTED GENERATION The benefits of flexibility Graham Ault, executive director at Smarter Grid Solutions, discusses the key values that flexibility can bring to an economically developed and operated grid. F lexible distributed generation connec- tions have matured into a standard generation customer connection option in many parts of the UK and are also being considered in other advanced electricity markets. While curtailed energy export and revenue have an impact on individual generators, there are strong upsides for overall sys - tem efficiency with dynamically managed curtailment providing a necessary and positive con- tribution to the smart, flexible system. Curtailment should also be seen as a starting point for additional innovative solutions and value creation in the whole system context. Flexible connections are an established part of the distrib - uted generation (DG) connec- tion market in the UK. Flexible DG (FDG) solutions range from simple single-DG export limiting and time of day export limiting schemes to more sophisticated so--intertrip and Active Network Management (ANM) enabled real-time, dynamic control. The outcome and acceptability for customers varies significantly across this range of solutions, with better customer outcomes resulting from the greater sophistication of FDG, with real- time dynamic curtailment. The impact of curtailment on customers is a fundamental con - sideration, with a clear trade-off between customer shouldered CAPEX (known up-front with some precision), ongoing revenues (not known up-front and subject to change over the project life) and time to connect. These issues are complex to assess but good practice has emerged in estimating and then balancing CAPEX (benefiting from FDG reduction), revenue (subject to some reduction) and time to connect (typically short - ened substantially from FDG). While any loss of generation export impacts ongoing rev- enues directly, curtailment is valuable in the whole system optimisation context. Studies in the UK, Germany (with its '3% rule' for curtailment) and the US show the benefits to customers and the system from flexible generation connection and curtailment. Germany's shallow connection cost regime and ac - companying socialised network reinforcement costs led to much higher electricity costs for all consumers. The additional costs for network reinforcement were second only to the generous Feed in Tariff (FiT) mechanism in driving up the very high customer costs of the energy transition in Germany. In most studies in these ad - vanced DG markets, the usable DG connection headroom, when flexible connection and curtail- ment is factored in, increases by 50 to 100 per cent, with some studies even showing 200 per cent headroom increases when network capacity is managed in a dynamic, real-time manner. This represents a significant customer connection oppor- tunity and reduced network investment requirement. Recent studies in the US and Europe have focused on the quality of the FDG solution with clear