Abstract Summary
The massive adhesion of new technology on the consumer side as electrical heating, solar PV and electrical vehicles are causing a structural change in electricity consumption patterns and taking the grid capacity to its limit, especially in densely populated urban areas. As a result, it is becoming more complex for distribution grid operators (DSO) to guarantee the grid capacity, control the power flows in real-time, and ensure stability and reliability of their electricity networks. Once that the maximum transport capacity is reached, congestion is build-up, which can lead to a local power outage and, eventually, to structural black-outs. A traditional solution would be reinforcing the critical parts of the grids, however, this is a multi-year and high-cost process, amplified by the severe shortage of qualified field technicians. As a solution, applying flexibility in medium and low voltage (MV\LV) grids has been identified as a key requirement in future power systems to manage the uncertainty and to solve congestion. Flexibility is the ability to change the energy usage/provision of assets in a certain time frame, which could be done by reducing consumption or providing more energy to the grid, or by curtailing renewable generation. For residential households, this yields load-shifting, rescheduling, load-control, vehicle-to-grid, (heating) storage, amongst others. One of the options to invoke such flexible behaviour, is by trading through a dedicated flexibility market in such a way that the consumer can sell its flexible capacity, as a service, to the DSO to resolve congestion. This paper will review local flexibility markets that are currently in operation (e.g., GOPACS, NODES, Piclo Flex, Enera, NEBEF and PJM) to provide trading platforms for local participants, including distribution system operators and aggregators with the objective of managing congestion. The paper will start with a review around the key elements and technologies of a flexibility market. Afterwards, the proposed markets are compared, and future research directions and challenges are suggested. The results of this paper allow a well-weighed tradeoff between the application of (explicit) flexibility from a DSO’s perspective, and will provide insight into the systemic adaptations needed to roll out such approaches.
