Capacity factor enhancement for an export limited wind generation site utilising a novel flywheel energy storage strategy

The percentage of generation provided by wind power sites is ever-increasing, bringing with it additional challenges and benefits. An increasing number of wind generation sites in Great Britain are subject to export limitation schemes (ELS) that ensure generation does not exceed the rated capacities of distribution network infrastructure. This leads to reduced generation resulting in loss of revenue and increased costs. This export limitation is exclusively performed on a site-by-site basis, in contrast to large-scale curtailment to meet national distribution limits. This paper presents for the first time a study highlighting the increasingly common issue of ELS restrictions and how the capacity factor at such sites can be enhanced by deploying Flywheel Energy Storage Systems (FESSs). FESSs can enhance the system performance metrics by storing energy that would otherwise be wasted and using this to increase the capacity factor of the site. In this paper, a novel model is demonstrated by showing for the first time how a FESS can be utilised to enhance the performance of a site subjected to export limitation. A FESS integration and sensitivity analysis performed on a 1MW wind power site with varying degrees of export limitation in place show that the site could generate an additional 6.1–38.5MWh over the course of a year. Subsequent novel economic analysis of the installations showed that the system is economically viable across a wide range of scenarios, increasing the Net Present Value of the site by up to 1.25%. Finally, the performance of the FESS is compared to a Lithium-Ion Battery Energy Storage System (BESS), highlighting the novel contribution of using a flywheel for this application by showing the excessive cycling a BESS would experience and the knock-on effect this has on economic viability. This work can have a significant impact on owners of distributed generation across Great Britain and beyond.