Strategies to increase grid flexibility for an isolated system with over 80% renewable electricity in 2030

As renewable electricity targets rise around the world, relatively isolated systems reliant on variable renewables, such as wind and solar power, are rapidly facing unresolved issues regarding system security, flexibility costs and remuneration structures for market participants. Although system service payments exist in some electricity markets, there is often insufficient incentive to invest in greater flexibility, either in the demand or supply side. Here, the economic benefits of various flexibility options are considered, leading towards a discussion of market incentives and strategies for reform. In addition to a range of traditional sources of flexibility from conventional generation, interconnection, and short duration batteries, the importance of system stability is emphasised, including synchronous condensers to supplement inertia, as well as medium-duration storage, and a more active balancing role for heat, transport and industrial loads. Each strategy alleviates the use of fossil fuel based gas plants during periods of system stress and enables the absorption of excess renewables. With over 80% of annual energy to be provided mostly by wind and solar power by 2030, Ireland provides a pertinent case for analysis.