EMEC has delivered a detailed modelling study exploring how to optimise the integration of tidal energy and battery storage with alternative offtake routes (e.g. hydrogen production) to overcome barriers to commercial scale tidal energy deployments.
The study has been published as part of the FORWARD2030 project, supported by the European Union's Horizon 2020 research and innovation programme. FORWARD2030 aims to deliver a series of high-impact cost reductions to achieve large-scale tidal energy array deployment by 2030.
Challenge and opportunity
Many of the UK's most promising tidal stream sites are in remote coastal areas with limited and frequently disrupted grid connections. These grid limitations pose a barrier to meeting national and international deployment targets.
The introduction of alternative offtake routes is a promising opportunity where local businesses can take advantage of the local generation of green electricity at advantageous pricing as part of a behind-the-meter power purchase agreement . This not only reduces reliance on expensive retail electricity or diesel generators but also opens the door to attracting new industries to these regions.
The predictability of tidal stream energy makes it a strong candidate for alternative offtake applications. While tidal generation varies throughout the day, its cyclical nature means this variability can be accurately forecast.
When coupled with battery storage to smooth generation, continuous power can be fed to the grid or to an offtake.
However there has been limited practical analysis of how such integrated systems would operate in real-world conditions.
Modelling with real-world data
EMEC developed a comprehensive model to explore how tidal energy could be optimally used to power local offtake, using its vanadium flow batteries and hydrogen electrolyser as a case study.
The model uses EMEC's resource data collected at its tidal energy test site in Orkney, alongside site acceptance data from its adjacent onshore R&D facilities where integration of tidal energy converters, battery storage and hydrogen are gearing up to be trialled.
This real-world data was used to undertake a detailed analysis to understand what tidal generation will look like for a typical annual cycle, how batteries may be used to ensure consistency of supply and how operation of a partially islanded system can maximise a limited grid connection.
The findings from the model were then qualitatively assessed to understand how they may be extended to larger tidal farms and how these may be integrated with wind farms. This was then extended to investigate the potential for grid balancing services and other potential offtake industries such as synthetic fuel production.
Key findings
The modelling revealed that tidal energy technologies, when combined with appropriately-sized energy storage systems, can deliver stable, near-continuous behind-the-meter power to industrial offtakes.
