Integration of Wind Power Generation with Compressed Air Energy Storage 1=Energy 2=Wind Power

Lead Research Organisation: University of Warwick
Department Name: Sch of Engineering

Abstract

In the UK, with the retirement of fossil fuel power plants, the margin between power generation capacity and peak load demand was less than 5% for the winter of 2017-2018. Therefore any major unpredicted generation fluctuation may cause power shortfall. Simultaneously, the penetration of intermittent wind power has rapidly increased in the past five years. As a result it, has become extremely challenging to maintain generation and load balance, impacting greatly on grid stability and reliability.

Conversely, operational and maintenance costs of wind turbines, especially offshore, can be high. Wind turbine gearboxes possess relatively high failure rates when compared to other turbine subsystems. This is compounded by the severity of gearbox failure (0.154/yr major failures per turbine - the highest of any subsystem), the long repair time (estimated at 300 hours for a major repair/replacement) and high repair cost (estimated at 230,000 Euros on average for a major repair or replacement). A significant cause of gearbox wear and failure is the high torque spikes experienced during operation, which are common in wind turbine gearboxes owing to sudden wind gusts.

Development of storable secondary energy carriers for decoupling fluctuating supply is widely accepted as a feasible solution to the identified challenges. Among various energy storage technologies, this project considers Compressed Air Energy Storage (CAES). CAES has the advantages of being clean, safe, cheap, sustainable, low maintenance, long lasting and large scale (large capacity and power). There are two principle reasons to choose this technology:
-Rich storage capacity, It is recently reported that the UK has a minimum of 6TWh suitable underground storage capacity for compressed air energy, where also, the suitable storage sites are close to the existing wind farms or planned future wind farms.
-Gearbox lifetime, A hybrid wind turbine with a direct mechanical connection to a wind turbine shaft studied by a PhD student prior to 2017. Initial analysis indicated that a direct connection with CAES may produce a mechanism to absorb high torque spikes, prolonging wind turbine gearbox lifetime.

The project aims to study the potential of CAES in supporting wind power generation. Research will address technical challenges in hybrid wind turbines and conduct techno-economic analysis. The project tasks are organised as follows:
1. Investigate the potential for using CAES to maximise wind power generation;
2. Analyse the UK opportunities of integration of wind power with CAES;
3. Conduct the research on hybrid connection system structure for wind turbine integration with CAES and the current technology gap for improving system round trip efficiency;
4. Optimise the gearbox design for system loading capacity increase (e.g. from 1MW to 8MW) from individual part design, micro-geometry, materials, and optimisation;
5. Improve shock load capacity via hybrid mechanical connection of wind turbine shaft to CAES for prolonging gearbox lifetime.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R513374/1 01/10/2018 30/09/2023
2052267 Studentship EP/R513374/1 01/10/2018 31/03/2022 Marcus Jonathan KING