Turbine in the water!

From the 19th to the 21st of September 2023, GKinetic Energy deployed a 12kW hydrokinetic tidal turbine just downstream of Sarsfield Bridge on the river Shannon, in central Limerick City. Backed by the Limerick City Council and other local partners, this represents a major step forward towards utilising the river for energy generation in the city. The deployment saw successes in a number of areas, and pioneers a design that showcases the most advanced urban deployment of river turbine technology to date. Congratulations to all +CityxChange partners involved in making this possible!

The deployment of a river turbine in Limerick was targeted considering the limitations of generating energy through other sources. Due to the protected status of much of Limerick’s buildings, utilising roof and wall space for solar and other renewable energy sources was not feasible. Instead, an alternative energy source was identified – the river Shannon. Over the last few years, GKinetic, a leading developer of innovative turbines that generate clean energy from flowing water, has been working on a technology to convert hydrokinetic  energy from the city’s river into electricity. Working closely with Limerick City & County Council,other partners and stakeholders, the turbine has been iteratively designed, taking into account the technical, environmental, and societal factors that impact its deployment. 

The process that led to the turbine’s deployment in September 2023 saw GKinetic and partners implement a number of activities to continuously improve the design of the turbine. Read on below to discover how this was done.

Minimising Impact to Aquatic Life

In early stages, objectives were set to ensure that the turbine would not disrupt aquatic life. This involved understanding the dynamics of the river from an environmental and ecological perspective, to identify the potential impacts of the turbine. Then, the design could be adjusted to limit these impacts. The main outcome of this was the development of turbines with a low rotational speed, where interference to aquatic life is minimised, with the turbine rotating at the same speed as the river flows. Power generation starts from low river flow speeds of only 0.6m/s, and in its current state of development reaches rated capacity at 2.2m/s. The turbine is also able to naturally deflect debris with its counter-rotating turbines, to both minimise impacts to aquatic flora and fauna and retain maximum efficiency. 

Validating with Citizens

Throughout the ongoing development of the turbine, citizen validation processes were implemented where impressions and feedback were collected from local communities. This involved open discussions during outreach events, and targeted consultation with key stakeholders. The deployment of the turbine in September 2023 was one of these processes, where a physical display of the technology served to demonstrate the finely tuned design, able to benefit societies without impeding their activities. One key aspect here is the deployment of multiple smaller 12kW floating devices, instead of one 60kW design as initially planned. Making the turbines float on boat-like structures ensures that they can be moved depending on environmental factors and when the river is needed for social activities. The interest and support of local stakeholders in the longer term deployment of the river turbine helps to secure planning permission to begin generating energy from the turbines en masse for Limerick City.

Continuously Editing the Design

A major driver of the successes of the river turbine, in exceeding expectations for energy generation, is that the design was iteratively developed by engineers. The developers constantly looked for ways to improve the system, such as replacing complex mechanical parts with simplified bespoke components that reduced weathering and increased efficiency. Such changes have led to the low cost, high efficiency blade pitching system on the unit, which facilitates maximum power generation. This process of “tinkering” with the design has constantly improved the potential energy generation, to the point that during its deployment in September 2023, more energy was being produced than could be used up by the on-board systems in place to demonstrate functionality. This process also takes into account the physical characteristics of the site, to maximise possible energy generation. This is exemplified by the turbine’s ability to float and rest on the riverbed to accommodate varying water levels.

The deployment of the turbine in the river Shannon in Limerick, in September 2023 has seen successes in a number of areas. Not only is the design for the turbine the most advanced and effective on the market, it is also kind to aquatic life, moulded to the needs of citizens, and able to efficiently produce clean energy. But the work does not stop here, GKinetic and partners continue to work on the design of the turbine in Limerick. Not only this, but the deployment process has also been expanded into learnings for other cities, including reflections on how to secure regulatory approval, effectively test generation, and connect to flexibility markets. This and more information on the turbine can be found in D4.9: White Paper “Regulations Unlocking Innovation Potential”.

Stay tuned with the +CityxChange project for more updates on the development of innovative technologies and processes, as with Limerick’s river turbines. As the project concludes, there is much to be learned from. Check out the How to PED Cookbook for a summary of our main outcomes and achievements.

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