Queensland-based renewable energy company Kinetic NRG engaged composites technology specialists Advanced Composite Structures Australia (ACS-A) to design and manufacture a hydro-electric turbine blade for its Hydro-kinetic Energy Generator. The move enabled a cost-effective, lightweight solution saving up to 70% in mass compared with initial metallic designs.

In Australia, most high-head hydro energy – such as Snowy Mountains Hydro, for example – has already been harnessed, and in most cases large civil infrastructure is required to create dammed reservoirs. However, there is an opportunity for low-head hydro power generation to become more accessible and with lower barriers to entry, while being sustainable. Kinetic NRG’s modular turbine design will be able to generate power from existing streams, irrigation channels and discharge canals.

“We have been helping Kinetic NRG with composite solutions for their hydroelectric turbine,” says Paul Falzon, General Manager at ACS-S. “They were very impressed with the quality and dimensional accuracy we could achieve with the highly complex part. As an added bonus, we were also able to take out 70% of the blade mass compared to the steel design!

The key advantage of using composite materials in Kinetic NRG’s turbine is its mass savings, amounting to approximately 50%-70% compared with metal-based components. This makes it more suitable for micro turbines and installation in remote areas. Moreover, using composites meant a modified design and manufacturing process, allowing reduced material, labour and installation costs. This in turn enables Kinetic NRG to achieve a more competitive energy cost.

A method to manufacture the complex-shaped, hydro-dynamically designed geometry was developed, along with the lightweight structural design. Low-cost composite tooling was created to achieve the desired composite turbine shape. Using a specially designed assembly fixture, the sub-components were laminated together producing a one-piece, dimensionally accurate, complex blade assembly, with an integrated internal hub for the coaxial drive shaft.

The current blades are made from epoxy resin and glass fibre non-crimp composite materials. Carbon-fibre is being considered in other parts of the system for further weight reduction opportunities. Composite materials enable Kinetic NRG to modularise the components, facilitating local assembly of the turbines.

“Each of the blades were manufactured in two sections and joined during final assembly,” explains Johannes Straub, Senior Engineer at ACS-A. “The precise location of the interlocked composite blade components was challenging. 3D-CAD was used to design the moulds and an assembly jig enabling positioning and joining of all components on a common shaft.”

Finishing of the part included a marine top-coat in order to operate in submerged fresh and salt water environments, while a rotational balancing of the turbine blade was completed at ACS-A’s facilities in Melbourne.

Kinetic NRG integrated the composite turbine into the completed assembly at its Gold Coast workshop. This initial prototype Hydro-kinetic Energy Generator will be used for in-water trials. Kinetic NRG is set to achieve an optimal 20 years design life, maximising durability with minimal maintenance. The low-head 1.5m diameter micro hydro turbine is projected to generate approximately 30kW at flow rates of 2.0m per second.

“Kinetic NRG undertook an international search to find an organisation that was aligned with our vision and technical aspirations,” says Darren Wren, Director at Kinetic NRG. “We are delighted not just with the product, but also the co-operative relationships that have developed. As our disruptive hydro-kinetic energy generating technology enters the market, our future success is through developing key partnerships with great people.”

Falzon adds: “We have been fortunate to work with a number of clients in the renewable energy space where composites can play an important role in delivering energy-efficient solutions. Our work with Kinetic NRG is a great example of this.”