Generators: Increasing Output and Extending Life

Our passion for achieving a net zero future relies heavily on renewable energy sources. With hydro energy representing the largest renewable energy source, and a requirement to increase hydro output by 3% annually to achieve this goal, according to the International Energy Agency, it is critical to maintain and increase hydro generation levels. However, over the past five years, less than half of the required increase in output has been achieved.

The average age of hydro generators in established markets such as North America and Europe exceeds 40 years old, which is of serviceable age, presenting a significant risk to the installed base of hydro generation. In addition, the opportunity to build new hydro facilities in these regions is limited by suitable locations that haven’t already been utilised and the investment required to build them, which is made challenging by legislation and economic pressures.

So it is difficult to build new hydro infrastructure in North America and Europe, and the existing fleet requires refurbishment and modernisation, yet there is a desire to increase the amount of energy being generated by hydro. While the expectation in the industry is for high-quality formed windings that last for decades. Therefore, a favourable solution provides a high-quality and reliable refurbishment while an opportunity is present to utilise the existing assets to increase their output.

Preformed Windings has identified this challenge and opportunity in the market and, due to its independent status as purely a product manufacturer, is well-positioned to collaborate with the industry to carry out research and development related specifically to high-voltage windings. This R&D, made up of over 25,000 hours over the past three years and in collaboration with leading OEMs and insulation manufacturers, has resulted in significant steps forward in winding technology.

The hydro industry is already benefiting from this. For example, Project Holter, which was voted a finalist at the prestigious AEMT awards, resulted in a modernisation program at the Holter dam in Montana, USA, which upgraded the output of its six generators by 42%, resulting in enough renewable energy to power 16,500 additional homes and businesses in the surrounding area. This example – involving a redesign of the turbines and generator core – highlights the opportunity across the industry, and when compared to developing new hydro facilities, this approach is also exceptionally cost-effective.

James Stevens, Global Sales and Marketing Director at Preformed Windings, commented: “We are dedicated to a sustainable future and excited to collaborate with leading organisations and end-users in the industry to answer a specific and solvable problem; how do we modernise this ageing fleet and capitalise on the huge untapped potential of additional hydropower generation from existing assets using a circular economy approach.”

Due to the age of much of the installed base, significant output gains are often achievable without major redesign activities beyond the windings. For example, the principle of increasing the output of generators centres around increased output and improved efficiency, both of which can be achieved by utilising the available slot space in the core of the generator more effectively, capitalising on advances in insulation technology and cutting-edge manufacturing techniques to increase the number of turns and cross-sectional area of the copper. Optimising the design of the coil geometry and achieving exceptionally tight tolerances can offer benefits such as reduced mean-turn-length of the coils and uniform windings. When coupled with coil specifications that offer previously unheard-of levels of tan delta and partial discharge levels, the result is a refurbishment of the generator designed to last, and with increased performance.