Global Hydropower Day: Verdeg Renewable Energy11 October 2022
Lars Boerner, Managing Director of VerdErg Renewable Energy, shares details on the company's Venturi-Enhanced Turbine Technology (VETT) installation on the river Great Ouse in the UK
“Sustainable hydropower has an enormous potential worldwide to help solve the current energy crisis and to meet net zero ambitions,” says Lars Boerner, Managing Director of VerdErg Renewable Energy. “More work needs to be done by the industry working together to attract the attention of governments, investors and the public to hydropower’s benefits and how it can positively contribute to renewable power generation. For example, hydropower has the potential to restore lost natural habitats, regulate river flows and reduce flooding risk. These benefits should be supported by wider promotion and greater understanding, especially considering the growing concerns and recent events from climate change.”
Boerner cites VerdErg Renewable Energy’s standard Venturi-Enhanced Turbine Technology (VETT) installation on the river Great Ouse in Eaton Socon, Cambridgeshire, UK, as an example of the positive ecological impacts that can be designed into hydropower installations.
In operation since 2020, the 17kW VETT scheme exploits the 1.2m net head between a marina and mill pond with an energy output of 70MWh annually. The VETT is submerged within a disused underground culvert, following key design criteria to integrate into the existing infrastructure of a Grade-II listed former mill, preserving the natural surroundings of the river site which is situated between two nature reserves.
The Great Ouse is a navigable stretch of river prone to flooding. VerdErg Renewable Energy therefore coordinated the VETT scheme with the management of water levels by an Environment Agency controlled moveable weir. Its careful eel passage design newly opened this stretch of water to migrating eels after decades of being an unpassable barrier. Installation and operation were also designed to protect juvenile coarse fish nursery areas, although in a pretty much stagnant marina and mill pond. The installation has significantly improved water qualities with visible improvements and increase in fish population. VETT’s remotely controlled operation allows the hydro installation to be adjusted according to changes in water volume or due to boating activities in the nearby marina.
On average 3500l/sec passes through the VETT at Eaton Socon. The turbine is 440mm in diameter and emits zero noise with all infrastructure submerged underwater. This means local wildlife is not disturbed, nor are the patrons of the neighbouring pub and restaurant which is served by the generated electricity, with excess exported to the National Grid. The installation saves 35t of carbon emissions per year with electricity generated equivalent to the consumption of 30 homes.
Lessons learnt from this project have helped development of the new VETT-in-a-Box which is a compact ‘plug and play’ development of the Standard VETT. Ideal for smaller or remote run-of-river projects, as well as wastewater outfalls or pressure reduction points, it targets on-or off-grid installation with 1-5m head and flow rates up to 2000 l/s, generating up to 40kW.
The low-head VETT installation at Eaton Socon, Cambridgeshire, UK, is concealed underneath the decking of a local restaurant