In a project worth approximately US$708,000, UK-based Gilkes has delivered and installed a 250kW Turgo hydro turbine to Eire-based Kerry County Council, resulting in the recovery of power that would otherwise be lost to the region. The project involved full installation of the mechanical and electrical contract at Lough Guitane, near Killarney, Eire.
Gilkes supplied, designed and manufactured the turbine, generator, control panel and hydraulic power units for the project at its facility in Kendal, UK. The Gilkes twin jet turgo impulse turbine has been designed to utilise existing infrastructure at the Lough Guitane site and recover 250kV which is used by the Lough Guitane pumping station to provide drinking water to the Central Regional Water Supply Scheme in County Kerry. The turbine has been developed to run at 750rpm, generating approximately 250kW from a 50m head and 650 litres/sec flow rate.
Through careful design and co-operation with Kerry County Council engineers and the river authority, Gilkes has been able to use an existing old pipeline which supplied water from the river Owgariffe as part of the project. The pipeline now provides water to the turbine to generate power adjacent to the Lough Guitane pump house. Power for the pumping station is now more secure and less expensive because both the hydro turbine and national power grid provide power, says the company.
‘The power in the water was not being recovered, resulting in wastage,’ says Simon Kay of Gilkes. ‘This is no longer the situation, and once the payback period for the finance is complete, the turbine installation is paid for. Therefore the power generated will also be essentially free – except for minor maintenance. Compare this with continuing to buy 250kW of power from the grid.’
Turbine control
The control panel used in the project features three bespoke requirements for the Lough Guitane installation. The hydro turbine flow control spear valve is directly controlled by feedback from level controls at the river Owgariffe intake, ensuring the river flow is maintained. For simplicity and economy, says the company, the turbine is not governed but follows the grid frequency. This requires use of Gilkes auto-synchronising technology at start up and also requires reverse power relays to be used. Reverse power relays break the grid connection when necessary to prevent the hydro turbine generator being driven as an electric motor by the national grid.The generator used in this instance is a Marelli induction generator, rated at 295kV
The project has also been developed to minimise environmental impact through the use of existing infrastructure and compensation flow at the river Owgariffe water intake. Compensation flow regulates the amount of water used by the turbine such that the river Owgariffe always has more than adequate flow downstream of the hydro turbine intake.
Foot and mouth impact
During installation of the project, Gilkes was faced with a difficult problem. When the contract and delivery schedule was initially agreed, the foot and mouth outbreak in the UK was not a matter for consideration. However, as the project approached the critical delivery and installation phases, the foot and mouth epidemic was reaching its height in the UK, particularly in Cumbria where Gilkes is based.
To help minimise the impact of the outbreak on the project, Gilkes developed procedures such as written disinfecting procedures, carrying disinfectant, personnel restrictions and education. This helped towards the successful management of potential foot and mouth transmission at the site.
According to the company, as a result of co-operation and detailed planning between Gilkes and Kerry County Council, it was possible – despite the foot and mouth epidemic, – to successfully deliver the project on time and to budget. Commissioning is currently under way and due to be finished in September 2001.
