Chichester Dam Mini-Hydro

Grid-connected, distributed generation, renewable
Location: Chichester Dam, NSW

The site

Chichester Dam is owned and operated by the Hunter Water Corporation and supplies water to the Newcastle region via Dungog Water Treatment Plant.The Dam was commissioned in 1923 and recommissioned in 1985 following remedial work.

The Chichester Dam mini hydro has been built to take advantage of environmental flows released into the Williams River as required by the Healthy Rivers Commission.

Environmental flows of 30 ML/day during peak periods generate 75 kW; smaller flows at other times create negligible generation for an average release of 14 ML/day. It is anticipated that the dam will spill for 35 per cent of the time where full capacity of the mini hydro can be utilised at 120 kW.

The Dam wall and valve house were commissioned in 1923. The concrete walls to thepipework and valves were very thick compared with today's standards with extra steel reinforcement. As a consequence, five days were needed to cut through the concrete wall to enable connection to the riparian pipework.

Energy purchase and supply

The plant is expected to produce 0.4 GWh of electricity per annum. Power generated from the project is sold to Country Energy under a long-term agreement.

The generator operates in the electricity peak periods for scheduled water releases and full-time when the dam is spilling. A signal from the dam is transmitted to the mini hydro to indicate when the dam is spilling, which removes operating restrictions.

The generator is registered as an embedded generator and accredited generator under the Mandated Renewable Energy Scheme.

Fuel and connection

Fuel for the plant is supplied by Hunter Water Corporation.The plant is connected to Country Energy's 11 kV distribution system.

Success of the project

Chichester has been generating since November 2001 and is meeting production targets. Delta Electricity is currently planning to install mini-hydro generators at a number of State Water sites in NSW. Another mini hydro is being commissioned at the Dungog Water Treatment Plant, which treats the water from Chichester Dam.

The project is expected to save 380 tonnes per annum of greenhouse gas emissions.