Dairy Green
Biogas project
Biogas project
A ground-breaking project implementing a prototype methane recovery system on a 950 cow farm in Southland has demonstrated for the first time the commercial viability of this technology within a cool climate. With 4 years of monitoring under a range of conditions, good data is available on the systems performance. The generator averages nearly 7 hours running per day and generates an average of 27 kW hours for each hour it runs. For each 1 kW of electrical energy produced, 1.5 kW equivalent of hot water is also captured for use in the dairy shed
Dairy effluent storage ponds are known to produce methane, a greenhouse gas more than 21 times worse than carbon dioxide in effect. This job involved constructing a biogas digester pond and covering it to capture the biogas.
Dairy Green Ltd was contracted by the Fortuna Group to implement methane recovery and electricity and hot water generation at the Glenarlea Farm property. Great South (formerly Venture Southland) assisted by arranging EECA involvement and funding NIWA’s initial involvement completing a feasibility study
A generator shed was built to house a secondhand spark ignition motor and 75 kW generator. A control system was installed to manage the motor and generator and allow grid synchronisation. A plumbing circuit was installed to utilise hot water produced by the motor to heat water for the dairy shed. This heats water to 90°C for plant cleaning purposes.
The dairy shed electricity demand ranges from less than 10 kW between milkings after the milk refrigeration unit has turned off, up to 45 kW during milking
The generator is run to minimise the amount of power purchased from the grid. It can also be used as a standby generator
Photos of the biogas recovery project
