Mangere Biogas Cogeneration

Watercare contracted AECOM to provide technical services for an upgraded cogeneration plant at the Watercare Mangere Wastewater Treatment Plant. The new biogas engines produce 6.8MW of electric power and 8MW of process heat.
Description of facility: 

The gas engines burn waste methane gas from the sewage treatment process and co-generate heat which is used within the sewage treatment process and electricity which is used within the overall Watercare site. This project generates up to 6.8MWe electricity and 8MW(th) hot water from methane gas from the digestion process.
The key features of the project included:
• $/kw installed 25% below budget for client
• Overall efficiency approaching 89%
• Parasitic loads minimised
• Automated tariff based engine management system
• Standby generation modified to improve system availability.
The scope of project design services were as follows:
• Heat balance & electrical system modelling
• Financial modelling for business case
• Condition Assessment of existing plant
• Process, automation, electrical, mechanical, architectural design
• Equipment selection and procurement documents & evaluations
• EPC tender specification
• Maintenance contract scope and evaluation
• Tie in and commissioning strategies
• Functional descriptions
• Detailed design
• Cost estimating
• Operating and maintenance manuals

Facility type: 
Electricity
Application: 
Water Treatment
Technology type: 
Gas Engine
Fuel/Feedstock: 
Biogas
Primary Output: 
Electricity
Co-generation: 
Yes
Address: 
500 Island Rd, Mangere, Auckland 2022, New Zealand
Region: 
Upper North Island
Geo Location: 
Owner: 
Watercare Services Ltd.
Consultant: 
AECOM NZ Ltd
Fuel provider: 
Watercare Services Ltd.
Equipment supplier: 
GE Jenbacher GmbH & Co OG