Melbourne Water – St Albans Mini Hydro

Elevating Solutions With Tamar Hydro

Brief

Melbourne Water tendered for works on Stage 3 Mini-Hydro Development.  During the tendering process prospective tenderers were asked to submit concept designs for various sites to design and install Mini-Hydro systems.

Tamar Hydro was successful in winning the Stage 3 contract for the design and installation of three (3) Mini-Hydro systems, of which St Albans was one of the sites chosen.  The contract was issued in 2020.

before image of the site at st albans before building the Mini-hydro installtion

Site prior to Mini-Hydro installation

Melbourne Water’s design criteria

The parameters specified by the client were:

Location In-line prior to St Albans Reservoirs, Melbourne-Victoria
Supply Greenvale & Western Transfer Mains
Water Type Mains Supply
Network Connection 22kV/400V Transformer
Maximum Gross head at turbine inlet 89 metres
Maximum Differential head 75 metres
Minimum Differential head 30 metres
Turbine Design Flow 55 ML/Day at 59m
Maximum Design Pressure Rating PN16 (16 Bar)
Design Life 30 years

Design

The Tamar Hydro design included the supply of a turbine, generator, electrical switchboard, inlet & outlet butterfly valves, associated minor pipework, and water hydraulics for valve actuator control.  This also included the supply of a building, which in this case Tamar Hydro utilised its expertise with Containerised Solutions, by supplying a 40-foot container to house the turbine and generator in one room and the switchboards in a separate room.  These containerised designed are done inhouse by Tamar Hydro.

black and white digital layout of a containerised turbine

Drawing 1 – Overall Assembly

The turbine mechanical design was performed by Tamar Hydro, utilising a fixed flow Francis Type Turbine or Pump-in-Reverse (PiR) with no guide vanes, supplied by Flowserve.  This PiR selection is a high efficiency pump with a horizontal split case.

The ventilation requirements of the building were designed to control the inside temperature and evacuate hot air from the building.

The noise level of the plant was required to be under Boundary Noise Levels for the site of 40dBA since there were residential neighbours to the Melbourne Water site.  This was controlled by designing the container to have insulation on the inside and removable acoustic covers that extend from both the inlet and outlet sides of the container that housed the butterfly valves and pipework.

The electrical design was performed by Electropulse Projects, included using an 870-amp variable frequency drive (VFD) to control the TECO generator with a maximum demand of 530-amp export energy.

Workshop Manufacture

The manufacture of the containerised mini-hydro was done at our Exeter workshop in Tasmania, utilising Tamar Engineering personnel and the electrical switchboard and equipment assembly and factory testing was done by Electropulse Projects personnel at Exeter, Tasmania.

Green 40-foot shipping container

Modifications to the 40-foot Container

two green completed containersied Mini-hydro

Design & Manufacture of the containerised mini-hydro was completed in 2021

man spray painting inside of 40-foot container

Internal fit-out of the 40-foot Container

Internal fit out of 40-foot container. Walls have been installed and electric cable fitted

Internal fit-out of 40-foot Container

Site Installation

Site installation commencing in late 2021 and was completed in early 2022 by Tamar Hydro personnel.  Commissioning of the system was completed in late 2022.

There were many delays during this process caused by COVID-19 restriction and personnel suffering illness form the virus.

Pipework & Valves

Generator

Turbine (pump-in-reverse)

Turbine (Pump-in-Reverse)

Performance

The mini-hydro installation has met the requirements of Melbourne Water under the contract and exported energy amounts have exceeded initial concept design predictions by 10%.

The contract sum for the project was around $1M, with an expected payback period of 5-7 years based on the predicted annual energy generation revenue.