By replacing its old, open air water ReservoirNo.1 with a new enclosed reinforced concrete water reservoir that incorporates energy recovery equipment, the City is not only reducing emissions but also expecting potential energy savings between 750,000 – 1,000,000 kWh per year. The new system works in tandem with the City’s new Water Treatment Plant and supplies filtered water to Nanaimo residents.
Success Story Snapshot
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Energy Savings / GHG Reductions: Total potential annual energy savings: 750,000-1,000,000 kWh per year (if the station was running at its full capacity potential increases to 1,400,000 to 1,800,000 kWh equates to 26-31 tonnes CO2 equivalent.) Additional annual available power of approximately 1.4- 1.8 GWh; enough to power 160-190 homes [8]. Utilizing gravity in energy recovery is expected to save 650,000 kWh per year in energy; enough to power 60-70 homes
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Business Case: System generates revenue from energy produced to sell back to BC Hydro and will help recoup operating costs. Expected to generate between $70,000 and $90,000 in additional annual revenue to the City’s water fund. Minimizes municipal operation costs. Cost sharing of project generates a short payback period of less than 10 years.
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Co-benefits: Project created short term design and construction jobs. Increased attractiveness of the city. Provided a provision of fire protection and emergency storage. Continued access to safe, clean drinking water. Encourage competition in a growing number of small and green projects in the marketplace. |
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Total project cost: Total project cost: $11.2 million. Grants from the Gas Tax Fund ($7.68 million). Remaining $3.5 million cost covered the City Water Fund. |
Project Summary
The City of Nanaimo replaced its century old, open air water Reservoir No. 1 with a 14-million litre enclosed reinforced concrete water reservoir, associated pipelines and an energy recovery facility. The new reservoir has been constructed in tandem with the City’s new South Fork Water Treatment Plant. The reservoir will receive and protect filtered water that will supply 30 per cent of the city.
The reservoir also incorporates energy recovery equipment in the control building. Energy recovered from the reservoir is fed into BC Hydro’s grid. The energy will generate enough electricity for at least 60-70 homes. This is an example of a sustainable means of managing the City’s water supply infrastructure, meeting a key goal in the Water Supply Strategic Plan, and bringing the region a step closer to meeting a community-wide GHG emissions reduction target of reaching 39% of 2007 levels by 2050 under the Community Sustainability Action Plan (CSAP).
The new water supply system takes advantage of the area’s topography and hydraulics. The city’s main source of water supply is from the Jump Creek Reservoir on a tributary of the Nanaimo River. Due to the elevation difference, the distribution of water from the Jump Creek reservoir to the water treatment plant and subsequently to Reservoir No 1 can be done without the use of pumps. Reservoir No 1 is about 110 meters below the elevation of the new water treatment plant, creating a significant amount of potential energy to recover.
Nanaimo’s gravity municipal water system uses common globe-styled control valves to control the filling of a reservoir. Water filling the reservoir by gravity passes through a control building containing pressure reducing valves (PRV’s); the PRV’s dissipates the excess pressure, which is hydraulic potential energy, enabling the filling of a reservoir to a set water level. In most cases, this potential energy is lost; however, in the case of the new Reservoir No 1, there was a potential to use hydroelectric turbines instead of PRV’s to dissipate the excess energy while filling the reservoir; recovering this energy in the form of electricity to be sold back into BC Hydro’s grid.
This project marks an important collaboration between the City of Nanaimo and BC Hydro under the Energy Purchase Agreement to provide locally-generated power to the community. Through BC Hydro’s Standing Offer Program, the City is able to create revenue by selling the electricity generated from the energy recovery system back into the power company’s grid. This further agrees with both partners’ goals in carbon footprint reduction set out in the 2007 BC Energy Plan and the 2010 Clean Energy Act.
Community-scale energy and emissions modelling (CEEM) is a tool that allows local governments to assess the impact of projected land use changes on future energy use and GHG emissions through 
