Making the case for cleaner energy with geoexchange

Like many municipalities, the Town of Oakville has adopted carbon reductions targets by 2050. In 2019, Oakville joined other municipalities and organizations around the world by declaring a climate emergency, doubling down on our commitment to reduce our carbon emissions. We currently stand at an approximately 80 per cent reduction as compared to our 2014 baseline and continue to be hyper focused on meeting our targets. As we continue to seek opportunities to reduce our carbon footprint, incorporating onsite renewables, such as geoexchange systems into municipal facilities is one approach we are taking to curb our emissions and meet our targets. This is one way the Town of Oakville is leading by example, to showcase the benefits and impacts of low carbon technologies in corporate facilities.

 What is geoexchange?

Geoexchange is a technology for heating and cooling that draws energy from the ground and injects it into a facility, subsequently reducing the facility’s overall carbon footprint. All the equipment used in a geoexchange system can be powered by electricity, thus removing the need to use natural gas, one of the largest contributors of carbon emissions on a building.

Case study: Oakville Trafalgar Community Centre

Let me introduce you to the Oakville Trafalgar Community Centre (OTCC), which is a practical example of community energy in action. In operation since 2019, this state-of-the-art, 53,000-square-foot facility is home to a variety of amenities, including a 25-metre lap pool and a therapeutic pool with accompanying change rooms, a fitness centre with walking track, a gymnasium, various meeting rooms and a café.

Focused on providing services to our community year-round, while also understanding that we needed to tackle carbon emissions and energy use from a holistic perspective, when constructing this facility we elected to implement a geoexchange system for the heating and cooling of the centre. Working collaboratively with OEC and Geosource Energy, we integrated a 64-borehole system. We also constructed two large water heaters to complement domestic hot water usage in the facility, with the additional ability of supplementing temperatures in the geo-exchange loop if needed. However, these two water heaters are only for auxiliary purposes and do not consume a large amount of natural gas on an annual basis.

Here are some of our findings as compared to a similar 69,000-square-foot community centre within the Town of Oakville whose heat and cooling is generated by a conventional system:

*Values are reflected over a period of 12 months

·      The CO2 equivalent associated with natural gas at the comparable centre was 100 times more than OTCC.

·      From a carbon perspective, the OTCC achieved savings of 99.1 per cent compared to the comparable centre, meaning that OTCC operated with nearly net-zero emissions.

·      The total capital cost of the project was just over one million dollars, plus additional funding to integrate the geoexchange system into the facility. When you factor in the cost of the carbon tax—$170 CAD per tonne by 2030 —the OTCC has an operational cost of $240,000 annually. The comparable centre’s cost is approximately $397,000 annually, which accounts for a difference of $157,000 per year. Using this logic, we can achieve a simple payback of seven years for the system alone.

Benefits of a geoexchange system

From a maintenance perspective, the geoexchange system is low maintenance. It has been operational since December 2019, and it has not required any major repairs. We do foresee exchanging some of the components within the next 20 years but, for the most part, the system will not require any major maintenance for the foreseeable future.

As you can see by the data I have highlighted, the benefit of incorporating geoexchange for the heating and cooling of a community facility is clear. But there’s more. An unforeseen benefit that we have experienced since the community centre has opened is more anecdotal in nature. Both staff and community members have told us that the air within the facility feels cleaner. It seems that the indoor air quality benefits from the geoexchange system, and it’s something we’ll want to corroborate in the future.

Lessons learned from a geoexchange installation

The installation of a large system of this nature is not without its own set of challenges. I’d like to close off this case study with a few lessons learned:

1.      If you are thinking of using geoexchange as the main heating and cooling system, make sure to integrate it into the building design from the beginning. This will avoid future additional costs.

2.      Make sure everyone on site knows exactly where the system is going and have accurate drawings shared with your contractor and subcontractors. This will avoid the potential of incidents.

3.      Look at your facility from a holistic energy management perspective. Although geoexchange allows us to greatly reduce carbon emissions, it uses more electricity to run the heat pumps and auxiliary equipment. We’re working to compliment energy use at the OTCC facility with a solar photovoltaic system and are in the process of installing a 250 kW DC system, with an additional 250kW to be installed in the near future in the adjacent parking garage. Once implemented, the system will provide enough electricity to power the geo-exchange, providing us a truly net zero energy and very low carbon heating and cooling facility.

4.      Finally and, probably the most important lesson learned through this project is finding a good partner to work with to achieve your goals. There are a number of companies that offer geoexchange systems and it is important to do your research and find a company with the knowledge and expertise you are looking for.