Groundbreaking Report on Ontario's Water-Energy Nexus

A new report just released by the POLIS Water Sustainability Project provides the first-ever estimate of water-related energy use in the province of Ontario. The report’s insights are relevant to anybody interested in the water-energy nexus as it provides a valuable place-based analysis and contribution to the relatively small, but growing, body of literature on water-related energy use. Among the reports key findings: pumping and treating water and wastewater in Ontario consumes enough energy to light every single home in the province. When water heating and steam generation are included, the energy used in Ontario for water-related services could heat every home in Canada.

The POLIS Water Sustainability Project has been doing some incredible work investigating the water-energy nexus in Canada and raising awareness of the soft-path approach to water management and its myriad water, energy, social and financial benefits.

The new study is called Ontario’s Water-Energy Nexus: Will We Find Ourselves in Hot Water…or Tap into Opportunity? and it provides a groundbreaking analysis of water-related energy use in Canada.

The report was researched and written by Carol Maas, the Innovation and Technology Director at POLIS. Carol’s prior research into water-related energy use can be found in the March 2009 report Greenhouse Gas and Energy Co-Benefits of Water Conservation, which revealed that, “The energy savings associated with pumping 20% less water [i.e. by reducing per capita water use by 20% through water efficiency] in 2029 could achieve a whopping 34% of the reported energy reduction potential for Ontario municipalities.” Carol was also the coauthor of a peer-reviewed paper called Incorporating Energy Impacts into Water Supply and Wastewater Management, which looked at two case studies to describe how analyzing the energy embedded in water and wastewater can help planners identify innovative ways to save energy and reduce greenhouse gas emissions through the water use cycle.

In Ontario’s Water-Energy Nexus, we learn, among many other things, that:

Although the energy-intensive nature of providing water services is often un-recognized, these activities consume enormous amounts of power and fuel. The energy embedded in the water we use for activities such as pumping, treating and heating water and generating steam consumes 40% of Ontario’s natural gas and 12% of our electricity. In fact, providing water services uses more natural gas than any single economic sector in Ontario; this is more than the natural gas used by each of the industrial, transportation, residential and commercial sectors. Eighty percent of all energy used for water services is generated by fossil fuels, meaning it is typically dirtier than the energy used to power lights, appliances and electronics in our homes and businesses. This has significant negative consequences, including:

• Substantial costs to municipalities for the energy to pump and treat water;
• Release of greenhouse gases that contribute to climate change, resulting in the further need to find and treat more water;
• Rising water and energy costs for homeowners, business owners, farmers, hospitals and schools;
• Significant environmental, social and economic impacts of developing new energy sources to provide more water.

One of the most interesting aspects of this report is that it quantifies the energy required for steam generation in Ontario, which amounts to about 84% of the water-related energy use. Because steam generation requires so much energy, the energy required for pumping, treating and heating water is dwarfed in comparison.

In The Carbon Footprint of Water, River Network’s look at water-related energy use in the United States, we estimated, without considering steam, that water heating accounts for about 75% of water-related energy use with pumping and treatment making up the remainder. Because steam generation is so energy intensive, our numbers would have likely been more similar to those found in Ontario, where water heating accounts for only about 14% of water-related energy use and pumping and treatment accounts for 2% (see graph below).

The significance of including steam generation in an analysis of water-related energy use is that it allows people to make the types of connections that will foster Integrated Resource Recovery, which is a way of managing limited resources by viewing waste as a valuable commodity that can be used to supply water, generate clean energy, grow food and reduce greenhouse gas emissions. In this case, waste energy from steam generation can be incorporated into district heating and cooling systems or into industrial processes. On page 16, Box 7 of Ontario’s Water-Energy Nexus: Will We Find Ourselves in Hot Water…or Tap into Opportunity? two case studies are described:

Kalundborg, Denmark is considered the gold standard of industrial ecology practices internationally. Over a period of 20 years, this community increased synergistic linkages between power generation, industry, greenhouses and heating of homes and businesses. Since 1987, cooling water has been piped from an oil refinery to the coal-fired power plant to be used as boiler make-up water. Steam from the power plant was piped to both the oil refinery and a pharmaceutical manufacturing plant in 1982, a 2 mile pipeline that paid for itself in two years. Reuse of the steam reduced thermal pollution from the power plant in a nearby fjord. In 1991 the same oil refinery began treating wastewater to a sufficient quality that the power plant could utilize this water for cleaning purposes. Overall this innovative approach has been estimated to save 1,200,000 m3 of water every year, and avoided 130,000 tonnes of carbon dioxide emissions (Ehrenfeld & Gertler, 1997).

Closer to home, the Bruce Energy Centre in Tiverton, Ontario, has been applying the concept of industrial ecology since 1998. Steam from the Bruce Nuclear Power plant is used within local industries such as an ethanol and biodiesel plant, a food processor and a biodegradable plastics manufacturer. Bruce Tropical Produce Inc. uses low grade steam for space heating of an 8-acre greenhouse, after which the cold water condensate is recycled to the power plant (Canadian Eco Industrial Network, 2010). Greenhouses have been identified by a number of studies as an ideal user of waste heat from cooling water, which could utilize the energy for space heating (Connecticut Academy of Science and Engineering, 2009; Lawrence National Centre for Policy and Management, 2009). Depending on the configuration, using greenhouses or other industries to “cool” the cooling water could simultaneously reduce the volume of raw water withdrawn from local ecosystems.

These case studies along with the general water-energy analysis conducted in Ontario’s Water-Energy Nexus lead to some key recommendations for integrated strategies around water and energy. As Box 9 on page 18 outlines, these "Opportunities for Integrated Thinking and Action on Water and Energy" include:

1) Choose the Water and Energy Soft Path by prioritizing conservation of water and energy over new infrastructure. Recognize the impacts of new water infrastructure on energy use, and new energy infrastructure on water use.

2) Better Integrate water and energy monitoring, reporting, management and efficiency programs. Examine energy use and efficiency opportunities across economic sectors through a “water sector” lens that includes cold water, hot water and steam.

3) Collaborate by bringing together water and energy expertise together to encourage the development of innovative, synergistic solutions.

4) Inform the public, policy makers and practitioners of the mutual benefits of reducing water and energy use.

One final thing that’s worth noting in this report is its apt explanation of the subtle difference between embedded energy and end-use energy in the water use cycle – a distinction that I frequently blur. I must confess that I tend to refer generally to all water-related energy use as “embedded” or “embodied” energy, regardless of the stage in the water use cycle. Although it might sound like mere semantics, there are important differences between end-use energy inputs and inputs that occur either upstream (water supply) or downstream (wastewater treatment) from the end-user. As explained on page 10 of Ontario’s Water-Energy Nexus:

The energy input upstream of the end-use, primarily the energy for pumping and treatment, is commonly referred to as the embedded or embodied energy of water. Energy input at the point of use is defined as end-use energy and for the purpose of this report is generally the energy to heat water and generate steam. End-use energy may also be applied for water cooled chillers and on-site treatment systems such as water softeners and UV disinfection.

End-use energy is often under private control, whereas embedded energy inputs tend to be publicly managed – at least in the case of municipally supplied water services. For example, a homeowner can install a water efficient clothes washer (hot water / end-use energy), while only a municipality can reduce leakage in the water distribution system (pumping / embedded energy). Energy inputs for hot water and steam also tend to employ a wider variety of fuels such as natural gas and petroleum products in comparison to pumping and treatment, which generally rely on electricity. In addition, though the embedded energy may appear small in comparison to end-use energy, the energy consumption for water-related uses relative to other activities may still be significant to an individual or sector. For these reasons, a separate examination of embedded and end-use energy is warranted.

For convenience and accessibility, this technical report is composed of three sections: an executive study (PDF), the full report (PDF) and a technical appendix (PDF). To help you select which version to download, read this from the preface:

The report is highly quantitative in nature and was therefore written with a technical audience in mind. The study has been structured in three pieces – an executive summary, a main report and a technical appendix. Given the importance and wide reaching implications of the water-energy nexus both the executive summary and the main report body have excluded many of the technical details and assumptions in the interest of providing a concise, accessible report and summary. The appendices have been drafted with the intention of providing a clear statement of the methodological approach, including equations used and assumptions made, for the benefit of readers looking for specific technical details or to replicate this study elsewhere for other contexts. To avoid excessive length, the narrative and graphic representation in the Appendices has intentionally been kept short and direct, with summary tables included in Appendix A.

I hope that this report is widely read and that its findings help inform decision makers in Ontario (and the United States). Leveraging the connections between water and energy should be a central consideration as communities chart out paths toward environmental sustainability, economic prosperity and climate resiliency.

Download: Ontario’s Water-Energy Nexus: Will We Find Ourselves in Hot Water…or Tap into Opportunity?

Disclosure: I served on the steering committee for this report.