The Future of Home Heating? It’s in the Dishwater

Every time someone takes a shower, washes the dishes, runs the laundry or flushes the toilet in Vancouver’s Olympic Village, something special happens. The heat from the raw sewage produced by those everyday acts is captured and put back into homes.

“I feel bad for the first person who had to try and pitch this idea,” said Derek Pope, associate director of neighbourhood energy at the City of Vancouver. “At first glance, it sounds kind of crazy, but once you crunch the numbers, you realize how much thermal energy is there.”

If you visit an urban neighbourhood on a winter’s day, you might notice snow melting on the road if there’s a sewer system underneath. It’s proof that there’s valuable heat being lost.

“It’s a really exciting source of waste heat that’s constantly being replenished,” said Pope.

The price of energy like hydro and fossil gas might fluctuate. But we’ll always be producing wastewater in our homes.

An Olympic feat

The technology to capture and use the heat of wastewater was mostly a European innovation, used in countries like Denmark and Germany. Vancouver was the first city in North America to build a system to capture it.

The 2010 Winter Olympics was the inciting event that inspired municipal workers in Vancouver to start exploring the viability of building such a system here. The city, with help from a federal grant, invested in the technology for the new athletes’ village, a group of residential buildings that now form the core of Vancouver’s Olympic Village neighbourhood. The community of mid-rises and highrises is on the southeast shore of the city’s False Creek, a former industrial area.

Two days before the launch of the Games, the False Creek Neighbourhood Energy Utility was turned on. The heat from the grey water of baths and the black water of toilets came back to heat up the neighbourhood.

Today, Olympic Village residents pay energy bills close to what other providers are charging, proving that sewer power doesn’t break the bank and is also cleaner for the environment.

The False Creek utility is now in its 14th year of operation and has grown beyond the Olympic Village to include nearby buildings in the hip and historic neighbourhood of Mount Pleasant as well as the False Creek Flats, a burgeoning tech and medical hub.

The system covers over six million square feet of real estate. When built out, it is expected to heat almost four times that.

How sewage heat is saved

In Vancouver, buildings that burn fossil gas for heat are a significant contributor to emissions, accounting for 55 per cent of the city’s pollution.

Which means that systems like False Creek’s have a key role to play, reminding us that we shouldn’t let the heat from wastewater go down the drain.

There are two key facts to know about how the False Creek utility works.

The first is that it’s a district energy system, heating and cooling multiple buildings using a centralized plant. Buildings that belong to such a system do not need individual boilers or heating systems of their own. This saves space and carries the potential to cut costs.

There are a growing number of district energy systems in the Lower Mainland, each responsible for heating an area about the size of a neighbourhood or two. But how each district energy system chooses to heat its buildings varies. Everything from fossil gas boilers to steam to biomass from urban wood waste is used.

The second thing to know about the False Creek utility is that it’s a unique district energy system that makes use of raw sewage to produce heat for its residents.

Here’s how it works.

Each building’s sewage — everything from bathwater to dishwater to toilet water — is filtered for solids and passes through the system’s energy plant, located under Vancouver’s Cambie Bridge.

At the energy plant, a liquid refrigerant absorbs the heat of the incoming sewage, usually between 20 and 25 C. The refrigerant turns into a gas, which is then run through a compressor to be pressurized, causing it to heat up intensely, up to 80 C.

The hot gas is used to heat pipes that contain clean water, which is then distributed to buildings in the system.

The refrigerant, having passed the heat on, turns back into a liquid and cycles through the plant again to do its work. The cooled sewage continues its journey to be treated elsewhere.

When it comes to introducing energy systems that reduce greenhouse gas emissions, an expert on waste-to-resource recovery at the University of British Columbia says the trick is to avoid an “energy penalty.”

“It’s all about whether you spend more energy than you recover,” said Anthony Lau, an associate professor of biological and chemical engineering.

On that front, the False Creek utility is a positive, he says.

It runs at 320 per cent efficiency: for every unit of electricity used to run its heat pumps, a little more than three units are created.

Thank the water, not your waste

A number of media reports on the False Creek utility have played up the angle that human feces are powering buildings with their heat.

The writer of a Seattle Times feature who toured the False Creek utility noticed the building’s “faint whiff of poo” and the pipes that carry “a river of human waste,” with no mention of the contribution of water from sinks, showers and washers. Closer to home, an article from Vancouver Is Awesome is titled “34 Vancouver Buildings Are Heated Using Human Poop.”

That’s not quite accurate. It’s toilet water that deserves the credit, clarifies Pope, because it “warms up to the temperature of your room.”

“So when you flush your toilet, it has some thermal energy as well,” he said.

Planning for power

The construction of the Olympic Village, then a new neighbourhood on the site of an old industrial area, was the perfect opportunity for a city like Vancouver to innovate with energy.

“We had nine buildings all with the exact same occupancy day. When do you ever get that opportunity?” mused Pope.

It was going to be a dense neighbourhood, which meant that there’d be enough people taking showers and using their dishwashers to get the system running.

The utility is owned by the city, which ensures control. The City of Vancouver was able to link up the system with existing public infrastructure like the sewer network, set pricing, mandate new buildings to connect to the utility and set environmental performance targets.

For example, 70 per cent of the area’s heat comes from the utility’s sewage heat, a renewable form of energy.

But the remaining 30 per cent comes from fossil gas boilers, which lend help during the coldest months of the year. The city wants to do away with fossil gas and be entirely reliant on renewables by 2030.

Hot matchmaking

As city staff connect with developers looking to build projects that will be connected to the system, they are able to keep an eye out for future energy opportunities.

It’s not just heat from raw sewage that can be captured. The system can make use of the waste heat generated by non-residential buildings, too.

In 2020, the Mountain Equipment Co. opened its new store and headquarters on Second Avenue. The building, erected with mass timber, requires a lot of cooling and generates significant waste heat. The owners took advantage of the opportunity and became the first in the area to sell waste heat to the False Creek utility.

“We’re really interested in the potential for something like a data centre,” the City of Vancouver’s Pope said.

Data centres, which run every day around the clock, are heavy energy consumers and produce huge amounts of waste heat in turn. A large-scale example of capturing that heat is in the works in Helsinki, Finland, where two of Microsoft’s new data centres are set to heat 250,000 households.

The diverse collection of buildings in False Creek — with everything from a dense residential community to pockets of light industry to institutional buildings and a growing centre for business and tech — makes it the ideal place for a district energy system to continue its growth.

Clean and compact

For cities looking to start their own low-carbon utility like False Creek’s, Pope suggests taking stock of what’s in the service area to see if it makes sense.

Is there enough density? What are the types of buildings in the area? How do they use energy? Where is the waste heat that can be captured?

Cities looking to usher in greener neighbourhoods have to consider how to power them in clean ways.

“Figuring out how we can optimally deliver low-carbon buildings is starting to come to the forefront of planning,” said Pope.

A number of players have been setting up or building out their district energy systems. Aside from municipalities, there are institutions like the University of British Columbia and Simon Fraser University, which established a biomass plant in 2021 that cut emissions by 85 per cent.

The technology has also attracted private real estate developers with multiple buildings in their portfolios. Their efforts to establish district energy systems have run into some controversy, with the BC Utilities Commission concerned about their monopolies if residents had no choice but to turn to a single private provider to heat their homes.

Sewer power has also made it across the border. Last year in Washington state, King County’s Wastewater Treatment Division started partnering with private developers to install the pipes and pumps to capture sewage heat in their building, the same technology used in False Creek.

Pope, at the city, who joined the False Creek utility back in 2012, has watched it become a local leader in district energy and waste heat recovery.

“I think a big success of the [utility] is enabling other systems to go on and make their own confident investments in low-carbon energy,” he said.

If you stroll by the False Creek utility where the heat pumps do their work, there are five emissions stacks nearby with a special message for passersby.

The stacks have a playful design that cost a million dollars, but residents were so enthusiastic that city council approved it.

Depending on when you visit, the stacks will look different. When energy is in demand, the stacks glow fiery red and orange. When less heat is required, they turn a cooler blue.

It’s an educational reminder that there’s heat being harnessed in the neighbourhood.

---

This article runs in a new section of The Tyee called ‘What Works: The Business of a Healthy Bioregion,’ where you’ll find profiles of people creating the low-carbon, sustainable economy we need from Alaska to California. Find out more about this project and its funders.