Decarbonisation projects: wastewater heat for homes

North Vancouver’s municipal heating utility will soon begin heating its buildings using an unconventional source – raw sewage.

Federal and provincial governments this month announced a grant to Lonsdale Energy Corporation to build a $24-million plant that will capture waste heat and distribute it to more than 7,000 homes, businesses and utilities.

“This is exciting because it is the first major low-carbon energy project that we will be implementing,” said Karsten Veng, CEO of Lonsdale Energy Corporation.

How does it work?

Even on the coldest days of winter, water flowing through sewer pipes is about 20 to 25 degrees Celsius warmer than the ambient temperature. When the new plant, which will be built across from the city’s construction site on West Second Street, comes online in 2027, it will use industrial heat exchangers to capture heat from the sewer pipes and pump it back into the LEC system.

Despite the images that “raw sewage” may conjure up, it is primarily our appliances that heat our sewage, not our own BTUs.

“We take raw sewage from people’s homes, from washing dishes, from washing machines. Today, that heat is simply dumped into Burrard Inlet,” Veng said. “Instead of heating the ocean, we’re going to heat homes.”

By reducing LEC’s demand for natural gas, the wastewater heat recovery plant is expected to save approximately 7,600 tons of carbon dioxide emissions per year – the equivalent of taking about 2,700 cars off the road forever – helping LEC meet its commitment to source 40 percent of its energy from low-carbon sources by 2027.

North Vancouver city councillor Jessica McIlroy, who represents the council on the LEC board, said the new plant is a very positive step forward for climate action.

“As strange as it may sound, recovering heat from wastewater may not sound very attractive, but in itself it is an exciting way to use waste, be resilient and use the resources that are available to us,” she said, adding that the technology has been well-proven around the world.

The federal government is contributing $4.78 million to the project, while the province is providing a contribution of $12.76 million.

McIlroy said external support from senior levels of government had been “extremely valuable”.

“The effort to not only expand the system but also decarbonize it requires significant investment. It’s not a cheap process and will require a variety of different sources of funding,” she said.

The project comes shortly after the LEC’s 20th anniversary and at a time when governments at all levels are trying to transition away from fossil fuels.

What is district energy?

The concept of heating multiple buildings from a central location dates back to ancient Rome. New York City introduced a steam-based system in the 1870s.

The City of North Vancouver won provincial approval to create its own heating utility in 2003, with the goal at the time of providing a revenue stream for the municipality while also reducing the city’s reliance on electricity from the relatively dirty and inefficient Burrard Generating Station during peak demand. BC Hydro decommissioned the plant in 2016, but LEC’s gas boilers remain in operation.

Currently, all new buildings over 1,000 square meters located within the LEC service area must be connected to the system.

Today, LEC has grown to provide heating for about 7,000 homes in 108 buildings in Lower and Central Lonsdale, Moodyville and the Harbourside district, using heat generated by eight power plants connected by 15 kilometres of hydronic pipes. The water heats these buildings and their hot water supplies, then flows back to the power plant to be reheated.

Decarbonization

About a quarter of North Vancouver residents use LEC heating, but the 2003 design and technology behind the system no longer work as well.

LEC is committed to achieving carbon neutrality by 2050, Veng said, and is actively working on a roadmap to achieve that goal.

Natural gas still accounts for about 85 percent of the energy used to power the LEC. That equates to about 19,000 tons of carbon dioxide emissions per year. The remaining 15 percent comes from low-carbon sources — mostly renewable natural gas — but also from solar panels on the roof of the city library, a geothermal system at the North Vancouver School District office and a heat recovery system built into the winter ice rink at The Shipyards.

The LEC also operates a small electric refrigeration system that powers several Lower Lonsdale buildings. During the summer months, the LEC recovers enough waste heat from the refrigeration system to keep the rest of the showers and dishwashing water warm without the use of gas.

Although Veng could not provide details, among the technologies LEC could implement in the future are ocean heat pumps, all-electric boilers, geothermal power plants and capturing heat released by large banks of computer servers.

“This is where it gets interesting because we have some really ambitious plans,” Veng said.

In 2021, the cryptocurrency company went public with a proposal to provide heat from new bitcoin mining computers, but that plan never came to fruition, Veng said.

Is LEC the right way to go?

However, the LEC is not without its critics.

The utility has been criticized in city council chambers for its monopoly position in the market, higher home heating prices for consumers, the amount of debt the city has had to finance its growth, the lack of regulatory oversight by the BC Utilities Commission and the fact that it forces developers and consumers to buy heating from a high-carbon source when zero-carbon options — heat pumps that can also provide increasingly important summer cooling services — are now readily available.

The LEC still owes the city $26.6 million in capital loans that were used to get the system to its current state, but the utility is on track to retire the debt by 2037. It currently pays interest at 3.51 percent. According to the LEC’s 2023 annual report, the utility reported $157,000 in net income in addition to paying the city $1.8 million in principal and interest payments.

McIlroy, who also works as a policy analyst at the clean-energy think tank Pembina Institute, acknowledged that buildings can now be designed and built to such high energy efficiency standards that they may not need a utility like LEC. But she said there are many different paths to net-zero emissions.

“It’s not necessarily helpful to be very specific about how we get there. We’re working toward the same end goal,” she said. “We need to give people the flexibility to achieve the goals we’re trying to achieve.”

There are other benefits to the city’s power grid. The system has built-in redundancies thanks to multiple power plants, meaning there’s virtually no downtime. And because LEC already uses renewable natural gas, solar and geothermal energy, it already has a smaller carbon footprint than most buildings that aren’t connected to the system.

“If all of these buildings had independent systems, they would emit more. The emission levels would be higher,” McIlroy said.

With the launch of projects such as the sewage heat recovery station, the transition away from coal will be much smoother for LEC customers than for residents of other buildings.

“If we had these buildings built in a typical way with gas boilers and other types of systems, we would want to retrofit all of those buildings, one by one,” McIlroy said. “We’re also working very hard to upgrade, decarbonize and retrofit the system, which is expensive, but not as expensive as retrofitting those 105 buildings.”

Veng echoed the same sentiment and stated that the LEC is entering a new era.

“We’ve been developing LEC for over 20 years. It was a growth phase,” he said. “We were waiting for renewables to mature so we could keep rates affordable but move to renewables.”