Going underground, large-scale

Opinion

Hey there, time traveller!
This article was published 13/07/2023 (820 days ago), so information in it may no longer be current.

It is never easy to change. Natural gas has been connected to most homes in Winnipeg since the 1950’s and ‘60s and produces almost 3.7 million tonnes of CO₂ annually. Some gas lines have been in the ground for more than 60 years. Their life expectancy is about 75-85 years. Gas companies in Canada spend close to $3 billion annually to renew and expand the pipelines.

This is the problem. The cost of building gas lines is amortized over the expected life of the pipeline. Basically, the infrastructure is paid with a very long-term mortgage. That has kept the price of delivering gas to our buildings low. If gas lines are being renewed and extended, the term of the mortgage is 80 years. If we want to move away from gas to heat our homes, how is the utility going to pay the mortgage when no one is buying gas?

The alternative? Electricity. We can use electricity directly (think toaster elements), use it to extract heat from the air outside, or use it to extract heat from the earth.

Electric heat is more efficient than gas, but at today’s electric and gas rates, it’s about three times as expensive to heat your home with electric heat.

Air source heat pumps (ASHP) use electricity more efficiently because they draw heat from outside air. But they don’t work when it gets cold. Electric heat or gas is still needed in the coldest months of winter.

Ground source heat pumps (GSHP) draw heat from the earth. A few metres down the temperature is much warmer than the cold winter air. A GSHP operates efficiently through the entire winter, using about 70 per cent less electricity than electric heat and costs less to operate than a high-efficiency gas furnace.

MB Hydro is rightly concerned about the amount of power needed if everyone switches from gas to electric heat at the same time there are more and more electric vehicles (EV). To produce the power needed by thousands of electric furnaces and EVs, they would have to build more generating capacity. That means more dams, gas turbines, wind turbines, etc. It will stretch Hydro’s resources and electricity rates will have to increase.

ASHPs don’t solve the problem. They must switch to electric or gas heat when it’s cold. If gas is used the gas pipelines must be maintained and new lines built. And they still produce GHGs. But with lower gas consumption the cost of maintaining the gas pipelines becomes greater and customers will pay more. If electric heat is used Hydro will have to build more generating capacity.

GSHPs are a much better option. They use 70 per cent less electricity than electric heat or ASHPs even in our cold winters. The problem is that they need heat exchangers in the ground. They are expensive to install and homes in urban areas may not have enough land to install a heat exchanger.

Several utilities in Canada and the U.S. are helping their customers solve both problems. Instead of replacing old gas lines with new gas lines or extending gas lines into new developments, they are building large ground heat exchangers on available land and running geothermal pipes down the street instead of new gas lines. Instead of buying a billion dollars of gas from outside the province, they can extract heat from the ground in Winnipeg and deliver it directly to a heat pump in your home. Enbridge Gas is already doing this in Ontario. Eversource Energy and National Grid, two utilities in Massachusetts are building geothermal utilities in Boston right now. This can be done in Winnipeg. Instead of mortgaging our future in building and maintain a gas infrastructure that will be worthless long before it’s paid for, a geothermal utility can build a clean infrastructure and keep the money in Manitoba.

A significant advantage of a district geothermal system connected to several buildings is the ability to capture waste heat from ice rinks or wastewater, or from renewable energy sources such as solar thermal, store it in the earth till it’s needed the following winter. Integrating renewable and waste energy sources with larger systems provides the opportunity to optimize system performance.

There is only one thing preventing us from making the transition from fossil fuels to carbon free electricity. That is the political will and vision to create the policies that allow it to happen.

Ed Lohrenz, B.E.S., CGD, has worked across North America in the design of ground source heat pump systems.