Heating a home with ‘green’ natural gas to reduce emissions
Bullfrog Power and its use of biogas is one answer to reducing your residential carbon footprint
For Canadians who don’t fly much but who heat their homes with natural gas, home heating is very likely to be the largest part of their carbon footprint.
In a previous article for The Spectator (“Shrinking our carbon footprint,” Sept. 19, 2020), we showed how Thomas Cassidy reduced the greenhouse gas (GHG) emissions associated with heating his home by 94 per cent. Thomas replaced his gas-fired furnace with an air source heat pump that uses electricity from Ontario’s relatively clean grid to provide space heating for Thomas’s home.
John Loukidelis took a different approach. About six years ago, John started buying “green” natural gas (a.k.a. “renewable” natural gas or “biomethane”) from Bullfrog Power. Bullfrog collects biogas from landfills then cleans it and injects it as green natural gas into our pipeline system.
By “using” this gas to heat his home, John has reduced his GHG emissions by about the same amount as Thomas.
Green natural gas is refined from biogas emitted at landfills and sewage treatment plants. Biogas is about 50 per cent methane by volume. It results from the decay of organic material in the absence of oxygen. The most significant sources of biogas are food waste, livestock, sewage and wastewater treatment, and agricultural residues.
The carbon in biogas, and thus green natural gas, was captured from the atmosphere by the plants and animals that produced the organic material that produced the biogas. The plants and animals live only a few years before they died and their organic material broke down to produce biogas. As a result, burning green natural gas, while it releases carbon dioxide, simply returns the same mass of carbon to the atmosphere that was captured by the decayed organic material. Burning green natural gas does not add “new” GHGs to the atmosphere, in theory, and so it does not contribute to additional warming.
Bullfrog undertakes projects to collect biogas from landfills and wastewater treatment plants. The biogas collected is processed to remove moisture and impurities before the resulting biomethane is injected into the natural gas distribution network. Bullfrog promises its customers that it will inject an amount of biomethane into the network that is at least equal to the amount for which the customers pay. Ontario landfills emit a significant amount of methane, which is a very powerful GHG. By capturing this methane so that customers can burn it to heat their homes instead, Bullfrog significantly reduces GHG emissions.
Of course, customers pay extra for green natural gas. Currently, John pays Bullfrog $0.15 per cubic metre extra (including tax). This is on top of the roughly $0.25 per cubic metre that John also pays to his “regular” gas supplier. “Using” Bullfrog gas, John avoids about 5.8 tonnes of GHG emissions each year at a cost of about $80 per tonne (worst case and highest cost per tonne saved) and perhaps as low as $8 per tonne (best case, if the landfill methane would otherwise have reached the atmosphere).
(It should be noted federal tax policy does not help John with these costs: John still pays the carbon tax on his gas bill, but he does not receive any special credit for paying extra to avoid the emissions that the tax is supposed to discourage.)
For various practical reasons, green natural gas is not a perfectly renewable and carbon neutral fuel source. John significantly reduced the emissions associated with heating his home by buying green natural gas but he did not eliminate them. Bullfrog must emit amounts to build the infrastructure necessary for collecting, refining and delivering the gas. The gas distribution network needed building and ongoing maintenance. The ability to extract biomethane from landfills depends on our rather wasteful food-handling practices. Moreover, some of the biomethane produced for John inevitably leaks into the atmosphere as “fugitive emissions,” just like ordinary natural gas. Some climate scientists believe that, when we account fully for fugitive emissions, natural gas is as bad as coal for our climate.
Nevertheless, switching to a heat pump to heat his home would also have environmental costs. John’s gas-fired furnace is relatively new, and so simply replacing it with a heat pump would waste the emissions embodied in the furnace. A heat pump is also somewhat expensive. Thomas’ switch made sense in part because his furnace was at the end of his life, and so he had no choice but to buy a heat pump or a new furnace.
For now John will continue to use Bullfrog because it is the right stopgap for him at this time. He is planning to fuel switch eventually by installing a heat pump, but in the meantime green natural gas is the right fuel for heating his home.
John Loukidelis is a Hamilton lawyer who resides in Ward 1. He cycles to work every day and takes the bus when it’s too cold or wet. Thomas Cassidy has called Hamilton home from childhood to engineering school and beyond. He lives in a shared house in Ward 1 not far from a bike lane and green space.