The cleaner burning process (than diesel fuel) and price has made heating and cooking with natural gas quite popular in the last couple of decades. However, popularity put a pretty heavy dent in supply, so much so that alternative sources are being explored to meet demand. There are some potentially greener sources of natural gas, but unfortunately some very destructive ones as well - and the so-called green ones are also environmentally problematic as they centre around methane.
Ostensibly on the bright side, these biogas projects are harnessing methane escaping from landfill sites and other decomposing organic materials, rather than letting it escape into the atmosphere. While the biogas industry is still in its infancy, it is mostly injecting methane into the general natural gas supply lines, which due to their own problems with leakage and the very high Global Warming Potential (GWP) of Methane is a growing cause for concern.
One not so promising source is from fracking, which is a process for extracting natural gas from shale rock. It involves pumping water and chemicals into shale rock at very high pressure causing the release of methane gas.
While this was at first seen as a relatively harmless extraction method even by environmentalists, it now appears that tapping into this source could be among the more destructive of our fossil fuel operations.
Along with soil and water contamination, there are increased emissions due to unintended methane leaks during the fracking process. In some cases groundwater is so contaminated that water from household taps can even be ignited. Also, extracting natural gas can hardly be called an effective use of our dwindling freshwater supplies.
A study done at Cornell University estimates that over a 20 year period, natural gas fracking will have a greenhouse gas footprint at least 20% higher than coal, and according to the journal Climatic Change, "perhaps twice as great".
Methods for heating with natural gas:
With a condensing gas furnace or boiler: Water vapor formed during combustion is condensed and recovers the latent heat of condensation. This is a very efficient combustion system, somewhere in the area of 90% to 97%. There is also very little loss during the transmission of heat energy.
With a conventional gas furnace or boiler: This is a clean burn and it emits very few particles. However, overall efficiency is between 50 and 80%, much lower than a condensing gas boiler.
Both types of gas boilers are compatible with hydronic heating systems, and both types of gas furnaces blow hot air around the home.
Gas fireplace: A gas fireplace is a relatively efficient way to heat a home and it creates a nice atmosphere, but it still means having a gas supply to the home which is proven problematic and is starting to be banned around the world - including in the US and Canada.
Natural Gas is being phased out in Homes
As the true ramifications of using Gas in homes has become apparent, being that a significant proportion simply escapes into the atmosphere with a significant GWP, the upshot has been that most of Europe has already phased out natural gas in homes and now North America has also started to legislate against natural gas furnaces, gas boilers and gas water heaters in favor of electrification and heating with high efficiency heat pumps.
Now you know more about why natural gas condensing furnaces aren't sustainable, learn more about sustainable home comfort, energy efficiency and how to reduce the carbon footprint of homes on the following pages and in the EcoHome Green Building Guide.
Find more about green home construction and reap the benefits of a free Ecohome Network Membership here.