Columnists: Alan Meier, LBNL

Published on: 29 Nov 2016

Is natural gas becoming less appealing?

North American consumers have easy access to natural gas for space heating, water heating, and other activities.  For many decades, their gas supply has been both reliable and affordable.  In Europe, natural gas began later, has always been more expensive, and sometimes less secure.  But on both continents, we have long believed that natural gas is clean and environmentally friendly and thus the fuel of choice.  However, the situation in now changing in ways that prompt us to ask whether natural gas is becoming less appealing.

What has changed?  First, research has shown that natural gas is not as environmentally friendly as we once thought.  Direct combustion of natural gas in homes generates CO 2 – quite a lot of CO 2 – and there is no way the United States or Canada can meet their climate goals without reducing gas use.  That’s almost old news (even if we haven’t yet begun to deal with it), but the  latest research has found that methane leakage during extraction, transmission, and storage of natural gas is much greater than once believed. New monitoring techniques suggest that 25% more methane is lost through leaks than estimates made only a few years ago.  Methane – the primary constituent of natural gas – has a global warming potential of about 25 times CO 2 , so this upward revision is significant on a national (and global) scale.   A recent incident underscored the problem: last year, a catastrophic blowout occurred at the gas storage facility in Aliso Canyon, California. The injection of this stored gas into the atmosphere from this single accident resulted in emissions equal to 20% of the state's total CO 2 emissions in 2015 (including those from cars and power plants!).  That accident also created immediate local health effects, well ahead of future health consequences from climate change.  Deferred maintenance and aging infrastructure of the gas networks ­– in North America and Russia – are likely to create more such accidents, ranging from the nearly invisible to the spectacular.

On the consumption side as well, natural gas is less of a clear-cut winner than before, especially compared to electricity from renewable sources.  The best electric alternatives remain more expensive than gas, but their efficiency and other technical features are improving rapidly.  Heat pumps, the principal method of supplying low-temperature heat from electricity, continue to improve and supply heat at ever-colder outside temperatures.  Other applications of electric heat are also becoming more efficient. The latest generation of electric stoves—once disdained by chefs—now offer controllability and other features that make them competitive with gas units.  The laggard has been the electric clothes dryer, where heat pump versions are only now appearing.

Another strike against natural gas is that combustion occurs inside homes, and removing the exhaust products in turn requires more energy, negating  some of the fuel’s advantage. For example, safe indoor combustion may require extra ventilation – often in the form of uncontrolled infiltration – and the extra incoming air must be heated. Electrically-heated homes with low infiltration are easier to build and their ventilation systems are simpler to operate than homes with gas-fired appliances in them.

In global climate negotiations, natural gas is sometimes called a “transition fuel”, that is, from coal to carbon-free alternatives.  That may still be true, though the numbers are not so overwhelmingly favorable as we once thought.  But even as downsides of natural gas become more apparent, its price is falling, supplies are plentiful, and its use is therefore becoming more attractive.   These contradictory signals are a recipe for confusion among both consumers and policymakers.   How do we reconcile the short-term benefits with the long-term environmental costs? Policymakers, building scientists, utilities, and regulators will need to develop clear recommendations to the building community as natural gas ceases to become the obvious fuel of choice.

An earlier version of this article was published in Home Energy Magazine .

The views expressed in this column are those of the columnist and do not necessarily reflect the views of eceee or any of its members.

Other columns by Alan Meier