Retail electricity providers, especially Community Choice agencies, should move quickly to help their customers “fuel-switch” their home heating fuels from (natural gas, heating oil, propane) to electricity that is more and more being generated from low carbon energy sources. New high efficiency heat pump water heaters plus ducted or ductless heat pump systems for space heating exist that can replace natural gas furnaces, and boilers. Moreover, such systems are easy to install, offer improved living environments, and are rapidly coming down in price. Such systems can combine with rooftop or community supplied solar energy, or an increasingly clean electricity grid, to create ultra-low emission homes and commercial buildings. The next time you need to replace your gas-fired furnace or water heater, think about switching to a modern, efficient electric system.
Background of the Problem
Previous estimates grossly underestimated the severity of the green house gas threat posed by methane, the principal component of natural gas (~85%). Methane emissions from natural gas leakage during oil and gas extraction and distribution, as well as emissions from animal feedlots and public waste facilities, all threaten to push global warming past the tipping point where unstoppable melting of frozen arctic soils could lead to catastrophic releases of naturally occurring methane. To avoid this outcome, several steps should be taken. In particular, public policies that tout natural gas as a “bridge fuel” to cleaner energy should be discarded as misguided and dangerous.
Because methane, carbon dioxide (CO2) water vapor, and other greenhouse gases (GHGs) remain in the atmosphere for vastly different lengths of time, scientists calculate their combined effects over an arbitrary time frame, usually 100 years. This allows, for example, the effects of the gas HFC-134, a refrigerant used in automobile air conditioning systems (~13 year atmospheric life), to be summed up with the effects of other gases like carbon tetrafluoride (atmospheric life ~50,000 years).
Scientists use the term “global warming potential” (GWP) to describe the characteristics of each gas individually. The GWP compares each gas to carbon dioxide (CO2). The result is a number that indicates the climate changing effect of the gas when compared to CO2 over a 100 year span. Nitrous oxide, for example, has a GWP of 298, meaning it has 298 times the global warming effect of carbon dioxide over 100 years.
The serious flaw in this approach comes from the short term effects of common gases that remain in the atmosphere for only a few days or a few years, and represent a danger not considered in the arbitrary 100 year time frame used to measure combined GHG effects. Methane, the other big GHG besides carbon dioxide, remains in the atmosphere for about 10 years, so combining it with CO2 and other gases into a 100 year time frame effectively masks methane’s actual short term effects. Methane is second only to CO2 as an anthropogenic (man-made) contributor to warming, but it is increasingly the focus of scientific attention because of its short term threat to push the planet past a tipping point whereby global warming may increase rapidly due to natural positive feedback loops. Two such feedback loops cause considerable concern. One is the vast amount of natural methane that will be released into the atmosphere as arctic soils warm, methane that will be created from long frozen biological material in the ground (mainly frozen plant matter). Another feedback and potential tipping point comes from a warming atmosphere that can hold more water vapor, itself an extremely potent greenhouse gas, that will increase as the atmosphere warms.
Policymakers should, therefore, take methane’s effect over its 10 year atmospheric presence into consideration, not simply the arbitrary 100 year time frame that is still widely applied. In a 10 year time frame, methane is known to be about 100 times as powerful as CO2 as a greenhouse gas, not the 28 to 36 times figure that is still used to guide public policies.
It is important to note that since the industrial revolution worldwide oil and gas development, large scale agriculture, and other factors have caused the absolute amount of methane in the atmosphere to not only go up about 250% (Figure 1), but to continue to increase even though its atmospheric life is only ten years. This strongly indicates that the sustained increase over the last few centuries has been caused by human activities, and thus can be reversed.
Figure 1: The Rise of Atmospheric Methane Since 1750
Notice how worldwide atmospheric methane appears to have leveled out around the year 2000 and then started increasing again around 2008. A great deal of scientific debate centered on this development. Some scientists argue that the new increase is primarily due to increases in emissions from the tropics, from wetlands, or from agricultural sources. However, recent research points to natural gas recovery and distribution as the main source of increased emissions. This research points to shale fracturing, which expanded rapidly around the year 2008, as a primary driver of newly rising methane levels worldwide.
Underestimating the global warming effect of methane is common when setting public policy. The chart below indicates the estimated sources of GHG emissions in Sonoma County, California (Source: Climate Action Plan 2020 by the Regional Climate Protection Authority, Sonoma County). Notice that the amount of GHG emissions from the “Building Energy” sector is estimated at 33% of total emissions.
2010 Countywide GHG Emissions by Sector
Building emissions in this chart are derived almost entirely from natural gas consumption. Moreover, solid waste emissions and a substantial portion of livestock emissions in the report are from methane as well, leading to a total of about 40 percent or more of reported emissions to be from methane.
In the case of this report, the multiplier used for calculating building emissions was considered to be 28 times that of CO2. Clearly, if the true short-term methane to CO2 GWP ratio is about 100 in the short term, not 28, then the effect of natural gas emissions should occupy a much larger fraction of the pie chart. Whether relatively more resources should be spent on reducing transportation emissions, as opposed to building emissions, rests largely on the accuracy of such assessments.
It should be clear why some scientists have argued that total methane emissions, including agricultural emissions, may represent as big or bigger a GHG threat as do CO2 emissions from the transportation sector.
These facts point to the need to rapidly fuel-switch from natural gas as a fuel used for heating buildings and water, to cleaner electricity derived from renewable sources for those purposes. All retail electric service providers, including the big utilities, should be adopting fuel-switching to electricity as a high priority, but they are conflicted. However, Community Choice agencies are very well-suited to this purpose given that they operate exclusively in electricity service and exist to serve the interest of the communities they serve, as well as the broader public interest.