This past week we had a discussion with a subscriber regarding reducing one’s impact on Global Climate Change. The discussion started with Renewable Energy Certificates (RECs – purchased to offset electricity consumption) and their associated positive attributes. However, it became apparent that the subscriber wanted to do more, as RECs don’t offset the burning of fossil fuels that are consumed for most domestic heating and hot water applications. The conversation quickly turned to carbon offsets. Carbon offsets are generated from projects that reduce greenhouse gases. The critical word in the previous sentence is “reduce.” There are many approaches to the problem. Some are simple, cheap and actually mitigate Global Climate Change – but they may require thinking a bit differently about decreasing one’s impact on the environment.
Global Climate change and CO2
There are six major gases that account for almost all of our atmosphere’s ability to hold in heat. Most of the earth’s ability to hold in heat is attributable to carbon dioxide (CO2) – the product of burning fossil fuels to power our homes, industry and cars. Because CO2 level has been correlated with human activity, it has received the most attention in addressing GCC. And that makes sense – why highlight a problem that has no solution? The association of our lifestyle with GCC has been effective in getting people to focus on the challenge. Unfortunately, this approach has also had the effect of crowding out other solutions that may be as good as – or even better – than energy efficiency and conservation, especially in mitigating GCC Global Warming Potential in the short-term.
Global Warming Potential
The ability for a gas to hold in the earth’s heat is quantified by its Global Warming Potential (GWP). But, not all gases are equal when it comes to their ability to hold in the earth’s heat.
The GWP scale assigns CO2 with the value of 1 (one). According to the EPA, “Methane (CH4) is the second most prevalent greenhouse gas emitted in the United States from human activities” and CH4 has a GWP of 21. So for every pound of CH4 you keep from getting into the atmosphere, it is equivalent to reducing 21 pounds of CO2 emissions. If one can find a way of reducing CH4 emissions cost-effectively, there is a multiplier effect in reducing GCC compared to reducing CO2.
From US EPA website:
What is Methane and where do CH4 emissions come from?
Methane is the major component of natural gas. It is the gas that heats many homes and is used for many industrial applications beyond generating heat. The most notable is fertilizer production. It is also the energy source for about 20% of the nation’s electricity production.
Methane is emitted unintentionally into our atmosphere from many sources. Included are: fugitive emission from the production of natural gas; the melting of permafrost in arctic regions (caused by a warming climate), agricultural production and the breakdown of organic material. Included in the “breakdown of organic material” is gas that is emitted from landfills (i.e., municipal dumps).
Landfill Gas Flaring
Organic waste in landfills anaerobically (in the absence of oxygen) digests predominantly into methane (55% of gas emitted from landfills is CH4). To comprehend the magnitude of the landfill gas emitted in the US, over 135 million metric tonnes of greenhouse gases are attributable to the food left on the plates of Americans each year. And this is only a small portion of organic waste that finds its way into our landfills. Methane emitted from these concentrated areas can be captured through piping collection systems, routing the gas for some industrial use or to be burned (flared). Purifying, drying and compressing landfill gas for industrial use typically isn’t cost effective, so the next best option is to flare the gas. Flaring converts the methane to carbon dioxide. While on the surface it doesn’t appear that making CO2 makes sense, converting a gas with a Global Warming Potential of 21 (i.e., methane) to a gas with a GWP of 1 (one) does make sense. QED
There are usually multiple solutions to any problem. And as conditions change, some solutions make more sense than others either with regard to environmental or economical factors. Understanding the critical issues that create the problem and contribute to the solution is the best way to adapt to our changing environment.