|data from US EPA|
Over the last two hundred and fifty years, the concentration of methane in our atmosphere has increased by 151% to 1.8 parts per million. Methane is the primary component in natural gas, methane is emitted to the atmosphere during the production, processing, storage, transmission, and distribution of natural gas and because gas is often found alongside petroleum which is much more valuable, methane is sometimes vented to the atmosphere rather than captured during oil production. Methane is also produced from the decomposition of human and animal waste as well as garbage and is the major component of landfill gas. Methane is also released from the natural biological process of enteric fermentation which is fermentation that takes place in the digestive systems of animals. In particular, ruminant animals that have two stomachs and eat grasses (cattle, buffalo, sheep, goats, and camels) produce and release methane from the microbial fermentation that breaks down the grass and hay into soluble products that can be utilized by the animal. Also, when natural gas and other petroleum products are used as a fuel incomplete combustion releases traces of methane.
Methane emissions come from diverse sources and sectors of the economy, unevenly dispersed across the landscape and not well tracked. These uncertainties have resulted in estimates of current and projected methane emissions by simplified models and rules of thumb for the source of methane emissions. Nonetheless, the estimates below are the best available and the Administration has launched a methane mitigation plan.
The President’s Strategy to Reduce Methane Emissions targets reductions in methane emissions from landfills, coal mining, and agriculture, and oil and gas systems that include action on four fronts:
- Landfills: This summer, the EPA will propose regulation to reduce methane from new landfills and begin the process to tighten the methane standards for existing landfills.
- Coal Mines: In April 2014, the Department of the Interior, Bureau of Land Management will begin the process of developing a program for the capture and disposal of waste mine methane on lands leased by the Federal government.
- Agriculture: In June 2014, in partnership with the dairy industry, the U. S. Department of Agriculture, the EPA and U.S. Department of Energy will jointly release a “Biogas Roadmap” outlining voluntary strategies to reduce U.S. dairy sector greenhouse gas emissions by 25 % by 2020. Maybe the administration will reduce the U.S. consumption of dairy products, beef, buffalo, sheep and goats and thus reduce the herds of rumens.
- Oil and Gas: This spring EPA will assess potential sources of methane and other greenhouse gas emissions from the oil and gas industry and in the fall of 2014, EPA will determine how best to pursue further methane reductions from these sources. EPA is expected to develop additional regulations if necessary by the end of 2016. Later this year, the Bureau of Land Management will update the rules to reduce venting and flaring from oil and gas production on public lands. In addition the Administration will identify “downstream” methane reduction opportunities. Through the Natural Gas STAR program, EPA will work with the industry to expand voluntary efforts to reduce methane emissions.
One downstream area for reduction of methane is our natural gas distribution systems. In 2012 and 2013 two scientists mapped the gas leaks under Boston and Washington DC using a new, high-precision methane analyzer provided by Picarro installed in a GPS-equipped car. They found that there were approximately 4.3 leaks per mile of street in both cities. Levels of methane in the surface air on some streets exceeded 15 times the normal atmospheric background value.
For some time we have failed to maintain our unseen infrastructure systems as a way to cut costs. We have failed to maintain and upgrade the oil and gas distribution system. Gas distribution companies are well aware of the leaks in the system. The companies calculate the difference between the gas pumped into the distribution system and what is metered at the end user. This is referred to as "lost and unaccounted-for" gas is often a surcharge on customer bills. These leaks are wasteful, dangerous and a significant source of greenhouse gas released into the environment.
Distribution companies try to prioritize finding and fixing leaks likely to be explosion hazards, where gas is collecting and concentrating and ignore the small losses from deteriorating iron pipe and the deteriorating distribution system in our cities. Natural gas distribution leaks and explosions cause an average of 17 fatalities, 68 injuries, and $133 million in property damage each year, according to the U.S. Pipeline and Hazardous Materials Safety Administration. In 2010 a natural gas pipeline exploded in San Bruno, CA, just south of San Francisco. There was no warning and eight people were killed, 58 were injured and 38 homes, the entire section of a neighborhood, destroyed. In 2011, a leak from an 83-year-old cast-iron main in Allentown, Pa., caused an explosion that killed five people. And just last month a gas explosion killed eight people in East Harlem.
Detecting and reducing gas leaks are critical for reducing greenhouse gas emissions, improving air quality in cities and consumer safety, and ultimately saving future generations of consumers from loss of life, property and wasted money. Right now, repairing our infrastructure will be very expensive, but as the pipes that distribute gas (and the other essential utilities of water, sewer, and electricity) continue to age failure will become more frequent. Infrastructure is the foundation of our economy, connecting businesses, communities, and people, making us a first world country-we need to repair and maintain it.