One of the areas in which we have made substantial progress with respect to quick wins on GHG emissions over the past 20 years is landfill emissions. During the Clinton administration significant strides were made to drive the collection and flaring of methane from landfills, reducing the GHG potential of the flared gas by 95% (depends how you count, but generally methane is much more potent a GHG than the CO2 left after burning it). Methane emissions from landfills in the U.S. are down more than 30% from 1990 as of 2012:
www3.epa.gov/...
Additional steps have been widely made to use collected gas to provide useful energy (electricity, pipeline gas, or garbage truck fuel), rather than simply flaring it, thus displacing conventional fossil fuel use, and effectively eliminating the almost entire GHG impact of the landfill. In fact, in California alone, 81 landfills were producing electricity using their methane output, as of 2016.
Unfortunately, that number appears to be headed down in 2017.
www.latimes.com/…
More than one landfill gas generation installation that is already in service and displacing fossil gas has shut down as of or prior to 1/1/2017 and is now flaring the same gas without using the heat to displace fossil fuel consumption. The net result is an increase in GHG emissions as the lost energy production is replaced by existing sources, which on margin will likely be fossil gas. The generator installations themselves were manufactured, installed, and now removed, not without GHG impact, either. The local electrical distribution grid will need to accommodate additional loads which these generators had offset, resulting in construction, and/or electrical system losses will increase. One step forward, two steps back.
Why?
The proximate cause is newly restrictive AQMD NOx restrictions, likely excellent in overall effect, but which throw the baby out with the bathwater when it comes to landfill gas. AQMD traded reduced smog for increased climate change, in a way that ran directly counter to previous regulatory incentives of other agencies.
Every energy source, conversion, and usage is a compromise with positive and negative impacts, even wind, solar, and landfill gas. Our hodgepodge regulatory climate created an incentive for the construction of landfill gas generation, and then created a disincentive. The net result: More GHG emissions.
The root solution to the landfill emission problem is to reduce the wastestream to landfills, but as long as we have landfills producing methane, and have fossil fuels in use elsewhere, using that methane to offset use of fossil fuel seems environmentally prudent in most locations. Maybe the smog reduction here (also attainable via other alternatives) is worth the increased GHG emissions (which could also be offset via other alternatives), but if so, that’s counter-intuitive in the extreme.