Decrease in Direct GHG Emissions
Decrease in Gas Flaring
Our normalized greenhouse gas (GHG) emissions decreased 36 percent in 2015, while direct greenhouse gas emissions decreased 3.6 percent.
One of our key accomplishments was a 41 percent decrease in greenhouse gas emissions in our Equatorial Guinea operations. A large portion of the improvement was due to a reduction in flaring by reinjecting gas. Globally, we have reduced our flaring emissions by 61 percent since 2013. Emissions from mobile sources, while a small portion of our overall GHG emissions, increased in 2015; this uptick was primarily due to heavy helicopter use during our Falkland Islands drilling campaign.
Our overall air emissions in the U.S. increased with the addition of Rosetta assets. An increase in carbon monoxide emissions in the U.S. reflects not only the acquisition of the Rosetta assets, but also improved tracking of equipment inventory and associated emission levels for some Colorado assets acquired in 2014.
In Colorado, we implemented new environmental management software that enables us to better analyze emissions data and evaluate opportunities for minimizing burner downtime, which in turn reduces volatile organic compound (VOC) emissions. We also worked with a third party gas gathering company to significantly reduce line pressures, thus reducing the potential for VOC emissions. This allowed us to reduce the horsepower required in our operations, resulting in a measurable reduction in nitrogen oxide (NOx) emissions.
We also adopted an alternative truck loading system, for offloading oil from tanks to trucks at many locations in the DJ Basin. This system, called ATLAS, was developed as part of a consent decree signed in 2015 and replaces manual sampling of tank volumes, oil temperature and grade with automated systems. By eliminating the need for a worker to ascend tanks to open a tank-top valve to take readings, the new technology increases worker safety and reduces air emissions. The Bureau of Land Management approved ATLAS for use on some of Noble Energy’s federal wells, and the Colorado State Land Board approved it for use on our state leases. We trained our contract truck haulers to safely and responsibly employ the technology at our DJ Basin locations where automation is available, which includes approximately 60 percent of our locations.
Building on our experience with Leak Detection and Repair (LDAR) in Colorado, Noble Energy implemented a voluntary LDAR program in West Virginia to reduce the potential for leaks at our production facilities where limited regulatory requirements for LDAR exist. These efforts have successfully identified alternative gasket material and other best management practices that we have implemented across the Marcellus Shale area.
Note that Noble Energy does not produce fuels or refine petroleum products. We also do not use, produce or consume any ozone-depleting substances in our operations.
Noble Energy continues to rely on natural gas to power its onshore drilling and well completion operations. Almost half of the produced water at our facilities is moved by trucks and vehicles fueled by compressed natural gas (CNG). Our commitment to CNG may encourage additional fueling infrastructure and use of CNG vehicles. Using natural gas produces fewer greenhouses gases and less sulfur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter than gasoline.
In October, Colorado Clean Cities awarded Noble Energy its statewide Innovation Award for our efforts around natural gas in the transportation sector. Our CNG School Bus Investment Initiative has contributed nearly $3.1 million toward new CNG-fueled vehicles and encouraged funding more than twice that amount by our program partners, which include the Regional Air Quality Council, Colorado Department of Local Affairs, Upper Front Range Metropolitan Planning Organization and local school districts. To date, the initiative has provided 29 new school buses in Weld, Adams and Denver counties as well as a CNG truck and new CNG school bus maintenance facility with a CNG fueling station in Weld County.
Our operations require the transportation of people and supplies to work sites and the transportation of produced oil or gas to central distribution hubs. The more we are able to streamline these processes, the less we contribute to air emissions and impact other environmental factors.
In the DJ Basin, we transport more than 99 percent of our freshwater for hydraulic fracturing by pipeline, eliminating approximately 156,000 water truck loads from Colorado roads in 2015. In the developed operational areas of the Marcellus Shale, we continue to eliminate at least 112,500 truck hauls from the road by utilizing available pipeline infrastructure.
Transportation related to our operations affects more than just air quality. In the Falkland Islands, a traffic management plan for supplies and personnel was developed that addresses increased road use and subsequent traffic in the capital city of Stanley and reduces the impact of our operations on the city, which has a population of just 2,500. Separately, to reduce the disturbance to residents and wildlife from onshore helicopter activity, arriving and departing crews are transported by road from the main airport to a helicopter base at Stanley Harbour. Helicopter transport is used from the harbor to the rig, reducing the potential for interference with other sea vessels and marine life.