In support of our greenhouse gas (GHG) emission and flaring intensity reduction targets, we track and monitor air emissions at each of our assets and undertake a variety of emission reduction initiatives
Our efforts focus on our largest emitting facilities and on opportunities that are technically and economically feasible and where we are able to achieve stakeholder approval. In 2017 ongoing reduced oil and natural gas production related to the continued low price of oil again presented us with a reduced pool of emission reduction opportunities. We have, however, been able to continue achieving emission reductions through a number of ongoing programs.
The following case studies supplement those found in our 2017 Sustainability Report.
Flexible Hose for Freshwater Transport
In North Dakota, we continued to utilize flexible hose to transport fresh water directly from the water source to our wells, instead of using trucks. Over the past four years, we have steadily increased the percentage of water we supply to our fracturing operations by hose rather than by truck, which reduces noise, GHG emissions and the potential for accidents associated with truck traffic. In 2017, 100 percent of the water we used for hydraulic fracturing in North Dakota (approximately 7.4 million barrels) was transported using flexible hoses, eliminating 64,000 truck deliveries and 2.8 million miles driven and cutting about 6,100 tonnes of transportation-related GHG emissions. As an additional benefit, in winter months we use line heaters along with the hoses to deliver 75-degree Fahrenheit water into insulated tanks, eliminating the need to heat water on location. In 2018 we will continue this program, and with the anticipated increase in the number of active drilling rigs during the year, the amount of water pumped via flexible hose will continue to increase. Our goal is to avoid transporting fresh water by truck for all well completions moving forward.
Replacement of Diesel with Natural Gas
Since 2016 we have operated a compressed natural gas (CNG) fuel facility near the Tioga Gas Plant in North Dakota. The facility – which includes one CNG compressor, four light-duty filling stations and two heavy-duty filling stations – uses captured gas that had been previously flared. The CNG generated from this captured gas is partially displacing diesel in high-horsepower engines for drilling and well completion operations in the Tioga area and fueling Hess’ fleet of 25 CNG/gasoline, bi-fuel light-duty trucks. We also use it to power nine boilers that have been converted to operate exclusively on CNG during winter operations. This use of CNG is helping us meet our GHG goals by reducing flaring and providing a lower-emission fuel for our vehicles and operations. It also reduces costs by displacing the need for more expensive diesel or gasoline fuel.
In 2017 our use of CNG as a fuel increased markedly as we ramped up our activities in the Bakken. During the year, the use of CNG from the fueling station alone eliminated the need for 1.68 million gallons of diesel or gasoline, which in turn reduced carbon dioxide equivalent (CO2e) emissions by approximately 4,900 tonnes.
We began piloting power generation utilizing gas from our Bakken operations in 2014 and, building on that experience, implemented gas generation at a second site in May 2016. As part of this project we replaced eight diesel-powered generators with 170-kilowatt gas-fueled generators. In 2017 we were able to use 340,000 standard cubic feet per day of natural gas, which would otherwise have been flared, to directly power the sites’ electrical needs. This reduced our use of diesel fuel and eliminated 312 fuel deliveries by truck, equating to 26,000 miles driven. In addition, by using natural gas instead of diesel we reduced CO2e emissions by about 2,700 tonnes and VOCs by 1,570 tonnes.