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.
The following case studies supplement those found in our 2018 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 2018, 100 percent of the water we used for hydraulic fracturing in North Dakota (approximately 18 million barrels) was transported using flexible hoses, eliminating 130,000 truck deliveries and 5.6 million miles driven and cutting about 12,200 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. Our goal is to avoid transporting fresh water by truck for all well completions moving forward.
Replacement of Diesel with Natural Gas
Hess Midstream Partners LP’s compressed natural gas (CNG) fuel facility near the Tioga Gas Plant in North Dakota has been in operation since 2016. Due to increasing CNG demand, we initiated an expansion of the facility in the fourth quarter of 2018. By adding a second CNG compressor and two additional heavy-duty filling stations, we were able to double the existing facility capacity. The facility expansion became operational in early March 2019.
The CNG is partially displacing diesel in high-horsepower engines for drilling and in water heaters for well completion operations in the region and is capable of fueling CNG/gasoline, bi-fuel light-duty trucks. We also use it to power six boilers and up to six frac water heaters that have been converted to have the capability of operating exclusively on CNG – although they also maintain the flexibility of operating on diesel or propane – during cold-weather operations. This use of CNG is helping us meet our GHG goals by reducing flaring and providing a lower-emission fuel option for our vehicles and operations. It also reduces costs by displacing the need for more expensive diesel, propane or gasoline fuel.
In 2018 our use of CNG as a fuel continued to increase as Hess and other operators ramped up activity in the Bakken. During the year, the use of CNG from the Tioga fueling facility alone eliminated the need for approximately 1.2 million gallons of diesel, propane or gasoline, which in turn reduced carbon dioxide equivalent (CO2e) emissions by approximately 3,500 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 2018 we were able to use 400,000 standard cubic feet per day of natural gas, which would otherwise have been flared, to directly power the two sites. This reduced our use of diesel fuel and eliminated 360 fuel deliveries by truck, equating to 28,800 miles driven. In addition, by using natural gas instead of diesel we reduced CO2e emissions by about 3,134 tonnes.