Universal is no stranger to dual-fuel engines. The pressure pumping company, part of Patterson-UTI, first put the technology to work more than a decade ago on frac sites in the northeast United States, where field gas is readily available on location.

“As an early adopter of dual fuel, we’ve always been engaged with our customers in taking advantage of the inherent fuel savings that come when you displace diesel and utilize natural gas instead,” says Jeff Beach, Universal’s vice president of technology. “In today’s environment, the use of dual fuel is amplified even more because of our customers’ ESG [environmental, safety and governance] targets.”

A “green” solution where it counts

Growing customer demand for lower-emission, less-diesel-centric power is why Universal currently is in the midst of upgrading its fleet of Cat® 3512E Tier 4 Final diesel engines to Tier 4 Final DGB™ engines.

DGB stands for Dynamic Gas Blending™, and it’s a Caterpillar innovation that automatically maximizes the amount of gas used to displace diesel. That gas can take many forms: compressed natural gas, liquified natural gas, pipeline gas and even field gas, which otherwise is often flared into the atmosphere. The technology received the U.S. Environmental Protection Agency’s 2020 Clean Air Excellence Award.

“Dual-fuel technology has evolved over the years, and in our opinion the Cat Tier 4 Final DGB solution is by far superior to the competition both in performance and overall cost,” Beach says. “It was the first to market, it performs better and we can get into the system cheaper — it covers all the bases for us.”

Universal was most impressed by the way Caterpillar’s DGB technology leverages fuel mapping to maximize diesel displacement. The company views that metric two ways: the real-time displacement that occurs during engine operation and, more importantly, the amount of diesel that’s displaced over the course of a day, week or month when an engine’s not pumping 24/7.

Beach expects that second number to rise as much as 10% when Universal’s 20 newly upgraded Cat Tier 4 Final DGB engines go into operation. In addition to fuel mapping, the engines’ automatic start-stop technology — which can cut nonproductive idle time by 60% and fuel consumption by 8.5% — should contribute to that gain.

“Depending on which ‘green’ you’re talking about, the Caterpillar solution will save money on fuel and result in better emissions,” Beach says.

Just as good as — if not better than — electric

Some other pressure pumping companies are exploring or have already made the move to electric fracking, or e-frac, which typically involves using gas turbines to drive natural gas generators on site. But based on years of experience with dual-fuel technology, plus analysis drawn from data collected from various OEMs, Universal believes Cat Tier 4 Final DGB engines are just as good a solution — if not better.

“Just because something is electric doesn’t mean that it’s better,” Beach says. “Yes, you can reduce your footprint on location and save on some operating expenses with a turbine, but our customers are more interested in the emissions discussion.”

There, the Cat Tier 4 Final DGB solution delivers a big advantage — not just in reducing pollutant emissions but in taking down greenhouse gas (GHG) emissions as well.

“Methane slip, the unburned, unignited natural gas that passes through the engine as exhaust, is significantly reduced with the Cat Tier 4 Final DGB system,” Beach says. “Everyone’s focus today is on the carbon footprint, so for us to be able to reduce methane slip has a lot of visibility and importance.”

DGB upgrades made easy

Cat dealer Cleveland Brothers is handling the DGB upgrades for Universal, with each engine taking about 10 days to two weeks to convert from Tier 4 Final diesel to Tier 4 Final DGB.

“We literally just drop off the unit, and Cleveland Brothers takes care of everything,” Beach says. “It’s a seamless process.”

Universal expects the 20 upgraded engines to be in the field and pumping in the third quarter of 2021. Stay tuned for updates on their performance.