Displacement Vs. Substitution: What’S The Difference?

You know that well service engines with Dynamic Gas Blending™ save you money by letting you burn gas and reduce diesel fuel consumption. Exactly how much less diesel will you burn? That’s where you’ll start hearing the terms “substitution” and “displacement.” They don’t mean the same thing, so it pays to understand the difference.

• Diesel substitution is calculated based on the percentage of total energy required to run a DGB engine. In other words, what percent is gas and what percent is diesel? A 70% diesel substitution rate doesn’t mean you’re only burning 30% diesel fuel, though. You’re likely burning more. That’s because the energy value of natural gas varies depending on the source — and that’s why substitution isn’t the best way to measure your savings.
• Diesel displacement is calculated based on the total volume of fuel required to run a DGB engines. In other words, how many gallons of gas and how many gallons of diesel? So when we say the Cat^® 3512E Tier 4 Final DGB engine has a maximum diesel displacement rate of 85%, that means it’s very likely you’re burning just 15% diesel fuel — and your costs will go down accordingly. Displacement is a much easier number to measure and a simpler metric for you to validate on your frac trailers.

If you’re still unclear on the difference, take a look at infographic for a simple, visual explanation.

Download PDF

GET THE LATEST STORIES AND TIPS FROM CAT OIL & GAS – SIGN UP FOR OUR E-NEWSLETTER