If you’re considering electric motors to drive your gas gathering and processing equipment, you’re in good company. The industry has seen a steady increase in electric power over the past decade, largely due to the challenges of emissions permitting and a lack of qualified engine technicians. Electric motors bring a number of advantages to gas compression operations — but so do traditional gas engines and gas turbines. Which is right for you?

Top 5 Reasons to Choose Electric Motors

1. Permitting is easy. Because they run on electricity, electric motors produce zero emissions on site. That’s a big advantage if you work in a highly regulated region. Bonus: They’re also quieter than gas engines, which is great for workers on location and any nearby residential areas.
2. Maintenance is practically nonexistent. You need to change the oil once a year and occasionally replace a sensor — that’s it. There’s virtually no downtime required for electric motor maintenance, and no need to search for technicians who know how to service them.
3. The purchase price is lower. An electric motor costs significantly less than a gas engine up front. That said, the price of electricity typically runs higher than that of natural gas. If you don’t already have high-power electric lines running to your location, make sure you add the expense of purchasing right-of-way and installing power lines, poles and other infrastructure. And if you want variable speed control, know that installing a variable frequency drive (VFD) also costs extra.
4. Less complexity means simpler installation and packaging. Since electric motors are smaller, lighter and not as complicated as gas engines, they’re easier to install — no radiator pipes to hook up, for example. In addition, a smaller overall footprint makes transporting electric motors from packager to site simpler and less expensive.
5. Compressor options include centrifugal and reciprocating. Electric motors come in different speed ranges so you can match them to your compressor to get the performance you need.

Top 5 Reasons to Choose Gas Engines

1. The power is already there. You can run a gas engine anywhere, because it burns the natural gas you’re compressing to generate power. You don’t need to pay — and in many cases, wait — to bring electricity and its associated infrastructure on site.
2. Power supply is constant. A gas engine runs on site available fuel, which means there are no worries about a snowstorm, lightning strike or other issue with the electricity supply shutting down your equipment and interrupting the flow of gas.
3. Controlling gas flow is simple. Say two of your four wells are undergoing maintenance, and you want to slow engine speed to cut the flow of gas in half. With a gas engine, that’s easy — variable speed control is built right in. It’s possible with an electric motor, but requires that you pay extra to add a VFD.
4. Operating costs are less. Your capital costs are higher with a gas engine than an electric motor, but over time, it should cost you less to operate. That’s because natural gas is cheaper than electricity, and gas engines require less in the way of infrastructure than electric motors.
5. They’re proven and familiar. There’s a lot to be said for sticking with what works — and gas engines have gotten the job done reliably and productively for decades. (Cat^® gas compression engines have logged more than 2 billion operating hours around the world.) People in the industry know how to spec them, run them and work on them in the field, so there’s no learning curve.

What About Gas Turbines?

Gas turbines, like those manufactured by Caterpillar subsidiary Solar Turbines, also offer a viable solution in certain applications. They produce low emissions due the nature of their continuous combustion cycle, and maintenance costs are similar to those of gas engines.

Gas turbines operate most efficiently within a specific pressure range, which can make them a smart, economical choice for processing and booster stations where a significant amount of gas — hundreds of millions of cubic feet a day — moves down the pipeline with minimal pressure drops. They’re less effective at the wellhead or for gas lift or gas gathering, however. In these applications, where gas pressures can start as low as zero to 50 psi in unconventional wells and must be raised to an average pipeline pressure of 1,200 psi, electric motors and gas engines tend to be more efficient.

Whichever Option You Choose, We’ve Got You Covered

The electric-or-gas decision comes down to a number of factors — emissions, costs, maintenance and availability of electricity all play a role. Here’s the good news: Once you’ve selected the best option for your operation, you can count on Caterpillar to deliver exactly what you need. We offer a full line-up of both electric motors, gas engines and gas turbines built specifically for gas compression applications, all backed by service and support you can trust. Talk to your local Cat dealer for more details and expert advice on selecting the right power source for your needs.