Some oil and gas companies are turning to devices that harness energy produced from ocean waves to power some of their offshore oil and gas operations in an effort to further drive down costs and become more efficient.

Italy’s Eni is among the latest companies testing the power of ocean waves. As part of an 18-month project underway in the Adriatic Sea, Eni is testing Ocean Power Technologies’ (OPT) PowerBuoy wave system called PB3 to power autonomous underwater vehicles (AUV) for marine environmental monitoring.

George Kirby, president and CEO of New Jersey-based OPT, described ocean wave energy as the most predictable of renewable energies, considering its persistent ability to provide power anywhere offshore via wind-driven wave activity. To overcome the seasonal drawback of having little or no wave activity, OPT puts energy storage onboard the buoy.

“Think about the Gulf of Mexico in the summer months; you have much less wave activity than you would in the winter months,” Kirby said. “We’re able to ride through weeks or oftentimes, depending on what the load requirements are, up to a month or more of low to no wave activity.”

Kirby spoke with Hart Energy about the company’s technology and its plans for the future.

Hart Energy: Will you explain the technology behind the PB3 Power Buoy and how it works?

Kirby: Within the wave energy community, our buoy is considered a point absorber. What that means is the buoy sits in the ocean. It’s a rigid body that stays stationary in the ocean, except for the float on top of the buoy, which rides up and down on the waves, and that float will drive an input shaft, which acts like a piston. The buoy actually converts the linear up-and-down motion or the heaving motion of the waves. It converts that linear motion to rotational motion and we spin a generator inside; that generator creates the power. The power goes through our battery management system, which we created for our PowerBuoy. The system conditions the power, which means it smooths it out and brings it into the batteries where it’s ready to be provided to whatever load needs power.

Hart Energy: So how much electrical power does it produce?

Kirby: It produces up to three kilowatts of power at any given time. Our buoy is more analogous to something called a UPS—an uninterruptable power supply. The power generation part of it is actually more of a trickle charger for the batteries; the power is actually used from the batteries.

We can deliver very large quantities of power over a given duration of time. If you think about the total capacity of our batteries is a nominal 150 kilowatt hours; that means for one hour we could deliver, nominally speaking, 150 kilowatts of power, or over a 30-minute period we could deliver 300 kilowatts of power. Now, most of the loads that we’re looking to service require power either continuously or they require peak loads. If you think about some of the subsea operations, a continuous load might only be watts. It might not even be kilowatts of power that are needed and we can provide that type of continuous power. Whereas, in order to actuate a valve or some other type of instantaneous power requirement, we can also provide large amounts of peak power in order to do those operations. Then, the power generation system simply recharges and tops off the batteries in order to be able to do it again and again and again.

Hart Energy: What kind of demand are you seeing for this technology? Is it mostly from oil and gas companies or are you generating business from other industries as well?

Kirby: For the most part, we’re seeing large demand from oil and gas and I think that’s predominantly due to their tech-savviness, their desire to look for new technologies to be able to do things differently or to cut costs in their operations. But at the same time we’re also working with the U.S. Department of Defense through the Office of Naval Research in developing a totally new power buoy that does not require any mooring systems. It’s anchorless and self-propelled. That is to power a sonar, essentially to hunt submarines.

Hart Energy: How much can this technology cut costs for oil and gas companies?

Kirby: It really depends on the application, but the answer is a lot. We’re looking at applications where mostly the PowerBuoy is being considered as an unmanned station where we’re able to bring expensive vessels and crews off the water and replace those vessels with an unmanned station, which is our PowerBuoy. So, when you’re talking about taking boats and crew off the water for any period of time, that translates into potentially large savings for the customer as well as increasing safety by bringing crews off; not even considering the enabling effect of having power onsite continuously. The operators are starting to think, “Wow, what could we do if we had a continuous source of power on site where we don’t have to bring diesel fuel out to refill the generators and so forth?” We also have a platform where we can transmit real-time data back to land.

Hart Energy: What does the contract with Eni involve?

Kirby: Eni is very focused on advanced technology and part of that is around subsea charging. There is a desire, not only by Eni, but by many operators in the offshore oil and gas industry to use AUVs, or I like to call them subsea drones, more and more for operations. Eni is really on the cutting-edge, looking at how our device could be used to recharge AUVs in the future. Eni is leasing our buoy in order to prove out subsea charging using the buoy. Next steps could be to develop an AUV charging station where our buoy directly provides power to that charging station. [The project has] already started. The buoy should arrive in Italy this summer, and we’re looking to deploy the buoy as early as August or September.

Hart Energy: Have any other oil and gas companies or oilfield service companies shown interest?

Kirby: Absolutely. We’re wrapping up a study right now with Premier Oil that is not only looking at how our PowerBuoy could be used for surveillance and monitoring in order to replace guard vessels around the decommissioning, plug, and abandonment of wells, but also to provide subsea power in order to monitor the well.

Hart Energy: How do you see your technology evolving to meet the future needs of the oil and gas industry?

Kirby: From my perspective, I’d see an acceleration effect happening as more and more oil and gas companies see the benefits, both financially and technically, to use our PB3 PowerBuoy. This is going to allow us to continue to collect information from the market—what are the needs of the market—to develop products that the market needs. It might be larger, more powerful buoys; it might be smaller buoys for different applications. I also directly see a need for our anchorless buoy that I mentioned for the U.S. Navy within oil and gas as well. As we discuss that particular product with the industry, I see a lot of excitement around it. It truly is a game-changer.

Hart Energy: Do you currently have any plans to increase the power or will you wait to see what the industry needs?

Kirby: We have an ongoing program on what we call a PB15. It’s a much larger device; it’s probably about two to three times the size of the PB3 but provides four to six times more power than the PB3. Right now, we’re really focused on commercializing the PB3, gaining market acceptance on that product and communicating with the markets to understand the need for a product like the PB15.

Velda Addison can be reached at vaddison@hartenergy.com.