In this episode of the Pipeliners Podcast, Andre Scholtz, Technical Director at Solarcraft, joins to discuss the challenges of powering remote shutdown valves in the oil and gas industry.
The episode explores the considerations for providing reliable power to valve actuators in remote locations, touching on issues related to infrastructure, power sources, and technological solutions.
The conversation covers the unique challenges of actuating valves, the role of solar power in these scenarios, and the importance of designing systems with reliability in mind.
Listen to the episode now to learn more about the necessity of careful design, the viability of solar power for high-voltage devices, and the critical role of monitoring and maintaining consumption levels for optimal system performance.
Powering Remote Shutdown Valves Show Notes, Links and Insider Terms
- Andre Scholtz is the Technical Director at Solarcraft. Connect with Andre on LinkedIn.
- Solarcraft, Inc. is a Houston-based full-service manufacturing company that engineers and builds industrial Solar Power Systems, Backup Power Systems, Control Panels, and Electrical Shelters for critical automation and communication.
- Remote Shutdown Valves: Valves used in the oil and gas industry, typically located in remote or hard-to-reach areas, designed to quickly and safely shut down the flow of fluids in pipelines during emergencies or maintenance.
- DC Actuator: An actuator powered by direct current (DC) electricity, commonly used in applications where precise control is required, such as shutdown valves.
- Locked Rotor Current: The high current that flows when an electric motor is initially started, needed to overcome inertia and set the motor in motion.
- PLC (Programmable Logic Controller): A digital computer used in industrial automation to control machinery and processes, often involving analog and digital input/output modules.
- Pyranometer: An instrument used for measuring solar irradiance on a planar surface, providing data on the solar resource available in a specific location.
- VSAT (Very Small Aperture Terminal): A satellite communication system that serves as a two-way ground station with a small dish antenna, commonly used in remote areas to establish data connections.
- Induction Motor: An electric motor in which power is supplied to the rotor by means of electromagnetic induction from a magnetic field produced by the stator winding.
- Rectifier: A device that converts alternating current (AC) to direct current (DC), commonly used in various electronic systems.
- Multi-Phase Devices: Devices that operate with multiple phases of alternating current, common in industrial applications where precise control and power efficiency are required.
- UPS (Uninterruptible Power Supply): A device or system designed to provide a continuous and reliable power supply to connected electronic equipment during power outages or fluctuations in the electrical grid. UPS units typically incorporate a battery that is automatically engaged to supply power when the regular electrical supply is interrupted, preventing data loss and damage to sensitive devices. They are commonly used in various applications, including computer systems, data centers, and critical industrial processes, to ensure uninterrupted operation and protect against power-related issues.
Powering Remote Shutdown Valves Full Episode Transcript
Russel Treat: Welcome to the “Pipeliners Podcast,” Episode 321, sponsored by EnerSys Corporation, providers of POEMS, the Pipeline Operations Excellent Management System, compliance and operation software for the Pipeline control center to address control room management, SCADA, and audit readiness. Find out more about POEMS at EnerSyscorp.com.
Announcer: The Pipeliners Podcast, where professionals, Bubba geeks, and industry insiders share their knowledge and experience about technology, projects, and pipeline operations. Now your host, Russel Treat.
Russel: Thanks for listening to the Pipeliners Podcast. I appreciate you taking the time. To show that appreciation, we are giving away a customized YETI tumbler to one listener every episode. This week, our winner is Gary Winfrey with Enbridge. Congratulations, Gary. Your YETI is on its way. To learn how you can win this signature prize, stick around till the end of the episode.
This week, we speak with Andre Scholtz with Solarcraft about powering remote shutdown valves. Andre, welcome to the Pipeliner’s Podcast.
Andre Scholtz: Good day, Russel. How are you doing, sir?
Russel: I’m doing very well. Very well, thank you. Before we dive in, Andre, why don’t you tell us a little bit about your background and what you do and how you found yourself in your current position at Solarcraft?
Andre: It’s a short story. I started with Solarcraft about 12 years ago. Currently, I’m the Technical Director. I spend most of my time consulting with customers about what problems they have so we can apply our products for them.
I started in this line of work about 20 years ago or so in South Africa, building solar power supplies and UPSs, funny enough, for things like gas stations and vaccine fridges in the middle of nowhere. Moved to the US — my wife is from here — and ended up at Solarcraft, where the business happens to be very similar.
It was a shoe-in, man. The things that we do on oil and gas pipelines are not that much different from powering motors and control systems outside of it. It’s just a more fun application.
Russel: I think that we’re learning a lot about DC power, and solar power, and battery banks, and all that type of thing, but it’s very different when you start powering motors.
I’m a sailboat guy. There’s a big difference between running your lights and your refrigeration because the refrigeration on a boat has no motors or compressor with it really, versus running your air conditioner on a boat.
It’s a whole different challenge if you will. That’s a great tee-up for why I asked you to come on the episode and talk about powering remote shutdown valves. Let me start by asking you, what are some of the key challenges in powering remote shutdown valves? What are pipeline operators trying to address and deal with?
Andre: That’s a good question. When you lay a big fat pipeline through the middle of nowhere, the primary concern, in the beginning, is the right-of-way, and where’s the pipe crossing rivers, and where you going with it, and how are all the challenges with that.
By the time people start laying in the pipe, they very often delay the consideration of, how do you get power to the sites where you need valve actuators or measuring stations or things like that.
It’s frequently an issue that people go, “Here’s the location where a shutdown valve will be. Let’s phone the local power supply company and let them give us a rundown of what it’ll take to power our stuff.”
It gets harder and harder these days to do that. The valves are often three-phase, 480-volt, or some high-powered single-phase devices. You then have to sit and wait a year or so until they can finally get around and lay line power over the hills, which has its own right-of-way concerns.
Then they charge you an arm and a leg for that connection, where they won’t gather any revenue from the power that you consume because you burn too little of it. Now, you consider, “Certainly, let’s put nitrogen out there and run maybe nitrogen or pressure-operated valve actuators.”
Those come with a slew of extra concerns and maintenance issues, where anybody who has run at Christmas Eve with more nitrogen bottles in the snow over two sites will tell you it’s not a very viable solution.
Line gas on gas lines is a reliable solution but it’s becoming increasingly more difficult to do because there are very stringent emissions or regulations on…
Russel: To that point, Andre, there’s a huge rulemaking coming that’s working its way through PHMSA right now that people are referring to as leak detection and repair, but it’s really a methane emissions reduction rule.
For all of these guys that are operating the natural gas line pressure valves, and there are a lot of them, because they’re highly reliable and very affordable, they’re all going to have to be looking for a different way to actuate those valves.
Andre: That’s right.
Russel: Many of those valves are in very remote areas with no power anywhere close. That’s a big deal for sure.
Andre: That’s right. Your problems are compounded if it’s a liquid line. There, you said, “How do you pressurize this business then?”
Russel: Your comment about nitrogen bottles, I don’t know if you have this experience, but I certainly do. On more than one occasion, I’ve been working with a control center where they were trying to shut something down in the valve. Even though everything looked good on the nitrogen bottles when they tried to crank the valve, they might get it started, but they didn’t get it completed.
You might have all the pressure you need, but might need three nitrogen bottles to completely move the valve and only one of them is good, then you don’t know. It’s problematic for sure.
Russel: What do you think the solution is? Obviously, Solarcraft is a solar power company. We probably ought to start by talking about how you do it in a simpler case, where you have a DC-actuated valve, so a smaller valve, lower horsepower, that sort of thing.
What are the considerations and issues for having a reliable system just to operate a DC actuator?
Andre: I see what you mean. A very good analogy would be something like an access gate at a farm, where you’ll see a solar panel off to the side and there’s a battery in there somewhere in a box. There are two considerations with that gate.
It is assumed that the gate is not opening and closing and opening and closing all the time. It’s occasional. The first consideration would be, how much power does it take to get that gate moving, how much power does it take while it’s swinging, and how long did it swing for?
The second consideration would be, how often is that going to happen? Is this a busy gate where 20 people are living and they go in and out the whole time? There are gates. It could be anything. Or, is this just a remote gate on the side of the farm and once a week, somebody goes there?
That would determine the size of the battery that’s in there and the size of the solar panel, but it wouldn’t change the size of that DC motor. The secondary consideration is, how much energy, on average, does it take to operate the control system?
The thing that sits there listening for the remote that the farmer has to press, the little red light that’s on keeping the radio going, maybe keeping the thing from freezing in winter. In that regard, a valve station, let’s take for instance a 12-inch liquids line. The same considerations count.
If it’s a remote-controlled shutdown actuator, like an emergency shutdown, you can expect that actuator to run maybe once a year, or let’s say once every six months when people do partial stroke tests or something. It’ll run at its most while they commission the thing.
They may test the limits, run it left and right, 10, 20 times or so. After that, when everybody leaves and the dust settles, once every six months or so. It is typical. We would then consider, how much power does it take to get that valve turning? How much does it take to keep it running for the two or three minutes that it takes to get the job done?
Then secondarily, how much energy on average do we have to spend on the telemetry, the PLC, at the site? Because you’re also going to measure some pressures, some flow rates, who knows what people are analyzing? Those are continuous loads. There are occasional loads and they are continuous loads.
Russel: Those loads for the instruments and the PLC and all that are relatively small.
Andre: That’s right.
Russel: Although they’re continuous, but they’re small versus the load for the actuator is large, but for a short period of time.
Andre: But for a short period of time.
Russel: I would assume that one of the other considerations where you have a situation where you’re operating an actuator, particularly on a shutdown valve that doesn’t operate frequently, is how quickly can I recharge the batteries or how even quickly do I need to recharge the batteries?
Because I could afford, with a battery bank for an emergency shutdown, I could probably afford to run those batteries almost all the way down, and then take some time, a day, to get them recharged back up before I need to open the valve back.
Obviously, that’s got to be engineered and understood, but that dynamic, for anybody that works with solar systems or remote power, they understand that dynamic is quite different than managing a base load for a set of electronics.
Andre: That’s right. We run the electronic load and the motor load in our solar motor UPSs from the same battery bank. Typically, we want our system, if some catastrophic event happens, like somebody steals the solar arrays, you want the system to still at least be able to stay up about a week. Maybe five days or a week or so.
Funny enough, counterintuitively, one stroke of the actuator in any direction will consume maybe about two percent of the capacity of that battery bank. No more. Very large actuators, maybe five. We would say put something like 800-amp-hour–I’m pulling a number out of the air–putting 800-amp-hour battery bank at a site.
Russel: Now, that’s blowing my mind a little bit, Andre because having done this in the past, and now it’s been some time since I’ve sat down and done the math and tried to size batteries for a remote control panel, but the idea of oversizing the batteries to that level, that’s a little different than what I was doing. It’s been 10-plus years ago.
Given where batteries are and what’s happening with lithium and the price points, that’s a more affordable thing to do. It certainly goes to reliability.
Andre: It absolutely does. If you’re drawing 100 watts for your control system to keep a couple of radios in the network switch and a PLC going, that’s 2.5-kilowatt hours a day. If you run, for argument’s sake, a 2.5 kilowatt motor, but you only run it for three minutes every six months, how many kilowatt hours did you burn in those three minutes?
You can do the calculation offline, but it’s very little. The consideration with the actuator is not the amount of energy that you have to store, is can you deliver the locked rotor current reliably out of the set of batteries? The capacity of the batteries is not the primary consideration.
Russel: I should, for people who are listening–and it’s engineers a lot that listen to this–but I should probably decode something you just said. I had to when we were getting ready for this podcast, but locked rotor current was a new term for me. Basically, that’s the surge in current necessary to get the motor moving.
Russel: From starting to moving. That’s a very short-term, but very high spike in power requirement.
Andre: That’s right. The draw is very large. The challenge with powering induction motors through, say, three-phase, 480-volt, pick a number, from battery banks, is reliability. Many people will attempt to do this with commercial or consumer-grade equipment that’s available, but they will disappoint you in short order. Solarcraft has developed…
Russel: Before you go there, tell me a little bit about why that’s so. Why will commercial off-the-shelf not get the job done? What’s missing in that equipment?
Andre: Something like UPSs, inverters that you can buy, generally, they are designed to…The first thing they power is a rectifier or a resistive load. When you power your television, the very first thing that happens to the AC power coming in is it gets converted to DC right there. Most electronics are like that.
Certainly, computer UPSs are like that. UPSs in server rooms, you get very large ones, but their loads are almost entirely rectified. Once they are that size, tiny things like a refrigerator or some sort will work just fine from them.
A thing like a coffee machine that for some consumer grade UPS wouldn’t be a challenge because it’s almost entirely a resistive load to boil water, but a tiny motor load that it can handle easily.
Russel: The point you’re making is the nature of the load is critical to understanding how to design a system, and the commercial stuff is more real, is more designed for resistive loads, not inductive loads.
Andre: That’s right. That first spike and energizing motor energizing transformers and the locked current of a motor is incredibly hard on such converting equipment. To do it so that you can install the system but 20 years later it’s still running reliably takes some doing. We have spent millions in R&D, and devised what we call our ultra-drive, which is the correct thing for this application.
Russel: I want to talk a little bit about that because, just on the surface of it, the idea of using solar to power a 480-volt, three-phase motor in the field in a remote application — I could see doing it or to do it as a backup to AC power maybe — but to have it be primary, just on the surface of that, that seems inherently risky and problematic.
I guess you’ve laid out why people have had a lot of problems doing this because they’re using commercial off-the-shelf system that just doesn’t have the survivability or the life usage that’s necessary for this application. This is something that needs to be industrially hardened and built for purpose.
Andre: That’s right. You spend a lot of time thinking and a lot of money paying the guy who thinks to think about heat mitigation materials and that. Once you’ve covered that, the reliability of the conversion, the next thing you look at is, how do you make sure that this battery bank is always full?
At that stage, it’s not that much different from a UPS or a field UPS such as we make anymore. We know when we deploy these units exactly where they will be used. It’s part of the initial series of questions we ask, what are these locations?
In every one of these locations in every zip code in the country, there’s little weather stations at just about everywhere. Part of them is what they call a pyranometer that records what the solar resource looks like and how it looked over the last, say, 15 or 20 years?
Then we look at, how bad did it get? We assume that such an apocalyptically dark event will occur again, and then we size our solar array to be able to survive that. It’s typically in the middle of winter. That’s the time when it’s cold, the sun is low on the horizon. It’s always hazy in some sort of way.
Then we make sure that the size of our battery bank and the size of our solar array is correct for it. You will also be surprised to find that the size of the solar array doesn’t really have that much to do with the size of the actuator. It has more to do with how often it operates.
If you have to run it 20 times a day, OK, now we’re draining things. We have to put up bigger collectors. On a shutdown valve, just about all the power, 90-stupid percent of it is consumed by the telemetry, the PLC gadgetry.
Russel: That’s also interesting because that’s counterintuitive to me. It would seem like if I’ve got a 480-volt, three-phase motor, and I’m going to power it off of a 12-volt DC battery bank, intuitively, it would seem like I’m going to need a lot of solar, I’m going to need a lot of battery to do that.
What you’re telling me is, “No, you don’t. What you need is a properly designed set of electronics that provides that power in the right way.”
Andre: That’s right, yeah.
Russel: That’s a different way of thinking about it. It’s a very different way of thinking about it.
Andre: It’s easy to get that wrong if it’s the first time you do it.
Russel: Yeah, you’re right.
Andre: By now, I just do it for a living, so I’ve got a rule of thumbs on the wall.
Russel: This is a domain, too, Andre, where technology is evolving very quickly. The capabilities of the batteries, what we’re finding in the rectifiers, and the charging systems, and the solar panels themselves, all that stuff’s improving and it’s improving quickly. If you haven’t worked in this domain like me for 10 years, there’s a lot that’s different.
Andre: There’s a lot that’s…You got to catch up. A case in point is, say, lithium batteries these days. Wonderful, amazing technology and you’d think that that’s what you’d have to use then. However, we have issues with it. Number one, we need the weight. We also need to be able to operate when it’s -20 outside, which lithium has a problem with.
We take, for short periods of time, enormous currents out of these batteries, which lithium batteries struggle with because their BMSs restrict the stuff to keep their things reliable. In that regard, yes, we watch another technology growing outside of the field where it’s useless for it (this application).
However, when it comes to the power conversion that we do from DC to the three-phase AC for the actuators, that is cutting-edge. We always have one or two engineers constantly working on improving the units, getting the efficiency better, and getting the reliability up.
What do you do if some of the components are not available anymore because this and that factory shut down? Do you have the next alternatives loaded so you don’t have a gap in your product delivery? Things like that develop so fast, and you got to dance to keep up.
Russel: That’s why I do the podcast, because I’m helping people dance to keep up.
Andre: That’s funny.
Russel: How do you address the reliability issue? A couple of takeaways from me from this. One is these systems need to be engineered for purpose. Another is that there’s some unique and proprietary technology that you guys have that is delivering the high-voltage multi-phase power for actuators, which makes sense to me why that would be important.
What else should somebody be aware of from a reliability standpoint? The thing about a shutdown valve is I don’t use it very often, but when I need them, I need them to work.
Andre: Got to be there, cannot fail. Developing the technology and the hardware in modules is done. That’s a process on its own where you want to use the best people and the best equipment.
Where people very often fall on their faces when building a system that’s reliable is they don’t gather enough information or they don’t spend the right amount of time making sure that the information that they have is correct. A good example is we’ve put out a battery bank and a solar array size to support the site that’s very carefully calculated of what we think the continuous load will be.
If we ask the customer, what do you think the continuous load from your telemetry and PLC system will be, and he comes back with a number like 100 watt, and we write down 100 watt, and then we build our system like that, he may be wrong. It’s important for us to go, “How’s that 100-watt built up?”
He goes, “I got this radio over there, I got this network switch, and then I’ve got this panel heater that we always use.” You go, “Wait a minute, you didn’t mention the panel heater, but you said 100-watt, so let’s delve into that.”
Getting the average power draw of the site correct is by far the biggest consideration with the reliability of the system. Very often, somebody would put in a cell modem for the telemetry. Somebody takes down that cell modem six months later, and the company puts up a VSAT that now burns easily 20 times more power than this cell modem, burns our battery bank…
Russel: I wish I could say I’ve never seen that happen before.
Andre: That’s right.
Russel: The other thing they’ll do is, even with a radio, they’ll put a radio in and they’ll say, “I’m going to transmit every 15 minutes,” and then something will happen and somebody will go, “You know what, I’m putting in leak detection, I need to transmit every 30 seconds.
“All of a sudden, I just multiplied my power consumption by 20-fold, and all I did was change the configuration in the software.”
Andre: Exactly. What we do is we measure the design load, and if you exceed the design load, we’ll know, or the customer will know, they’ll make an alarm in the telemetry.
We’ll save an analog input somewhere on the PLC that says, if this design load increases beyond this number, somethings happening over there that you got to know of, because this now jeopardizes the reliability of the system. That is absolutely by far the easiest way to make a site like this fail. You just have to know about it.
As long as you measure for it, you alarm properly for it, you’re 90 percent there. Redundancy in your battery banks is an issue. Redundancy in your chart controllers is an issue. Not using rubbish components.
It burns me that it’s absolutely always possible to make a system cheaper by using crappier components. It’s always possible to do that, and it’s always at the cost of uptime and reliability down the road.
Russel: There’s also the cost associated with the maintenance, keeping it running when you got to run out and replace parts. Let me tell you what I think my takeaways are. This is a fascinating conversation for me. Here are my takeaways.
The first takeaway is the systems need to be designed and you need to very carefully and thoroughly consider what your design load is. That’s the first thing. The second thing is that you actually can power these high-voltage multi-phase devices with solar, but you’ve got to have the right electronics designed for the right kind of load for that to work well.
The other key takeaway is reliability starts with design and ends with monitoring consumption versus the design, because the minute my consumption goes beyond what I designed for, I need to investigate what’s going on there. How do you think I did, in terms of takeaways from this conversation?
Andre: Three out of three, sir.
Russel: Great. As the listeners know, we will put together show notes and we’ll build some links into the website page for this episode.
If you guys want to know more about what Solarcraft is doing with powering remote shutdown valves, if you’re trying to do methane mitigation, if you’re trying to look for alternatives for power, I’d recommend you get in touch with these guys. Andre, thanks for your time. I appreciate it.
Andre: You’re most welcome, sir.
Russel: I hope you enjoyed this week’s episode of the Pipeliners Podcast and our conversation with Andre. Just a reminder before you go, you should register to win our customized Pipeliners Podcast, YETI tumbler. Simply visit pipelinepodcastnetwork.com/win and enter yourself in the drawing.
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