In this episode of the Pipeliners Podcast, Andre Scholtz from Solarcraft returns to discuss Remote Power where the Sun Don’t Shine, or, powering remote sites where solar energy isn’t viable.

The conversation explores alternatives like generators, fuel cells, and wind turbines, diving into the challenges of selecting and maintaining appropriate power sources for remote operations.

The episode highlights key considerations around equipment maintenance, fuel sources, and energy storage, offering practical insights for optimizing off-grid power solutions.

Remote Power where the Sun Don’t Shine 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.
• Check out Episode 321 with Andre discussing Powering Remote Shutdown Valves here.
• A very small aperture terminal (VSAT) is a two-way ground station that transmits and receives data from satellites. VSATs can help oil and gas companies communicate in harsh environments where infrastructure may be lacking.
• 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.
• 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.
• Load: The consumption of power from the instruments being used in the system.
• Online UPS: Always powers the load through an inverter, providing continuous and clean power.
• Offline UPS: Powers the load directly from line power until it switches to the inverter during a power failure.
• Line Interactive UPS: Corrects minor power issues like brownouts and frequency changes while also switching to inverter power during failures.
• SCADA (Supervisory Control and Data Acquisition) is a system of software and technology that allows pipeliners to control processes locally or at remote locations.
• RTUs (Remote Telemetry Units) are electronic devices placed in the field. RTUs enable remote automation by communicating data back to the facility and taking specific action after receiving input from the facility.
• Base Load: The amount of power made available by an energy producer to meet the demand of its consumption.
• Parallel Batteries: Have their capacities (measured in amp-hours) added together.
• Series Batteries: Have their voltages added together. Batteries wired in series and parallel configurations should all have the same voltage and capacity.
• Thermal Runaway: An incident where one exothermal process triggers other processes, resulting in an uncontrollable increase in temperature. This can destroy the battery or, in severe cases, cause a fire.

Remote Power where the Sun Don’t Shine Full Episode Transcript

Russel Treat: Welcome to the “Pipeliners Podcast,” Episode 353, sponsored by Solarcraft, providing high-quality engineered solutions for powering, sheltering, and operating critically field automation infrastructure. Find out more about Solarcraft at solarcraft.net.

[background music]

Announcer: The Pipeliner’s 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. We appreciate you taking the time. To show that appreciation, we give away a customized YETI tumbler to one listener every episode. This week, our winner is Xavier Strittmatter, with National Grid. Congratulations, Xavier. 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, Andre Scholtz of Solarcraft returns once again to discuss Remote Power Where the Sun Don’t Shine. Andre, welcome back to the Pipeliners Podcast.

Andre Scholtz: Thanks, Russel. How are you doing?

Russel: I’m doing well. Again, if you would, a quick intro and we’ll dive in.

Andre: Russel, thanks. My name is Andre Scholtz. I’m the technical director and the lead SME over at Solarcraft in Houston.

Russel: Before we dive in, I have to tell the listeners that Andre and I are working, we’re recording several episodes and we had a little break. I was talking to Andre about the cool stuff he’s doing with the power management at his house.

For you guys that are nerds and want to talk about off-grid and high reliability and all that kind of stuff, I think Andre’s got a real got…I think there’s a lot of value in that conversation, Andre. Look Andre up and drop us a note through the podcast site or something and we’ll tell you what we think you ought to do for your house. [laughs]

Andre: I can fill people in on a lot of information for a six-pack.

Russel: There you go. Look, our topic today is Remote Power Where the Sun Doesn’t Shine. Our last episode together, we talked about hybrid power, so combining solar and battery with other kinds of power sources.

What I think we want to do this time is talk about those other power sources and dig into them. All the power sources that are not solar cells, solar panels. Probably the biggest of those is generators. Talk to us a little bit about some of the selection, how you should think about using generators in remote power situations.

Andre: Let’s bracket it with two extremes that are good examples of bad examples.

A generator that is too small that you would use to power a load that is running from a battery bank may be impractical because you’d have to run up to such a system with a small generator, charge it back up, and leave again because somebody’s going to steal your generator there. That is one impractical way to use it.

On the other end of the spectrum, and what happens too often, is people have a small control system standing in the middle of nowhere, and then they rent a 80 kVA diesel-powered trailer that stands idling for years only powering 100-watt load and never being called upon for any heavy power.

Somewhere in the middle there is a responsible use of a generator where the maintenance and the fuel consumption were taken into consideration to optimally choose the unit and the hardware that has to go with the site.

Russel: That’s interesting. I think one of the things that when you start talking about remote power, there’s a presumption that all of the power to the process is going to come through the batteries.

There is a big distinction between having a generator capable of driving a particular load versus having batteries capable of driving the load and a generator capable of keeping the batteries topped off. The math of those two considerations is very different. Have I got that correct?

Andre: You do. Your load in such a case would be the determining factor. You would put a battery bank there that’s capable of maintaining the load for a period of time, say, when the generator fails.

If you get notice that the generator is not starting or the battery bank is running down, you still want a bit of time to be able to hop in a truck and make your way over there without the load going down. This would be in a situation where the sole source of energy for the site is that generator. It may not run continuously.

It may only be called upon to charge the battery bank occasionally if the load is small and the battery bank is big, or the load may be a continuous load, the generator may run continuously, and the battery bank will just serve as a UPS for when the generator, say, runs out of fuel. Then you get a notice of that and you got a day to go refuel. Something along those lines.

Russel: Again, I’ve done this several times that we’ve had this series of conversations, I keep referring back to what I know on sailboats. What you typically find in sailboats is they’ll have a solar kit, particularly guys that are doing crossings that are operating off-grid. They like lithium batteries.

They like lithium batteries because they can charge them quickly. They can fire up the generator and they can top-off their batteries in fairly short order, versus if they were doing the same thing with lead acid, it would just take a lot longer. There’s a consideration where, if I have a load and the load is…What am I trying to say?

If I have a battery pack and it’ll support the load for three days, if I add a generator to it, then depending on the generator I add, I could support that load indefinitely or for a period of time, because if the generator is not large enough to keep the batteries topped off, and that’s different than I want to quick charge the batteries.

Understanding all that as you’re selecting the generator and sizing it is a critical consideration.

Andre: Yes. The big distinction between a lead acid battery and a lithium battery, or the differences in them show up right here. If you have a 12-volt unit that is a lead acid battery, you can easily pull 500 amps from that guy. He’s not going to mind. A lithium battery is not going to be able to deliver 500 amps. It may limit its output at, say, 100 amps or 50, something like that.

Conversely, a lead acid battery, you don’t want to charge it at more than about, say, a fourth of its capacity. 100 amp-hour battery, you can’t really put more than 25 amps worth of load on it. Some of them a little bit bigger, some of them less, but a quarter is a good rule of thumb. A lead acid battery, don’t charge it from empty to full in less than four hours.

Where that lithium battery, you can drain it at about its nominal rate. 100 amp-hour battery, you can pull about 100 amps from it. It’ll very often be able to charge at 100 amps also, as opposed to 25 amps for the lead acid battery.

When you select your charges, this is very important, if this is the only thing you remember from this podcast, then you’ve succeeded, you can have a larger charger — which rhymes — for a smaller lithium battery bank. The reason you would do that is that your generator wouldn’t have to run so much.

Generator maintenance schedules is measured not in energy delivered, it’s purely just time. If your generator has a 200-hour maintenance interval, you want to run that generator exactly optimal.

You can select your charger and your battery bank so that, when the generator fires up and a minute later it starts charging, you’re running it at, say, 70 percent of its capacity — different generators would have a different number — and rack up the least amount of hours for the highest amount of energy.

If you do that with a lead acid battery bank, now you have to go, “Oh, I have to have a much larger battery bank,” which is much heavier and unwieldy. A smaller generator, in some cases, it’s way cheaper to put a more expensive lithium battery bank if your sole source of energy is a generator.

Russel: I think the other thing, too, is — my experience with generators is very dated. It comes from when I was in the Air Force. Being a civil engineer in the Air Force, we had everything from 25 kVA to 750 kVA generators — one of the things that was true is the bigger they got, the more fuel they consumed and the more challenging the maintenance.

Doing a turn on a 750 kVA generator is a way different thing than doing a turn on a 25 kVA generator. I guess the question becomes, am I right in saying the smaller the generator, the lower the operating cost for that generator?

Andre: Yes, it is. It very much depends on your situation, because some sites are so remote that to get out there is a big deal. Somebody who has to go service the thing has to sleep over somewhere, and that adds to the cost now.

We find that, more often than not, you are better off with a generator with the biggest oil sump you can find, where the maintenance intervals are, here, somewhere around 400 hours. If it’s just oil changes you’re chasing, you can automate that with a big drum on the one side and another drum on the other side. I think Murphy makes such a automated oil change system.

Russel: That stuff’s hard to find for the very small generators, but you find it pretty quick…

Andre: Yeah, that’s right…

[crosstalk]

Russel: The trailer-mounted generators, that’s pretty common, but it’s a little tougher on the small stuff.

Andre: Yeah, there’s that. The big cost around these generator systems is maintenance intervals. What does it take to go and maintain them? Who’s going to go do it? What sort of resources do you have to deploy? What is it that that guy’s not doing today? The cost of the oil, OK, that’s probably not such a big deal.

Russel: No, it’s the drive time. It’s not the oil cost. It’s not the filter cost. It’s not really even the fuel cost. Right?

Andre: Yeah.

Russel: It’s the drive time and then how long you have to be on site to do a turnaround on the generator.

Andre: Exactly. And then, what is the risk and the exposure and the insurance costs for that guy to go and do that?

[crosstalk]

Russel: Oh, yeah. When you start talking about a guy in a truck doing that kind of work, you very quickly get to 250 bucks an hour cost.

Andre: I know. It’s nuts. Your hardware selection depends on those sort of peripheral considerations also. The unit itself, I think the important thing to remember is try to always run the generator at its optimal, most efficient power delivery. A generator that is oversized, will just idle, burn up hours that are expensive to maintain, and you just don’t get that much energy.

You are definitely better off having a larger generator and buffering your energy in a battery bank. Deliver it through an inverter and have the generator only come on, run optimal for the least amount of hours, and go off again, and then slowly bleed the energy out of the battery bank.

Russel: Particularly in the cases where you need a larger generator because the cost of maintenance is lower on the larger generator.

This is something that’s a bit counter-intuitive. If I can get a larger generator and it has automated oil changes and it’s built for long life and it’s trailer mounted — this is another thing, too, it’s trailer mounted — that is actually cheaper than a smaller generator that doesn’t do automatic oil changes and is not trailer mounted.

Andre: Interesting.

Russel: The reason is I have to send somebody out there to service it. Typically, what people do, particularly for these really remote generators, is they run out there and they switch it and take it back to the shop to turn it…

Andre: [indecipherable 16:02] .

Russel: …because that’s, “I don’t need to have a technician in the field. I just need to have a driver.”

Andre: That’s right.

Russel: That price point’s way different. [laughs]

Andre: Yeah, that’s right.

Russel: I guess the point we’re making, particularly the point we’re making with generators, is they need to be sized appropriately, but the real consideration is maintenance cost.

Andre: Yes, absolutely.

Russel: And a big part of that maintenance cost is just getting to it to work on it.

Andre: Exactly

When we built this house, I saw the framing crew run a generator from morning to evening. In that generator, they had a compressor plugged in and then a saw and a radio, because you got to have that.

I was standing there watching this generator, which is not an inverter one. It was just running, I think, 3600 revs, maybe like that, and it’s screaming at the site. Most of the time, the compressor is not running, nobody’s operating the saw, but this generator is ploughing along and OK, the radio keeps going.

How much better would it have been, instead of racking up maybe 10 or 12 hours of runtime, they could have racked up half an hour of runtime on that same generator if there was a battery bank and an inverter connected next to it? What does it cost to maintain that generator every 100 hours? Maybe a little bit less…

[crosstalk]

Russel: What they probably do in a construction crew is they just run until it dies and go buy another one.

Andre: Yes. [laughs]

[crosstalk]

Andre: That’s a fact. Still, the analogy is valid. Right?

Russel: Yeah. I’m being a bit flippant. I want to move on. I want to talk about a couple of other types of common sources of power for remote operations that are not solar kits, not solar panels, one of those would be fuel cells.

We talked about that a little bit in our previous episode on hybrids, approaches for remote power. Again, tell us a little bit about what a fuel cell is, how they generate power, and what are those selection and sizing considerations?

Andre: Let me just add right now that I am not a fuel cell expert, but I have used a few of these in installations. We’ve built a number of systems for oil field installations and pipeline installations and a number for railroad installations.

The premise of a fuel cell is that it takes in hydrogen on the one side and puts out electricity and water vapor on the other side. The chemical process is black magic. That’s how those work.

The fuel source may be something like propane or methane or methanol. Then in that case, the first thing that happens is the unit would crack out the hydrogen and feed it to the fuel cell process. How that works, go read about it. I can’t tell you exactly.

Russel: I’ll deal with it very, very simplistically.

The process is electrolysis. Basically, what they’re doing is they have a process upfront and they can do this with filter separators or other chemical processes where they strip the hydrogen off of the other molecules. Then they use the hydrogen and feed it through a secondary process where it combines with oxygen. When it does that, it puts off electricity.

Andre: There you go.

Russel: It’s basically, I have a dipole and I’m moving those electrons between two dipoles, and that is what’s generating the power.

Andre: See, I told you it’s black magic

Russel: [laughs]

Andre: That’s it right there.

Russel: You’re the kind of engineer that knows all about electricity and everything else is black magic. I’m the kind of engineer, I know a little bit about a lot of things and not a lot about very much. [laughs]

Andre: That’s right. Of the three kinds that I am familiar with, which is direct methanol, straight hydrogen gas, or the ones that would use methane or propane, for remote installations with very low power consumptions, such as you would find with PLC and radio systems, I like the solid oxide fuel cells the best.

There’s a company, I think they’re in Ann Arbor, called Edge Autonomy. They make the coolest fuel cell products for this kind of application. Why I liked it is the fuel for these things are not hard to find. Very often, it’ll just be on a natural gas line anyway, and it can feed from that, or you would give it propane, which is easy to find anywhere.

They do operate warm. They burn up to, I think, 800 degrees Celsius on the inside, and you can use that heat to keep things warm in places where it gets ridiculously cold, where your battery banks don’t want to work anymore because it’s too cold.

Russel: In fact, it’s very common to use these on gas systems in the northern tier simply for the heat.

Andre: Isn’t that cool?

Russel: Yeah. The reason they like them is it’s a chemical reaction, not a flame, that’s driving that heat.

Andre: That’s right.

Russel: Which gets them past all the classified area restrictions.

Andre: The hydrogen fuel cells that you would use straight from hydrogen cylinders, you see that or — rephrase that — I see that more often in backup situations, such as at cell phone towers and other telecom installations. Then it’s cheaper to store energy in the form of hydrogen gas than it is to store that same amount of energy in batteries, and it’s significantly cheaper.

To go and refuel with hydrogen gas as a prime source of fuel is not practical. The smaller solid oxide fuel cells for installations up to [indecipherable 23:44] one, two kilowatt or so of continuous consumption, those tend to work very well, and they also hybridize very well with other forms of battery charging, if you will, such as solar power or wind turbines.

Russel: That technology is evolving extremely rapidly.

[crosstalk]

Russel: There’s a lot of people investing in moving that technology forward. I think the other thing about fuel cells, we talked about generators and all the maintenance considerations, one of the other things that’s really cool about fuel cells is they’re extremely low maintenance.

Andre: Right. They’re…

[crosstalk]

Russel: They’re virtually zero maintenance. Right?

Andre: That’s right, because there’s…

[crosstalk]

Russel: They run until they don’t run, and then you replace them. Right?

Andre: Right.

Russel: They’re pretty simple, but the cost is whatever they’re using as a source fuel.

Andre: Exactly. Like we talked about the generators, the real expense for these remote installations is not really the hardware you put there, it’s what it takes to keep it alive in difficult circumstances, especially cold winters. Longer maintenance intervals are so cheap to operate.

Russel: Exactly. Let’s pivot, because the other thing I want to talk about is wind turbines. Again, because of my boating background, I have just a little bit of experience with wind turbines. What are the considerations with selection and sizing of wind turbines?

Andre: We install them on our systems when people ask for them. We do not rely on them as a prime source of power. The size selection comes down more to what is practical at the site.

You would look at a small wind turbine for, say, a yacht, for instance. It would say 300 watts on the box, and you go, “Wow, that’s cool, because I have a 200 watt consumption when something is blinking.” Meantime, that would be 300 watts at some very fast wind speed. It’s more like 30 watts in the breeze. Can I, in the middle of nowhere on land, rely on the wind? Mostly, you can’t.

There are places where you can, and you would put these things for sure. Especially after you have gained some experience with how the wind blows in an area like on top of a mountain on the windy side of it, you can start relying on them for that.

The considerations for charging them is, what is the average wind speed at the elevation that you intend to put this thing? You can’t put it at ground level, the wind is slow.

You look on the little chart of what it says, how much power it will generate on average there, say, 40 foot up in the air, or however long the pole is, and then build yourself in a fair margin of error over there, because you cannot count on the wind like you can on the sun.

Your charger also, you have to keep in mind, must not be bigger than your battery bank will allow. Like I mentioned with the batteries earlier, don’t put more than 25 amp into 100 amp-hour battery or something like that.

Some of these wind turbines are big. Sometimes you would want to put six of them out there because you can’t get up high. Look at how much power you can put into your battery bank, and very carefully look at the average wind speed at the elevation, or how long the pole is where you intend to put these in.

Russel: Again, as you had the disclaimer about you don’t know much about fuel cells, I make the same disclaimer about I don’t know much about wind turbines.

What I would say is that there’s a couple of problems with them. One is if you get high winds and you don’t have a way to cut that off, you can actually damage your batteries and voltage regulation systems. You actually have to have some power management on the output of the turbine to have long life and reliability.

Then the other thing is wind turbines have a lot of moving parts, and moving parts wear out and they make noise and they have other difficulties.

Andre: That’s right.

Russel: But, they do have some good. What I would say is wind can be a way to add power so that you don’t have to do other things. It’s never, should never, I would never want to rely on it as my primary power source…

Andre: Exactly.

Russel: …or my primary method because wind goes away, and sometimes wind goes away for a long time.

Andre: That’s right.

Russel: Actually, the wind going away is not as big a problem as getting the wind blowing too fast.

Andre: That’s right. I’ve learned a reliable rule of thumb for wind turbines is don’t buy the cheap ones.

Russel: [laughs]

Andre: You will just keep buying the cheap one over and over and over again.

Russel: That applies to a lot of things in this whole domain, Andre, is don’t buy the cheap one. Right?

Andre: [laughs] That’s right.

Russel: The cheap one is going to cost you less when you go to the store and a whole lot more over the life of when you’re using the system.

Andre: That’s right, and that’s how I feel my marriage works. Right?

[laughter]

Russel: Now we’re really getting off the reservation.

Andre: [laughs] It’s working very good.

Russel: Exactly.

Andre: One prime source of failure we have found with wind turbines is right here when the weather is rainy and sleety at about zero degrees Celsius, right here when it’s wet but icy and then wet again. That wet ice backs on the blades and it backs on the hub of the thing, and then the sun goes down and it freezes rock solid, and there’s your extra source of power down the drain.

Russel: In Houston in the summertime, particularly in the Dog Days when it gets really hot, we do not have a lot of wind. A windy day is five-mile-per-hour wind, which is no wind. Right?

Andre: Right.

Russel: Then we have a storm in the Gulf, and then we have a few days where we have winds of 80 to 125 miles an hour. That’s not a good place to be putting wind turbines…

Andre: Nope.

[crosstalk]

Russel: …because they don’t work well in either of those two situations. [laughs]

Andre: West Texas seems to be an OK place for it.

[crosstalk]

Russel: Yes, because they have, particularly if you get up a little bit, sustained winds of 15 to 30 miles an hour for days and days and days and days at a time.

Andre: That’s beautiful.

Russel: It works really well.

Andre: I think I mentioned in a earlier podcast that there are pyronometers and solar measuring equipment in every ZIP code in the country, and often more than one per ZIP code, so to speak. They have been recording the solar resource for years over there.

We can tell how bad the sunshine got over the, say, 10 or 20 years, in which year, and then we can design our system to be able to survive such apocalyptically dark conditions again, but no such resource exists for wind. It’s too unpredictable.

Can you augment a solar system with a wind turbine? You absolutely can. I wouldn’t bother looking at how the wind typically blows in summer because there’s plenty sun shining, but how does it blow in winter? Then you also have to keep in mind how high are you going to get, because it’s very different 20 feet up than it is on the ground.

Russel: Those are all really, really good points. Really good points. Andre, I got to tell you, man, that this whole series of episodes that we’ve recorded together, I have learned a ton.

Andre: Nice.

Russel: I thought I knew a little bit about remote power, and it turns out that the little bit that I knew was a lot less than the little bit I thought I knew, so there you go.

Andre: [laughs] I’ll have to replay it to understand what you just said.

[laughter]

Russel: I’m just saying I knew I knew a little bit, but now that we’ve talked to all these conversations, what I know is that little bit’s a very little bit. [laughs]

Andre: That’s funny.

Russel: Anyways. It’s been great. This has been great information. I hope it’s helpful to pipeliners. Certainly appreciate you taking all the time to share all this information with us.

Andre: Anytime. Thank you, Russel. I appreciate it.

Russel: I hope you enjoyed this week’s episode of the Pipeliners Podcast and our conversation with Andre.

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[background music]

Russel: If you have ideas, questions, or topics you’d be interested in, please let me know on the Contact Us page at pipelinepodcastnetwork.com or reach out to me directly on LinkedIn. Thanks for listening. I’ll talk to you next week.

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