In this podcast episode, Andre Scholtz from Solarcraft returns to discuss hybrid solutions for remote power systems, particularly in challenging environments. The conversation covers the fundamentals of hybrid power, the various energy sources that can be combined, and the critical considerations for designing reliable systems. The discussion emphasizes the importance of thoughtful design to ensure cost-effectiveness and operational reliability, especially in remote or harsh locations.

Hybrid Solutions for Remote Power 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.

Hybrid Solutions for Remote Power Full Episode Transcript

Russel Treat: Welcome to the “Pipeliners Podcast,” “Episode 352,” sponsored by Solarcraft, providing high-quality engineered solutions for powering, sheltering, and operating critical field automation infrastructure. Find out more about Solarcraft at solarcraft.net.

[music]

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. We appreciate you taking the time. To show the appreciation, we give away a customized YETI tumbler to one listener every episode. This week, our winner is [indecipherable] with Sunoco. Congratulations, [indecipherable] . Your YETI is on its way. To learn how you can win this price, stick around till the end of the episode.

This week, Andre Scholtz with Solarcraft returns to discuss hybrid solutions for remote power. Andre, welcome back to the Pipeliners Podcast.

Andre Scholtz: Hi there, Mr. Russel. How are you doing, sir?

Russel: I’m doing well today. If you would, just quickly tell us who you are and who you’re with and what you do. Then we’ll dive into our conversation.

Andre: My name is Andre Scholtz. I’m the Technical Director and chief SME over at Solarcraft in Houston.

Russel: All things remote power. That should be the title on your business card, Andre. I’m learning from you left and right.

Andre: I like it.

Russel: Our subject for today is hybrid solutions for remote power. Probably the best thing to do is let’s just start with some simple stuff. What’s the definition of hybrid power?

Andre: For a particular load, normally you would have one power source or one energy source. If you have more than one energy source, especially when they are different, you can call that a hybrid installation. For instance, a solar installation that also has a wind turbine on it or a solar system that has a line power connection can be defined as a hybrid system.

Russel: What’s the inventory of all the possible things I could do for power?

Andre: You mean what sort of sources is it that we can combine, right?

Russel: Yes, exactly.

Andre: We have built systems that maintain loads from a combination of line-powered charging systems, solar-powered systems such as people are familiar with, wind power — pretty common, not too complicated — fuel cell installations.

Very common is solid oxide fuel cells. Take time and look that up. Also, generator power. Those are the most common ones. There are others that I’m probably not qualified to speak of.

Russel: I know that anything that you can use to turn something, you can harvest electrical power from that. Wind, flowing water, wave action, all that kind of stuff. You don’t tend to find those more obscure things in what we do with remote power.

That’s a pretty healthy inventory, when you think about it. I could use the power company. I can use solar kits, solar cells, solar panels, all that stuff. I can use a wind turbine. I can use a generator. Then I can use a fuel cell.

For people that don’t know, probably ought to define what is a fuel cell and how it generates power. Just in general terms, what is a fuel cell? How does it generate power?

Andre: Fuel cells, in general, will take hydrogen in and put out water or water vapor and electricity, just in those simple terms. Often, it would collect…

Russel: They’re basically generating electricity through a chemical reaction.

Andre: Absolutely. There are cold processes. There are hot processes. The cold ones, you have to feed with gases or methanol. The hot ones, with things like line gas or straight methane.

Russel: Why do I look at hybrid? Why isn’t everything just solar panels and batteries?

Andre: In places where the sun shines very nicely and reliably, you are just fine with solar panels and batteries. It is highly predictable. There are years and years worth of numbers from every zip code in the country on how the weather behaves.

Then there are places where it’s more challenging, let’s say in very northern areas or maybe the far Northeast or Northwest areas of the country. The sun doesn’t really shine in winter. How do you make it through the winter if you are off-grid? In summer, the sun shines fantastically. In winter, you’ll have to supplement with something.

You need something that is dead-reliable. Very often, there are two or three feet of snow on the ground. You can’t get to these sites. A hybrid solution would make more sense there. What fuel would you pick to carry it through winter? That’s a different consideration. Usually, it’s a reliability issue.

Russel: That’s certainly one. Another one I can think about is if I have available line power, I might use available line power as my primary mechanism. If I have something that is a high…I need a high reliable, highly reliable process…Sorry. Having trouble speaking today. I don’t know why.

If I have a need for a highly reliable process, then I need to have something available if line power is not. If line power drops, I have to have a mechanism for getting to something else.

Andre: One thing all these systems have in common is a battery bank. If you’re in a place where line power is a consistently unreliable, i.e., it’s on and off and on and off, you may be just fine with a UPS.

If you don’t know that it may be off for a week or two, such as what happens when a hurricane rolls through and downs all the power lines in the area, it becomes too expensive to put a large battery bank there that can carry you through.

In that case, to hybridize such a UPS with, say, a generator is not a bad idea, provided you keep in mind you’ve got to keep the generator out of the flood water. You’ve got to exercise it regularly, something like that.

Very often, we would put solar arrays on our line-powered UPS systems, especially if we build PLCs into the same enclosures, for two reasons. The one is the solar power keeps the enclosure in the shade. You need that shade because you’ve got batteries in there, things that need to stay cool.

Also, what we designed as, say, a two-day UPS now becomes a four or a six-day UPS. In summer, the solar panels may carry it indefinitely. Well, indefinitely. Just for the summer.

The point is there are so many configurations. You have to look at all your options for the particular application and pick what makes the most sense right there.

Russel: If I’m above the Arctic Circle, where there’s no sunshine half the year and where, in the winter, I can’t get easily to remote sites — I’ve got to get a helicopter or something to even get there — very different consideration than I’m at the equator in the forest, versus I’m at the equator and in a desert.

All those are very different considerations in terms of the nature of what are the alternative power sources that are available to me.

Andre: Wind power, for instance, generally, for land-based installations, you cannot count on wind power to be reliable, but you can count on it to be supplemental. In places like offshore platforms, it’s a different picture. The wind blows pretty darn consistently from a pretty consistent direction, almost always. Then you can rely on it.

To build a hybrid system for an offshore platform, I would absolutely look at wind turbines, together with solar and good monitoring. For north of the Arctic Circle, I wouldn’t consider wind turbines. You get thick ice over there when the temperature is at zero degrees Celsius. When it’s sleety slush, it freezes up wind turbines. There’s moving parts there. How sure can I be that the wind will blow?

For critical installations, you don’t consider it. Then you start looking at a generator installation and what do you have to keep warm, how much energy would it take to keep it warm to keep that hybrid installation reliable.

Russel: The other thing we should talk about, just in general about this, is that it also depends on what’s the nature of the load. If I’m just trying to power a PLC and the instrumentation and some communications, that’s a very different thing than I’m trying to power valve actuators and motors or computer equipment. They all have very different load requirements.

In this whole series of conversations, Andre, with you, one of the things I’m taking away is that the complexity of designing these systems, it just increases exponentially. We really hadn’t talked about this. One of the questions that’s coming up to me is, how do you know when enough engineering is enough? Does that question make sense?

Andre: Yes. It’s a very good question. You can overdo it. Overdoing it is ridiculously expensive. The benefit we have, after building thousands of these, is we learn where the limits are of when does it stop working.

Then you have to go get out there. You learn how do you have to augment or bolster this thing so it doesn’t fail anymore when it gets ridiculously cold or there’s been a hurricane. Once you are familiar with where the failures are, you get better at not wasting people’s money, at making the thing reliable to just get it over the hump of what would be good design for the site.

Russel: The other thing that we talked about is one of the reasons that you want to look at hybrid is you want to look at overall operating cost. Again, it’s one of those things that can very, very different depending on where you are and what the load requirements are.

If I can make it smaller…When I look at operating cost, it’s what is the system I’m putting in and then what is the maintenance required to support that system.

I know that one of the things that comes up in West Texas is the dust. The dust gets on the solar panels. The dust cuts down the effectiveness of the solar panels. You actually need to, on some frequency, get out to those solar panels and dust them off.

Andre: Definitely. Luckily, people do visit the sites. Once in a while, they give them a look. Funny enough, birds and what they leave on the panels is a bigger problem for us than dust. Seagulls — oh my goodness — big story there. With solar panels, a good example would be a solar generator hybrid. You can reduce the cost of an installation by introducing a generator.

For instance, if I need a one kilowatt solar array to power my load through the middle of the average winter, then it would take a one and a half kilowatt solar array to be able to absolutely guarantee that the site will never go down. You would probably add half again to the battery bank. It’s not insignificant. It’s about 50 percent more.

When you get to really big installations where you have to have, say, 15 kilowatt of solar panels but people don’t have the space for it because they’re in a fenced-in area on a shutdown site, you can bring down the size of that solar array, which you size to be absolutely reliable, by introducing a generator that will pick up the slack in the middle of winter.

During the summer, you have way more energy available to you than you need. The generator will never be called upon to charge the battery bank. You may cycle it every two weeks to just keep things stirring or stirred. Come November or so, the battery bank will dip below a certain voltage level. The generator will be told about it. It will fire up, bring it back up again.

That’ll go on till, say, January, February like that, by which time the solar resource may be strong enough again. Now I don’t have to have a 15 kilowatt installation anymore. I can have a seven kilowatt installation. Generators are not that expensive.

Russel: They’re getting cheaper.

Andre: They are. You bring down the cost of the overall site. What you do jack up is the maintenance requirement. You have to at least size the fuel tanks, the oil reserve if you want to automate oil changes, how much oil do you keep at the site, so that this thing can autonomously work right through the middle of winter when nobody can visit.

Russel: That all makes sense to me. Redundancy, reliability, being able to operate through the seasons, all those kind of things make sense to me. One of the things I wanted to ask you about…Again, I’ve said this several times in our conversations. I’m a sailor. There’s a lot of electrical systems on sailboats. They can get fairly complex.

Just a sidebar. I have a partner. I have a boat. I have a partner in the boat. We divvy up all the tasks. Anything that is a communications or electrical task generally falls on me. I stumble my way through that. Anything that’s a mechanical thing or a resin or that sort of thing, it tends to fall on him.

What I know about remote power comes from what I know about my sailboat and what I know about doing field automation. When we start talking about some of these more complicated systems, one of the questions I have is, to what extent does the power management, power regulation, get more complex to select and design as we add all these additional power sources?

Andre: Usually, like I’ve said, at the heart of these hybrid systems, there’s a battery bank. Your loads would draw from the battery bank regardless of whether something is putting energy into the battery bank or not. It may be through an inverter, say, for 120 volt or something three-phase or just straight 24 volt DC to a control system or something.

Coming from a battery bank through an inverter or straight from a battery bank is extremely consistent, regulated power already. If you’re straight from a battery bank, you may vary, say, between 22 and 28 volts or so, but usually, things can handle that.

On the other side of the battery bank are things that put energy into the battery. For instance, a solar panel on the front of the boat and a wind turbine on the back. You may drag a generator in the water behind it. I’ve seen some very cool stuff.

Those different power sources typically don’t have to have any form of control so that you either draw from the one or the other or that there’s any switching arrangement that they have to work in series or parallel or something funny. You can literally have two or three or very many charging sources directly into a battery bank.

A good analogy would be a big, hot room and two one-ton window air conditioners or one two-ton air conditioner. Both of those will get the job done exactly the same. If you have two one-ton air conditioners, you don’t have to put up a control system to let them know about each other.

You can just turn them both on. They’ll both start trying to get the temperature that they see down to a level that they’ve been told. One of them may turn off before the other one because he reckons he’s cooler at that point. The other one will fill in the last little bit. Charging from multiple sources onto one battery bank is no different.

Russel: Let me ask a follow-up question. If I have a system that includes a generator and that generator has the capacity for an AC output so that I don’t have to run the batteries through the inverter, does it make sense to just use direct AC power off the generator when it’s available?

Versus running it through the batteries and I always run my AC power through the batteries. If I need AC power and it’s beyond what I have available, I just got the generator on. It’s going through the batteries and then out through the inverter.

Andre: That’s a good question. The short answer is both would work. I have such an arrangement at my house, a battery bank, inverters, a generator. I exclusively use the generator to charge batteries.

I can take the AC and introduce a switching arrangement. The inverters that I have is totally capable of that. At that point, I do introduce another point to failure. You also introduce a little switching time if…

[crosstalk]

Russel: You also introduce the potential of dirty power, I would think, as well, meaning power from the generator is not as stable as power coming out of an inverter off a battery bank.

Andre: Yes, absolutely.

[crosstalk]

Russel: You actually isolate yourself from other kinds of issues.

Andre: There’s that. Many smaller generators have inverter output so that the engine speed doesn’t matter that much. That’ll be clean enough, but you’ll still have a bit of switching time.

If you have a critical load that, say, has a PLC in it that’s not a big one, that little unit may care for the bit of switching time from the one source to the other source. It may reboot. We see that often enough. In which case, no, just run a charger with a generator.

Russel: You brought it up, so I have to ask a follow-up question about what you have at the house. Are you running your house off of battery power?

Andre: No. I have it as a backup, a split-phase system and a battery bank with a solar array. All the solar array does is battery charging. I’m not off-grid yet. In fact, the power never fails, so these things are just sitting here. [laughs] I have it because I like it.

[crosstalk]

Andre: big battery bank, three forms of charging on the battery bank. One is from a solar array. That is not grid-tied. It’s just directly to the batteries. The other one is a generator that keeps an eye on the battery voltage so that when the voltage drops below a level I told it, it’ll fire up.

All its power goes into a battery charger. It just brings it up to a certain level, not 100 percent full. That last bit of charging is too slow. It burns all my propane up. Then it goes down again. Three forms of charging. One battery bank into the house runs it.

Russel: I want to come visit your house and have you walk me through your tech.

Andre: You’ve got to see it.

Russel: I’m geeking out a little bit. I have a little bit of tech envy going on right now, Andre. I have to be honest.

Andre: Bring it on. I’m ready for you.

Russel: [laughs]

Russel: Let me just summarize what we’re talking about here and draw it down to a few points. Then I’ll ask you to give me any comments you have on this. Hybrid power is ideal whenever the location I’m in or the environment I’m in makes any one source of power not reliable enough. Too far north, I don’t have sunlight in the winter, that type of thing.

Hybrid power systems have to be very thoughtfully designed. There’s a lot of considerations. I would say, for somebody that’s looking at a hybrid power system in a particular location, maybe once you get the first one designed, you can take that and replicate it and run on your own power, but it makes sense to have some extra outside expertise when you’re getting the first one in.

One of the things that I really take away from this conversation is you don’t know what you don’t know. There’s a lot of details.

Andre: That’s right. Literally, like with any profession out there, you pick it up with experience. Why you have somebody else do it if you’re not going to do that for a living is they’ve made all the mistakes already.

[crosstalk]

Russel: That’s right. You don’t have to step in all the potholes that they’ve already stepped into.

Andre: Yes. That’s what you cut the little check for.

Russel: Exactly. Really, that’s the key takeaway. There’s a lot of things you can do that can reduce your operating cost by doing hybrid approaches where you don’t need as large of a battery system, but you can still get to the same level of reliability. That’s important to understand.

Andre: The installation at my house would have been double the size if I didn’t have a generator. That’s too much money. A generator is nice and cheap. I need it so infrequently that it makes sense to save money that way.

Russel: I actually think that in today’s environment, with everything in your house having computers and electronics in it and all the LED lights and everything else, there’s some actual value to running a big part of your house through batteries and an inverter just because it cleans the power up. You get a lot more life out of all your stuff because of that.

Listen, we have one more conversation coming up. We’ll do that in our next episode. What we’re going to talk about is how do you get remote power when the sun don’t shine.

Andre: Thank you, sir. Catch up with you later.

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.

If you’d like to support this podcast, please leave us a review. You can do that wherever you happen to listen. You can find instructions at pipelinepodcastnetwork.com.

[background music]

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

[music]