What Needs to be Done to Move the Microgrid Industry Forward? Q&A with SEL
Scott Manson, engineering technology director at SEL
Tell us about your company.
SM: In terms of microgrids, our story started in about 2002 with a project in Greece. That was an interesting story of learning about how the physics of low inertia microgrids operate and how to basically use protective relays or blue boxes to solve microgrid challenges.
This was before Professor Robert Lasseter [Professor Emeritus of Electrical & Computer Engineering, College of Engineering, Wisconsin Energy Institute] even came up with the word “microgrid.”
I reconvened with him here about two years ago. And, it turns out, all the research that he’d been talking about in theory, we were doing for real. And it was like, “Wow, really?”
We were practicing what was happening real time in terms of academia in the early 2000s.
If you weren’t using the word microgrid back then, did you have another word for it?
SM: Just an islanded and power system. It was a power system that required islanding. That first system went into service in 2003 or 2004. That was the year that the fires raged through southern Greece. The fires put their transmission system out of service.
An oil refinery — one of the most critical refineries in that region of the world — lost electric power from the utility seven times, and, seven times, our system detected the fault, isolated the facility, load shed to balance generation with load and saved the facility. It paid for itself seven times over plus many times more than that.
What needs to be done to push the industry forward?
SM: First thing, we need to place a much greater value on reliability. People like to use the word resiliency, but I’ll use the word reliability because it’s the older term.
Fundamentally, electric power is so critical to our quality of life that without reliable power, it directly affects our quality of life.
Second is the cybersecurity of supply chains; they go hand in hand. You can’t pretend to be cybersecure if you don’t have full control over your supply chain.
We need to be more stringent about who’s supplying parts, where they’re coming from and how we’re tracing every single component in your electronics. And then every single line of code, where it’s coming from, who has looked at it, who has had their hands on it. These smart electronic devices that are proliferating in our power system must be designed, manufactured and assembled in the US in secure facilities. No longer can we allow parts to be made in uncertain locations, assembled in America and furthermore updated willy-nilly.
There may be some embedded code that we’re unaware of in the components coming to us, correct?
SM: That’s right. Risks abound. We need to get out there and we need to teach. And, so, if you are an expert and you have experience in actually performing real microgrid projects, then get out there and teach others. That has to be done. And technology is at the forefront of that teaching.
Lastly, we need to really hold suppliers to the standards built by the senior engineers. They work very hard to put together specifications. We must hold suppliers accountable to those. If you follow those standards, the outcome is better for all of us.
What are the three biggest customer trends that you’re seeing right now?
SM: This is a great worry of mine. I actually have, at times, lost sleep over this. As we know, electric power is critical for our society to function. When I see immature technology like the DC to AC inverters proliferating throughout our power systems, I know that our power systems are becoming more fragile.
The irony is renewables may be justifying microgrids in many cases because as we add renewables, our grid gets fragile. Microgrids suddenly can be what helps you through those tough moments.
When you have a photovoltaic farm, that means there’s an inverter. Most wind turbine farms have inverters. These are all things adding to making a fragile grid. And, in a strange turn of events, it actually is due cause for power consumers to consider a microgrid.
A customer, of course, would want more reliability. So, therefore, if they’re concerned about reliability and fragility of the grid, they’re going to get a microgrid.
Watch a related interview with Will Allen, principle engineer at SEL
Many utility customers are interested in microgrids. The first question I hear is “Where do I start?” Talk to your electric power system experts at your local utility. Many of those utility companies have done power for over a hundred years.
We can make the power systems smarter with things like decentralized intelligence and programmable intelligence. I think this is best accomplished by secure devices, like the protective relay that we make and that is decentralized plus distributed programmable intelligence that can actually partly correct for this more fragile grid.
One last trend that I think is important to note: I see a lot of microgrid customers investing in combustion engine driven generators. It’s just a simple matter of math. Batteries run out of energy. They’re expensive. They’re not terribly recyclable, and renewable energy, like photovoltaics, is only working some of the time. And, quite frankly, you can still buy diesel fuel reliably. Its energy density is high. And, so, in a strange twist of fate, we’re seeing a lot of customers going toward conventional solutions for their microgrids.
Let’s talk about technology shifts advancing microgrids.
SM: First, the same plug-and-play convenience that we have when we buy consumer electronics needs to be adopted into microgrids.
It would give you that simplified experience of adding photovoltaics and batteries to your job site, to your home, to whatever microgrid you need to add to.
I’d like to make a call out here and kudos to the US Army for doing this. They’ve built a new standard called the military tactical microgrid standard (TMS).
It is a revolution in the power industry. It is taking us very close to plug-and-play microgrids. As such, like I say, congratulations to them for funding it. That was a very good use of our tax dollars. That is now a game changer for our industry.
Is there an example of a project using TMS?
SM: Fort Stewart in Georgia is now a TMS microgrid.
You mentioned the fragile grid problem. What are the solutions?
SM: To solve the fragile grid problem, we’ve found that there are really two answers. We need bigger inverters. And then, secondarily, after the inverters, we need a smarter grid with distributed intelligence. That’s a two-part technology solution: bigger, better specified inverters and more distributed intelligence. A good example is that fuses don’t work in an inverter-based microgrid. To replace that fuse, you now need a programmable protective relay and a circuit breaker. So that’s an example of how our grid needs to get much smarter.
Why is a bigger inverter needed?
SM: That’s a physics answer. Inverters are limited in their ability to produce current by two things. One is their silicon limitations. They can only handle so much current, and bigger silicon can handle more current. The second is the heat sink that silicon produces as it transmits current. In the power system that heat has to go somewhere. Just like your engine has a radiator, there has to be heat extraction on an inverter. The way that you get an inverter to provide more current is by making it bigger.
If you buy a 1-MW inverter and a 1-MW generator, that 1-MW generator could put out 7 MW or 7 KVA of current because that’s the way generators are built. There’s a huge disparity between how inverters are constructed and how generators have been built since [Nikola] Tesla’s time. And so that 7-1 ratio can be solved by making your inverters bigger.
There is a simple answer to grid fragility, and it is bigger, better inverters with a lot more protective relays throughout your power system.
What are the biggest customer misconceptions about microgrids that you run into?
SM: Seamless islanding and restoration is not expensive nor is it complicated, and the common misconception is that it is expensive and complicated. This technology that provides seamless islanding and restoration is decades old and has been used in the transmission distribution industry since I started.
You’re saying microgrids are not going to cost a lot if they’re doing it right?
SM: If they use the right technology, sometimes it’s not a cost adder at all. The way that you get a low-cost, high-performance system is to start early with a comprehensive design from experienced engineers. It may be a microgrid, but it’s a macro challenge.
I enjoy the microgrid challenge for many reasons. One of them is that microgrids are kind of a petri dish or a microcosm of the engineering challenges that you don’t get to experience on utility scale jobs — things like low inertia, intermittent fault currents, sub-synchronous control interactions. They’re really not something your utility power system engineer gets to see but once in a lifetime, but I see them daily in a microgrid. So it’s a much, much more dynamic environment with a lot more first principle challenges and what a joy to work in this field.
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