Hydropower represents the biggest renewable energy source. Besides, it is a well-established and highly reliable method to support a transition toward a low or zero carbon grid. But hydro also has a significant impact on ecosystems, water quality, and biodiversity.

In this episode of Hardware to Save a Planet, Dylan is joined by Abe Schneider, Co-founder and CTO of Natel Energy, to discuss how the company has developed a new hydropower turbine model, which allows the safe passage of fish in already existing hydropower plants.

Abe is a mechanical engineer and fly fisherman. Before Natel, he worked at Timken in power transmission R&D and then at Makani, a Google X project, designing kites to harness high-altitude wind energy. His expertise includes renewable energy product development, the design of hydraulic turbomachinery, mechanical engineering, machine design, and supply chain management.

If you want to discover more about Natel Energy’s hydropower turbine model, check out the key takeaways of this episode or the transcript below.

Key Highlights

  • 03:43 – 06:31 – The motivation behind Natel Energy – Hydropower represents a reliable solution for generating low-carbon energy. However, it has cost and environmental issues. Natel Energy focuses on solving these problems by designing innovative turbines with superior efficiency and low cost. 
  • 06:31 – 08:27 – Why is hydropower important – Solar and wind power growth rates have been significantly greater and necessary to meet climate goals. But hydro could potentially support a transition toward a low or zero-carbon grid for several reasons. One is the resource availability of hydropower which is significantly higher than solar and wind. For example, the sun doesn’t shine on solar panels at night, and the wind doesn’t blow all the time. That creates a demand problem. Hydropower can also support increased generation from other renewables in a manner that doesn’t require carbon dioxide emissions.
  • 11:35 – 15:52 – Hydropower’s downsides – Hydropower has several issues, like high costs and environmental and social impact. It disrupts the natural movement of organisms in the water, like fish that historically freely moved up and downstream. Specifically, with fish passage, there are a few key species that are heavily impacted and threatened or endangered by the building of dams and the operating of hydropower facilities. Whether turbines are small or large, their blades have sharp leading edges, which move extremely fast. The mortality rates for fish come close to 50% in one turbine. And some species go through several turbines before reaching the ocean. 
  • 21:09 – 27:20 – Innovative turbine design – Natel Energy has worked to change the shape of the blades by using a combination of a thick leading edge that has a significant degree of slant to it. The turbine blades emerge from the hub where they are attached and almost immediately start to sweep forward in the direction of its rotation so that by the time it reaches the very outer diameter of the blade, it is pointing forward by about thirty degrees.


Dylan Garrett: Hello and welcome to Hardware to Save a Planet. The fight against climate change, of course, depends on having enough clean renewable energy sources to replace fossil fuels and the emissions they generate. In the renewable space, wind and solar get a lot of attention but actually, the biggest source of renewable energy in the world today is hydropower. It produces more energy globally than all other renewables combined. I’m really excited to have Abe Schneider on the show. He’s the CTO and co-founder of Natel Energy. We will be talking about the hydropower industry and what Abe and Natel are doing to make it sustainable for the future.

Abe is a mechanical engineer and fly fisherman which will become relevant soon. Before Natel, he worked at Timken in power transmission R&D and then at Makani a really cool Google X Project, designing kites that looked like airplanes to harness high-altitude wind energy. Before all that, I understand that Abe grew up in Texas in a log cabin built by his dad, who was also an engineer and inventor himself and a big proponent of low-impact living.

Abe, it’s awesome to have you. Thank you for making the time today.

Abe Schneider: Great to talk with you. Thank you for having me.

Dylan: I normally ask people how they got into climate tech but it almost sounds like you were born into it. How much has your upbringing been an influence for you?

Abe: My upbringing and my co-founder and sister’s upbringing, both of us were immersed in the values of sustainability from an early age, thanks to our parents. Back in those days in the mid-’80s through the ’90s, it wasn’t really a popular thing to talk about climate change. At that time, actually, I think that the closest that it came to climate change was global warming. Our dad would constantly correct people that it’s not global warming, it’s climate change because some places will get warmer, some places will see colder temperatures locally or just worse weather locally.

Anyway, that’s a reflection on our dad. He was constantly thinking about sustainability and actually trying to create a lifestyle that was low-impact. Certainly, we emerged from that experience with some pretty deep feelings of responsibility to do something good for the earth with our lives.

Dylan: You mentioned your sister. Do you have other siblings as well, or was it just you and Gia?

Abe: We have a brother Andre as well who is older and also works in energy.

Dylan: Okay. Three for three. You mentioned your sister, she’s your co-founder, the CEO of Natel. Would your childhood selves be surprised to know you’re running a company together? Did you get along growing up?

Abe: I think we did. Actually, I have two young daughters so I’m starting to get this out-of-body experience like watching how siblings grow up again. Yes, we got along. Obviously, we had our sibling disagreements. I think it’s just normal. Strangely, I think actually we’ve been talking about business ideas in some sense or another together since we were kids. I haven’t really thought about that too much like those early days and this idea of being in business together or creating a business together. It’s not too surprising.

Hydro is this incredibly well-established and highly reliable method of generating low-carbon energy. But it has several issues like cost and environmental and social impact. The way we have steered and evolved the company has moved towards focusing on resolving those impacts in the simplest possible way from a machine design and product standpoint.

— Abe Schneider

Dylan: That’s awesome. How did the idea of Natel specifically come about?

Abe: I think the real genesis of the idea of Natel, which is a company focused on sustainable solutions at the intersection of water and energy, this was definitely the impetus came from our dad. He was amongst other things a pilot and a sailor. He’s also a farmer, a doctor, and a professor. He’s a thinker above all else but he had a lot of personal interest in fluid mechanics. Having grown up on a farm himself and then operating a farm that Gia and I grew up on, he was also mechanically inclined.

He had been thinking about how to reduce the cost of generating carbon-free energy from low pressure, large volumetric flow rates of fluid for a long time. His first efforts in that were actually in wind. He worked on some novel wind-generating devices and then took those fundamental concepts that he was working on and then transitioned into water power realizing that the energy density of water power is significantly greater than wind and so it’s possible to create the same amount of energy from much smaller machines if you’re dealing with water.

His ideas were driven or were born from his experiences as a sailor and a pilot. He had been working with linear moving foils so aircrafts have– He was not a helicopter pilot, he was a fixed-wing pilot. His experiences there with fixed-wing lift and the same in sailing so he was experienced with this concept of lift and drag. Basically, his idea was that if you sail a sailboat around a couple of buoys in a race course, you are in that boat intersecting a massive quantity of area. If you can imagine putting several sailboats all following each other and sailing that course around those buoys and then tie them all together with a rope, then you could maybe put a gear in there and then use the gear to turn the shaft and the gutter.

That was basically the core idea of a linear turbine that he was very, very interested in that I grew up with and thought about. That was the seed of a practical concept of how to come up with something new in hydro. Of course, hydro is this incredibly well-established and highly reliable method of generating zero carbon energy and low carbon energy but it has a number of issues. Amongst those are costs but also environmental and social impact. As it happens, the way that we have steered and evolved the company has moved towards focusing on resolving those impacts while doing so in the simplest possible way from a machine design and product standpoint.

Dylan: Can you help us understand why hydropower is important and what’s happening in the industry generally?

Abe: Hydropower is unique and well-suited to support a transition towards a low-carbon or zero-carbon grid in the future for a number of reasons. One is that the resource availability of hydropower is significantly different naturally from solar and wind. For example, one of the issues with solar power is that the sun doesn’t shine on solar panels at night. That creates a problem for demand that doesn’t necessarily go away at the exact moment that the sun sets.

Same with wind, the wind doesn’t blow all the time. In some places, the wind blows more at night, which is nice in terms of balancing the solar load. As you can see, there’s a significant issue with the availability of wind and solar. Hydropower has a much different availability, it is also a seasonally varying resource. In many places, autumn represents a relatively low-flow period of the year but in the spring and through the summer, and in some cases in the winter, you’ll have quite a lot of water to work with. For a very large fraction of the year, hydropower facilities can be relied on for a relatively firm generation.

Hydropower can help support increased generation from other renewables in a manner that doesn’t require emissions of carbon dioxide. Other ways to firm up the grid include the construction of thermal power plants like natural gas-burning power plants or other thermal generation sources. Of course, that’s not what we need to be doing if we’re trying to reduce our carbon emissions. Globally, hydropower has an even more important role to play. In some countries, hydropower is the dominant source of generation and it’s abundant globally. It is advancements that we can make and hydropower can have a positive benefit all around the world.

One of the biggest opportunities to make a difference in hydro is to provide a solution that addresses the combined problems of aging equipment that needs to be modernized as well as responding to new and current concerns about biodiversity and the environment.

— Abe Schneider

Dylan: I think I just saw an article actually on Natel installing new hydropower plants in Congo, was it, and supplying electricity to something like 90 million people who don’t have any electricity access today.

Abe: That’s the goal. We’re working with a developer in Africa. One of the exciting things about that effort is that it’s successful. These hydropower facilities will be built for the first time with modern, efficient, fish-safe technology. In some of these places, the local cultures still rely on their rivers for fish as part of their nature, just their daily activity. That would be a very, very closely felt benefit from such an installation. We’re also excited about the first international plant that is using one of our turbines which is currently in the commissioning process in Austria.

Dylan: Cool. Tell me about this. It feels like in the US, we’ve tapped a lot of the available hydropower sites but there’s a lot of growth opportunities in other parts of the world places like Congo where there’s rivers where you’re building new power plants using hydro. Is that accurate?

Abe: Actually, there’s a tremendous amount of additional generation capacity here in the US and a tremendous amount of capacity globally. In the United States, there are tens of thousands of existing dams that do not generate power. A substantial fraction of those have flow and ebb, and the pressure able to support commercially viable hydropower today. It’s measured in multiple gigawatts of additional potential. That’s in addition to the existing fleet, which represents an opportunity to improve its environmental performance and to upgrade aging equipment.

Dylan: Then just one more thing on the benefits of hydropower. I’ve read that it can be used as a storage energy storage solution as well. One of the challenges is having energy available when you need it. Where people are working on grid, scale batteries for energy storage, and stuff like that but it seems water is pretty natural. It lends itself pretty naturally to being used as an energy storage mechanism. Is that another benefit of hydro?

Abe: Oh, absolutely. That’s one of the most active areas right now in hydro development is in development of pump storage hydropower. Pump storage hydropower is possibly the most efficient way of storing and then regenerating energy, but exceptionally high roundtrip efficiencies. Pump storage hydro can be also built either on a stream or can be located completely in a closed loop system, where you have a static source of water that you basically pump up and down a hill.

Dylan: Oh, interesting.

Abe: That can actually help to reduce some of the environmental impacts of a plant like that. Generally speaking, pump hydro is a niche within hydro that’s parallel to river hydro where the water flows through the once and then flows downstream.

Dylan: Is Natel focusing on one type or another?

Abe: We’re primarily focused on run-of-river hydropower and others in the industry are heavily focused on pump storage hydro.

If hydropower needs to be repositioned as a truly sustainable resource, those passage rates need to approach 100%, especially if fish need to pass through numerous facilities.

— Abe Schneider

Dylan: Let’s talk about the Natel solution. Can you describe that and how it addresses some of these problems?

Abe: One of the biggest issues in hydropower today is its environmental impact broadly speaking. From here forward, I’m going to be speaking when I say hydro, I generally am talking about run-of-river hydropower not pump storage hydropower.

Amongst one of the issues with a hydropower facility is that it inherently touches quite a lot of different aspects of society. Hydropower facilities often provide great opportunities for local recreation like local fishing in the DM, in the lake, swimming, or other things. People build houses next to the lake to enjoy the view. These are just examples of the way hydropower has a positive impact on the surrounding community.

Hydropower also has significant negative impacts. The lakes themselves disrupt, in some cases, the natural movements of organisms in the water. Fish or other animals that historically freely moved up and downstream. Also sediment transport is an issue for stream health. Some kinds of fish rely upon certain types of gravel in order to complete their spawning process.

For example, in dams, the presence of dams can cause problems with the natural transport of gravels from upstream to downstream, whether it’s eel or smolts of salmon, basically, the younger salmon that need to move down to the ocean. Any of these fish that need to move downstream as part of their life cycle are passing through turbines, which are spinning very rapidly with sharp blades.

In addition, some kinds of turbines have blade shapes that as they rotate inside of the housings of the turbine inside of the pipe in which the turbine blades are rotating, those blades actually have a curvature which can lead to a problem of fish getting stuck or scissored in between the spinning moving parts and the stationary part. Fish either get chopped directly on the leading edge or they get squeezed into these crevices and then basically cut up like scissors.

It’s not a pleasant situation and, in some cases, mortality rates for fish can be in excess of 30% to 50%, in one turbine. It gets worse from there because in many cases, you don’t just have one hydropower facility in between the headwaters and the ocean. You have many hydropower facilities. Many of these migratory fish species actually, come from high up in the watershed and then they need to move all the way to the ocean. They need to pass potentially numerous of these hydropower facilities. It becomes a fairly simple mathematical problem where if you have a 50% passage rate, it only takes a couple of hydropower facilities where you’ve severely impacted the population.

Dylan: There’s this gauntlet of perfectly designed fish blenders they’ve got to get through, it sounds like.

Abe: Yes. In reality, there are some turbines out there which have much better passage rates. I don’t want to somehow imply that all existing turbines have horrible fish passage rates. There are definitely many examples of some turbines who for various reasons could have passage rates in the high ’80s or even in the low ’90s, which is great.

Fish in nature are subject to many other challenges including predation from other fish or predation from birds or disease, or just like all the things that they’re struggling with. Anyhow that specification puts the hydropower facility at a point of neutrality compared to the other challenges that fish reach.

That ends up becoming an extremely important criteria in the design of our turbines. Thankfully, we’ve been able to build upon some fairly simple, but powerful means to rethink how hydropower turbine blades are shaped to reach those very high passage targets and to do so without compromising the conventional design criteria of hydraulic efficiency and small size and fast shaft speeds and inexpensive turbines that have a great deal of flexibility in how they’re deployed.

Dylan: You’ve mentioned the cultural significance of these species. Is there a bigger environmental impact of losing these fish populations outside of the fish populations themselves? Are there knock-on effects in that they’re supporting populations in the ocean when they go to sea or other bird or other animal populations? What’s the right way to think about that total impact?

Abe: Yes, there is absolutely a much wider web of impacts, and those can be expressed in various terms including economic terms from the various groups of people who are attracted by the presence of fish whether it’s native cultures or sport fishermen or commercial fishermen. There’s a very significant dollar value that’s derived from the presence or absence of fish.

Also interestingly, these migratory fish species have a lot of other impacts on their surrounding environment. Personally, I’ve been an avid fisherman since I was a kid, but I’m still learning things every day. Particularly as we have been working with eels, eels have been completely unknown to me until we really got deep into this issue of how to design turbines and capacity safely. I think that’s actually true for a lot of our society. Eels are just maybe seeing the first little blip of cultural popularity now.

There’s a few best-sellers out there that are talking about eels, but eels carry– I’m not an expert on this. I’m probably going to completely butcher the explanation of this but as I understand it eels actually have a symbiotic relationship or a relationship with freshwater mussels. There’s some types of endangered or threatened freshwater mussels, which have also seen severe population declines on the East Coast watershed to the United States.

It turns out that those mussels hit your ride eels as the eels move around in the watershed. As we restore populations of eels, then what I’ve seen in some of the literature is that we’re starting to see positive impacts of the presence of these freshwater mussels. The freshwater mussels, of course, have their own part to play in the ecosystem. They have filter feeders. They tend to clean up the water where they’re present, and they may have other ecosystem functions that aren’t widely appreciated yet.

In the case of salmon, it’s a pretty blunt but powerful role they play. Salmon, unlike eels, which eels go upstream as babies and then they go downstream as big adults, salmon are the opposite. They go upstream as big adults, and then they spawn and most often they die. The upper reaches of a watershed, and then they’re young emerge from the eggs and then move downstream to the ocean where they feed.

What’s happening is you have this process where very small amounts of biomass in the form of young salmon go downstream. Then they grow in the ocean, they absorb biomass from the ocean, and then transport it upstream into historically nutrient-poor areas of the water stream, high reaches with few nutrients. The presence of healthy runs of salmon is a really important way to take nutrients from the ocean where nutrients in general are collected.

Just in this miraculous fast move, recharge those nutrients right back up into the headwaters of a watershed. It’s really amazing and so then those nutrients feed the trees, they feed the entire food web, basically. Very much not humans aside, those salmon have a role to play in the ecosystem.

Dylan: That makes sense. I would not have thought about that, but that is incredible. I have to say, I had no idea there were three-foot-long eels migrating down rivers in the US. I’m going to have to go look this up.

Abe: It’s so amazing actually. Almost every single moving body of water that touches the Atlantic Ocean has or has historically had eels. There are very few examples, and that’s just a general rule. Do you think about the map of the United States? It actually is something on the order of 30% to 40% of the hydropower generating assets in the United States are on waters that are either currently or historically had been occupied by eels.

I’m still shocked to learn this. I grew up in Texas, in rural Texas. I spent every spare moment I had playing in the creek, and apparently there are eels. In those waters, I personally never saw them but I’ve seen examples of researchers who’ve located them. It’s so crazy.

Eels are present on I think every continent except Antarctica. There are Japanese eels, there are New Zealand eels. The eels in New Zealand grow to more than six feet long and they’re called tuna by the native peoples. They’re enormous. The world’s largest eels. Strangely, eels are not present on the west coast of the United States naturally, but I think that the native people call them eels. That gets a bit confusing, especially since they look so similar.

Dylan: Okay. Thanks for that. That makes a lot of sense. It lines up because I feel like, throughout human history, we’ve learned over and over that if you introduce or remove a species from an ecosystem, the knock-on effects are just so vast and hard to predict. Your salmon example is a great example of that.

Is it just about changing the shape of the turbine blades? Is that the main way you reduce? You’ve said you’ve been able to maintain the diameter. These almost sound like drop-in replacements for the existing technology and the same turbine speed. Is it then just about changing the shape?

Abe: Yes, that’s right. Our goal is to create hydro turbines that are as close to if not actually drop-in replacements of existing turbines. The simple answer is yes, it is all about the shape of the blades and those requirements are driven by the speed, which is not a shape, but it’s a constraint because the speed at which the turban rotates–

Not to get too into equations but power is basically to just torque time speed. For a given power, the faster that you can spin, the less torque you need, the smaller that you can make the generator or the turbine itself. Especially if the goal is to have a drop-in replacement, you’re replacing a turbine that was in most cases designed to have relatively high shaft speeds. That creates a problem for fish because quite intuitively, the faster you go the more risky it’s going to be if you’re going to be striking fish.

Plenty of efforts has been put into designing hydro turbines “that are fish-friendly” but nothing has been created that’s been successful in the area of the market that is actually the most relevant in terms of magnitude of power generation potential, real projects currently that also have real fish issues. This basically sits in the operating range of what’s classically called propeller turbines or Kaplan turbines. These are axial flow reaction style turbines. As you might imagine, a propeller turbine literally looks like a ship propeller. If you can envision a ship propeller, that is what these turbines look like. That is the basis around which we have worked to change the shape of the blades.

Specifically, the simple insight is that a combination of a really sick leading edge and a leading edge that has a significant degree of slant to it so that turbine blades emerge from the hub where they’re attached, and almost immediately the blade starts to sweep forward in the direction of its rotation so that by the time that you reach the very outer diameter of the blade, the blade is pointing forward by about 30 degrees. The reason for this is that we wanted to– We didn’t want to, we had to create a blade that allowed for the maximum possible rotating speed while still respecting the physiological limits of fish that would pass through the turbine.

Then the reason for having a very blunt or very thick leading edge builds upon a lot of prior work, that’s been done a decade and more ago at a number of labs here in the US and also internationally but that work showed that–

Actually, this is really interesting. A long time ago, and actually, still to this day in certain important circles, it was thought and it is, then those thoughts translated into mathematical models that assumed that if a fish contacted a blade of a hydro turbine, the fish would die. This is important because when you start looking at permitting, you need to make some estimates of how many fish are being killed, going through a turbine. Not every fish will contact the turbine blade.

Think about the example of a 21-foot diameter turbine with 4-inch long fish passing through it, a very, very large number of those fish will never contact a blade. That creates this concept of a strike probability. Let’s say that 80% of the fish never contact a blade, 20% do, I’m just pulling numbers out of the air, but old models would say that those 20% of the fish would be considered mortalities.

It’s actually only recently that engineering data through experimentation with live fish has shown that fish can survive strikes. Not only that they can survive strikes, but some quantitative nomographs basically of what geometrical and other factors lead to their ability to survive strikes under different conditions.

Specifically, this decade-old research that I referred to studied blades of different thicknesses and fish of different lengths, they found that the ratio, the fish lengths to blade thickness, is very important in the maximum survivable strike speed. They found that if the fish is quite long compared to the blade thickness that the fish must be struck at a very low strike speed in order to survive, but that as you increase the thickness of the blade relative to the length of the fish, especially if that ratio show is somewhere between 1 and 2, then the safe strike speed could be doubled, the strike speed for a very thin blade.

That’s very useful engineering information, but that alone isn’t enough to engineer a turbine that has a rotating speed fast enough to compete economically with the existing turbines that weren’t designed with fish safety as a constraint. That’s where the slant angle comes in. By adding a slant to the recipe, a slanted blade plus a thick blade allows us to then create turbines that have a fast enough rotating speed to be small enough to either literally drop in and replace an existing turbine or come quite close to it.

That was the theory, then of course we had to embark on a pretty heavy-duty process of biological validation, which has involved first “bench level tests” or laboratory strike tests with blade analogs. Not actually turbines but just blade shapes, which we did a few years ago and that validated this hypothesis. Then we very rapidly moved from that point to the design and construction of complete turbines. Some of the most exciting work on fish passage validation has been on passing fish of different sizes of different species through these turbines under extreme conditions to validate the safety of the machines.

Dylan: No, it’s really cool. It makes intuitive sense. The bigger, the less like a knife that turbine blade is the more surface area that that force has distributed over. It sounds like the shape of the blade has enabled you to maintain the orthogonal component of that force regardless of the speed of the blade which increases as you get further from the center of the turbine. Those are the two.

Abe: That’s right. The fact that it is intuitive is helpful in communicating it but actually when the original research reports came out, I remember reading them a decade ago and my reaction at the time was, “This is so intuitively obvious that it seems like a waste of people’s time to do this type of work.” Then I came back with more interest, I guess, and maybe a more open attitude because we reached a point in our own product development where truly developing fish-safe blades became a real priority. I found that there are some really interesting effects that are happening below the surface that are not intuitive, that have a pretty important role to play.

These strike tests that were done a decade ago were filmed with high-speed 1,000 frame-per-second video cameras, which at the time, I think must have been pretty unique. There are images published, which are really interesting that compare the dynamics of the fish body as it is approached by the blade and then struck by the blade and then as it reacts to that strike. A fish body that is struck by a thin blade shows no evidence of the blade approaching until physical contact occurs and then there’s this shockwave thing that passes out the spine of a fish and its spine gets forced around the thin blade and those fish die from spinal fracture.

The fish that are struck by a thick blade in these high-speed videos, you can actually see the fish start to deform and take the shape of the leading edge of this thick blade far in advance of physical contact. Then by the time that physical contact occurs, the curvature of the leading edge of the blade is so large that the fish spine is in a form that is a natural swimming arc, and fish bend their bodies to swim. Then it slides around the blade and it lives.

There’s a few things going on there. One is that actually any object that’s moved through a fluid will have a distribution of pressure around that object. There will be a stagnation region right in front of that object where there’s a relatively higher pressure zone. Then you’ll have a region of lower pressure where the fluid is accelerating around the object.

That stagnation region or high pressure is actually what is causing those fish bodies to adopt the shape of the blade far in advance of an actual contact. This is also, I think, one of the things that causes dolphins to like to surf in front of boats or ships because the ship is pushing a pillow of water in front and the dolphins are basically just taking advantage of that to get around.

We actually then studied these strike videos and quantified the change in velocity of the fish body as the blade approached. We found that there is a more than 30% reduction in the strike velocity purely from the effect of this stagnation region that the blunt thick blades are pushing as they approach the fish, whereas the thin blades have a 0% reduction in velocity. That’s completely apart from and it’s actually also completely apart from the intuitive aspects of well blunt things that will hurt the list.

That gives you an indication of one of the most exciting things about this process as well for me has been we’ve been able to create turbine blades that have these very odd-looking leading edge shapes, very thick and very slanted leading edge shapes, but the resulting turbines are well over 90% in efficiency, in some cases now predicted to exceed 92% or even greater efficiency.

Dylan: How does that compare to conventional?

Abe: Yes, that’s right on par with conventional good quality turbines. The best quality, the highest turbine efficiencies out in the marketplace are perhaps at 94%, but most of the turbines that we are actually would be matched against what we’re creating are closer to 90% to 92%, though that’s pretty unintuitive to be able to reach those levels of efficiency with these odd shapes.

Dylan: Yes. Has it been a challenge then translating that into the real world and actually producing real physical turbines that make good on those requirements?

Abe: Yes, because these blades are quite thick, they’re at least 10 times thicker than a conventional blade that they definitely have posed and continue to pose some pretty interesting manufacturing challenges but also some really significant manufacturing opportunities.

For example, the conventional turbine blades, hydro turbine blades are almost always made from metal and in many cases from various specific alloys of steel. If you were to manufacture one of our blade shapes, large diameter runners say like six feet in diameter, the resulting turbine rotor would be dramatically heavier, dramatically more expensive to produce than a conventional turbine.

This is not the case as the turbine’s diameter is reduced so if we manufacture a runner that’s only half a meter in diameter, then simply making it completely solid steel or bronze or something like this is completely feasible. The problem is that we’re very focused on making utility-scale megawatt glass turbines and those are going to be over a meter or over two meters in diameter.

How do you make a fish-safe blade? The thickness provides a great opportunity to cut down on one of the classic sources of cost in hydro turbine blades which is the finishing operations. A lot of times hydro turbine blades are finally finished. The surface finish is ground. It’s a pretty time-consuming process.

Going back to the discussion around wind, one of the reasons that wind power has seen such a significant reduction in its cost of energy is because the fabrication of the blades has become highly optimized. Wind turbine blades are produced at that shape from molds using, in most cases, an infusion process with resident-reinforced fiberglass. Our blades can be produced the same way.

We’ve been operating for three years a turbine that’s just around six feet in diameter with fiber composite blades in Oregon with one of our fish-safe designs. It’s interesting that these fiber blades, one of the common sources of damage for a turbine blade, in general, is foreign objects being ingested so you have gravel or rocks or sticks and whatever comes through the hydropower turbine hits the leading edge. We’re borrowing techniques from the aerospace industry to armor our leading edges with nickel plate. Some aircraft engines have a replaceable nickel leading edge which bears the brunt of foreign object impact.

The fact that that exists actually allows for really cost-effective production of these armor plates, surprisingly cost-effective actually. It’ll just be the leading edge is metal, and then everything else is composite.

Then we’ve also needed to develop alternatives for in the case that a customer says a large utility is too risk-averse to even consider composites. We need to be able to have a metallic option. We’ve also then gone down the route of a variety of options like hollow metal castings or more interestingly using additive metal techniques to build up the blade with a hollow center. We are actually actively working on multiple options in parallel because the market is actually– it is not possible to basically force everyone to use one solution. It’s one way to think about it.

Dylan: You’ve mentioned market acceptance a little bit. It sounds like one thing you’ve done is make the turbines as similar as possible to the existing equipment that they’ll be replacing at these power plants. You’re also working on materials to help people feel comfortable with how long they’ll last and be as similar as possible to what they’re replacing. What other hurdles do you have to get over in the sales process to actually get people to go with your turbines over the state-of-the-art or the conventional technology?

Abe: Yes, I think one of the most interesting things comes back to why we are doing all this work for fish safety, well, it’s not entirely out of the goodness of our arts. It’s that regulations are forcing plant operators to deal with downstream passage. Anywhere on the East Coast, this might not be too much of an overstatement but we know from experience that if you develop a hydropower project on the East Coast, you will be required to install eel exclusion screens which have a spacing between metal bars of three-quarters of an inch. This is in comparison to the trash racks that would normally be used on hydro that have a spacing between bars at a minimum two inches and up to four inches.

Putting a screen across a hydropower intake on the East Coast where you have lots of deciduous trees that shed their leaves in the fall which is when the eels migrate, passing all that water through tiny, tiny gaps to keep these slithery animals out ends up becoming not only a significant capital cost but significant reduction in energy generating potential because the screens will have an increased loss of pressure. There’s head loss as water passes through these screens they clog with leaves. If it freezes, the screens become tangled in the ice. It’s an operations and maintenance hassle at best.

What we’re finding is that there’s a lot of interest because both the hydropower operators and the regulators can meet their goals of, on the one hand protecting the fishery and on the other hand, having the simplest possible and functional hydropower facility by implementing fish-safe turbines because at fish safe turbine it lets the eels go through in the fastest possible way safely without the need for any of the fine screening and all the operations and maintenance hassles that it comes along with.

It’s a pretty cool opportunity basically where you take people that normally spend all their time arguing with each other and say okay, we can meet both goals.

Dylan: Regulation is going to be a big part of helping to get this technology out into the world.

Abe: That’s right. I think that there are plenty of examples of how there’s a healthy cycle between technology development, regulatory development, and product development, and then market development.

In other industries, maybe an imperfect example would be coal scrubbers. The technology to remove pollutants from the production of energy from coal wouldn’t be possible with the technology to do that didn’t exist so why would you create laws that mandate the adoption of these scrubbers if it’s just not technologically possible? Once it becomes technologically possible to do this, then it makes sense to steer regulations to encourage their adoption. It protects the public good and then that encourages product development of more effective ways of achieving the same scrubbing.

That’s what we’re I think seeing already even with our relatively short amount of time doing what we’re doing. I expect to see that continue to evolve in hydro as it becomes clear there’s definitely a way to achieve all these different goals in a simple way and update various regulatory structures so that this is not only from a permitting standpoint but also on the compensation standpoint. I think it makes sense that hydropower facilities who invest in modern fish-safe technologies make sense that they would be compensated more for their power.

Dylan: Absolutely.

Abe: There isn’t anything necessarily right away where they are seeing that here in the US but there’s definitely moves towards that in other countries. Here in the US, there is a low-impact hydropower certification which helps certain hydropower-like certified hydros to achieve or receive RPS credits but there’s no levels in the standard. There is an aggregation of many different types of hydropower facilities. Maybe in the future, you might see more tiers like lead platinum versus lead gold to recognize additional efforts to invest in sustainability and sustainable hydropower operations.

Dylan: Thinking a little more about the future of hydropower and metallic, are there other opportunities for innovation and hydro?

Abe: Yes, there definitely are. Wind compared to the amount of innovation happening in solar and wind hydropower can sometimes look like it’s relatively stable, and it’s true. Hydropower has been a reliable source of generation for a hundred years, and wind and solar have required an exponential amount of innovation simply to become a viable generation source. Happily, that’s happened and continues to happen.

There are plenty of opportunities though to continue innovating. One is a more intelligent understanding of the water resource. Not to plug another thing that the net’s working on but Natel has a sister company called Upstream Tech. Upstream has created the best surface water inflow forecasting tool. It’s a machine learning enabled system that ingests automatically a huge amount of data now on a very frequently updated basis, including satellite imagery and multispectral imagery and uses cutting-edge computational techniques to turn all that information into actionable forecasts of available flow for hydropower operators.

This is then allowing hydro operators to make better decisions about when to run their turbines. If they know that they’re going to have flow availability changing a week ahead or a day ahead or a month ahead and they know that maybe there’ll be differences in power prices or other factors that could result in a monetary benefit. Now they can make better decisions. That’s all, this is a technology and a product that literally couldn’t have existed five years ago. Just like many other people are building tools on top of the technologies that have exploded in AI, we’re leading in that field with Upstream.

Dylan: A few last questions to close us out here. How optimistic or pessimistic are you about the future of the planet and why?

Abe: I want to be very optimistic, pretty concerned. I think that sums up my feelings there. I think the possibilities for improvement in our ecosystem impacts are huge. I think they can be surprising. I think we can make surprising advances in improving our collective impact on the planet that’s enabled by explosions in technology for one thing, and also by a real ground swell in concern and prioritization of sustainability in general, by the generations of people who are going to have the most capacity to effect change. Young people inherently value these things.

Those two things taken together I think are already resulting in very surprising and quick changes in how much wind energy is being generated by the adoption and development of electric vehicles, just electrification in general. I think we can be surprised by the rate of progress but at the same time, the rate of progress that’s required to happen in order to prevent really painful effects is extremely rapid. I’m not sure we understand them nor do we necessarily appreciate the magnitude of the changes that might be coming our way. I’m pretty sure that very, very positive and very encouraging and surprising things will continue to happen and we might make it.

I also think we’re going to have to learn to adapt and that adaptation process is going to be painful.

Dylan: Who’s one other person or company doing something to address climate change that’s inspiring you speaking of?

Abe: I would say that I’m very inspired by certain people and groups that are developing and have made huge progress, for example, in electric vehicles, really just have shown through tremendous effort and cleverness or literally forcing the rest of the automobile industry to change and show them that it’s possible.

A company that I would highlight that’s a bit closer to home to watershed restoration is the work that we do, I would mention Natural Systems Design. They’re a small civil engineering consultancy based in the Pacific Northwest. They’re founded by hardcore civil engineers who have I think similar values to our company in that they care deeply about watershed restoration. They’ve chosen to focus their company on finding ways to help in that. They’re bringing techniques and the training of their civil engineering background to bear on that problem.

They’re thinking very creatively about ways to hybridize conventional industrial engineering approaches with natural systems, such as one example is the use of engineered log jams. Log jams are something that occur naturally in streams that flow through forests. When a big heavy tree falls into a river it has a substantial impact on the velocities around it, it creates a scour hole upstream but it also creates a deposition zone downstream. Then the presence of its complicated branching structure introduces complex woody habitats into the stream that then is used by migrating salmon.

Historically, there was quite a bit more natural woody material in our streams in general than there is today that’s been actively removed by people. One thing Natural Systems Design has invested effort over the years is in how to engineer log jams to help restore rivers.

Building infrastructure and rivers that achieves goals for the protection of human-built infrastructure for example, like revetment around highways that are adjacent to streams as one example, but in doing they’re also improving the environment by introducing new woody material habitat for migrating fish and then creating new gravel bars, service boning grounds, and so on. It’s a really inspiring model of a future of engineering in which engineered systems don’t have to necessarily look artificial. They can take advantage of the natural environment, which is what everything else on earth has been doing. I think they’re inspiring.

Dylan: I love it. I will check them out. Last question. Do you have any advice for someone who’s not working in climate change today or climate tech today who wants to do something to help?

Abe: I think that there are so many ways to become involved. It’s truly economy-wide. Sustainability touches every aspect of our climate. No longer is it like you need to be an engineer to create a product that’s somehow related to climate change, like creating a new tour or something like that. It’s absolutely not required. I think the first thing is to recognize that like whatever you do, there is a way that you can get involved. You can become educated simply by learning about the problems. Developing an interest in it is actually probably the first thing.

Just recognizing that you can start with your own personal actions, making decisions in your consumption, the resources in your relationships with people in how you participate in civic processes, I think that’s one of the most important things that we in the United States we have, is our exceptional ability to participate in our governance and effect change that way. That’s something that everyone who can vote can do. There’s no end to the ways that you can become involved in helping with the effort to improve sustainability.

Dylan: Awesome. I love it. Abe, thank you very much. That’s been really fun to talk to you. I’ve learned a lot and I’m inspired about what you’re doing and really excited to see Natel evolve. So thank you so much for your time.Abe: Really appreciate it. Thank you for the opportunity.

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