In this episode, Jennifer Garson of the Department of Energy’s Water Power Technologies Office discusses the state of hydropower in the US and where the industry is headed.
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Text transcript:
David Roberts
For decades, hydropower has been most common source of renewable electricity in the world. (In the US, it was passed by wind a few years ago.) Pumped hydro — large hydropower facilities in which water is pumped up and run down hill to store energy — remains the most common form of energy storage, both in the US and in the world.
Even as the vast majority of media attention in the clean-energy world goes to wind and solar power, hydropower continues churning away in the background, generating and storing vast amounts of renewable energy.
Hydro has a long and storied past, but does it have a future? What's going on with hydropower these days? Is there any prospect of building new dams or of finding more power in existing dams? What's going on with small hydropower, on rivers, streams, and reservoirs? And is ocean energy ever going to be a real thing?
I've taken hydropower for granted for a long time, so I decided it was finally time to dig into these questions. To do so, I contacted Jennifer Garson, head of the Department of Energy’s Water Power Technologies Office (WPTO). The WPTO oversees a sprawling network of prizes and grants meant to encourage hydro and marine energy projects. I talked with Garson about the future of large dams in the US, the promise of small-scale hydro for local communities, and the uncertain future of marine energy.
Alright, with no further ado, Jennifer Garson, welcome to Volts. Thank you so much for coming.
Jennifer Garson
Thank you so much for having me.
David Roberts
Alright, so we normally normally here on Volts, we do the sort of deep dive into one thing. But this here we're going to attempt something slightly different, which is a broad overview of a fairly large category, larger than I think I appreciated before I started digging around and just try to get a sort of global sense of where it's at. Because I know that from my experience in clean energy, I've sort of, like, had hydro in the back of my head as kind of this steady presence, a little bit like nuclear, like a steady presence in the background, but not something where anything kind of dynamic or new is happening. And I think you probably disagree with that.
So let's get into it. So just to start with, what are the technologies encompassed by the terms "hydro" and "marine energy" that your office covers? What is the remit?
Jennifer Garson
Yeah, so glad you asked that. And it is, sort of, just by nature of our office as we're structured that, we have two very interesting, but two very different types of water power technologies. So the first that you mentioned is hydropower. Hydropower really has been delivering power for the last 100 plus years. It's both the conventional hydropower, so very large behind the reservoir, big dams that people usually envision when they're thinking about hydro. We also have smaller non-powered dams that we power with hydropower. We also have run-of-river systems that actually have diversions in addition to dams, where you actually have water flowing to the side of the river. And then we also are thinking about hydropower. Even in conduits and canals, how do you use existing water infrastructure to provide power, whether it's for water treatment or irrigation, a whole number of different ways that you could use existing infrastructure for water power.
Jennifer Garson
On the other side of the portfolio, we have marine renewable energy. So while hydropower is probably the oldest form of renewable power — although potentially, arguably wind is too — marine renewable energy is the most nascent form of renewable energy. And that's really looking out to the power of the ocean. Everything from how do we kinetically capture power, how do we use gradients to capture power. So everything from tidal power, wave power, ocean thermal energy conversion, even salinity gradients and even pressure gradients, really looking at a multitude of ways of when you look out at the ocean and see all the power that's contained in it, how do we use different power capture systems to harness multitude of ways that the ocean generates power?
David Roberts
Got it. So water on land and water at sea ...
Jennifer Garson
Water everywhere.
David Roberts
Water everywhere. So let's start then with big dams, because I think this is when you say hydropower, this is what springs to people's minds as sort of the conventional form. I think conventional wisdom is that we've got a lot of big dams in the US creating a lot of power and it's steady and it's good, but that's more or less it. And so this is my first question. It's just do you think we're going to build any more large dams in the US or large, dam-wise, are we basically tapped out?
Jennifer Garson
So that's a really excellent question. I think there's a general agreement that we are not going to be building. Any large dams on existing waterways. I think in terms of large conventional hydropower, we are most likely tapped out. Particularly here, I should say, in the United States. That isn't necessarily true elsewhere across the world.
David Roberts
Right.
Jennifer Garson
We do think about building other big structures like pump storage, but those have been now leaning more towards what we call closed-loop systems, which are two bodies of water connected, but they're usually constructed and fabricated bodies of water. They're not connected to an existing large river. So I think for the United States, we're not going to see any large behind the reservoir, conventional hydropower, big dams built on any of our riverways anytime soon.
David Roberts
Also on the subject, I've heard conflicting things about the carbon emissions of big dams. I feel like there's been some new research lately that shows that those emissions are higher than we thought. Because you're disrupting a bunch of soil, you're creating a pool where things rot and produce methane. So what's our latest state of thinking on the large dams that exist? Are there large dams that exist that we think are less of a carbon asset than we thought, that we think need to be closed down for environmental reasons?
Jennifer Garson
So I think those are actually two separate questions, one is what is the science behind say, methane or reservoir emissions, particularly given vegetation? We are conducting studies right now at the Department of Energy really trying to understand what types of sensors and measurements are needed to either validate or invalidate that as a theory. I think that there's still unsettled research on the magnitude of the impact, also the timing of the impact. So the other thing that we talk about when thinking about reservoir emissions is, if you're talking about vegetation rot at the bottom of a reservoir for a dam or a facility that's been around for a long time, does it still hold that you have emissions or methane challenges? And I think we still need to do more research on both the kind of temporal nature and the magnitude of the problem. It's not to say that we think there's no problem at all or there's a major problem.
I really think it's a critical research question that we are fundamentally trying to address with kind of true scientific method. On the environmental piece, there's obviously been a lot of both discussions and controversy about dam removal. And I would say even ten years ago, it was not a conversation that the hydropower industry was really actively engaged in or even potentially willing to engage in.
Jennifer Garson
But over the last few years, there's been a really interesting kind of convening between the environmental and the hydropower community actually under ... it's called "The Uncommon Dialogue", it was run by Stanford University that was really trying to get together the environmental and hydropower community to have tough conversations like dam removal, but also dam repair, rehabilitation, and retrofits. And we actually just announced a few weeks ago, through funding that we received under the bipartisan infrastructure law, that DOE is actually going to fund more participation in that uncommon dialogue stakeholder strategy sessions, so that we can really understand where some of the opportunities at both environmental benefits like flood management, temperature control, but also the types of tools and research that we need to understand, "What are some of the environmental implications either of leaving power dams in existence?"
Dam removal isn't necessarily something that we do within DOE, but we do support this kind of ongoing dialogue between the environmental and hydropower community, because ultimately the future of hydropower needs to be one that is sustainable and compatible with both from a climate perspective and from an environmental perspective.
David Roberts
Right. Well, on the flip side of that, my other question is not all large dams in the US are producing power, and the ones that are powered aren't necessarily producing the maximum amount of power they could produce. So how much sort of runway do we have in powering existing dams or upgrading existing hydropower facilities?
Jennifer Garson
Yeah, so there's kind of a couple of pieces in there. One is that there are 90,000 dams in the United States, and only 3% actually have power.
David Roberts
Oh, no kidding.
Jennifer Garson
Yeah.
David Roberts
Is it mainly small versus big is, like, the biggest ones have power and a bunch of smaller ones don't? Or is that not the dividing line?
Jennifer Garson
It really varies. It's not necessarily the big ones do, I mean, you think about some big dams that do have power. I think predominantly you're looking at small to medium-sized dams that aren't currently powered, and many of them were built for other reasons, like flood control, recreation, irrigation, you name it. But still, it's always been incredible to me to kind of dig into those numbers where you think that every dam must have hydro associated with it, and it doesn't.
We've been doing a lot of research, looking at what are the attributes of non-powered dams that we could potentially tap into for power purposes; how do we take advantage of this existing infrastructure and potentially provide power to it? And so, only about the top 600 dams that we have have more than 1 megawatt of potential, but they account for, actually 90% of the total non-powered dam potential. The top hundred largest dams represent about 8 gigawatts, and the top ten represent about 3 gigawatts.
Jennifer Garson
So there is quite a bit of power even within those non-powered dams. And actually, from 2000 to 2020, there were actually 36 non-powered dams that were retrofitted that added about a half a gigawatt of capacity. But then you also talk about, what do we think about for the expansion of the existing hydropower fleet?
Jennifer Garson
We all know that hydropower right now accounts for about six and a half percent of total load nationwide, but the capacity expansion, even at looking at what do we do with the existing hydropower fleet that we have, you could actually have a combined growth of about 13 gigawatts of new hydropower generation capacity through existing plants, adding power to non-powered dams and some new stream reach. We had initial estimates of about 36 gigawatts potential for new pump storage hydro capacity, too.
David Roberts
So there are then potentially gigawatts of new power to be had with dams that are already built?
Jennifer Garson
Yup.
David Roberts
And so why is it that already happening? Is it the economics? What needs to happen to really ... because we need all the clean power we can get, so it seems like this is something we should be pursuing unless there's something stopping us. So what are the barriers to making that happen?
Jennifer Garson
I mean, the answer is it's complicated because it's very dependent upon the site that we're talking about. So it could be that adding existing capacity requires additional capital and if the capital gets too high is there a customer willing to pay for that higher price of electricity? There's also complications, especially for the existing fleet for relicensing. The relicensing process for hydropower is incredibly difficult. It's surmountable, but it is difficult.
It's actually more difficult. We did a study about a year ago looking at the licensing and relicensing process for hydropower, and the number of agencies even involved in hydropower licensing actually exceeds that for nuclear.
David Roberts
Take that, nuclear-whiners.
Jennifer Garson
Exactly. Hydro has got it worse. But even with the challenges for licensing and finding capital, we still think that there's enormous promise by tapping into this existing generation fleet, particularly given the firm flexible, baseload generation power of renewables through hydropower, specifically. We even looked at a study looking at what's the black start capabilities that hydropower currently provides. Right now it's 40% of the black start capabilities is actually provided by hydro.
David Roberts
Interesting.
Jennifer Garson
And whether you're talking about spinning reserves, ancillary services, other grid services, I think we're going to need to both expand what we have in our existing fleet, but also maintain that existing fleet in order to provide the critical services that we need as more renewables come online.
David Roberts
One of the big worries in nuclear is you've got these plants that are up and running and they're scheduled to close, basically. And so there's all this agita about we've got this clean power, we're about to take it off grid. It's crazy. Are any of our big dams scheduled to close or are they more or less like can run forever as long as you maintain them?
Jennifer Garson
Again, it depends. Some are subject to licensing and relicensing. Also half of the hydropower fleet is actually federal, so part of it will stay online as long as the federal government wants to maintain those dams. But the threat of licensing or the threat of not being able to get through the relicensing process for our existing fleet could leave up to about 50% of our fleet in the next ten years is up for relicensing. We don't get that through relicensing. That means we lose a substantial amount of our power if they can't get through the regulatory process. And so we're trying to focus on even things like how do we improve the environmental performance of existing dams? How do you really think creatively about some of the upgrades that could expand some of those grid capabilities? Because if you're going to take a facility that's been online and it's been load following, it's really for keeping the lights on.
Jennifer Garson
How do you change the operational nature of those plants to also provide those grid services without degrading the existing hardware at those facilities? It's a totally new operating environment, one that we can almost take advantage of the relicensing process and do these types of upgrades, but it does mean that we have to get that non federal fleet through the relicensing process in order to keep them online.
David Roberts
This story of excess bureaucracy and paperwork slowing things down pops up ...
Jennifer Garson
Everywhere!
David Roberts
Everyone I talk to.
Jennifer Garson
Yes, sadly, but I will say we've actually seen a lot of interest on the Hill, on Capitol Hill, over the last probably two years, I'd say through a bipartisan nature at thinking about some of the challenges and opportunities in particular on hydropower regulatory reform. Now we again at DOE really just take a sort of analytical approach to understanding what that regulatory process looks like and how it exists. But even last spring there was actually a Hill committee meeting specifically on the regulatory process. It was actually in a follow on a Hill committee staff meeting that was specifically on hydro last January. So I think there's both a recognition that something needs to change and I think potentially some momentum behind trying to really take a hard look at what the hydropower fleet has to go through from a regulatory perspective.
David Roberts
Yeah, I guess it just strikes me it would be a little crazy for us when we're in this mad scramble for clean power and we have this infrastructure, a lot of which is already built, that we could just get a lot more clean power out of that we're not going for it, Gangbusters. final question about large dams, which is one of the things you hear about the future of hydropower is the threat of climate change itself and the threat of droughts and the threat basically of hydro output, which has typically been fairly reliable, becoming more sort of unpredictable and variable and a little bit less reliable. Is that something you think about a lot?
Jennifer Garson
So actually last year we conducted a really comprehensive look at the effects of drought on hydropower generation in the United States. So we did a couple of different analyses, but I'll touch on this one first. Drought obviously can and has impacted hydropower in the west, but if you actually look at it from a fleet wide perspective, the Western hydropower fleet still sustained 80% of its average generation during the worst drought this century. Now, that was a lot of times reliant on what you had as storage behind the reservoir and so we are doing a second order analysis to say what happens when you have less reservoir ability to really do an overall assessment. But there are so many smaller subregions in the west that still they don't typically always have drought super decentralized. It's usually essentialized in certain areas. So it is certainly a threat and we have a lot of work, I think, that we've been doing it. How do we look at from a forecasting perspective, not just looking at hind-cast models, don't use past as precedents, also look to the future for future climactic modeling and how do we begin to plan from both a climate resiliency perspective?
Jennifer Garson
What are the localized impacts going to be on individual sites? But when you look at it from a fleetwide perspective thus far, we actually haven't seen that much of a decline in power production across the west. That's because sometimes where we have more acute drought in some regions, we might have an abundance of water in others. If you take a look at even California, whether it's through the impact of atmospheric rivers or a historic snow pack.
David Roberts
The snowpack they've got now historic highs. Is there going to be an abundance of hydropower next year?
Jennifer Garson
It certainly could help make sure that there is a reliable amount of water to help sustain hydropower production. There's a lot of hydropower in California, but I think we still have more work to be done on both what's the forecasting and looking at snowpack melt and what it's going to mean for a next season's. Hydropower availability and how do we plan not just on a year to year basis, but over a longer period of time? So we're committing a lot of resources towards this hydrologic and climate science analysis. We also just did the most comprehensive assessment through Oak Ridge National Laboratory, it's called. And this is because of the Secure Water Act, the 9505 assessment, which really looked at an analysis of hydropower generation affected by long term climate change, specifically at the Power Marketing Administration.
Jennifer Garson
And our most recent report, which we actually just published last year, is that long term average runoff and hydropower generation are actually projected to slightly increase across the continental US, but some summer runoff is projected to decrease by the mid 21st century. So you're talking about seasonal change and so that will require us to think about storage in different ways when we can rely on hydropower. Do you shift the kind of seasonal expectation of it really fitting summer loads and potentially more in spring or even winter loads? But maintaining that flexibility and operation is going to be a key challenge, whether it's because of projected seasonal availability or just water management strategies or just the fact that when you look at it from a purely sort of quantitative perspective, our ability to know where water goes is not nearly as sophisticated right now as where electricity goes.
Like, our sensors and measurements are so far behind that which you see in the electricity sector that we feel like there's a lot of opportunity to increase sensors, monitoring and models to be incorporated into hydropower forecasting so that we have more predictability and a better understanding of just how climate change is going to impact hydropower availability. It's not to say that it's going to be easy, it's just it's more complicated than what you would imagine just looking at pictures of drought in the west.
David Roberts
So let's talk about then smaller scale hydro on rivers, streams, canals, conduits, smaller forms of river. I've heard about these sort of in the background for many, many years. As far as I can tell, it hasn't really amounted to much. And just like intuitively, when I think about building like a little dam or a little generator just for the amount of power that's coming through a stream or a river, it sounds like a lot of infrastructure for a small amount of power. So I wonder about the economics. So maybe you just tell us what is the deal with small scale hydro?
Is it a real thing? Is it growing or shrinking? Is there a lot of potential there? What do we know about it?
Jennifer Garson
Sure, I want to just set a little bit of context.
Jennifer Garson
When we talk about small hydropower, we're talking about anything between as small as 100 kilowatts, all the way up to 10 megawatts.
David Roberts
Got it.
Jennifer Garson
And, we do have this picture that large-scale hydropower is really the predominant form of power. But actually, 72% of our hydropower fleet — it's almost 1,700 plants out of the almost 2,300 total plants — produce less than 10 megawatts apiece. So even though it may be more obvious that we think about hydropower as large, it's actually almost 3.65 gigawatts of hydropower capacity is actually small.
And I think that when you think about these small hydropower facilities, a lot of times they're in places that it's serving a local load or it's serving a direct facility. And so, to me, I think the value of these smaller facilities is how they're providing power to local customers. Many of them are owned even by what you would consider more like mom and pop hydropower operators. But also when we think about the potential for non-powered dam development — so we talked a little bit earlier about, "Are the big non-powered dams big or are they small?" — 71% of the potential for non-powered dam development is actually in small dams with small reservoirs. So it may not be a simple form of power capture, but there really is a lot of potential untapped through non-powered dams.
And then you talked a little bit about run-of-river. The run-of-river potential is also there. We have been talking to different communities that are considering run-of-river systems for power. And a lot of times soon we're thinking about some of these small power dams. We get approached a lot by say, communities in Alaska where they're looking at what are their power potential in places where they're not going to be able to harness solar on a year-long perspective or be able to potentially get wind reliably. And so some of these small hydropower facilities in more kind of remote and isolated areas could provide really meaningful power to places that may not have another form of renewable energy accessible to decarbonize their systems. And to me, that's just as meaningful as adding big, huge gigawatts everywhere.
Jennifer Garson
We need to add big, huge gigawatts everywhere of renewables. But I think the potential for some of these smaller hydropower facilities could be incredibly meaningful. We also even just did an assessment last year, looking at underserved and distressed communities in the Appalachia region, where could you power non-power dams and add different forms of storage to provide almost essentially quality-base load power. And there were quite a few sites where you could provide reliable, relatively cheap power for these communities.
Jennifer Garson
Now, when it comes to the economics, it is more expensive when you look at it from a per megawatt basis. But when I think about the critical value of having hydropower serve, essentially, around the clock, I think this is where we think about decarbonizing everything from the electricity sector. We're going to have to have a higher willingness to pay for firm, flexible power.
I think, when we're thinking about the economics of small scale hydropower, we think about it in a couple of different ways. One is, what is that power going to provide at that small scale? When you're thinking about it as a firm baseload power, is it providing power to places that might not have otherwise access to renewable electricity or a clean grid? Is it in combination to with, say, a solar array and storage? We've seen a couple of small hydropower developers who are looking at it as almost like a mini micro-grid with hydro as the small baseload power. And so rather than it just being the project economics is just the hydropower facility itself, thinking about it from a project perspective: hydro with storage plus solar. And how do you think about it within that overall kind of portfolio context and not just the facility itself? That being said, funding these types of projects is not easy, whether it's because of the licensing or relicensing process or because of the high capital costs.
David Roberts
Is that a hassle for small run-of-river stuff too, the licensing stuff?
Jennifer Garson
Sure, you still need a license to operate. There are some exceptions, but you typically still need to get a license from FERC. But they have been trying especially for non-power dams and closed lip pump storage. FERC has been trying to have an accelerated permitting for these types of facilities. So the new stream reach, which is where there's no dam, that's a little bit more complicated, but for powering non-powered dams, FERC and other partners have recognized that there's already essentially been disruption to the local ecosystem. So you're not talking about a complete new build, you're talking about adding infrastructure to existing infrastructure.
But it also depends on who the owner of the dam is. A lot of developers are actually looking at powering non-powered dams that are owned by the Army Corps or the Bureau of Reclamation, trying to take advantage of existing infrastructure that's already been built by the federal government and add power. And there are a number of developers that are trying to think about developing these non-power dams through a portfolio of different non-power dams. So rather than treating it as a kind of one off project, how do they do kind of feasibility analysis, looking at a number of different non-power dams of power and treating it more like a portfolio package of power.
And that is different from the way that we've traditionally financed non-powered dams. I still think we have a way to go, and we're actually about to set out on a study with the National Renewable Energy Laboratory and Deloitte to really look at the investment landscape in hydropower. Because ever since I've been in this space, I've always heard that investment in hydropower is really hard. But when you start asking the second order question of why, you kind of get a jumbled answer of, "It's the licensing, it's the customers, it's the PPA."
So we're really trying to put a lot of rigor behind, "How do we get more momentum into developing non-powered dams? How do we try to increase the investment appetite to looking at these types of facilities and facility buildouts, whether it's expanding existing capacity at hydropower facilities or small hydropower through non-powered dams, to really fill that gap that we see 10-20 years down the line of the need for firm, flexible power resources." So I think we're in the midst of a changing investment landscape, too, about how do you value firm power?
David Roberts
Right. So it's fair to say then, when it comes to the smaller hydro on rivers and such, it's not so much the raw sort of like dollar per megawatt where you find the value. It's more in the firmness, right, which we don't fully value yet, but will, I think, soon. And the local benefits, local resilience and stuff like that.
Jennifer Garson
Yeah. And even so, we just did a demonstration last year in Idaho Falls, the Idaho Falls Power, and they were looking at how do they optimize their smaller run of river hydropower systems and tried to see whether or not adding some sort of storage medium. Ultimately, it was super capacitors. But if they add a storage medium to those smaller facilities, can they actually provide black start capabilities for their local community, recognizing that they're tied into a larger grid? And if the larger grid goes down, they don't want to lose access to the electricity they need for critical services.
Jennifer Garson
And so it's thinking about, too, in the context of some of these smaller projects, can you use them to help jumpstart the grid or provide more consistent power or provide a more predictable load for electricity consumption? But I still think it is still higher on a project economics of $70 a megawatt, roughly. But what we're trying to really dig into is what is the value inherent between, say, the $20 per megawatt you would see for solar and the 70 for hydro? Are there enough services and economics behind that higher threshold to really kind of catalyze investment into that space?
How do you provide that investment theory that shows why it's really important that some power you're going to have to pay more for?
David Roberts
There's probably a ton more to talk about there, but we have other things to hit, one of which is storage. I think Volts listeners are probably savvy enough at this point to know that the vast, vast bulk of existing energy storage is in the form of what's called pumped hydro storage, which is basically just you pump water uphill when you have power, and then when you need power, you run the water downhill through generators. Pretty simple. This is how we do most of our energy storage today. So one of the things that people say about pumped hydro is that it is geography dependent.
You have to find the right body of water in the right place with the right whatevers. So I'm curious, have we built out the sort of traditional pumped hydro that is possible or is there more room sort of same question about the large dams. Is there more room to build new pumped hydro and is there more room to get more capacity out of existing pumped hydro facilities? I know we have this new technology that's closed-loop pump hydro, which we'll talk about in a second. But just in terms of the traditional kind, is that tapped out or is there more to be had there?
Jennifer Garson
Yeah, put it in order of magnitude. About 93% of the long duration storage or even just storage capabilities. Right now on the grid is pump storage. And that's actually just from 43 pump storage plants.
David Roberts
They're very big.
Jennifer Garson
They're very big. They were actually originally built to complement nuclear.
David Roberts
Interesting.
Jennifer Garson
Yeah. So now we're thinking about what's going to complement next or continue to complement nuclear. But when you think about even the potential in our existing fleet, between 2010 and 2019, we added 1.3 gigawatts of PSH capacity just at the existing facilities that we already have online.
David Roberts
Interesting. That's a lot.
Jennifer Garson
It's almost the same amount as all other energy storage types combined that were added at that period of time. Yeah. So just making these capacity upgrades is huge.
David Roberts
How do you add capacity? Is it bigger pipes, bigger pumps? Is there any magic to that?
Jennifer Garson
Bigger pumps, different turbines, different upgrades to better not impede flow, even management practices utilizing it more. So even some of our storage facilities aren't necessarily utilized to their full capacity. And so you usually either need better control systems or kind of control strategies or equipment upgrades or environmental upgrades. There's a multitude of different upgrades that can happen to add capacity at our pump storage facilities.
David Roberts
And that's ongoing. There's still more. There's more to be had there.
Jennifer Garson
There definitely is more to be had. But I actually also want to point out we have typically thought of pump storage as these big open-loop systems. So you mentioned closed-loop. All of our facilities right now are open-loop, which means they're connected to existing waterways and rivers. So if you looked at where are we going to have big diversions from big existing waterways to other storage medium to other reservoirs, that's probably more limited. But we actually just did a whole assessment on pump storage resource characterization and resource assessment here in the US and found there's actually 15,000 additional sites for pump storage development.
David Roberts
Oh, good grief. And that's the open-loop kind you're talking about.
Jennifer Garson
That's closed-loop, actually, specifically. Closed-loop, there are more than 15,000 sites that you could actually have for additional facilities to be brought online. And there are some major closed-loop facilities that are getting pretty close in the regulatory process, and we've actually been working with some of those sites through our pump storage valuation project where we were looking at what's the cost benefit analysis and return for these different types of closed-loop systems.
David Roberts
Explain what a closed-loop system is just so people get it.
Jennifer Garson
It's basically very simple mechanical energy. You have an upper reservoir, so basically an upper ground tank, for lack of a better term. It could be at the top of a mountain, it could be at the top of a hill, but you need some sort of head so it can run down. But you have a top reservoir and a bottom reservoir and basically pipes that connect between the two. And when you have excess electricity, electricity pumps the water from the lower reservoir up to the upper reservoir. And when you need that power, you run that water right back through the turbines to go back down to the lower reservoir. So it's just basically mechanical movement of water between two bodies of water.
David Roberts
And so if you can create your own reservoirs, then all you really need, geographically, is a hill.
Jennifer Garson
Correct.
David Roberts
And there are lots of hills.
Jennifer Garson
We got a lot of hills.
David Roberts
What about underground? I feel like I've seen this bandied about where you just dig a hole and sort of use the surface of the earth as your upper reservoir and the hole as your lower reservoir. Is that a thing?
Jennifer Garson
Yeah. We've been working with a couple of different companies that are looking at underground reservoirs. There are ideas, everything from utilizing old mines, which there's some worry about from a geotechnical perspective. Will you actually have enough stability to have an upper reservoir and then the lower reservoir in the mine? But there is potential. But then there are companies like Quidnet who is essentially injecting water underground and using it to come back up and spin through a turbine for more modular underground pump storage. So I think there's definitely opportunity both above and below the ground. It just all really depends on sort of the geotechnical feasibility, site availability and just what are you going to get from round trip efficiency for different types of power?
David Roberts
Well, this closed-loop pump storage seems like a huge opportunity. Do we know, I mean, if there isn't any built yet, do we know what its economics are going to be relative to other storage possibilities?
Jennifer Garson
Yes, we know the economics pretty well. I mean, obviously the economics has changed as with every other storage technology out there with the inflation reduction act passage. But we have done a lot on sort of valuation from a per megawatt perspective. How much would you pay for these newer closed-loop pump storage facilities? The biggest challenge with anything pump storage-related is the high capital cost at the beginning of a project. And so where some of the project economics get a little more complicated is: are you looking at a ten-year payback period for storage or are you looking at it from ... some of these assets can last 100 years.
Like what's the appetite when thinking about entering into a PPA or building out a project? And there's also the complication — and this is similar to other forms of storage: Are you generation or are you transmission? Are you deferral or are you providing that power? How does your power count essentially within a PPA? The other challenge is too is oftentimes when we're looking at some of these bigger closed-loop pump storage systems, you're building them to complement renewables that haven't come online yet. So how do you also enter into types of contracts?
You're like, "Hey, we want to build this facility because there's going to be a ton of wind and solar." And if there isn't a ton of wind and solar, it's like, well, we actually need that storage. So you run into this chicken and egg scenario. What do you build first? A big closed-loop pump storage facility that's going to take seven to ten years to commission? Do you wait for the intermittent renewables to come online to a point where you need the storage? Or do you really start to look now at thinking about what does your grid look like in ten years and take a more long-term capital risk to build out some of these larger things?
David Roberts
Weird planning for the future. What a thought. When we think about the potential, if there are 15, what did you say ... ?
Jennifer Garson
15,000.
David Roberts
... sites where closed-loop pumped hydro could work, then do we know what sort of capacity that represents? I mean, that's a lot of storage.
Jennifer Garson
It's a lot, a lot, a lot, a lot of gigawatts. Now that's the site feasibility. The practical feasibility of how much could we actually develop is something that we're analyzing right now because it was only just last year that we decided to kind of reopen the book on, okay, let's not just thinking about it from where we see site developers coming in and applying FERC permits, FERC licenses, where others are really trying to determine where the best sites are suited. Let's use an analytical perspective to say, where, from a geographical perspective, could you feasibly build closed-loop pump storage?
But we're working on a second order analysis to kind of scrub, what does it look like from a total, not just technical feasibility, but practical feasibility of how much pump storage we could add? Because we don't want to say that it's going to be thousands of gigawatts without really having some analysis behind it. But we are really looking at this through both a hydrofuture study and a pump storage study that we'll have going pretty soon to look at that total, feasible storage that we can actually capture through closed-loop pump storage.
David Roberts
Because you hear all these talks about long duration storage, all this buzz, people are banding about all kinds of wacky technologies and possibilities, but you just don't hear pumped-hydro mentioned a lot in those discussions.
Jennifer Garson
I think ...
David Roberts
Need better PR.
Jennifer Garson
We do need better PR. We need better PR and all forms of water power technologies — no offense to the technologies I care about a whole lot. But no, you're right. A lot of times we're talking about long-duration storage technologies that are still kind of bench-scale prototypes. And it's things that I fundamentally believe in. But I actually, before I was in the waterpower office, spent a majority of my career in DOE on commercialization, and I've seen how long it takes for products to get from a lab prototype to bench scale to first of a pilot to actual commercializable technologies.
And my concern is if we bank all of our long-duration storage needs on technologies that are still at that pilot or commercial demo scale, we may run into kind of a tipping point on the grid where we really need what works now. But I do think that there has been more momentum both here and abroad looking at pump storage as a practical solution. And even Secretary Granholm has expressed interest in pump storage. The Loan Guarantee office is also looking at pump storage. So I do think they're slowly but surely gaining more momentum at the potential feasibility for pump storage.
We're even working now with the Tennessee Valley Authority actually looking at pump storage. Duke is looking at pump storage. I just talked to someone in Pennsylvania, in the governor's office, that's also looking at pump storage. So I think as people are looking at the practicalities of the grid, 10 to 15 years out, if we really are going to scale wind and solar, we need to start planning for storage facilities now. And the reality is that closed-loop pump storage can work. You do have high capital costs. There are geotechnical concerns, but we know that it works because it's a water battery.
You're pushing water up the hill to let it come back down. We know how to do that.
David Roberts
Very simple.
Jennifer Garson
We've been doing that a long time.
David Roberts
Final question about water as storage, which is just, and this might be kind of a naive or a silly question, but it just seems like in the future, one of the things you're constantly hearing about is water is going to become more scarce. Basically, there's a lot of competing demands for water, and climate change is messing up a lot of our sort of seasonal water provision and just there's going to be water wars, et cetera, et cetera, et cetera. So I'm just wondering, is that something you worry about, using water for this versus using water for other things? Do you think water itself is going to become sort of contested and difficult to get your hands on?
Jennifer Garson
I mean, I think clean potable water is a challenge that we are definitely going to face as a country and as a world. I mean, as a country, we're actually pretty privileged to have pretty abundant freshwater resources. Now, whether or not those would be clean enough to drink I think is a key outstanding question. But in places like the Pacific Northwest and New England and even the Midwest, water availability isn't necessarily the top concern.
Is it in the West? Yes. We actually wonder sometimes, or have been analyzing the potential for almost water abundance in areas where we don't want to have too much water because of flooding concerns or extreme events. So there's the kind of flip side of that, is it's not just about lack of water availability. Are we also building out infrastructure that can withstand higher forces of water, particularly through rivers and streams and waterways? But if you're looking at things like closed-loop pump storage, you're not going to have a ton of evaporative loss. So when you have these storage facilities, you're not really competing for fresh water availability.
You're just trying to keep the reservoirs filled. And that is very different than trying to have the water needs for, say, fossil fuel plants or even nuclear, which have pretty high intensity water needs. But on fresh water availability, that's something that on the marine side of our portfolio that we think about as a potential for wave power to actually address, is the delivery of potable water. Because I do worry a lot about our ability to provide continuous fresh potable water for not just here in the United States, but abroad.
David Roberts
Right. Well, you've set up my segue perfectly then. So let's talk about the other side of your portfolio, which is energy in the ocean and how to get it out of the ocean. This is another area where I feel like it gives me like cellulosic biofuels vibes in that there's like super exciting ten years out and then was like super exciting ten years out 20 years ago and still super exciting ten years out. Is there —
Jennifer Garson
It's like fusion! No.
David Roberts
Not that bad. Come on now. Not that bad. I'm wondering, is there reason to think that any of these ocean technologies are any closer than they were ten years ago? Is this a real thing? And maybe just also, while you're at it, tell us, what are those technologies? I know there's tidal. I know there's something with buoys going up and down. There are probably others. What are we talking about in the ocean? And is it real? Is it really going to happen?
Jennifer Garson
I think I wouldn't be directing a program for marine renewable energy. If I didn't think it was real, I'd probably try to find myself another job. No, the second question you actually asked is what are we talking about in terms of marine energy? And so the biggest sort of marine energy capture that we concentrate on are waves, tides, and then river and ocean currents. So the big buoys that falls into sort of the wave category, you can have everything from bottom mounted flaps that are trying to capture wave power to surface riding systems to systems that are within the water column.
So the complication with waves, there really hasn't been a kind of convergence on the right structure or even where in the water column is most optimal for a power capture system. But I would say unlike even ten years ago where wave energy, you had a couple of projects that were out in Europe, we now are seeing an increasing number of in water deployments of wave energy systems, and it's working. So I would say here in the United States, we just had the longest wave energy demonstration project off of the Scripps Pier in California with Calwave, where they were producing electricity using the power of waves. And they even were able to sustain through a pretty powerful storm surge because that's always really complicated matter for waves, is being able to withstand a range of different forces.
David Roberts
Right. Well, this is what comes to mind. Intuitively, out in the ocean is just a brutal place. You got the wind and the tides and the storms, but also just saltwater corrosion and I don't know, fish. There's so many things to deal with. Are they being dealt with?
Jennifer Garson
I think this isn't the first time we've dealt with infrastructure in the ocean either.
David Roberts
Right.
Jennifer Garson
It's hard, but it's not insurmountable. We're talking about materials for corrosion. We're doing research and even looking at can you use different methods to reduce corrosion impacts? Everything from coatings and materials to even the use of lasers for different etchings into materials to reduce corrosion? Biofouling is an issue. I mean, there's a lot of stuff that grows on infrastructure that's in the ocean, but we're trying to work on a multitude of ways for us to address or even potentially embrace biofouling from an environmental perspective. We do a lot in environmental monitoring around these devices. We put a substantial amount of funding on trying to understand the interaction of mammals, fish species, both from an acoustics perspective to any sort of entanglement perspective.
And thus far, with our in water deployments, we're actually seeing compatibility instead of conflict. From an environmental perspective, that's because we're trying to design these systems with the environment in mind. But it is a hard environment. But the thing is, waves, tides, they're more predictable than other forms of electricity. So if we're really trying to hit our 100% decarbonization goals in 2050 or beyond, we're going to need solutions like marine energy in order to actually hit those targets.
David Roberts
Tides come in every day.
Jennifer Garson
Tides come in every day. And actually on the West Coast, waves are predictable because you're talking about predicting waves that are coming basically from Asia. We have waves. I'm serious. It's why actually wave energy is almost easier on the west coast of Europe as it is sort of the West Coast or here for the United States because we have pretty complex models that actually can give us forecast for what our wave conditions are going to be like. So it gives us some good sense of predictability. Tides definitely 100% predictable. Unless the moon changes, which who knows?
David Roberts
Who knows? What does tidal energy look like? What do those machines look like?
Jennifer Garson
So there are a couple of different types of device designs right now in tidal energy. You're seeing more of a convergence on what tidal energy systems might or could look like, particularly looking both in the US and out in the EU. Some of them, like Verdant Power, which we supported a demonstration in New York, would look familiar to any of your listeners. It looks almost like tiny wind turbines on a triblade that goes underneath the water. So it's using the same kind of findings from wind of running a turbine, generating electricity, providing it to shore. There are other systems that are surface riding.
So there are some European companies and Canadian companies that essentially have the operations and maintenance basically on the surface and then have turbines that go and submerge underneath the water, but they're still running either two or three blade turbines to capture power. So it's taking a lot of the lessons that were already learned in the wind industry and applying it for tidal power. And tidal power, I mean, we believe it a lot for here in the United States. Is it the largest resource to capture? No, that's wave. But there's a lot of tidal energy in New England, in the Pacific Northwest, and in particular in Alaska, where the potential resource is pretty massive.
So actually we are in the next coming weeks, we have a notice of intent out already on this, but we're going to be funding a $45 million solicitation focused on tidal energy here in the United States. So both a commercial site with about $35 million and also for remote and islanded communities, and isolated communities another 10 million. So I think the the maturity of the tidal industry is definitely more mature right now than wave, but I think wave is starting to catch up. But if you look over at Europe again, they've had gigawatt hours of power provided by tidal energy at some of these sites that have already been delivered to the grid.
So it may not always be as visible. Maybe it's because it's underneath the ocean or just on top of the ocean, but there's a lot of technological progress that we see in tidal and I see in the very near term for wave.
David Roberts
And this is in financial terms the same challenge basically you're facing with all these other technologies we're talking about, which is high upfront capital costs and then that pay off over a very long period of time, which is just always a difficulty when you're talking about financing.
Jennifer Garson
It is. And one of the challenges, too, for marine energy, and it's similar, I would say, to newer geothermal energy or long-duration storage, is in order to prove that it works, you have to be willing to fund some pretty serious demonstrations. And that takes a lot of capital that oftentimes, say, venture or even philanthropic capital isn't necessarily willing to take a risk on. Because to prove that the marine energy works, you have to get it in the ocean. And putting things in the ocean is a non-insubstantial cost. And so we're really trying to think about how do we demonstrate these systems take a lot of the risk and ownership on the US federal government in a way that we think will ultimately pay off. But that willingness to pay for demos or demonstrations of arrays is still going to be pretty high until you get to economies at scale.
And so we either have to bet big, which I really hope we do here in the US, or we leave potentially this enormous 57% of all US power generation potential in the US stranded because you don't have that willingness to pay for these really expensive demos. But those demos are the only way we learn.
David Roberts
Didn't we just pass a bunch of legislation that is basically fire hosing money at all these things? Is some of that money going to do what you're just talking about going to kind of kickstart marine and tidal?
Jennifer Garson
So in the bipartisan infrastructure law, we did receive about $110 billion for marine renewable energy, $40 of that is for our national marine energy centers and the other $70.4 was actually for marine energy. But if you look at that in comparison to say, the funding that we're putting into direct air capture or hydrogen, it's nowhere near the level of investment that we've received from the federal government. And it's not just ... for us, I think we've seen the same thing for sustainable aviation fuel demonstrations or geothermal demonstrations, like, I think there are still a number of technologies that's going to take a lot of capital in order to really demonstrate the feasibility and get to economies at scale that weren't necessarily funded with the enormous lug of funding that we got now. There's a lot of money going around, and it's very exciting for me as someone who's been at DOE for 13 years, but it's not going to be sufficient, I think, for really driving down the cost of the whole portfolio of solutions that we're going to need to decarbonize everything by 2050.
David Roberts
Well, and the loan office plays some role there and there's supposedly going to be a green bank did that end up making it in? I forget what ... I think the Green Bank made it in. So maybe there'll be some ongoing sources for some of this funding.
Jennifer Garson
Totally agree. And we work with our Loan Guarantee Office partners to understand what are those pathways into kind of commercial viability that. And we are also working with the Office of Clean Energy Demonstrations to understand what's the role of the Water Power Office at Derisking. Some of these pilot technologies moving into an office like the demonstration office and eventually being well primed for the Loan Guarantee Program office, because LPO really wants to see that these technologies have been successful at a pre-commercial scale. But even that gap between pilot and pre-commercial scale for some of these energy systems is more complex than just one off projects.
But we're thinking about it critically at having kind of an all of DOE approach to derisking and investing in these technologies and ultimately helping them scale.
David Roberts
The one marine technology we didn't mention is ocean thermal something something.
Jennifer Garson
OTEC is the acronym. It's Ocean Thermal Energy Conversion.
Jennifer Garson
Yes.
David Roberts
Right. I feel like I've been hearing that about that also for years and years and years and it never seems to amount to much. Is that going to, well, first of all, tell listeners what the heck we're talking about, but is that going to be a thing?
Jennifer Garson
So OTEC, for anybody who isn't as familiar with all forms of marine energy, is basically using the thermal differentiation between the warmer surface water and the deep sea cool water to, essentially, use that to harness power, without getting into more technical details.
OTEC is also really hard. The round-trip efficiencies that we've seen for OTEC have been not awesome, but there are a number of sites that are looking at both. How do we potentially use seawater air cooling, so more like ambient temperatures instead of for power generation. There are some OTEC facilities too, particularly in the Pacific Islands. It is so geographically specific for OTEC feasibility. You really need to have a pretty quick drop off of the continental shelf in order to actually have that really cold deep water and warm surface water. So it's geographically constrained. The round-trip efficiency right now still needs a lot of work and similar to the story of other types of marine energy in order to do demos, it takes a lot of capital.
But I know that there are developers looking in like Puerto Rico and Hawaii looking at the feasibility of OTEC. So I wouldn't discount it. It's just it faces some of the same challenges. But we've also been looking at even, can you lessen the amount of gradients that you need to think about Ocean Thermal Energy Capture? So we're actually working with a startup that is trying to use smaller gradients to power ocean observing systems. So if it can power it by essentially dropping the system down not that far, and using the same principle of warm to low generating power, maybe we can think about gradients in a different way, to not just be the really big, really deep pipes that are trying to run from the surface down to the deep ocean.
David Roberts
One more thing about marine energy. Tell us what is the connection between marine energy and desalination? Or what is the, let's say, the hoped for connection between marine energy and desalination? Because I often hear them kind of discussed in the same breath.
Jennifer Garson
So over the last few years, we've really been looking at the potential for how would wave energy provide potable water. It started actually with analysis that we did at the National Renewable Energy Lab, looking at the feasibility from a power perspective. Does the power performance potential for waves, is it potentially compatible with reverse osmosis or for desalination processes? And interestingly enough, we found that it could actually be a good power source. So we actually developed a prize competition called waves to water prize, where we basically opened the aperture to say, there's only a limited number of ideas here.
Can you bring us some really good ideas for wave power desalination, but starting small for things like disaster relief and recovery scenarios? Ultimately, over the course of three years, we developed systems that were both hydraulic, so kind of mechanically driven, and production of electricity to run RO systems. And what we saw through that prize, and now a subsequent $10 million solicitation that we're running right now, is there are a number of really promising solutions that, particularly on the hydraulic side, although some of the electricity, but using essentially the power of waves to run through membranes to desalinate water.
David Roberts
I have a super dumb question here, which is I'm picturing these wave machines out in the middle of the ocean. Are they producing clean water like on-site? Do you have to go harvest the water from the machine? How does the delivery of the water from the machine to where it's needed work?
Jennifer Garson
Great question. The answer right now is maybe both. I think it's more feasible to imagine that essentially the reverse osmosis system is running. You're basically pumping water back to an onshore reverse osmosis system in a high pressure pump. And so you're getting the fresh water at a tank act, actually at a pier or on the shore. So you're essentially just using piping systems so that the water delivery is onshore. There are some companies that are thinking about almost like bladders to be filled out for production in the more near shore. You're not looking at right now, like, really deep offshore, but could you collect water through these bladders, have some sort of collection methodology, and bring it back to shore?
So I think we're both looking at kind of on device production and essentially the system just being a conduit for either that power mechanical force to run a reverse osmosis system onshore. We're hopefully going to see over the next couple of years we're going to be funding a number of demos and we're seeing a number of demos also pop up in Europe in particular at looking at wave power decal. But I think we're going to need solutions for desalination that doesn't just require either really big, large energy systems or only diesel generators because we're going to need fresh water everywhere.
And we're trying to think about the simplicity of design of some of these systems so that you can essentially just throw them out in the water with an anchor and be able to provide potable fresh water.
David Roberts
That would be nice.
Jennifer Garson
It'd be awesome. Yeah, use the water to make water. What could be more simple but elegant if we can make it work?
David Roberts
So on marine energy, then, as you said at the beginning, this is unlike hydro. Marine is in a sense among the newest or nascent or sort of cutting edge versions of renewable energy. So I guess before we leave this subject, I'm just curious, the next decade in marine energy, do you expect it to reach meaningful scale in that decade or is the next decade mainly going to be about figuring it out? Sort of like where do you expect marine energy to be in ten years?
Jennifer Garson
It's a complex answer I think when you're talking about grid scale marine energy devices. I think it'll take us the next ten years to really figure it out, get these systems in and out of the water and really producing larger volumes of electricity. But what I think the next decade really holds, it's really interesting, is the possibility of marine energy powering. What maybe from an energy perspective seems less meaningful, but from an end use perspective is incredibly meaningful. And what do I mean by that? I think we're seeing a lot of interesting solutions for powering, things like ocean observing.
We know more about the surface of Mars than we do about the surface of our ocean floor and part of that is because of power limitations. And so we're working on a number of different companies that are either using kind of fixed platforms or floating platforms to provide power where we need it and that's to both understand and observe our ocean.
David Roberts
Interesting.
Jennifer Garson
And I think over the next ten years you're going to see a lot of different devices that are harnessing power for ocean observing. There's also been a lot of meaningful progress at sort of the micro-grid scale for marine energy, whether it's tidal or it's wave energy, where we actually have a device up in a community of only 75 people in Alaska and Igiugig that's producing power to their grid right now. And I think we're going to see more of these small scale devices in places where power is incredibly meaningful. Even if it doesn't sound like a lot from a megawatt or gigawatt perspective.
David Roberts
There's sort of bulk energy. Like we just need a lot of energy. But then there's also these, as you say, these local sort of resilience benefits and these benefits specifically to a lot of vulnerable communities. Maybe just say a little bit more about that sort of how you envision hydro working. Maybe not at a large energy scale, but in some of these, but like in this community in Alaska, that's quite significant for them to have steady power. So talk about that a little bit.
Jennifer Garson
I think it's a story for both hydropower and marine renewable energy that there are parts of our United States and parts of the world that they need to look to their waters in order to actually provide power, whether that's because of the seasonality or available resources. And we've been working with a number of communities, actually through a program called our Energy Transitions Initiative Partnership Project, where rather than say, here's a solution that you should have, maybe it's marine or hydro, but working with these communities to say what are your power and energy needs? And what are the types of systems that can get you to 100% renewables and off diesel dependency? And many communities that we're working with in Maine, the Pacific Northwest and Alaska in particular are looking at marine energy and small hydro as their pathways to releasing dependency from diesel generators or from really high cost other forms of energy.
And even though these are kilowatts or megawatts, it's huge.
David Roberts
Yeah, just to sort of put an exclamation point on that, you're talking about the sort of economics overall. But if you look at the economics specifically in these local situations, like diesel is gross, it's very expensive, it pollutes like crazy.
Jennifer Garson
Not only that, it's the cost, right? And right now, the last couple of years, the price vulnerability of some of our more vulnerable communities in the United States are so impacted by diesel going up to prices that are literally unprecedented. And if you're a small community, how do you absorb that?
David Roberts
Yeah, getting steady, predictable, just the predictableness of it, the predictable price of it. It's hard to put a value on that. That's very valuable in these local contexts.
Jennifer Garson
It is. And because if you are already paying a dollar, $52 a kilowatt hour, even if we're developing solutions that come in at say, 50-60 cents a kilowatt hour, that's still a substantial price savings, more predictable power and we have better health outcomes, better localized impacts. And so we take that really seriously and view it as a kind of core objective for our program, is that we really want to think about ways that we derust these technologies to give better pathways to getting off of diesel and providing more predictable power. And so when I think about the impacts in the near term, particularly on marine energy, this is one area where I think we do have the potential to make a real material impact on people's lives if we can really do wit these technologies and design them with the communities as partners and with them in mind.
David Roberts
Right, okay, well, I've kept you too long. This is all fascinating. I'm sure we could do an hour long pod on any one of these issues or topics or technologies. So by way of wrapping up, final question then. When you look ahead, you're sitting in sort of a unique place where you have a view of all these water related energy technologies over the next decade, let's say through 2030 or 2035, which is a very crucial, as you well know, a very crucial period for decarbonization. What do you think are going to be the big water power stories? Like, some of these are nascent, they're going to be developing. What do you think are going to be sort of the breakout significant stories in water power? If you had to pick a favorite one of your babies?
Jennifer Garson
Oh, you can't make me pick a favorite one. I'm going to give you a couple and break your rule. I think it's going to be the increasing importance of the role of the existing hydropower fleet in an overall grid context at really maintaining grid stability. I think we're going to see a first pump storage project, at least one break ground and start serving the grid in a way that we really need it to. And I think we are going to see a number of communities with small marine energy systems that are providing incredible, meaningful power. That's going to demonstrate the criticality of us thinking about this decarbonization at literally all scales that we need to solve everything from watts all the way through gigawatts.
But I think the backbone of the existing fleet pump storage and the criticality of small microgrid systems for places that may not have other options, where this is really well suited, are the things that I'm really excited about in the next decade.
David Roberts
Awesome. Well, Jen Garson of DOE, thank you so much for coming on. This has been hugely educational. I really appreciate it.
Jennifer Garson
Of course. Well, thank you for having me on.
David Roberts
Thank you for listening to the Volts podcast. It is ad-free, powered entirely by listeners like you. If you value conversations like this, please consider becoming a paid Volts subscriber at volts.wtf. Yes, that's volts.wtf so that I can continue doing this work. Thank you so much and I'll see you next time.
What's going on with hydropower?