David Corbus from NREL shows how wind can provide baseload power across the US eastern seaboard

Beyond Zero Emission's Mathew Wright, Scott Bilby and Patrick Hearps, talk to David Corbus, Senior Engineer, National Wind Technology Center, from the National Renewable Energy Laboratory in Colarado, about the Eastern Wind Integration and Transmission study, and wind energy in the United States.

Beyond Zero interviews David Corbus, Senior Wind Engineer at NREL

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Transcript

Scott Bilby:    Hello. Welcome to Beyond Zero, a show covering issues relating to climate change, including the latest news, science and solutions. Beyond Zero is produced in the studios of 3CR Melbourne, broadcast Australia wide on the Community Radio Network and syndicated internationally. This show is produced by Beyond Zero Emissions, an Australian based climate change campaign centre. It’s our understanding that human caused global warming has already exceeded safe limits and that we must act immediately to reduce our levels of greenhouse gas emissions to zero and below.

My name’s Scott Bilby, and speaking with us today is Matthew Wright. How are you going Matthew?

Matthew Wright:     Good thank you Scott.

Scott Bilby:  Now, today we’re going to be interviewing David Corpus from the National Renewable Energy Laboratory in Golden, Colorado in the USA. He works in their National Wind Technology Centre where he’s a senior engineer working on wind turbine loads testing for the small wind research turbine project. We’re going to be speaking to him about the eastern wind integration and transmission study: a detailed study which examines the feasibility of integrating up to 30 per cent wind in the eastern states of the United States. Welcome to the show David.

David Corpus:         Oh thanks very much. Good to be here.

Scott Bilby:  And it’s great to have you on the line with us. We’ve been very interested in this study. Now we’d just like to, as we usually do with a lot of our guests, is just ask you how you got interested in renewable energy.

David Corpus:         Ah well, it was a long time ago. It was about 1984 and there was a new program coming up in the university and it was actually combined – it was very forward looking – it was actually combining energy and atmospheric science. It was energy science with a bent on  engineering, but renewables, and then also a look at atmospheric science. And so, way back when, we were pondering this whole question, and so certainly those two disciplines have come to interact a lot in the recent past. So I got involved then and then worked in New York for a while and then came out to Colorado where they have a national lab. At that time it was a solar energy research institute, it wasn’t a national lab, but then it developed into a national lab. And there I’ve been working on all kinds of renewables, a lot of concentration in wind systems and then how those systems interact with the grid. But of course now we’re expanding, looking at solar and other renewables and how those grid interactions come about.

So that’s it in a nutshell.

Matthew Wright:     And can you tell us about when the interest arose to need to look at what sort of levels of penetration you could plan for? Like at what point did the debate, or the need happen that required this sort of study?

David Corpus:         Ah yeah, with the funding from the Department of Energy here, we’ve been looking at that question probably for – started to look at it 15 years ago, real seriously about 10 years ago. So there’s this whole body of knowledge and kind of methodologies and approaches that have been developed looking at the integration of wind on the grid, and it’s happened in Europe and the United States primarily, although all over the world.

Back then, we were originally looking at, you know, wind wasn’t very well understood – it’s being understood a lot better today – but then they were thinking, well, five per cent would be the maximum amount of renewable energy wind, primarily that you’d accommodate into the grid. As we expand over the years there’s been studies on individual areas like states up here: Minnesota or New York or California, they do these grid integration studies and as we got to better understand, really what was going on was wind is a variable resource, in other words one that fluctuates in time, and you can’t just put your foot on the pedal and ask for that energy, it comes when wind blows.

So back then it was about five per cent, people thought, of course often times people are very conservative when it comes to looking at the electrical grid and how much of available energy you can have because they want to make sure they have reliability. Got to think lights on, got to think reliability of the grid. But now this study, ten years later, after we’ve developed a lot of these experiences of these other projects, now we’re looking at the question is what – is 20 per cent wind possible in the Eastern Interconnect, and then we have a 30 per cent scenario too. You can see the evolution of our knowledge and also the experience that, hey, we can accommodate more and more of these renewable resources if we’re smart about it.

Scott Bilby:  Now David, can you just quickly tell us - because we’re very interested in this eastern wind integration and transmission study - can you tell us what that study is and tell us what your role in that study was?

David Corpus:         OK. That study answered the question in the Eastern Interconnect, which is the eastern part of the United States. It’s one big connection. Everybody’s connected to each other. That’s kind of important to understand because of the concept of interconnection, of people sharing electricity and sharing the resources. So in that we studied 20 per cent wind, we come up with very detailed ways to predict the wind on an hourly basis and model that wind into the electrical system. How that transmission connects that system together. What’s needed for that system? What are the changes needed in our current electrical system to make it so you can actually accommodate 20 per cent wind, and additional 30 per cent wind? So my role was project manager throughout, although I do like to roll up my sleeves and get in and do some of this nitty gritty work. And it’s really important for this project because there’s so many different opinions, and there’s regional opinions and there’s people that have different experiences, is to get a technical review committee together, so I was also co-chair of that technical review committee that brought the transmission folks, the electrical grid operators together and went through, as we did this two and a half year study, blow by blow, kind of met six times full-day meetings et cetera. Really reviewed all the methodologies and got consensus. Because again, we’re kind of doing something new here and any time you take on change, we want to do it in a consensual fashion. So that was my role as program manager.

Scott Bilby:  And the study concentrates a lot on, not just on the integration but also on the transmission and you had a good quote in the study that says because building transmission capacity takes much longer than installing wind plants there is a sense of urgency to studying transmission. It is already starting to limit wind growth in certain areas. Could you just run us through that a little bit?

David Corpus:         Sure. So, you know, with the conventional generation, like a fossil plant, you can build it wherever you want it. And you can connect the transmission directly to that. But with wind energy, and other renewables as well, you kind of need to spread it out -so spreading that wind out and connecting it with transmissions. Today in different wind plant developments in the Midwest of the United States, wind is being curtailed, curtailed means you have to shut it off. And that’s mostly because there’s transmission congestion, which means there’s not a way to get that electricity out from where it’s generated. In many cases, in the middle of the Midwest, where there’s low populations, means you have to get that transmission to where it’s used: cities and the load centres. So that’s that concept of transmission being very important.

And let me just add, what’s happening today is wind – because of transmission congestion - wind is being curtailed, it’s being shut off. And so that makes it so you’re getting less energy, and so the cost goes up. Because to get less energy for the same thing, you know, you have to turn it off, makes wind more expensive, so we don’t want to see that happen.

Patrick Hearps:       Hi David, it’s Patrick Hearps here. I work in the technical side of things at Beyond Zero. Now one of the important results in the area of study of the EWITS study was you did a lot of modeling on the performance of all of that wind that was distributed across the United States with the upgraded transmission. And you modeled things like, well basically, in layman’s terms was the effect of well, when the wind’s blowing in one part of the country, it may not be blowing in the other part of the country. But you had some very interesting results in finding how likely it was that there would always be wind blowing somewhere. Would you like to expand on that?

David Corpus:         Yeah, I mean, it’s very interesting when you look at wind because even for like a 400 megawatt, take a number of 400 wind farm, you never hardly get that much energy out. You always get a little bit less. Then when you sum them up it all kind of evens out. So you don’t have this situation – and this is what they thought in the old days, they thought if you have all this wind spread out it’s all going to be putting the maximum power out at one time and then going to zero at one time. And that’s a big jump - boom, boom, on, off. And so we found through modeling the weather and modeling the actual power output of existing wind plants, all of core studies [indistinct 8:49] that wind smoothes itself out as you add more wind. And so that’s very important because you never get that full amount output and you don’t get drops from on to off really fast which is hard for the grid to accommodate.

So what we did is kind of quantify the effect of spreading the wind out. Spreading the wind out is good because if you spread it out and you add more it smoothes out. And that’s the challenging thing with a variable wind resource, but as you smooth it out it becomes a little less variable, and you get to know and also the role of forecasting of what the wind’s going to be like and then adjusting like that. So a lot of knowledge has been gained and really we are able to accommodate 20 per cent wind with a certain set of assumptions that we have to make.

Scott Bilby:  So, for the sake of the audience, is it fair to say that the more you distribute your wind power, it’s spread out widely enough so that a certain percentage of it pretty much is always baseload power?

David Corpus:         That’s a good question. You can spread it out, and it naturally spreads itself out, because you don’t have to go far. The whole concept of baseload power, you know, having that coal plant, having that nuclear plant on all night, you know, where it’s not really moving up and down. Wind’s not going to give you that, but it’s going to give you something that we can – what we call in the electrical industry – capacity value. You’re going to be able to count on it with certain amount of time for your reliability calculations. And that’s the goal, to keep the lights on. So we did that in this study, and we came up with a pretty high value, up to 25 per cent capacity value in some instances. And of course that’s with the assumption that it’s all connected with the transmission. If it’s not connected, then you’re not going to get those high capacity values. You’re not going to get that, as you said, kind of time where it can be counted as a dependable load.

And those are very important for planners. But we did three years of studies for that and really you’d want to do more like seven years to have a longer time period where you’re actually estimating how much wind varies from year to year. So that’s interesting stuff too.

Matthew Wright:     If you say for a rule of thumb that wind turbines were getting, say, 30 per cent capacity factor across the board….

David Corpus:         [Interrupts] Ah wait, capacity factor’s a little different. Capacity factor’s how much output they get. The capacity value’s how much you can count on them towards like if you said that is sort of power and that’s a simplification there.

Matthew Wright:     Yeah, yeah.

David Corpus:         Capacity factor is how much, you know, how much of the time it’s producing it’s maximum power.

Matthew Wright:     Yeah, so….so if….

David Corpus:         ….and then that’s easy to confuse them.

Matthew Wright:     So from an annual average basis that’s like your capacity factor, but what I’m saying is if you said your planning factor was, say, 24 per cent, isn’t that something like 70 to 80 per cent of what you were expecting to get on an annual basis? That’s very high.

David Corpus:         Ah, yeah. We don’t relate it like that – we don’t look at it like that. We have a capacity factor which tells you how much of the time the wind plant is putting out peak power, and those are, you know, that’s a resource, kind of how strong the wind’s blowing question, and for some of our offshore sites that’s 45 per cent. For some of our screen and onshore sites in the Midwest you’d get up to that 45 per cent. But the capacity value – I mean how much they, the typical wind folks, I mean electrical grid operators count on wind – that’s much, much lower.

Matthew Wright:     Sorry, if it never sort of dips below, say, a range of 15 to 24 per cent, and that’s your firm amount for planning purposes, what’s the highest output you get aggregate across all of the wind turbines, because obviously it’s not going to hit 100 per cent everywhere because you mentioned that earlier, that you don’t end up with zero and you don’t end up with all the wind blowing. So what’s the highest figure you end up with?

David Corpus:         Oh yeah, you know I’m not sure that’s something we….. Let’s see, I don’t have that on the tip of my tongue, but it’s probably somewhere, you know, for the whole Eastern Interconnect, it depends on which scenario it is too, because we have different scenarios where the wind’s located more offshore or more onshore, so that can affect it a lot. But, you know, I’m thinking most of the time it’d be like 50 to 60, at the higher end, 60 to 70. Because the weather patterns are totally unrelated in north-west Maine compared to Texas, compared to Minnesota, you know. So it just kind of averages out. But what we do is we – for every hour of the year, for every generator, 8000 about(?), that generates electricity and then for all the loads we all connect them together and do that on an hourly basis.

Scott Bilby:  Now, we’re speaking with David Corpus. He’s from the National Renewable Energy Laboratory in Golden, Colorado. He works in their National Wind Technology Centre, he’s a senior engineer and he’s talking to us about the Eastern Wind Integration and Transmission Study, otherwise known as the EWITS study.

Now David, can you tell us a little bit about what - the plan has been released and so how have people reacted to that plan and have you got – are you overcoming the ignorance of, say, corporations who want to invest in this sort of thing? Are they starting to understand that this wind is actually not just a viable option, but an essential option for the US in the coming future?

David Corpus:         Oh absolutely, yes. The study was received really well. We kind of connected in with some of the ways you can get communication out these days. And so we got a lot of good press coverage and radio coverage. And also coverage from federal entities in the United States who kind of make these decisions and work on the grid, and FERC(Federal Energy Regulatory Commission) and the DOE(Department of Energy) offices of electricity and UNFO(?). So that’s been really positive. You know, we’ve been doing this for a while and this was an unprecedented large leap in terms of study size. And we have a western wind integration and solar study that just came out too for those interested in looking at how solar also plays in these integration studies. And then there’s a European wind integration study.

These studies have been received very well. Going forward there’s a lot of organisational co-operation that has to happen. Going forward, there’s a lot of leadership that has to happen on a federal level. Transmission is not something that’s easy to be said and working out how things, how the costs are allocated to different players. So there’s a lot of work to be done. And then there’s also work to be done in just changing the way markets are set up for electricity transactions in the United States. If you can make those markets have products at a shorter term, like within the hour. Because remember electricity’s scheduling, [indistinct 15:33] scheduling balance up. Those kind of changes are very important: how you balance electricity within certain regions – big questions. So there’s movement. It’s positive in all these directions, but it’s an enormous amount of change that needs to take place. And my message and the central theme of this study is: there’s a lot of things that we can do despite one region wanting to build transmission and the other not, or this and that. There’s a lot of things we can do that can help everybody involved in the process, right from the beginning, like 50 per cent of the transmission perhaps that needs to be built and 50 per cent of the market changes, 50 per cent of this [indistinct 16:10]. Things that we can do right away. You could really make fast progress on that. If we had consensus around that we could move forward. Because there are a lot of folks that have strong feelings about transmission. They don’t like it; it’s not so safely. It’s just one of those [laughs] it’s not a feel good technology like wind is. And so that has to be overcome. And also people that are not good at working with change, those people need to be worked with and kind of brought into the process. You can’t alienate people, you have to bring everyone in; educate them with that fundamental knowledge that we’re getting, and that’s an important process.

But we’re making some good strategies towards it.

Matthew Wright:     In terms of the EWITS study, the eastern grid, I understand in the US – and correct me if I’m wrong – that there’s three major grids and I want to know a bit about the interconnection or whether your study, or even other studies or other commentators are actually talking about how you could boost interconnection between the eastern grid, between the Texas ERCOT(The Electric Reliability Council of Texas) grid and between the North-West grid, is there anything happening on that front?

David Corpus:         Yeah, we’re doing – and again – step by step. So we move on form a state in small regions to the US and really three, and looking at all three interconnections. Again, that’s a western, an eastern one and a Texas one. And so the next logical step – and it’s a very good question – is what happens if you connect those grids? And they’re connected with just a little bit of – well think of them as pipe connections, really small. So not really – and they’re [indistinct 17:42] so there not on the same frequency. But yes. We’re looking at that. We’re looking at what would it look like for a national grid, and that of course includes Canada – we’ve modeled Canada in our study, because they’re within that same grid, and parts of Mexico too. So yes, that’s being looked at, but people that are very unsure about transmission in the short time frame are not going to want to swallow that right now.

So it’s something we’re studying, but I think, again we, we’re going to ask all these far out questions – and they’re really good questions, far out means far out time period, being like longer term penetrations renewal(?), but really these first couple of steps are so important. And you know there not the first couple of ones – kind of generation two – but to get the transmission in and to make some of these changes. So we’re trying to keep our energy power on some of this near term stuff to jump-start it somehow.

Patrick Hearps:       Hi David, so I guess to really clarify - obviously the study you did was very large. In simple terms you basically modeled wind across a grid with upgraded transmission and found that – what would you consider the conclusions of the study that really strengthened the argument for increasing more wind in the grid? So that’s conclusions about the impacts of variability and its reliability. What are the key things?

David Corpus:         The key findings of this study are that 20 per cent and 30 per cent wind energy in the eastern interconnection of the United States can be accommodated. It’s technically feasible. It makes sense to do, especially with the focus on carbon emissions. It makes sense to work towards that, but there are certain obstacles that are in the way that need to be addressed, and those are transmissions. So we analyse that a lot, and the study findings about transmission are: you need transmission or you will not get to 20 per cent wind energy in the Eastern Interconnect. And there’s a lot of more technical information that gives you a lot of insights about that whole transmission question in the report.

And then transforming from some of these markets so that they’re faster markets and so there’s more interconnections between the different regional grid operators: so pooling your resources together, pooling your generation, pooling your loads together and introducing things like forecasting the wind, more state of the art forecasts in shorter time frames. And also being creative about what kind of spinning fossil generation you need to carry to accommodate that variability. Those are major findings in the report that are understood by grid operators and now they can say, ‘wow’, well before it was five, and then it was ten per cent. But there’s really no limit in terms of what we can do in the next 10 to 15 years – we’ll never  get above 20 per cent in that time frame.

So let’s do these things that we’re talking about here. Let’s agree on this. We’ve got a lot of consensus from wide diverse groups that they are in the review committee. We have things that we need to focus on right ahead. So those are the things: transmissions, changes in markets, a little bit - different ways of how you think about integrating wind energy. Those are the findings.

Patrick Hearps:       OK.

David Corpus:         [Indistinct 20:54] as possible.

Patrick Hearps:       And we’ve got another question in a sec relating other renewables, but just to clarify that last point that we did discuss earlier about the reliability of wind. Now you modeled I think it was four different scenarios with different amounts of onshore offshore wind and different amounts of transmission. And I think even in the worst case scenario you found that there would, with that capacity factor we’re talking about, there would always be at least 14 per cent of the wind blowing all of the time.

David Corpus:         Yeah, that sounds about right. I mean the wind is never not blowing anywhere, and it’s never blowing peak anywhere, because it spreads out over such a great distance.

Patrick Hearps: And the scenarios where you had more like 20 to 25 per cent of that, what was required to get that higher capacity of wind?

Matthew Wright:     Guaranteed capacity, I guess.

David Corpus:         Well, there’s two things that affect the wind resource primarily. I mean, siting the wind plants in the highest capacity factor areas onshore.  Sometimes there’s a price for putting wind plants in the middle of nowhere because you have to build the transmission to it. And then the other thing is the assumptions on offshore winds, because offshore wind has a higher capacity factor. And it’s also – the nice thing about offshore wind – is some of the patterns in the Midwest in the United States, the wind blows at night. The wind blows when the electricity load is low; people aren’t using a lot of electricity in the middle of the night. But in offshore wind, the wind blows during the day so that respond to the peak load. So that helps out a lot. The value of the wind is higher there.

So those are important things; those are all captured in the modeling. And really, looking for the most extreme event that would happen once a year, that’s not as important. I mean, that’s important from a reliability standpoint, of course. But in terms of characterising cost and what’s needed, looking at every hour and then, you know, averaging it all out and then calculating those costs is what’s really important.

So we have costs for transmission in there; we have costs for fuel, fuel savings; costs for conventional generation needed for the future; costs to build [indistinct 23:07] new conventional generation; the capital cost of wind; the cost to integrate that wind, because you have to use a little bit more fuel and run your other generators, more to accommodate that variability. And those are and those are interesting costs, but one of the take homes is that the cost of transmission is not a huge cost by itself, about ten per cent for these different scenario, for your yearly bill, you know, what the whole grid costs.

On a yearly basis you look at that and it’s not that much, but if you actually look at the price tag for these different scenarios, for all the money. You know, $90 billion to build out the transmission system in the eastern interconnect, for one of the scenarios, that’s a lot of money. So it’s interesting how you look at it. But 90 billion, and what is that? Half of what we bailed out AIG at. So, it’s all relative.

Matthew Wright:     Yes, it’s a small amount really. And you talk about conventional generation. In the southwest certainly, they’re now looking at molten salt storage solar thermal plants. I know that NREL and Sandia National Laboratories are both working on that. So with pumped hydro already commercial and these molten salt solar thermal power systems, is it possible that they can be the firming power that builds into the integrated renewable energy grid instead of – as the conventional source – instead of using, say, gas and oil and coal?

David Corpus:         Yeah - it’d be really small though. It’d be really small. When you look at the process of integrating the technology wind – the ramp up time in new technologies, so those technologies will follow similar trajectories in terms of – and that’s just the reality from a financing and a technical point [Indistinct 24:48].

Matthew Wright:     So in that scenario, they actually had storage, it wasn’t just on solar?

David Corpus:         Yes, yeah, there was storage assumed CSP technology – solar technology you can get up to six hours’ storage from thermal storage.

Matthew Wright:     And did they model the towers that have the elevation tracking and work well during winter, or did they just model the trough plants?

David Corpus:         They vary it. I mean, you know, you have different scenarios. The worktop PV’s going to be non-tracking and a certain amount of utility grade PV that’ll have to act as tracking. So you have very detailed number – every little plant you model is an actual place with a resource and an hourly output and an assumption on the technology and the cost. So different technologies both were modeled.]

Patrick Hearps:       OK, so David, like you say, I mean there is – to get more renewables on the grid there is going to need to be growth. We’re already seeing several thousand megawatts worth of projects for solar thermal in the southwest that actually could be up and running within the next few years. Could you tell us a bit more as we finish off about where wind is going right now? So what kind of growth are we seeing in the wind industry right now over in the US?

David Corpus:         Last year we went down a little bit. A little bit of the aftershocks [indistinct 26:02] transmission’s going to play out  because if transmission doesn’t get built, the cost of wind’s going go up a little bit higher. It’s one thing to pass a regulation 20 per cent wind – it’s another thing to meet it. I’ve been in the United States where we had the Clean Air Act amendments and a lot of cities were out of attainment for decades. We had whole corporate fuel economy standards and we saw the rise of the great Hummer. So standards mean one thing but actually – so I could say to you, ‘oh 20 per cent is the standard by this date, but really doing it is the reality of the situation.

So, it depends on the policy and the climate and what happens, but I’d say 20 per cent by 2024 is a very ambitious goal. It takes a lot of work and that’s we assumed for our US study. But I’d love to see that happen – maybe 20 per cent by 2030 is more realistic. Not just for wind, so there’s other things going to happen, like clean energy efficiency. But those are my hopes. There’s a lot of work to be done.

Scott Bilby:  Thank you very much for speaking with us today David.

David Corpus:         Great to talk to you guys. I appreciate your interest in the study. Thanks.

Scott Bilby:  Thank you very much. That was David Corpus from the National Renewable Energy Laboratory in the US. He’s a senior engineer in their National Wind Technology Centre and we’ve just been discussing the Eastern Wind Integration and Transmission Study.