In this week’s episode, host Margaret Walls talks with Grace Wu, an assistant professor at the University of California, Santa Barbara, about the intersection of land use change and the adoption and implementation of clean energy technologies. Wu discusses the impacts of land use change on species and ecosystems, the land use requirements of different clean energy technologies, and strategies that can help us meet net-zero energy targets while minimizing negative impacts on habitats and ecosystems.
Listen to the Podcast
- Energy models to date lack important information about spatial scale and land use: “These energy models make important decisions about which generation technologies we ought to be investing in, and when … That leaves a gap between planning ambitions (including all of this infrastructure we think we need, and when we need it) and the actual implementation process. This growing and glaring gap is something that we need to address, because renewables have both large space and specific site requirements. Those two things together could potentially cause significant land use conflicts that threaten the success of the project and, ultimately, our ability to achieve climate targets and uphold the integrity of remaining wildlife habitats.” (8:13)
- Potential for siting energy infrastructure on agricultural land: “We see interesting land use dynamics in protecting lands with high conservation value. With these stronger land use protections, we anticipate a growing role for agricultural lands—both croplands and rangelands—for energy development, as well as a corresponding decrease in the number of people who may need to host energy projects, given a shift from wind to more solar.” (12:30)
- Minimizing the environmental impacts of new energy infrastructure: “In terms of minimizing environmental impacts, my approach is to take the mitigation-hierarchy approach, which is prioritizing avoidance first. Anytime we can incentivize rooftop and urban infill development for solar that avoids additional land use conversion, we should always go for that. Secondly, if we have to do utility scale, such as ground-mounted solar, we should do those in areas with lower conservation value, like marginal farmlands and brownfields.” (25:03)
Top of the Stack
- “Minimizing Habitat Conflicts in Meeting Net-Zero Energy Targets in the Western United States” by Grace C. Wu, Ryan A. Jones, Emily Leslie, James H. Williams, Andrew Pascale, Erica Brand, Sophie S. Parker, Brian S. Cohen, Joseph E. Fargione, Julia Souder, Maya Batres, Mary G. Gleason, Michael H. Schindel, and Charlotte K. Stanley
- “Clean Energy Solutions that Protect People and Nature in the West” from The Nature Conservancy
- “Does the World Need Hydrogen to Solve Climate Change?” by Simon Evans and Josh Gabbatiss
- Carbon Brief website
- “How Green Are Biofuels? Scientists Are at Loggerheads” by Dan Charles
- Knowable Magazine
The Full Transcript
Margaret Walls: Hello, and welcome to Resources Radio, a weekly podcast from Resources for the Future (RFF). I’m your host, Margaret Walls.
My guest today is Grace Wu. Grace is an assistant professor in the Environmental Studies Program at the University of California, Santa Barbara. Grace conducts research at the intersection of land use change and climate change mitigation.
Today, she’s going to talk to us about a paper she and several coauthors published in January in the Proceedings of the National Academy of Sciences on minimizing conflicts to habitats and ecosystems while meeting net-zero energy targets. We’re going to talk to Grace about the motivations for the study, describe her key findings, and then chat a bit about the implications for policy. Stay with us.
Hello, Grace. It’s good to talk with you today. Thanks so much for coming on the show.
Grace Wu: As a big fan of RFF, I’m thrilled to be here. Thank you so much for having me.
Margaret Walls: If you’re a fan of the show, then you know that before we dive into a discussion of your recent paper, I want to ask you to share a little about yourself. Can you tell us about how you came to be an environmental researcher?
Grace Wu: I studied insect ecology and evolutionary biology as an undergraduate, and my research interest stems from a fascination with little things in the natural world. I was working as a technician for the US Geological Survey and stationed at the Lake Michigan Field Station. I was tasked with looking at climate change impacts on the endangered Karner blue butterfly.
Even though I was looking at climate change, I learned that the butterfly lost 95 percent of its former range and habitat due to land use conversion and degradation. When I was traipsing around my field sites, it was very visible. I would happen upon a steel mill, housing developments, or roads fragmenting this little remaining habitat, and the species does not disperse far. Any amount of fragmentation inhibited its range. Luckily, its habitat is now protected under Indiana Dunes National Lakeshore.
Through our work, we established that climate change was driving this precipitous drop of the population in Indiana. Climate change is pushing them over the edge, but I found out that land use change was driving them to that edge. The experience working on that project inspired me to go back to school to examine drivers of land use change and work towards avoiding future habitat loss.
When I was a graduate student, I was exposed to a lot of visionary thinking about the future of the energy system. I was at the Energy and Resources Group at the University of California, Berkeley, and there was a lot of talk about how transformational a low-carbon transition would be, including in our use of land, for which there was little research and interest in at that time. It was going to be due to this massive, but yet unknown, build-out of how much renewable energy infrastructure we need and very little information about how land-consuming those technologies would be. That’s what brought me to this problem and this paper.
Margaret Walls: Let me give the high-level view of the paper. It’s all about the investments that we’re going to have to make in this country in the coming years in various renewable energy and other technologies, as well as in electricity transmission capacity. We’ll need to make these investments in order to make significant progress on the climate crisis, while, at the same time, ensuring that all this new infrastructure doesn’t create ecological problems in the process. Could you tell us a bit more about what specifically you set out to study in this paper and why?
Grace Wu: My coauthors and I were interested in whether conservation and the most ambitious climate goals, which we may need a lot of space to achieve, would be compatible or not. My colleagues and coauthors at the Nature Conservancy, including Sophie Parker, Joe Fargione, and Erica Brand (who is now at the California Energy Commission), have been thought leaders and forerunners on the issue for a long time. They’ve been working with state agencies and industries to identify ways for clean energy and biodiversity to coexist. The outstanding issue was compatibility at full scale as opposed to at a project-by-project level.
This study is the second of multiple versions of the study looking at this problem at different scales. What we were trying to accomplish with this study, which the Nature Conservancy refers to as the Power of Place-West, was to find ways to scale up this mission of compatibility. We asked a few questions.
First, we wanted to know what demand-side and supply-side energy-pathway choices are present. These are decisions that we make as a society through regulation and incentives that are going to help us reduce overall energy–land use needs for meeting an ambitious net-zero, economy-wide target.
Secondly, we wanted to know what and how much clean energy would need to be deployed to minimize habitat loss. As an important component of that question, we wanted to know where that infrastructure would need to go.
After answering the question of how much, we then are able to get at the last issue—to what extent do land use protections and ocean use protections avoid habitat loss? What other land use dynamics and ramifications would protections cause, especially on the social aspect of land use?
Margaret Walls: To give us more of a sense of how it advanced the literature, what do you see as the main contribution on this topic that you’re making? Was it the net-zero component?
Grace Wu: Yes. I alluded to the fact that this is one of multiple power-place studies at different scales. This study is the first to look at net-zero, economy-wide efforts with an explicit focus on the energy-sector component of that. Our main contribution is methodological. Our study wanted to develop and demonstrate a framework for integrating land and ocean use planning into an energy-planning process. We needed to add spatially explicit aspects to this typically aspatial energy-planning process. If it is non-spatial, it’s at least very spatially coarse.
In fact, it’s so spatially coarse that the energy-modeling inputs and outputs are fairly useless for our stakeholders interested in siting concerns. These are stakeholders involved in land management, the farming community, the conservation community, and even social justice communities interested in who becomes the host communities for these types of projects.
These energy models make important decisions about which generation technologies we ought to be investing in, and when. These are investment models that predict, forecast, or anticipate how much and which technology we choose and when we choose it. That leaves a gap between planning ambitions (including all of this infrastructure we think we need and when we need it) as well as the actual implementation process. This growing and glaring gap is something that we need to address, because renewables have both large space and specific site requirements. Those two things together could potentially cause significant land use conflicts that threaten the success of the project and, ultimately, our ability to achieve climate targets and uphold the integrity of remaining wildlife habitats.
Our study is the first study to bridge that gap methodologically by providing spatially specific assumptions about conservation-compatible land use in an investment decision model. On the output side, our modeling provides a way to take the coarse energy model outputs and figure out what that build-out of infrastructure looks like, which enables stakeholders to react to these possible scenarios in the future and participate more meaningfully in the planning process.
Margaret Walls: Also, it’s over a large geographic scale; the focus of your study is the 11 western-most states in the continental United States.
Let’s get into some of the different scenarios that you looked at. You have different energy pathways and different levels of siting restrictions for protecting environmentally sensitive lands. Before we dive a little deeper, what do you see as the big takeaway findings from the study?
Grace Wu: In terms of advancing our understanding of siting and the land use dilemma, we have four major findings. The first has to do with energy pathway choices. We determined, after comparison of the scenarios, that the choice of energy pathways has huge implications for how much land we’ll need. We could either halve or double our land use based on that choice alone. Siting challenges could be significant or far less. For that result, the high-electrification scenario, which uses energy the most efficiently, had the lowest land and ocean use requirements.
The second finding has to do with these land and ocean use protections that we developed. We found that stronger protections didn’t change things that much in the energy system. Yes, we see more solar and less wind, but it’s not a complete reshuffling of the major technologies we’d use in the absence of protections. The slight differences in the energy sector were reflected in energy-system costs. We found that costs only increased about three percent with the strongest set of land and ocean use protections. I like to caveat that three percent itself may be an overstated cost, because our accounting does not consider mitigation costs that are associated with projects located in ecologically sensitive areas.
The third finding, related to the land use protections, is the ecological risk involved. Comparing ecological risks to the counterfactual, we find that impacts to intact lands and wildlife corridors could be substantial if we don’t protect these areas from development.
Finally, for the fourth and last result on the social side, we see interesting land use dynamics in protecting lands with high conservation value. With these stronger land use protections, we anticipate a growing role for agricultural lands—both croplands and rangelands—for energy development, as well as a corresponding decrease in the number of people who may need to host energy projects, given a shift from wind to more solar.
Margaret Walls: Let’s talk in a little bit more depth about the scenarios and start with these levels of ecological or conservation restrictions that you decided to model. There are three different scenarios you use there. Could you explain what those are and tell us how much of a difference it made when we ramp up those restrictions?
Grace Wu: We created what we called three “siting levels,” and they’re based on different amounts and types of land and ocean areas that are protected from energy development. They include assumptions about what amount and type of biomass feed stocks are available. It’s not only siting restrictions for wind, solar, and transmission.
In siting level one, we designed a business-as-usual scenario in which we restrict development only in areas with legally protected designations. For example, these are national wildlife refuge areas, national parks, and marine sanctuaries. For biomass, we assume that all feedstock types would be available, but we exclude supply from areas that have been designated as conservation reserve programs.
In siting level two, we ramp protections up by increasing the types of restrictions to include administratively protected areas, which we define as places with existing administrative or legal designations that would trigger some kind of consultation or review at the state or federal level. These include lands that are owned by nongovernmental organizations where there are conservation restrictions. They also include places like critical habitats for threatened and endangered species. Another example is sage grouse priority management areas and wetlands.
On the biomass side of level two, we restrict supply to ensure there is no net expansion of land for any purpose-grown biomass crops. What that means is that land available for herbaceous biomass is limited to the land that’s currently cultivated for ethanol that is eventually consumed as core ethanol, which, in the model, is completely phased out in all scenarios by 2050. That ensures that we don’t convert any additional new land for purpose-grown biomass.
In the last siting level, which we call siting level three and is our most protective scenario, we add areas with high conservation values that are determined through a multistate or ecoregional analysis that contains lands with social, economic, or cultural value. These include prime farmland, bird areas designated important by the National Audubon Society, and big-game priority habitats and corridors. The biomass assumptions are the same as they are in siting level two—no net expansion of land.
We ran these three siting levels against all of the policy scenarios. I already gave one of the hot, top-level results, which is that we don’t see a big reshuffling of technologies. The results are much more modest than we anticipated, because we expected to find a large difference in the technology mix, given the type of work that we had been doing solely within the state of California. Something about moving to this larger 11-state scale allowed a reshuffling to happen without a major disruption in the technology mix.
I can give us a few more specific quantitative details. We see a reduction in wind generation by 25 percent and a corresponding increase in solar by 25 percent when we go from just legally protected areas to protecting high-conservation areas, too. As a result of that shift from more geographically dispersed generation, like wind, to a much more concentrated technology, like solar, which we can site closer to load centers along the coast, we also see an interesting reduction in the amount of transmission infrastructure. We see about 20 percent less interstate high-voltage transmission capacity, which is a promising finding, because it’s challenging to site long-distance transmission corridors. On the offshore-wind side, we see more offshore wind as we apply more protections onshore.
In terms of the energy choices, we see that the impacts may be modest, but those benefits for land use are significant. There’s about a 60 percent decrease in the development on intact lands, which we define as areas that have low habitat fragmentation and that are relatively undisturbed. We also avoid a ton of development—about 35,000 square kilometers of administratively protected land. That includes critical habitat up to 50,000 square kilometers in areas with high conservation value. To help put those numbers into perspective, about 52,000 square kilometers is the land area of Louisiana. These protections are equivalent to entire states where we avoid habitat impacts in exchange for a minor change in the way that we deploy these technologies.
Margaret Walls: You have three different energy cases that you label “high electrification,” “slow electrification,” and “renewables only.” That means no fossil fuel or additional nuclear in that last one. Did those make a big difference in the land use outcomes when you look across those three scenarios?
Grace Wu: Certainly. One of our top findings is that higher electrification is the winning choice, and it makes a big difference when we talk about this in the context of fewer siting protections. For example, under siting level one, we reduce total area requirements by about 50 percent if we can shift from slow electrification to high electrification. This reduction is less dramatic when we have the most inclusive set of siting protections—that drop is only about 5 to 10 percent. It does matter when we don’t have these siting exclusions in place.
The renewables-only case is interesting, because we were expecting to see it fall in between slow electrification and high electrification, but we actually find that under the highest level of siting protections, it would actually require 30 percent more land area compared to high electrification and also 25 percent more land than slow electrification. There are interesting dynamics happening between the energy pathway choices and the siting levels—but, on the whole, high electrification wins in terms of the least land area requirements across all of the siting levels.
Margaret Walls: You mentioned siting more infrastructure on agricultural land. I’m also thinking about additional concerns people might have or restrictions somebody might want to place based on rural viewsheds, recreational access, or other kinds of natural-amenity considerations. Do you think that would change anything in your results, or do you feel like that would keep the same general results you’re finding based on habitat?
Grace Wu: That’s something we’re actively looking into for this next installment of the Power of Place-West study, which is at the national level. We take a slightly different approach in this next installment. To give a little sneak peek of what we’ve been up to, we’ve been applying a social-impact and environmental-impact factor, as opposed to these wholesale binary exclusions. We’ve been letting the model decide how to trade off between the need for clean electricity and particular places that are sunny and windy versus the amount of impact it would have socially or environmentally. We’ve built in these viewsheds and recreational-access issues. We don’t have water quality, but both of those things are in there.
What we do see is that these impact factors make a difference in changing where things go, but the role for agriculture is still there. I don’t have the quantitative results yet, but it’s based on the sheer amount of agricultural land that is available in the United States. Agricultural land makes up one-fifth of all contiguous US land. It’s still going to be a desirable place for wind and solar development, even after accounting for viewshed and recreational area reductions in availability and land.
Especially in the Midwest, agricultural lands are flat, windy, sunny, and typically not too far from a road or a substation, making them ideal places for putting up a renewable energy project. My best guess at your question is that agricultural land is going to play a prominent role; it just may not be where we would see them in the absence of these additional natural-amenity considerations.
Margaret Walls: This is scenario-based analysis with many details—especially explicit details on cost, technical feasibility, renewable energy potential, and so forth. At the end of the day, we have a set of private markets in this country overlaid with federal and state policies, regulations, and widely varying local land use policies. Are you considering policies that we need in order to ensure that we can get these net-zero outcomes in a cost-effective way that also protects valuable natural lands?
Grace Wu: I have lots of thoughts about this, but I do want to caveat that these thoughts on policy levers and recommendations are my personal opinion and not that of the Nature Conservancy, with which I work closely.
In terms of minimizing environmental impacts, my approach is to take the mitigation-hierarchy approach, which is prioritizing avoidance first. Anytime we can incentivize rooftop and urban infill development for solar that avoids additional land use conversion, we should always go for that. Secondly, if we have to do utility scale, such as ground-mounted solar, we should do those in areas with lower conservation value, like marginal farmlands and brownfields.
Finally, if greenfield projects must happen, the best way to determine where they should be would be through an energy-planning framework that has these specific components so that we can conduct environmental- and social-impact assessments; for example, improving that planning process for ground-mounted greenfield projects.
One important consideration to add to all of that is related to the avoidance of the impact. Our first consistent finding from our work on this topic across these power-place-type studies is that, if utility-scale development is not going to be in places with high conservation value, it’s likely going to be in rural landscapes with working lands—in rural communities. That brings potentially significant benefits and additional hurdles with sitings in this agricultural landscape. Any policies that ensure compatibility of conservation with energy development must also maximize benefits and minimize the challenges associated with the host community. There are lots of project-level actions that we know are effective based on previous studies that increase the acceptance of wind projects, and we anticipate that many of these also apply to solar projects.
There’s an ongoing study on solar project acceptability, but those examples include ensuring that there are economic benefits for the host community through lease payments or tax payments, that benefits are equitably distributed, and also that there’s genuine community involvement in the project-planning process. It also helps to have the local government be involved to broker that engagement.
The last thing I’ll end with is that, in terms of a concrete set of policy recommendations, one of the best examples I’ve been able to find is coming out of New York State. They have an act that was passed a few years ago called the Accelerated Renewable Energy Growth and Community Benefit Act. It’s an all-encompassing set of policies that integrate many of the points that I just mentioned. To provide a handful of examples, they require as proof that community participation was part of the process in granting permits, and it also launches benefit programs that require compensation for host communities. They have an incentive program to promote low-impact projects on brownfields and industrial sites through this process of permitting, bundling, and the auctioning of these sites to developers. They really broker that process to make it easy for developers.
Most importantly, the law establishes a first-of-its-kind office of renewable energy siting to administer these programs and help with community participation. I see it like the mortar and pestle for all the other building blocks in this act, because it really ensures that degree of reliability, predictability, and confidence in the process, which ensures the success of the overall process itself.
Margaret Walls: Grace, this has been a great conversation and has flown by. We’re going to ask you to close with our regular feature, which we call Top of the Stack, where we ask our guests to recommend more good content, whether it’s a book, an article, or a podcast. Grace, what’s on the top of your stack?
Grace Wu: I have so many things, because I have been developing and teaching this new course at the University of California, Santa Barbara, called “Climate Change Mitigation Strategies.” I’ve been doing a lot of reading, and I’ve been asking my students to do a lot of that reading. Part of the challenge was for me to try to find sources that concisely summarize academic literature on timely topics for a broad but technically minded audience. It’s got a lot of these requirements. I’ve landed on Carbon Brief and Knowable Magazine, which are published by annual reviews, as my two most reliable go-to sources.
I recently had my students read a thoughtful and thorough piece on whether the world needs hydrogen to solve climate change. My students love that, because it cut through a lot of the misunderstanding and the mythical nature of hydrogen and lots of the ambiguities on the topic.
They also read a piece in Knowable Magazine about whether biofuels are green and the debate that was happening at the end of the last year between scientists over the sustainability of corn ethanol. I highly recommend that piece. It was a thoughtful and balanced take on a complex issue.
Margaret Walls: Those sound really useful. Thank you so much, Grace. It’s been a pleasure having you on Resources Radio. I appreciate you taking the time to tell us about your research and to talk to us about these important trade-offs and challenges. It’s just great that you’re doing this work. Thank you so much for coming on the show.
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