Why Don’t We Put Solar on ALL Rooftops?
Summary
TLDRThis video explores the potential of rooftop solar as an alternative to utility-scale solar farms, addressing environmental and social concerns associated with large-scale clean energy projects. It discusses the technical and geographical potential of solar power, the challenges of implementation, and innovative dual-use solutions like agrivoltaics and floatovoltaics. The script questions whether rooftop solar alone could meet our energy needs while avoiding ecological consequences, highlighting the complexity of balancing land use with renewable energy growth.
Takeaways
- 🌱 The expansion of utility-scale solar and wind parks is causing environmental and social concerns, not just aesthetic issues.
- 🏡 Rooftop solar is considered as an alternative to large-scale solar farms, avoiding some of the legal and ecological challenges.
- 💧 Solar farms can consume significant amounts of water during construction, affecting local water supplies and aquifers.
- 🐾 Construction of solar farms can lead to the displacement of wildlife and destruction of natural habitats.
- 📈 The U.S. is experiencing a grid connection backlog, delaying the implementation of new renewable energy projects.
- 🔄 Rooftop solar can bypass certain obstacles like impact studies and grid connection queues, using existing space.
- 🔆 The potential of rooftop solar is complex to calculate, involving physical, geographic, and technical factors.
- 📊 A study in Seoul's Gangnam district showed that rooftop solar could theoretically cover a significant portion of the city's energy needs.
- 🌐 The actual implementation of solar energy is influenced by a range of factors including costs, policies, and public acceptance.
- 🌾 Innovative approaches like agrivoltaics and solar grazing combine solar energy generation with agriculture for mutual benefits.
- 🌊 Floatovoltaics, or floating solar panels on bodies of water, offer a flexible and space-efficient way to harness solar energy.
Q & A
What is the main challenge of expanding renewable energy capacity according to the script?
-The main challenge is the delicate balancing act of land use, which involves not just NIMBYism, but also serious environmental and social concerns.
Why is the expansion of utility-scale solar and wind parks complicated?
-The expansion is complicated due to the potential negative impacts on water supplies, construction noise, dust storms, glare, and displacement of wildlife, as well as legal and ecological consequences.
What is the acronym 'NIMBYism' mentioned in the script, and what does it refer to?
-NIMBYism stands for 'Not In My Back Yard,' which refers to the opposition from residents to a project in their local area that they perceive as having negative impacts.
What is the potential of rooftop solar in terms of energy generation according to the script?
-The script suggests that rooftop solar has a significant potential, but it does not provide a specific figure, as it varies greatly depending on various factors such as location, available rooftop area, and the efficiency of solar panels.
What are the advantages of rooftop solar over utility-scale solar farms as mentioned in the script?
-Rooftop solar can avoid legal hassles, ecological consequences, and the need for land acquisition. It also allows for the use of power generated onsite without reliance on transmission lines.
What is the 'interconnection queues' mentioned in the script, and why is it a problem?
-The 'interconnection queues' refers to the backlog of renewable energy projects waiting for grid connection in the U.S. It is a problem because it delays the implementation of these projects, causing a bottleneck in the expansion of renewable energy.
What is the significance of the study conducted by Yonsei University researchers mentioned in the script?
-The study is significant as it provides a detailed analysis of the physical, geographic, and technical potential of rooftop solar in Seoul's Gangnam district, highlighting the gap between the theoretical potential and the actual electricity generation achievable.
What does the term 'technical potential' refer to in the context of the script?
-In the script, 'technical potential' refers to the maximum amount of energy that can be generated by a solar system in a specific environment, without considering market, economic, or policy constraints.
What is the concept of 'agrivoltaics' mentioned in the script, and how does it benefit both agriculture and solar energy generation?
-Agrivoltaics is a concept where solar panels are integrated with agricultural practices. It allows for mutual benefits such as protecting crops, reducing water usage, providing shade for animals, and attracting pollinators, while also generating solar energy.
What is 'floatovoltaics' as discussed in the script, and what are its potential applications?
-Floatovoltaics refers to solar panels installed on bodies of water, such as lakes or irrigation canals. It allows for the generation of solar energy while utilizing space that does not interfere with land-based activities, like farming or water management.
What is the conclusion of the script regarding the future of solar energy deployment?
-The script concludes that dual-use implementation of solar energy, such as agrivoltaics and floatovoltaics, is key to maximizing the potential of solar energy without requiring large-scale land clearance.
Outlines
🌱 Balancing Renewable Energy and Environmental Impacts
The video script begins by discussing the challenges of expanding renewable energy, particularly solar and wind farms, and the environmental and social concerns associated with their construction. It raises questions about the worthiness of large-scale projects and introduces the idea of rooftop solar as a potential alternative. The speaker, Matt Ferrell, sets the stage for a discussion on the feasibility and benefits of utilizing rooftops for solar energy generation, while also acknowledging the complexities of cost, priorities, and environmental impacts.
🔍 Exploring Rooftop Solar Potential and Its Limitations
This paragraph delves into the concept of solar energy potential, distinguishing between physical, technical, and realizable potentials. It explains how physical potential is based on solar radiation, while technical potential considers system capabilities and performance. The realizable potential, however, takes into account market, economic, and policy constraints. A study from Yonsei University in Seoul is highlighted, demonstrating the significant but not fully utilizable potential of rooftop solar in the Gangnam district. The summary emphasizes the gap between theoretical and practical solar energy generation and the multifaceted nature of assessing solar viability.
🌟 Innovative Solar Applications and Dual-Use Implementations
The final paragraph explores innovative applications of solar energy beyond traditional land-based installations. It introduces agrivoltaics, which combines solar energy generation with agriculture, offering mutual benefits to both sectors. The concept of floatovoltaics is also discussed, where solar panels are installed on bodies of water, providing flexibility in solar deployment. The paragraph touches on other niche applications like sound barriers and monuments, and it concludes by emphasizing the importance of dual-use implementations and the abundance of options for integrating solar energy into various aspects of life and infrastructure.
Mindmap
Keywords
💡Renewable Energy
💡Land Use
💡Utility-Scale Solar
💡Rooftop Solar
💡Technical Potential
💡Interconnection Queues
💡Agrivoltaics
💡Floatovoltaics
💡NIMBYism
💡Community Solar
💡IMBYism
Highlights
The challenge of balancing land use with the expansion of renewable energy sources, particularly utility-scale solar and wind parks.
The environmental and social concerns that complicate the creation of clean energy projects, beyond just NIMBYism.
The potential of rooftop solar as an alternative to large-scale solar farms, avoiding legal and ecological issues.
The cost barrier as a persistent challenge to the widespread use of solar power.
The impact of solar farms on local water supplies, particularly in areas with limited water resources.
The disturbance to surrounding life from solar farm construction, including noise, dust, glare, and wildlife displacement.
The lengthy process and bureaucracy involved in getting utility-scale solar projects online, including impact studies and interconnection queues.
The advantages of rooftop solar in bypassing many of the obstacles faced by utility-scale projects, such as the need for impact studies and transmission line dependencies.
The difficulty in estimating the potential energy supply from rooftop solar due to numerous variables.
The concept of 'potential' in solar energy, including physical, geographic, and technical potential, and how they differ.
A case study of Seoul's Gangnam district, illustrating the gap between physical and technological potentials of rooftop solar.
The importance of considering the quality of life and public acceptance in the viability of rooftop solar.
The variability of theoretical solar power potential based on different assumptions and estimates.
The idea of agrivoltaics, combining solar generation with farming to create a symbiotic relationship.
The concept of floatovoltaics, using solar panels on bodies of water to generate electricity.
The potential of dual-use solar implementations, such as agrivoltaics and floatovoltaics, as key to efficient solar energy use.
The call for public engagement in discussing and exploring dual-use solar implementations.
Transcripts
Growing the world’s renewable energy capacity has always been a delicate balancing act,
and one of the many plates we have to spin during that act is land use. Utility-scale
solar and wind parks are rapidly expanding in size and prevalence all over the world,
including right in my own backyard. But it’s not just NIMBYism that complicates
the creation of clean energy — it’s serious environmental and social concerns, too. When
are the negative impacts of siting these massive projects worth the benefits? When are they not?
With these questions in mind, it’s tempting to wonder: How much solar power could we squeeze
just out of rooftops? Could rooftop solar single-handedly provide us all the energy
we need while avoiding legal hassles and ecological consequences? At the
end of the day…do we have enough space for solar?
I’m Matt Ferrell … welcome to Undecided.
This video is brought to you by Surfshark, but more on that later.
We’ve discussed a lot of fascinating possibilities for increasing and improving solar power on the
channel from more simple modifications to the downright fantastical. But if
you’ve been watching for a while, you might have noticed a pattern in the tech I cover:
the most persistent barrier to widespread use is usually cost (at least, for now). In the
case of going all-in on rooftop solar, it’s not so simple. Instead, it’s a matter of priorities.
Let’s step back for a second, though, and talk about why you’d want to pitch a “cover all the
roofs!” approach in the first place. Utility-scale solar is definitely preferable to coal,
but there’s many more considerations at play than just aesthetics when breaking new (old) ground.
For one thing, as they’re being built, solar farms can soak up a lot of water — thousands
of acre-feet’s worth. In some areas, that means these construction projects threaten the water
supply for locals who rely on aquifers, which are difficult to monitor and preserve. Unfortunately,
the same areas that have lots of sunshine to spare also have limited water resources to live.
Then there’s the other ways surrounding life is disturbed: construction noise,
dust storms, glare, and of course, displacement of wildlife. So, when an undertaking like the
Aratina Solar Center involves the destruction of state-protected Joshua trees in California,
it’s not unreasonable to question whether going forward with large-scale construction is the
best decision. And by no means is this the only solar farm facing opposition from neighboring
communities and conservationists…trust me, there's some in my area too.
Even when these proposals successfully clear the tangles of bureaucracy and public comment,
it still takes a long time to get them online. This is especially true in the U.S.,
which is currently suffering from a grid connection backlog longer
than a CVS receipt. Before utilities can move forward with their plans,
they need to undergo an impact study. Off they go into what’s known as the “interconnection queues.”
Over 95% of the projects idling in these interconnection queues are for renewables,
with solar representing the vast majority of them. And by the end of 2023, the combined generation
capacity of projects waiting for an assessment amounted to nearly 2.6 Terawatts, which is more
than double the U.S.’ existing generation capacity…in total. Not all of these solar
hopefuls make it to completion — in fact, most don’t. So yeah, you could say we’re a bit behind.
However, rooftop solar can easily skip over a lot of these obstacles. While I can tell you from
personal experience that investing in solar panels definitely doesn’t spare you from permitting hell,
it’s not like you have to get in line for an impact study. You’re taking advantage
of space you already have to work with rather than carving out more land. And
you can use the power you generate onsite, so you’re not at the mercy of transmission lines.
So, what if we went all-in with rooftop solar? How
much of our energy supply could come just from rooftops alone?
Before we try to answer that tricky question, there’s another piece of tech that isn’t
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the description below. Thanks to Surfshark and to all of you for supporting the channel. So, what if
we went all-in with rooftop solar? How much of our energy supply could come just from rooftops alone?
Well…I can’t tell you. Not right off the bat,
anyway. Simply hypothesizing what we possibly could generate with rooftop
solar can’t be adequately diluted to a single statistic, even when you apply limitations,
like only covering a specific region. There’s just too many variables to account for,
so it’s no surprise that researchers have been trying to answer this question for years.
I can’t give you a meaningful back-of-the-envelope figure for
how much rooftop solar has to offer on a fully realized scale. What I can do,
is break down how researchers have been tackling the subject — and that would
be through various measures of potential. Even the concept of “potential” itself has
multiple subtypes in terms of calculating what we can accomplish with renewables. As a result,
you end up with different values depending on what kind of potential you’re looking at.
If you imagine a pyramid of potential,
like the U.S. National Renewable Energy Laboratory (NREL) has here…
…then the foundation begins with the physical constraints of rooftop solar. How much radiation
is hitting a given rooftop in the first place? Of course, the total amount of radiation that
a surface receives currently can’t come anywhere close to the energy that it ultimately produces,
and that’s not just because of a solar panel’s Shockley–Queisser limit.
That brings us to the technical potential of solar: what is a particular system capable of
in a particular environment, and how well does it perform? Here’s the thing: as the NREL defines it,
technical potential estimates what you can physically deploy “without regard to market,
economic, or policy constraints.” In other words, laying out a technical potential
figure for rooftop solar doesn’t provide a full picture. We still have to contend with how costs,
policies, regulations, and the public response restrains what it can actually
do for us in the real world. To PV or not to PV; that is the question.
For an example of how the differences between the potential and the possible shake out,
we can look at a 2016 study published by researchers from Yonsei University in Seoul,
Korea. The research team zeroed in on the capital’s Gangnam district (yes, that one),
and their analysis followed a three-step process of determining the area’s physical,
geographic, and technical potential. Within this particular study, “physical” refers to
“total solar radiation on the rooftop,” “geographical” equates to “available
rooftop area for solar PV installation,” and the technical potential is the final
electricity generation. Here’s a summary of results, which represent annual values:
Physical potential - 9,287,982 megawatt hours Geographic potential - 4,964,118 square meters
Technological potential - 1,130,371 megawatt hours
Note that “geographic potential” is expressed in meters squared, not megawatt hours,
because it represents the average amount of rooftop area compatible with solar panels.
So, you can tell right away that there’s a big gap between the physical and technological
potentials. As the researchers write, “only 12.17% of the physical potential can be
generated as electricity.” These results don’t mean rooftop solar isn’t worth it,
though. To put that number into perspective, CEIC Data estimates Seoul’s all-time highest
use of electricity between January 1997 and May 2018 fell within August 2016,
the same year as the solar potential study’s publication. That number was an average of
4.8 million megawatt hours. Just like that, rooftop solar in one of Seoul’s 25 districts
could cover a quarter of the entire city’s energy needs. That’s impressive.
However, my point is that the study shows how establishing the suitability of rooftop
solar is a layered and laborious task, even for a single region. That’s not
to mention all the other circumstances that can make or break the viability of
rooftop solar…including the quality of life considerations that drive its acceptance by
the people it's meant to serve (which we went over earlier). It’s not just about
solar’s literal star power. Researchers also have to take into account factors like this…
Basically, you can’t avoid making assumptions…and depending on what kinds of assumptions you make,
your theoretical solar power potential can vary wildly. That’s how estimates developed
by one research team can differ from others in orders of magnitude. You can see how pronounced
these differences are in this graph from a review of rooftop solar potential studies.
So, it’s hard enough collecting and refining the approximations necessary to make an educated guess
about solar potentials. But no matter how precise your data is, theoretical plans can’t predict the
future or anticipate every community, government, or individual decision. You might discover the
ultimate solar site…but not have any policy incentives available to help do something
with it. NREL pretty much sums it up in a study about community solar published earlier this year:
“Realistically, the potential accrual of benefits is a fraction of those high-end
estimates based on technical potential capacity.”
Where do we go from here? The truth is, weighing the trade-offs between utility-scale solar farms
and a widespread rooftop offensive might be missing the forest for the trees…or maybe
the sun for the rays. Because so much of solar’s efficiency is location-dependent, it doesn’t make
sense to broadly advocate for one over another, and we don’t have to stop at either. Panels can
infringe on the ecosystem they’re installed in, but they can also directly enhance it.
Agrivoltaics, for example, enables us to create a symbiotic relationship
between farming food and solar generation. Panels can protect crops from the elements,
reduce water usage, provide shade for animals, and act as hubs for attracting
pollinators — which happens to be(e) the most common application of agrivoltaics in the
U.S. I’ve got a whole deep dive video on the practice if you’re interested.
There’s also practices like solar grazing, or letting livestock loose on fields full
of solar panels and having them go to town. By partnering with sheep and cows, we can cut down
both overgrown lawns and maintenance costs as they take over the otherwise expensive role of
groundskeeper. If the concept of solar-over-soil gives you the warm fuzzies, I’ve gone into more
detail about augmenting agriculture this way on the channel before, so you know what to do.
Now that we’ve gone over the land, what about the water? Let me float an idea by you:
floatovoltaics, or solar panels that catch current in more ways than one. Any kind of water will do,
from the open ocean to lakes. But we can get some of the same flexibility enjoyed by rooftop
solar by integrating panels into all sorts of architecture…including irrigation canals and dams.
A while back I took a deep dive into the flow of canal floatovoltaics projects from
India to California. Since then, similar efforts have kicked off in Oregon and
Utah in the U.S. earlier this year. Just this summer, the Philippines inaugurated
its largest PV irrigation system yet, the first built over a canal.
And if you saw my video on small hydropower,
you might remember our discussion of one particular hydro titan:
the Itaipú Dam along the borders of Brazil and Paraguay. The dam already provides about 90% of
Paraguay’s electricity and 15% of Brazil’s. In a study published in May, consulting firm PSR
argues that the hydroelectric plant’s existing installed capacity of 14,000 megawatts could
be nearly doubled by setting aside just 10% of its reservoir’s surface area for floating PV.
That’s not to mention the sunny spectrum of solar niches like sound barriers, balconies,
billboards, fences, footpaths…heck, even monuments. By 2025, Amsterdam will allow
for solar panels on roofs within protected areas of the city. How’s that for “in my
backyard”? Should we come up with a new term? IMBYism, maybe? We just drop the N.
Once you start to examine how social and economic influences can help or hinder solar’s technical
potential, it quickly becomes clear that our main conflict isn’t space. It’s a deceptively simple
plan to cram as many solar panels onto as many rooftops as possible. It’s much more difficult
to assess priorities and anticipate impacts on a case-by-case basis. But if solar’s massive spike
in deployment, long-term drop in cost, and overall technological maturity has amounted to anything,
it’s that we’re not at all short on options. So yes, we do have space for solar that doesn’t
require clear cutting large swaths of land. Dual use implementation looks like it’s the key.
But what do you think? What dual use solar implementations pique your interest? Jump into
the comments and let me know and be sure to listen to my follow up podcast Still TBD where we’ll keep
this conversation going. Thanks as always to my patrons for your continued support and a big
welcome to Rikki, Mark Loveless, Aaron Addleman, and Bill Northrup. I’ll see you in the next one.
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