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  • This is a satellite image of the Mojave Desert in the US.

  • It's a fragile desert ecosystem, dotted with wildflower fields and Joshua trees which are iconic in this region.

  • But over the past several years, the landscape has started to change.

  • If you take a closer look in certain areas, you start to see more and more of these patches of blue.

  • They're are solar farms.

  • And in this part of the US, many environmental activists and local residents are not happy about them.

  • "Joshua trees are torn down to make way for solar projects."

  • "... causing quite an uproar..."

  • “...piles and piles of Joshua trees."

  • It isn't just the trees.

  • Solar farms in rural areas can take up valuable agricultural land and disrupt diverse ecosystems.

  • But transitioning to more solar power and a more sustainable future for the US requires a lot of land.

  • So, what if we could find some of that land inside our cities?

  • This video is presented by Delta Airlines.

  • In 2021, President Biden announced ambitious plans for the US to achieve net-zero greenhouse gas emissions economy-wide by no later than 2050.

  • Solar is a critical part of the plan.

  • And over the past several years as the US has ramped up solar power generation, the vast majority of solar arrays have been built in rural areas.

  • According to one study, over half of utility scale solar facilities were placed in deserts.

  • Another third in croplands.

  • 10% in grasslands and forests.

  • And just 2.5% in urban areas.

  • That makes sense.

  • Putting solar on undeveloped open spaces is often is often the cheapest and fastest way to do it.

  • But there are some major problems with this path.

  • Large scale installations often mean bulldozing massive amounts of land, altering plant and animal growth and migration patterns.

  • Or locals don't want a solar farm to ruin natural views.

  • Or they want to preserve farmland.

  • When you start to go bigger and bigger, then it starts to become less comfortable for people.

  • That's Joshua Pearce.

  • He's been a photovoltaics researcher for two decades and is a professor at the University of Western Ontario.

  • And so we've seen progressively more and more resistance in the middle of the US to large scale solar development.

  • That resistance has sometimes been funded by fossil fuel companies but people also have legitimate concerns.

  • And across the country from Massachusetts to Ohio to California, solar expansion has been stalled by protests.

  • One option that we're starting to see more of is agrovoltaics.

  • It's a way to build solar arrays that allow for agricultural use between the panels to preserve some farmland for crops, grazing, or native species.

  • But because the need for energy is mostly outside of rural areas,

  • any kind of rural solar still means building long distance transmission lines that can be expensive and an eyesore.

  • One thing that can help address some of these issues would be a kind of large, open, unused space closer to cities.

  • Enter: Parking lots.

  • The US has a lot of them, thanks to decades of designing cities around cars.

  • Parking lots cover over 5% of developed land.

  • These spaces could play one part in helping to fix solar's land problem, if we covered the lots in canopies of solar panels.

  • There is an awful lot of parking lot space in the United States that we can take advantage of that's already essentially unused.

  • It's wasted space except for parking underneath it, and it's not even used most of the time.

  • It's an idea that other parts of the world like France, are embracing.

  • A 2023 policy in France will require that outdoor car parks with more than 80 spaces cover at least half the surface area with solar canopies.

  • And officials estimate it could add ten nuclear power plants' worth of solar panels.

  • Importantly, policy like this utilizes space that's already cleared land with little biodiversity which is also close to consumers.

  • And parking lot solar canopies could also provide shade to cars in hot weather and cover from snow.

  • So why don't we see more parking lot canopies in the US, too?

  • Like canopies that could cover Disney World parking lots.

  • Instead of the solar farms, they built on nearby land that used to be orchards and forests.

  • Or covering some of LA's many parking lots instead of overbuilding in the desert.

  • Well, the biggest obstacle to putting solar on parking lots is cost.

  • The cost of putting in a solar canopy is going to be 50% to even 100% more than a conventional solar farm.

  • The thing that makes canopies more expensive than a conventional solar farm is they're higher up off the ground.

  • And so you need more structural material and you also need more weight at the bottom, holding them from blowing away.

  • And so why would a company want to invest even more money to put in a canopy?

  • They're actually is an answer to that question.

  • In 2017, Pierce coauthored a study looking into the economic potential of parking lot canopies and used Walmart Supercenters as a case study.

  • The study found that in places with high solar flux or more solar radiation in the area, solar canopies could be incredibly profitable.

  • Like here in Phoenix, Arizona.

  • But they also found that even in areas in the US considered to have less solar flux, like here in Michigan,

  • selling solar back to the grid at going rates could still be profitable enough to make solar canopies worth it in the long run.

  • It really goes down to how much are you paying for electricity and how much solar flux do you have?

  • And most of the US, barring Northern Alaska actually has fairly good solar fluxes.

  • I grew up in western Pennsylvania which has some of the worst and systems are still economic there.

  • In another 2021 study, Pearce and his team found the total capacity across all US Wal-Mart Supercenters would be 11.1 gigawatts of solar power.

  • That's around the high estimate of what the French parking lot program expects to make.

  • With that power, Wal-Mart could power about 100 electric vehicle charging stations at each Wal-Mart location,

  • or if they combine the canopies with rooftop solar, there would likely be more than enough to power the stores.

  • It would also create the opportunity to sell power back to utility companies on the main grid...

  • or stores could be the anchor for a local microgrid in the community, offering power to homes in the case of outages.

  • This isn't a one size fits all solution, but in good locations where companies can afford the upfront cost of installation.

  • Pearce's research shows canopy's could be a worthwhile investment.

  • It's guaranteed under warranty to generally work for 25 years.

  • That's an investment. You're investing in capital asset and it's providing you a return over its lifetime.

  • You should treat it the same way you would any other investment.

  • Only this one is actually good for the planet at the same time.

  • In some parts of the US, institutions like airports and universities are already trying solar parking lots.

  • Walmart and Target are just beginning to try them out in certain stores, and policy is slowly catching up too to make these kinds of solar projects easier,

  • like Maryland offering grants for solar canopies and a New York City zoning proposal that would allow for solar on more than 8500 acres of parking lots.

  • Parking lots can't fix solar's land scarcity problem on their own.

  • The amount of solar production we need will likely require a combination of efforts, including in rural areas,

  • utility-scale arrays, canopies where we can put them, arrays on rooftops, and in other places like along highways, over landfills, or on degraded lands.

  • But solar canopies are part of a large toolbox that could put a huge dent in our reliance on fossil fuels.

  • And point to a future where more cities are finding ways to give new life to some of America's most overlooked spaces.

This is a satellite image of the Mojave Desert in the US.

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How to fight climate change with parking lots

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    林宜悉 に公開 2023 年 08 月 23 日
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