字幕表 動画を再生する 英語字幕をプリント 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.
B1 中級 How to fight climate change with parking lots 17798 136 林宜悉 に公開 2023 年 08 月 23 日 シェア シェア 保存 報告 動画の中の単語