“Why don’t we just put solar on rooftops and parking lots?”
You hear this question a lot – the presumption is usually that if we just covered all available urban space with solar panels, we’d solve our energy problem – and that’s simply wrong, for a lot of reasons.
One flavor of the argument is that we should put solar panels over every parking lot. Great. Let’s do it – but first let’s be aware of the barriers that exist to make it happen.
Simon Mahan is Executive Director, Southern Renewable Energy Association.
There’s been a meme running around showing solar carports. Usually, the “take” is we should be installing solar carports instead of using farmland for solar. Here’s the thing: no one is stopping you from installing solar carports. So why don’t we do it more often?
First, parking lots are unusual things. They can be privately owned (a landlord), or publicly owned (city/school/etc.). Public owned lots/garages have to get budget line items through local/state appropriations. Private can go quicker, but still need permits, etc.
Next, regardless of parking lot ownership type, if the lot owner doesn’t have a way to use the solar (like a net meter agreement with a utility), or access to a wholesale market (being able to sell directly into the grid), they won’t recoup their costs.
Net metering policies have been under attack in the U.S. Many states have a cap on the size a project can be, usually well less than 100 kilowatts. That may be enough for maybe 10 houses. That ain’t nothing, but we’re not powering the U.S. economy with that.
Additionally, carports are estimated to cost upwards of $4 per watt. A rooftop system may cost just $2.5 per watt. Meanwhile, a large “farm” based system may only cost $1 watt. Carports must be tall for vehicles, tearing up asphalt is more expensive than dirt. More work and materials.
There are side benefits to carports – increased shading, happy customers. But there’s not great ways for the lot owner to monetize these benefits.
About 3 million acres of parking lots exist in the U.S. It may take 20 acres of parking lots for 1 megawatt of solar. If 100% of parking lots were covered with solar, that’d be 148,187 MW. The U.S. uses 10x that amount of power – 1.3 million MW. We need more power.
Meanwhile, 38 million acres of farmland is used for corn ethanol – fuel. Acreage that requires tons of fertilizers, herbicides, gasoline for harvesting, etc. We’re romanticizing farmland. It ain’t pure/small.10x more land is used for ethanol production than for parking lots!
Don’t misread me: carports are great, but their usefulness is highly, highly specialized. We won’t power the U.S. with parking lots. Farmland is private property, and the local owners are voluntarily leasing/selling their land. It’s a better deal for them.
Back to the meme…the “let’s do carports instead of farms” is from solar opposition groups. They’re not actively advocating FOR carports. Given the opportunity, they’d oppose carports too (eyesore! subsidies! poison!). These aren’t serious clean energy people.
This is all Nirvana Fallacy: that unless something is perfect, it should be opposed. Instead, I propose we let the markets work, let private property owners do with their property as they wish, while also pushing for improvements. This isn’t this/that, it’s yes/and. /fin
Global insect biodiversity has been in decline due to habitat loss, pesticides and climate change. Restoration of insect habitat paired with smart land use changes toward renewable energy developments could help reverse the course.
For instance, as a carbon-neutral source of electricity, expanded PV solar energy development is critical to mitigating climate change. According to the DOE’s Solar Futures Study, approximately 10 million acres of land in the U.S. will be needed for large-scale solar development by 2050 in order to meet grid decarbonization and climate change goals. But some lands are better suited for PV solar development than others. Disturbed lands such as former agricultural fields are ideal locations to hold rows of solar panels compared to lands that have been previously undisturbed.
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The two studied solar sites were planted with native grasses and flowering plants in early 2018. From August 2018 through August 2022, the researchers conducted 358 observational surveys for flowering vegetation and insect communities. They evaluated changes in plant and insect abundance and diversity with each visit.
“The effort to obtain these data was considerable, returning to each site four times per summer to record pollinator counts,” said Heidi Hartmann, manager of the Land Resources and Energy Policy Program in Argonne’s Environmental Sciences division, and one of the study’s co-authors. “Over time we saw the numbers and types of flowering plants increase as the habitat matured. Measuring the corresponding positive impact for pollinators was very gratifying.”
By the end of the field campaign, the team observed increases for all habitat and biodiversity metrics. There was an increase in native plant species diversity and flower abundance. In addition, the team observed increases in the abundance and diversity of native insect pollinators and agriculturally beneficial insects, which included honeybees, native bees, wasps, hornets, hoverflies, other flies, moths, butterflies and beetles. Flowers and flowering plant species increased as well. Total insect abundance tripled, while native bees showed a 20-fold increase in numbers. The most numerous insect groups observed were beetles, flies and moths.
In an added benefit, the researchers found that pollinators from the solar sites also visited soybean flowers in adjacent crop fields, providing additional pollination services.
CNN reached out to five of the top US retailers — Walmart, Kroger, Home Depot, Costco and Target — to ask: Why not invest in more rooftop solar?
Many renewable energy experts point to solar as a relatively simple solution to cut down on costs and help rein in fossil fuel emissions, but the companies point to several roadblocks — regulations, labor costs and structural integrity of the rooftops themselves — that are preventing more widespread adoption
There isn’t just one silver bullet. We need to overcome zoning restrictions for siting wind and solar, and then build it. And more car charging stations while we’re at it! Charge while you shop or work could be a great perk for EV drivers.
Support for EVs, as pluggable vehicles increase, could start changing the economics of solar-covered parking. If you have a lot of frequently-used surface parking, at a place where people might park for one or a few hours, setting up a parking lot with solar for shading, batteries for storing the output, and chargers for putting the power into cars could pencil out nicely in some cases where it wouldn’t make sense if all cars stayed gasoline-powered.
Big charging centers make maintaining the chargers a bit easier vs. driving to various individual spots, and by adding battery storage locally, the potential expense of beefing up a substation for more power draw might be eliminated, too. And siting it specifically at places with a good deal of parking spot turnover throughout the day means the chargers would support more cars, and would also make it possible for people without the ability to charge at home to add some (or a lot) of charge during the normal course of their week.
I’ve wondered about the same thing for multi-story urban parking structures, but without expecting solar to add much (can’t put a panel UNDER the roof of the top floor, and building shadowing). But setting chargers up in part of the structure specific to short-term vs. all-day parking would allow people to add charge when they head to a show or shopping or appointments or whatever they do with a few hours downtown. And again, having battery onsite would let the structure (or charging owner) buy power inexpensively during low demand and use that for charging, again with less stress on local grid infrastructure than simply pulling all the charging from remote generation in realtime.
One likely setting for parking lot solar are the community emergency power centers like those now set up in New Orleans for storm-related outages (the Community Lighthouse centers). Having enough power to keep the lights on, refrigerate food and provide some amount of air conditioning for relief after major power outages.