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? A thread... 
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
• • •
Missing some Tweet in this thread? You can try to
force a refresh
