Solar Mythbusters Episode #1: Solar hurts birds?

The internet. Its a double edged sword. It allows us to share information at volumes and speeds that are basically incomprehensible. It also facilitates incomprehensibly voluminous and speedy propagation of myth. In this episode, the Solar Mythbuster tackles: Is solar bad for birds.

The myth…

Not long ago we received a comment on facebook seemed to bring to light a negative impact of solar on the environment: that it kills birds. We had not heard such reports before, so we did some investigating. To start, we recite the relevant parts of the comment thread (poster identity withheld):

Facebook commenter” Solar energy is killing bees and birds you know we need them without we will run out of food. The heat that goes up the atmosphere is so great that birds flying over panels fall on the panels ready to eat and the heat also warms up the atmosphere making it hotter turbines also kill low flying birds and then we cry because we are killing the environment what an oxymoron!

EcoMen Solar” It would be great if you could provide a link or citation. EcoMen solar has nothing to hide and welcomes learning and transparency.

“Facebook commenter” please check the farms for dead birds.

Solar Mythbuster Investigation & Response…

Before trying to infiltrate conveniently close solar farm installations, we did some investigation and found an article that explains that birds are indeed killed by a very specific type of solar farm which concentrates light energy into a collector. This is a categorically different type of solar than EcoMen Solar (and basically all residential installation companies) installs.  Here is a highly relevant passage:

It’s a common refrain from desert environmentalists: Solar farms might help limit the carbon emissions responsible for climate change, but they’re harming delicate ecosystems and species, from desert tortoises and bighorn sheep to certain migratory birds. Many conservationists have argued that state and federal officials should prioritize rooftop solar panels over large-scale power plants. But at least when it comes to birds, those broad criticisms belie a more nuanced reality. Yes, birds have died at solar farms — most famously at the Ivanpah project in San Bernardino County, where birds have been incinerated as they fly through the “solar flux” reflected by fields of mirrors toward boilers atop three massive towers. But Ivanpah’s tower-and-mirror setup is the exception, not the rule. Only two big tower projects have been built in the United States, and it’s unclear whether there will be more, in part due to the technology’s high costs. Most solar farms use photovoltaic panels like the ones installed on many rooftops, which convert sunlight directly to electricity.

This article sheds more light on the scope of bird deaths: http://www.latimes.com/local/california/la-me-solar-bird-deaths-20160831-snap-story.html). It claims 6,000 birds are killed each year by the Ivanpah solar farm. That is indeed no small number.

Regarding bee deaths, we searched around and we just don’t see anything conclusively relating solar farms (of the majority photovoltaic variety) to mass bee death. In fact, we see the contrary: solar can HELP bees (https://www.beeculture.com/can-solar-sites-help-save-bees/).

We tried to further wrap our heads around your assertion by considering:

  1. How much energy do residential c-Si (crystalline silicon) photovoltaic modules reflect back to the sky? The c-Si technology that we (and all other photovoltaic installers for that matter) install reflects about 4% of the sun’s incident energy back to the sky. That means the solar panels are reflecting less than 1/20th of the amount of energy the sun is imparting to the solar panel. If birds and bees can safely fly in daylight, then they won’t be harmed by a tiny amount of the sun’s energy being reflected up at them from the ground.
  2. So that we can understand how big this possible threat could be, how much solar is in the United States? I did some calculations to understand the effective area of solar “sites” in the US. I found that at the end of 2017, more than 50GW of solar had been installed nationwide. If we assume module wattage to be 300W and module area to be 18.5 square feet, that amounts to about 71,000 acres of effective collector area. To be conservative (to handle row spacing in solar farms) lets assume that the effective solar “site” area is 120,000 acres. The United States is 3.797 million square miles in area (2,430,080,000 acres), so solar accounts for 0.005% of its total land area. Of that installed solar capacity spread over THOUSANDS of sites, there are only a few concentrator installations (the type that is known to kill birds, and presumably bees). The remainder are of the photovoltaic category.
  3. So that we can put 6,000 bird deaths into context, what other sources of accidental bird death exist? We found this article: https://science.howstuffworks.com/environmental/green-science/wind-turbine-kill-birds.htm which primarily discusses bird deaths due to wind turbines. However, there is an enlightening table near the end of the article which lists the top 7 bird killers. we recite them here:
    1. Cats. They kill hundreds of millions of birds per year.
    2. Power lines. They kill an estimated 130-174 million birds per year.
    3. Windows. They kill more than 100 million birds per year.
    4. Pesticides. 70 million.
    5. Automobiles. 60-80 million.
    6. Lighted communication towers. 40-50 million.
    7. Wind turbines. 10,000-40,000

So if you take the total bird deaths due to wind turbines AND 3 of the Ivanpah-like concentrator plants, you are in the ballpark of 40,000 + 18,000 = 58,000 bird deaths.

And 58,000 is 0.058% of the number of bird deaths caused by WINDOWS.

Solar Mythbuster Conclusion: For those of you who are anti-solar to save the “birds and the bees,” you may want act locally first, and reconsider your outdoor pet cat, subscribing to electrical service, using windows, and driving cars.