My solar panels save their volume in coal every year

Stack of solar panels in a garage

Solar panels tend to generate substantially less electricity when in garages.

Given the success of the global climate talks in Paris, it’s time to post a hyper-local piece on our household’s greatest carbon-mitigation endeavor: our solar panels.

Specifically, I got a wild hair to compare the volume occupied by the stack of solar panels to the volume of the coal that wasn’t incinerated thanks to their non-garage-based efforts over the past five-plus years.

I can do this because, thanks to a wicked hailstorm in June, we needed a new roof, which in turn meant our solar panels had to come off temporarily. They’ve been off since late October now, collecting very little sunlight where I’d typically park in our two-car garage (Denver’s roof inspectors face a crazy backlog, which today’s ten inches of snow is not helping). But this allowed me to actually measure this block of solar panels and, out of curiosity, figure out how much coal they’ve spared.

Solar panels in garage

A garage is not known as an appropriate natural habitat for solar panels.

Our east-southeast-facing, 2.86 kilowatt system (thirteen 220-watt REC Solar modules) generated 20,597 kilowatt hours of electricity from the time it went live on July 21, 2010 through their removal on Oct. 14, 2015.

Local utility Xcel Energy’s 2014 fuel mix in Colorado was as follows:

18.90% wind
1.20% solar
1.70% hydro
0.00% biomass
52.70% coal
25.30% natural gas

Note wind number — big. Solar is way up from just a few years ago, too, but still a rounding error.

Focusing on coal, multiplying the kilowatt hours the panels generated by the percentage of coal in Xcel’s Colorado energy mix, the panels displaced 10,855 kilowatt hours of coal-fired electricity. The U.S. Energy Information Administration estimates that it takes about 1.05 pounds of coal to generate one kilowatt hour of electricity, so that’s 11,374 pounds/5,170 kilograms/2.58 metric tons. (Note that, assuming coal is almost all carbon, burning it would amount to about 3.6 times that weight in carbon dioxide, thanks to the two Os hooking up with each of those liberated Cs).

Five cubic yards, in dirt form

Five cubic yards, in dirt form (courtesy Guins Yard)

Assuming 337 cubic centimeters of bituminous coal per pound (trust me), we get 135.4 cubic feet, or, thankfully, almost precisely 5 cubic yards of coal that wasn’t burned.

The panels themselves, stacked and parked in the garage, consume 1.07 cubic yards.

So: the panels have saved four times their volume in coal over their lifetime. They will, assuming they don’t degrade too much over their 20-year lifespan and that Xcel doesn’t continue to cut back on coal (this assumption, I hope, proves false) obviate their volume in burned coal — a cubic yard — every year they silently produce. That does’t count the roughly 10,000 cubic feet of natural gas they aren’t burning every year.

So good on ya, solar panels. And get on back up to the roof so I don’t have to keep scraping snow and ice from the car in the morning.

A couple of final notes:

  • I’m not sure if the EIA’s coal-to-electricity calculations include transmission and distribution losses or not. Looks like it accounts for about 6 percent of actual power generation in the United States, according to the World Bank.
  • The solar panels are not actually ours: they belong to Sunrun, which we pay $39 a month. This doesn’t count the $2,800 that vanished pretty much immediately after Sunrun’s IPO cratered from the $14-a-share at which we pre-IPO customers were so kindly offered to invest to the $7 range after hitting the NASDAQ (it has since rebounded somewhat). I find this a curious approach to building customer satisfaction, but the service itself has been great, and I still very much recommend them as a solar provider (just maybe not as an investment vehicle, but who knows).
  • Because Sunrun took ownership of the RECs (renewable energy credits) up front and most surely sold them to a utility who most likely used them as an excuse not to install renewable-energy capacity equal to that of our panels’ generation, it’s not clear that we technically saved any coal at all. (Because, the argument goes, had the utility not bought the RECs, it would have had to install its own renewable energy. But that’s a glass-half-empty view, isn’t it?)

AVs Drive Themselves Straight into a Service Model

Google AV

Google’s driverless, autonomous vehicles portend a radical chance in how we get around. (courtesy Google)

AVs (not audiovisual, but rather autonomous vehicles) are poised to change the developed world. It seems that about everyone who looks at transportation comes to the same conclusion. It takes a bit of explaining as to why, and a recent piece I wrote for Rocky Mountain Institute’s Solutions Journal takes a shot at. RMI is launching an AV-focused research group, led by longtime GM research executive Jerry Weiland. Weiland and colleagues the first to admit they’re not the only ones thinking about the implications of self-driving cars. But RMI’s involvement brings heavyweight intellect and a long track record in working with government and business to the party.

It’s one of those stories that was rewritten pretty heavily but came out just as well (freelance writers learn not to take these things personally). I had originally led with:

Perhaps discussions of lightweighting, electrifying and autonomizing vehicles doesn’t quite get your blood pumping. Maybe, to you, the notion of a deeply networked, multimodal mobility infrastructure optimized to move people with great efficiency, striking economy and minimal environmental footprint smacks too much of transpo-geekery.

Fine. How about the idea of slashing your annual driving costs by about 75 percent sound, then? With combined U.S. savings of a trillion dollars a year?

That’s a serious number, and it’s the bottom line of RMI’s latest transportation initiative, one riding a wave of academic and commercial recognition that our century-old, car-and-truck centric mobility system is about to be disrupted in a big way.

Where do the trillion bucks come from? We in the United States spend $1.2 trillion a year – 20 percent of our incomes, on average – for the privilege of paying 56 cents a mile to drive our personally owned, isolated, gas-powered vehicles, which the RMI team calls PIGs. (That’s not even counting the $2 trillion or so annually that pollution, sitting in traffic, roads and parking lots, and traffic accidents cost us). The idea is to shift to fleets of shared, electrified, automated, lightweight vehicles (SEALs), which would, if deployed broadly over the next 20 to 30 years, provide the same or better mobility benefits as PIGS for just 15 cents a mile, or a total of about $200 billion, the RMI team calculates. It all depends on cars going from being personal property to being fleet-based elements of networked, shared, multimodal mobility services.

When I wrote it, I was pretty sure “transpo-geekery” wouldn’t survive an editorial gauntlet of transpo-geeks. But I figured you, intelligent laypeople, and not transpo-geeks, were the true audience. And why not have a little fun?

The only line I’d like them to have kept is this: AVs drive themselves straight into a service model. To understand what I’m talking about, you’ll have to read the story.

Electricity pricing can be interesting. Really.

Solar panel installation

Our (or technically Sunrun’s) solar panels during installation in July 2010. Little did they know they would one day anchor a feature-article lead.

I’ve  done some writing for the Rocky Mountain Institute this year, which I’ve enjoyed because a) I have a ton of respect for Amory Lovins and his organization’s work (Natural Capitalism and Reinventing Fire being a couple of good examples). My latest piece, with a big assist from RMI editor Pete Bronski, posted today.

Pete called earlier this summer and said eLab, one of RMI’s many initiatives, was coming out with a report outlining a path to more rational means of pricing electricity in the United States. One’s first reaction to the idea of writing 2,000 journalistic words on electricity pricing should always be reluctance.

But within about 30 seconds on the phone I recalled that this is an important topic. It’s also a timely one, it turns out. States around the country are legislating, or considering legislating, added fees for solar and other renewable energy, which utilities say are needed because today’s century-old pricing approaches don’t reflect the system costs of solar (transmission and distribution, the need for baseload backup and so on). Solar proponents counter that they don’t reflect the benefits, either (environmental, peak-shaving and so on). So parties with very different motivations seem to agree that the system could use an overhaul, the outlines of which an RMI team sketched out.

So please spend 11 minutes reading  the story (that’s the RMI website estimate, and RMI people are pretty good with numbers).

The happiest doomsday clock

I’m on the Asahi Glass Foundation mailing list. Despite being made of glass, this is a serious foundation, most famous for its annual bestowing of the Blue Planet Prize.

When I say mailing  list, I mean this literally — you get paper-based mail. The interesting thing that, despite being based in Chiyoda-ku, Tokyo, my mail from the Asahi Glass Foundation comes via Brunei, on the northern tip of Borneo. I once spent a night in an airport there.

In addition to the Blue Planet Prize, the foundation does something called the “Questionnaire on Environmental Problems and the Survival of Humankind.” I fill it out every April (one can do this online). The most recent results were apparently released on Sept. 5, 2013. I just got them a few days ago, perhaps because they’re mailing via Brunei.

I was one of 1,364 respondents last April. The survey asked questions about the perceived nature of environmental problems and their possible consequences. Going in-depth here is beyond the scope of this post (all 22  years’ worth of .pdfs are posted here). Suffice it to say that we respondents collectively set the environmental doomsday clock at 9:19 p.m. At 161 minutes to midnight, we were considerably more optimistic than the folks over at the Bulletin of the Atomic Scientists, whose doomsday clock stands at 5 minutes to midnight. We gave the planet four more minutes than the previous year, though 90 minutes less than when the folks at Asahi launched the survey in 1992.

It is a very serious survey, querying our sense of major environmental concerns (biodiversity, climate change, pollution/contamination, water availability, population pressure, food scarcity, land-use problems) and the levers we might collectively pull to ease them (involving renewable energy, urban infrastructure, education, regulation, energy conservation, poverty reduction, tech transfer and other tools).

It breaks the prioritizations down by country and region, which is interesting. In the Middle East, zero percent of respondents believed that “stringent standards for auto emissions and energy waste” were desirable government measures to mitigate environmental burdens. Imagine that. In “Korea” (my guess this means South Korea, most North Koreans being too malnourished to type), 24 percent thought this might be a good idea.

The survey’s crowning achievement, though, was in a separate sheet of paper, which I photographed on my kitchen floor.

Asahi Glass Foundation Environmental Doomsday Clock 2013

This has not been photoshopped.

My eight year old was like, “What’s that?”

“It’s a doomsday clock,” I said.

“Oh,” she said, and was off to play Subway Surfer on her Christmas Kindle Fire.

My initial reaction was to chuckle at the depiction. I mean, who names a rabbit “Gring?” (As a white rabbit, “Gringo” might have worked, though). Or is the name “Grin” after all (see the bottom-center of the wheel)? And these other characters — what’s with the pumpkin dude and the three-eyed rabbit-alien? Why is the panda a doll and not real? And if that’s Dumbo, did you get the OK from Disney?

But on second thought, I began to wonder if maybe the Asahi people aren’t onto something. Scads of dry, terrifying IPCC reports haven’t turned much of a tide — certainly they haven’t affected Middle Eastern survey respondents. The great problem with environmental communication — particularly climate communication — is that it’s faceless. It’s about the fish tank and not the fish. Maybe we need more colorful little Grings and Woodins and crowned elephants and blue dragons. Hello Kitty, another Japanese development, may be widely mocked, but it’s universal. Maybe cute is just what we need to connect people with the drivers of environmental doomsday.

New climates, unknown consequences ahead

IPCC - global surface temperature now and in the future.
Aggressive climate action ASAP (left figure) minimizes future warming. Inaction (right figure) results in catastrophic levels of warming, 9°F over much of U.S. (Via ClimateProgress, IPCC)

If the Intergovenmental Panel on Climate Change’s fifth assessment report didn’t scare you, a study in the journal Nature should do the trick. It may have a dull title (“The projected timing of climate departure from recent variability”), but it makes up for it with alarming findings.

The abstract is, as abstracts tend to be, clinical:

Ecological and societal disruptions by modern climate change are critically determined by the time frame over which climates shift beyond historical analogues. Here we present a new index of the year when the projected mean climate of a given location moves to a state continuously outside the bounds of historical variability under alternative greenhouse gas emissions scenarios. Using 1860 to 2005 as the historical period, this index has a global mean of 2069 (±18 years s.d.) for near-surface air temperature under an emissions stabilization scenario and 2047 (±14 years s.d.) under a ‘business-as-usual’ scenario. Unprecedented climates will occur earliest in the tropics and among low-income countries, highlighting the vulnerability of global biodiversity and the limited governmental capacity to respond to the impacts of climate change. Our findings shed light on the urgency of mitigating greenhouse gas emissions if climates potentially harmful to biodiversity and society are to be prevented.

What’s this really saying?

These researchers considered the long-term average temperatures places all over the world, and then figured out how far into the future they would have to go until global warming pushed the average temperature in these places above the hottest of the 145 years from the end of the Civil War through 2005. When your hottest year becomes your average year, you’re in a new climate.

Alastair Doyle of Reuters explained it this way:

Billions of people could be living in regions where temperatures are hotter than their historical ranges by mid-century, creating a “new normal” that could force profound changes on nature and society, scientists said on Wednesday.


Temperatures in an average year would be hotter by 2047, give or take 14 years, than those in the warmest year from 1860-2005 if the greenhouse gas emissions continue to rise, with the tropics the first affected area, a new index indicated.


“The results shocked us. Regardless of the scenario, changes will be coming soon,” lead author Camilo Mora of the University of Hawaii said. “Within my generation whatever climate we were used to will be a thing of the past.”


The data suggested the cities to be hit earliest included Manokwari in Indonesia, which could shift to a new climate from 2020 and Kingston, Jamaica, from 2023 under the fastest scenario of change.


At the other extreme, Moscow would depart from historical variability only in 2063 and Anchorage in 2071.

The year 2047 isn’t that far away. My kids will be about my age then. I may still be alive, even. My kids will have every right to be angry with me for my part in all this.

Maybe it’s the federal shutdown, maybe it’s the fossil-industry-funded denier machine, maybe I was closer to it in 2007 when I covered the IPCC’s fourth assessment report as a writer for the Daily Camera in Boulder. But it feels like there’s less interest in these kinds of stories now than there was six years ago, despite carbon-dioxide concentrations having risen and its consequences becoming irrefutably clear.