hOWLing winds


owlWind power is on the rise in the U.S. In fact, 30% of new electricity generating capacity  in the U.S. between 2009-2013 came from wind power, and the U.S. could see 35% of its total electricity needs supplied by wind power by 2050 (per the White House). But, people are seriously worried about the noise.

The common complaints about wind energy are:

  • Noise made by the turbines (some people have even sued wind farm developers with claims that the noise has caused “wind turbine syndrome” – whose symptoms include headaches and sleeplessness – but the courts have found no convincing evidence that such claims are true);
  • Aesthetic disruption caused by the turbines (although, in my opinion, I’d much rather see a wind turbine than a smokestack…); and
  • Bird fatalities caused by the spinning turbines (which at 37,000 per year are remarkably fewer than those caused by buildings – 90 million – or power lines – 130 million).

Well, according to Bloomberg, the University of Cambridge may have a solution for the noise problem, and it’s got an unexpected source — owls. Owls are known for their unique and impressive ability to descend silently when attacking their pray, so scientists studied owl wings in an attempt to make the blades of wind turbines move through the air more quietly — with some success.

Evidently, researchers found that a downy, microscopic covering and a porous elastic fringe on the trailing edge of owl feathers scatters sound without impacting the wing’s aerodynamics. So, scientists tried to mimic that structure with a plastic covering made on a 3-D printer that could be applied to turbine blades, and they found that the covering successfully reduced noise by 10 decibels (to give you some context, that’s the difference between classroom chatter and a freight train 100 feet away — a significant difference). The technology’s success even caught the attention of Siemens AG, and the researchers are in talks with the company to test the coating on one of its turbines.

While I’m not sure how this covering impacts the cost of wind turbine technology, I like that this technology makes renewable technology more deployable. Noise reduction increases public acceptance of the technology and likely opens up new sites for installation if turbines can be located closer to residential and commercial areas. All in all, I’d call this another feather in the cap of renewables (yes, I went there…). :)

How many trees does it take to offset U.S. CO2 emissions?



The answer? Almost 467 billion!

I was looking through the EPA’s Inventory of Greenhouse Gas Emissions and Sinks (yes, I peruse reports like that out of pure interest; what of it?) and saw that, in 2013, the U.S. offset 881.7 million metric tonnes of greenhouse gases (GHGs) through “sinks” (such as forested land that naturally sequesters carbon). That’s 13.21% of total (not net) U.S. emissions for 2013! So, I started wondering more about naturally sequestering our carbon emissions with trees. How many trees would it take to sequester all of the CO2 we emitted in 2013? Would it be possible to do that? Could we do it if every city or town in the U.S. planted an acre of trees?

Let’s take a look at the numbers:
  • Total US GHG emissions in 2013: 6,673,000,000 metric tonnes CO2-equivalent
  • Total US CO2 emissions in 2013: 5,505,200,000 metric tonnes CO2 (Let’s use this number, since the research on sequestration by trees is based on CO2 absorption only, rather than methane, nitrous oxide, sulfur dioxide, and other GHGs)
Now on to the trees:
  • CO2 absorbed by 1 young tree per year: 26 pounds (Let’s assume they’re all young trees since they would be newly planted.) (Source: Arbor Environmental Alliance)
  • Average number of trees per acre: 700 (Source: Tufts University)
  • Amount of CO2 absorbed by 1 acre of trees per year: 8.255 metric tonnes CO2
So, how much forested land is needed to absorb our annual CO2 emissions?
  • Number of acres of trees needed to absorb all US CO2 emissions: 666,892,792 acres
  • Number of square miles of trees needed to absorb all US CO2 emissions (640 acres per square mile): 1,042,019 square miles
  • Size of United States: 3,805,927 square miles (Source: US Census Bureau)
  • % of US land needed to absorb all CO2 emissions: 27.38%
That’s a huge chunk of land that would need to be set aside to be planted with trees! Could we make a dent in that by having each city or town in the U.S. plant an acre of trees?
  • Number of incorporated areas in the U.S.: 19,509 (Source: US Census Bureau)
  • Amount of CO2 absorbed if each area planted 1 acre of trees: 161,054 tonnes of CO2
We’ll definitely need more than that! So, could we even set aside enough land to sequester all of that CO2? Well, the federal government only owns almost 28% of U.S. land (Source: USDA), so it would actually require setting aside all federal land and planting it with trees (and I’m betting a good chunk of federal land is already covered in protected forests).


How is our land actually being used? Only 2.6% of all U.S. land is urbanized and another 4.2% is rural residential land. A whopping 52.3% is used for agricultural purposes (e.g. cropland, grassland pastures, range, and forested grazing land). Another 21.9% is forested land used for timber, and 13.1% is categorized as “special use” land, which includes wilderness and wildlife areas, national and State parks, and national defense and industrial areas. The remaining 5.9% is taken up by miscellaneous land uses (Source: USDA). So, we do have a good amount of forested land in the U.S., but most of it is being cut down for timber. And, we don’t have an excess supply of unused land lying around just waiting to be planted with trees.


So to answer my question: It would take almost 467 billion trees (or almost 667 million acres of forested land) to absorb all U.S. CO2 emissions. That number is a bit smaller since we already have some forests providing carbon sinks. But, it would still take a large number of new trees. Theoretically, we do have the land for all of those trees, but – practically – it would require displacing other land uses, primarily agriculture and timber. I won’t say it isn’t possible, though…

New Regs are on the Way


airplane propellerI’m trying not to hold my breath, but I was excited to read that climate change-related regulations may change significantly this summer. Power plants aren’t the only ones being targeted with new emissions standards; the EPA is planning to draft three new rules regulating emissions this summer in a push to advance climate regulation leading up to the December UN climate talks in Paris. Potentially to be regulated are:

  • CO2 emissions from airlines
  • CO2 emissions from large trucks (e.g. the freight industry)
  • CH4 (methane) emissions from oil and natural gas operations

While I’m sure there are those who disagree, here’s why I think new emissions regulations are a good idea:

  1. It puts our eggs in more than one basket. Obama has been pushing regulation of CO2 emissions from fossil fuel-fired power plants for several years now, and his Clean Power Plan (which addresses state-by-state emissions from the fossil fuel-fired power sector) is expected to be promulgated this summer. This regulation could make a hugely positive impact on greenhouse gas (GHG) emissions if implemented — electricity from fossil fuel combustion was responsible for 35.22% of total US GHG emissions in 2013, or 2039.8 million metric tonnes of CO2. But, non-compliance by reluctant states (the WSJ reported that “Senate Majority Leader Mitch McConnell (R., Ky.), is urging governors across the country to defy the EPA by not submitting plans to comply with its rule cutting power-plant emissions.”) could hamper the regulation’s effectiveness. Branching out to address additional sources of emissions takes some pressure off of the Clean Power Plan by spreading the burden of emissions reductions across multiple industries — which makes it that much more likely the U.S. will meet its emissions reduction goals.
  2. They address a huge chunk of U.S emissions. As a percentage of net U.S. GHG emissions, these new regulations would address industries responsible for a collective 11.916% of emissions. Together with the Clean Power Plan, new regulations would address industries responsible for 47.130% of net U.S. GHG emissions. According to the EPA’s “Inventory of U.S. Greenhouse Gas Emissions and Sinks” —
    • Commercial aviation was responsible for 114.3 million metric tons of CO2 emissions in 2013
    • Medium and heavy-duty trucks emitted 393.2 million metric tonnes of CO2 in 2013
    • Oil and natural gas operations emitted 182.6 million metric tons of CO2-equivalent in the form of methane in 2013
  3. They’ll stimulate innovation. Regulating emissions requires leaving the status quo behind. It’s easy to become complacent when we’re not forced to move forward. New regulations will put fire in the bellies of these industries, driving them to create new and improved technologies that 1) lower our emissions, but also 2) represent new economic opportunities for the U.S.

I’m not saying new emission regulations will be a piece of cake to implement or that they won’t place any new costs on regulated industries. Change (and advancement) always brings along with it both costs and challenges; but, I believe these changes will create long-lasting benefits for our society, for our economy, and for our planet that far outweigh the costs.

[Just for Fun] Get Amped Up About Exercise


What would it look like if fitness fused with clean energy? A little device called Ampy.

Ampy combines the idea of a Fitbit or other similar activity-tracking devices with the ability to turn kinetic energy into electricity (you know, like those flash lights that you can crank to power them?). Basically, you move, and Ampy generates and stores electricity that you can use later to charge your devices, plus it tracks how many calories you’re burning in that process. The website indicates that you should be able to get 3 hours of smartphone battery life out of running for 30 minutes, cycling for 1 hour, or walking the recommended 10,000 steps per day.

So, you create your own clean, renewable electricity! How great is that? Plus, you can finally turn all that exercise you’ve been tracking into something you can use. Believe me, I’m all for exercising to maintain a healthy body and mind, but isn’t it nice to get a little extra boost from all that effort?

Ampy is expected to start selling devices in June 2015. Check out their video [below] or their Kickstarter for more information!

**Note: This post is in no way sponsored. I just think it’s a cool product!**

Green Vehicle Showdown


I recently posted about a former Prius exec’s comments on hybrid vs. electric vehicles and why I thought hybrids could only be a stepping stone on the way to all electric vehicles (EVs). And, that post got me wanting to know more about both hybrid and electric cars – what are their capabilities? How practical are they? How affordable are they? And, how much do they really cut down on emissions? Well, I did some digging, and here is what I found out:

Let’s compare the Tesla (most popular EV) with the Prius (most popular hybrid).

Range 265 miles max. 595 miles max.
Refueling time (assuming 40 miles/day) 1 hour 22 minutes in 240V outlet – daily Five minutes at any gas station – every 2 weeks
Refueling locations Electric charging stations

  • 8,642 public charging stations nationwide
  • 21,415 public charging outlets nationwide
Gas stations

Annual refueling cost (assuming 40 miles/day) $480 (using $0.11/kwh national average) $926 (using $3.086/gallon national average)
Annual CO2 emissions (assuming 40 miles/day) 5,077 pounds CO2 (using AZ energy matrix, which most closely mimics national matrix) 7,329 pounds CO2
CO2 difference between average gas-powered sedan (emits approx. 12,702 lbs. CO2/year when driving 40 miles per day) 7,625 pounds CO2 saved/year 5,373 pounds CO2 saved/year
Price $63,500 (after tax incentives) $30,000 (for Prius Five)

At first glance, the hybrid seems like the most reasonable choice. The hybrid goes farther and is easier to fuel, plus it costs significantly less to purchase upfront. The EV costs much less to refuel on an annual basis, but the upfront cost of the car would require 75 years of those savings to balance out overall spending. The EV emits fewer carbon emissions, but both vehicles offer a significant reduction from the standard gas-powered vehicle.

Yet, this chart doesn’t display the whole picture of this comparison because it doesn’t factor in driving habits here in the U.S. Do we really need to travel 595 miles before refueling? Turns out, most of us don’t!

  • According to the National Highway Traffic Safety Administration (NHTSA), the average vehicle trip length is 9.72 miles, and the average trip length to work is 13.36 miles.
  • According to the Federal Highway Administration, the average annual miles driven in the U.S. is 13,476 miles, which works out to a daily average of 36.92 miles (let’s call it 40 miles per day to make the math more straightforward).

So, if we’re only driving an average of 40 miles per day, the 265 mile range offered by the Tesla should be more than enough for most of us. We could plug in at home every night and be fully charged again with plenty of time for our next day’s travels. And, with charging stations popping up all over the country, traveling out of town is becoming easier as well. Tesla has over 100 “Supercharger” stations nationwide already, which can provide 170 miles of range in less than 30 minutes.

Plus, the EV will steadily grow more environmentally friendly. As the electric grid transitions toward more renewables, the carbon footprint of electricity will drop, while the carbon footprint of gasoline will remain constant. Already in states with more renewables, estimates indicate a tremendous CO2 savings with EVs:

  • Virginia (38% nuclear, 29% natural gas, 27% coal, 4% biomass, 2% hydroelectric) – EVs going 40 miles/day emit only 4,183 pounds of CO2/year
  • Washington State (69% hydroelectric, 10% natural gas, 7% nuclear, 6% coal, 6% wind, 2% biomass) – EVs going 40 miles/day emit only 1,142 pounds of CO2/year
  • See how your state compares! (multiply pounds per day by 365)

And, admittedly, hybrid CO2 footprints will drop as engines become more fuel efficient, but there is no chance a hybrid could reach zero emissions – while that is a distinct (albeit somewhat distant) possibility for EVs.

When it comes to reducing CO2 emissions, which is what’s necessary for climate change mitigation, there is no question in my mind that all-electric cars are the way to go. When you consider that day-to-day vehicle use for the average person falls well within the range of an electric car, the only factor becomes cost. But, EV prices are becoming more competitive. Teslas remain at luxury prices for now, but the Nissan LEAF (which has an 80 mile range) is only $29,000 – on par with the Prius. Plus, now that Tesla has opened up its patents to the public, the cost of EVs is likely to go down as their technology becomes more widely available and increased interest spurs on innovation. And, as assigning a price to carbon becomes a reality (and it is likely in at least some way, shape, or form, even if it’s not a direct tax, per se), electric vehicles are going to grow increasingly less expensive relative to hybrid and conventionally-fueled cars.

So, the more I look at the facts, the more I’m convinced that electric cars represent a reasonable – and necessary – transition.

I still think electric cars are a good idea…


“By definition we must move towards renewable energy. How can people argue against that?” –Elon Musk, Tesla CEO

Yale’s Environment360 blog recently featured an interview with former Toyota executive Bill Reinert, who was part of the team that designed the Toyota Prius. In the interview, Reinert reaffirmed his opinion that electric cars aren’t the way of the future, but rather we should continue to look to hybrid vehicles. And though Reinert has made important contributions to improving vehicle fuel efficiency and therefore reducing emissions (and while it’s interesting to hear his opinion on how we’ll power the cars of the future), I have some objections to a few of his comments.

Three quotes really caught my attention:

  1. “…it’s hard to see where the case for an electric car really comes in. Is it for carbon reduction? No, you’d have to decarbonize the whole grid to make that case, and that’s not likely to happen.”

Reinert assumes that we won’t transition our electric grid to one powered by renewable, low/zero-emission energy sources, yet that is exactly what we need to do. That transition won’t happen overnight, of course, but it does need to happen over the coming decades. And, even if we aren’t able to fully transition to a zero-emission electric grid, our electricity emissions should be a small fraction of what they currently are (and a small fraction of gasoline emissions).

  1. “So to ignore a car that gets 60 miles to the gallon – and the new hybrids will – and say that the electric car is better because it doesn’t use any gasoline is ridiculous. It doesn’t use any gasoline but it uses carbon somewhere.”

Again, Reinert assumes that we won’t transition to a low/zero-emission electric grid, when in fact we are (slowly) moving in that direction, and that is what we need to do. Our electricity production accounts for 32% of our carbon emissions, so it is imperative that we transform the way we generate our electric power. Couple the 32% from electricity production with the 28% from transportation, and a transition to electric cars paired with renewable electricity production would reduce our emissions by 60%. And that’s what I think must happen – a shift to electric cars must be accompanied by a transition to electricity generation dominated by renewable, low/zero-emission fuel sources.

  1. “In comparison, by adding just a little weight in the way of a few extra gallons of gas to a 50 mile-per-gallon hybrid car, there can be a big extension of the hybrid’s driving range. And while I don’t expect the battery car to get dramatically better, the internal combustion engine is getting phenomenally better…”

Reinert assumes gasoline will always be readily available and therefore limits himself to thinking that the choice is between a battery and a gasoline-powered hybrid. But, that may be a false choice as we approach peak oil and continue to increase fuel economy standards. Hybrids are an excellent stepping-stone, in my opinion; they will help us increase our fuel efficiency and lower our carbon footprint while we update our infrastructure, but they are just one step on the path to all-electric vehicles.

I’m not sure Reinert is thinking about the big picture of a changing energy landscape. Instead, he assumes certain limitations to innovation and development that could be overcome when we think about climate action in a broader context.

This interview reminds me that one of the most important pieces of successful climate action will be cross collaboration between a wide variety of groups. Vehicle manufacturers aren’t the only ones who should plan the future of our cars and roadways. Everything in our society is interconnected. Our society – and our economy – is a complex web of people, resources, and demands. Not much is done in isolation anymore. So, planning shouldn’t be done in isolation either. Of course, high-level cross-sector planning is difficult, time-consuming, and hugely complex, but it’s far better to take the time to plan well than to backtrack and change course in 10 years.

As a side note, electric vehicle sales are on the rise. Plug-in sales this year are already 30% higher than this time last year, and the total number of plug-in vehicles on the road is up 84% from this time last year. With Tesla opening up its patents to promote electric car development and competition, both Nissan (Leaf) and Chevy (Volt) recording impressive annual electric sales, and BMW getting into the game with the i3, electric cars would certainly seem to have a bright future. Looks like I’m not the only one who still likes electric cars.

More to come on comparing electric vs. hybrid cars!

Great Scot! Glasgow Scientists Make Hydrogen Fuel Breakthrough


Is hydrogen the answer to cutting our cars’ greenhouse gas emissions?

We may be hearing more about hydrogen fuel again in the near future. Researchers at Glasgow University have recently discovered what could be a breakthrough methodology for producing hydrogen fuel from water. The new method utilizes renewable energy sources to run an electric current through water (electrolysis) to create hydrogen fuel 30 times faster than the current state-of-the-art production method. This method is a vast improvement over the currently prevailing practice, which relies heavily on fossil fuels (and therefore offsets the benefit of using hydrogen fuel in the first place). Using the new methodology, Glasgow scientists are eliminating those GHG emissions by finding a production method that favors zero-emissions renewable energy sources.

Do you remember when hydrogen fuel was all the rage? The idea of hydrogen fuel seemed to be top-of-mind 10 years ago, with President George W. Bush calling hydrogen highways the way of the future in his 2003 State of the Union address. In fact, the primary use people envision for hydrogen – even now – is for automobiles so that we can replace emission-heavy gasoline. Hydrogen can be used by vehicles in 2 ways:

  • burning hydrogen directly (in liquid form) much like a car would burn gasoline, or
  • as part of a hydrogen fuel cell, which reacts hydrogen with oxygen to create electricity and power an electric motor.

So, why didn’t hydrogen technology take off? Cost, safety, and storage demands were driving factors.

Hydrogen has the tremendous benefit of being clean burning with zero emissions – great for the environment! Hydrogen fuel cells are also very efficient, making them an attractive means of deriving sustained power, and liquid hydrogen stores 2.8 times the energy per unit of mass of gasoline. But, hydrogen’s storage needs are stringent (in its liquid form, hydrogen needs to be stored at or below negative 273 degrees C! [p. 85]). On the flip side, hydrogen fuel cells do not work at very low temperatures (I don’t know what qualifies as “very low,” but this could be potentially problematic in Northern climates.) Additionally, there is a definite safety risk associated with hydrogen – it is highly flammable, even more so than gasoline [p. 89].

Some car makers already think the benefits of hydrogen outweigh the costs, though. Toyota is betting on hydrogen fuel cell technology as the future of automobiles rather than traditional electric vehicles, as the car maker is releasing its Toyota Fuel Cell Sedan in the coming months. Hyundai already released its Tucson Fuel Cell crossover vehicle in California this past June.

But, will hydrogen fuel be the way of the future? I don’t know; I still have some lingering concerns.

Safety is of course a primary concern; if hydrogen can’t be stored or transported with near-perfect safety results, it shouldn’t be powering our cars yet. Plus, any safety and security needs will factor heavily into infrastructure costs. Although, infrastructure will need to change regardless as we transition away from fossil fuels and will surely come at a hefty – but necessary – cost.

My other concern is about water availability. How much water is needed for this fuel creation process? Solar and wind production use a small fraction of the water needed by nuclear, coal, or oil-powered energy. How does hydrogen compare? But, hydrogen fuel cells can produce water as the exhaust/output, so does any upfront water use balance out? With the availability of clean drinking water becoming a global development crisis, water consumption should be an important factor in any far-reaching energy decisions.

I suppose the research over the coming months and years will shed more light on the pros and cons of hydrogen fuel and its commercial feasibility. But for now, I think using sustainably-generated electricity (from solar, wind, wave, and geothermal sources) to power both our homes and our vehicles seems like the more appealing choice, both in terms of safety and economic viability.