Western WA Clean Cities News

Posted on: September 18, 2017

20 Million Gallons & Counting


Did you know that 2016 was a record-setting year for Western Washington Clean Cities? For the first time, our coalition collectively displaced over 20 million gallons of petroleum! That’s the same as saving over 475,000 barrels of oil.

Not only that, our total greenhouse gas emissions reduction went from just under 100 thousand tons in 2015 to over 115 thousand tons in 2016, an increase of over 18%. Congratulations to all of our fabulous coalition members who contributed to these achievements!

Each year, we ask our stakeholder fleets to tell us how much they are using alternative fuels and other petroleum reduction strategies during the prior calendar year. Along with nearly 100 Clean Cities coalitions across the country, we then give this information to the U.S. Department of Energy, so that they can keep their finger on the pulse of alternative fuel usage and other petroleum reducing strategies throughout the country. As always, we extend our sincere gratitude to the many fleet managers in Western Washington who not only take strides year after year to reduce their petroleum consumption, but also take the time to carefully track those savings and share the information with us.

For simplicity, we talk about our petroleum reductions in terms of gasoline gallon equivalents (GGEs) displaced. Alternative fuels that displace diesel rather than gasoline, such as biodiesel and renewable diesel, are converted to GGEs by a simple calculation based on the amount of energy contained in a gallon of each fuel. Gaseous fuels like CNG are converted by a similar calculation. GGEs saved by electric cars and hybrids are based on the amount of fuel that would have been used by a conventional internal combustion engine (ICE) vehicle driving the same number of miles. Similarly, fleet efficiencies are calculated based on the fuel that would have been burned had the efficiency measures not been put in place. These efficiency measures include trip reduction programs such as rideshares and VanPools; use of idle reduction technology and practices; low rolling resistance tires and proper tire inflation; route optimization and more.

The pie chart below shows the distribution of fuels and strategies that made up the 20 million GGEs of petroleum saved by our coalition last year. Nearly eight million GGEs, or 37% of the total, were displaced by natural gas, including both compressed (CNG) and liquefied (LNG). Hybrids and electric vehicles made up an additional 26%, and fleet efficiency measures accounted for 15%. Use of biodiesel, which also included a small volume of renewable diesel, displaced 9% of the total, and propane autogas (also known as liquified petroleum gas or LPG) accounted for 10%. Ethanol (E85) usage has declined in recent years, and accounted for only 3% of total GGE displacement in 2016.

GasolineGallonsReducedThe next pie chart shows the distribution of strategies that contributed to our coalition’s 115.8 thousand tons of greenhouse gas emissions reduced last year. This pie chart is based on the exact same information as the one above, but the distribution is quite different, and it is interesting and informative to compare the two.


One thing that is noticeable right away is that the green wedge for hybrid and electric vehicles has greatly increased in size. The yellow wedge for fleet efficiencies is also larger than it was in the GGEs pie. By contrast, the teal wedge for propane autogas and blue wedge for natural gas are much smaller. Why is this?

The answer is fairly intuitive when you think about it:  when you no longer need to use a gallon of gasoline (through better gas mileage, let’s say), you’ve eliminated that gallon’s greenhouse gas emissions. Nothing replaces the gasoline, so the greenhouse gas emissions reduction is 100%.

By contrast, when a gallon of gasoline is saved by replacing it with a different fuel, any greenhouse gas emissions are only saved if the replacement fuel has a lower net carbon lifecycle than gasoline does. For example, if you replace an engine that runs on gasoline with one that runs on natural gas, then you save a lot of gasoline but only a little bit of greenhouse gas, since natural gas is still a fossil fuel.

On the other hand, if you reduce engine idle time, improve the fuel economy of a vehicle, or optimize routes to drive fewer miles, then you have done doubly-good work: eliminated gasoline and all of that gasoline’s greenhouse gas impact as well.

Hybrids and electric cars also have far lower greenhouse gas emissions under this framework because electricity has a much lower carbon impact than the burning of fossil fuels. (Although, we note that this is not always the case if the electricity is generated in a dirty way, such as from coal.)

This is not to say that natural gas and propane are lesser choices than other petroleum reduction strategies. In fact, they do still reduce greenhouse gas emissions:  natural gas is estimated to emit 6-11% less carbon than regular gasoline, and the reduction from propane autogas is similar. And there are many other reasons why CNG, LNG and propane autogas can be extremely beneficial to the environment. Their tailpipe emissions are significantly lower in harmful air pollutants like carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons.

The chart below shows the progression of Western Washington Clean Cities coalition’s petroleum displacement accomplishments over time. Our goal is to displace at least 35 million GGEs per year by 2020 – and the light-purple lines show the targets we hope to achieve in each of the next few years in order to meet that goal. This is no small task:  we want to increase our coalition’s petroleum displacement by over 70% during the next four years. In order to accomplish it, we need to grow the size of our coalition, double down on helping our fleets become cleaner and greener, and help our members who produce, distribute or install clean transportation technologies to get more of their products out on the roads. With all of the new technologies and products available today and improving all the time, we believe that together, our coalition can meet or exceed this goal.


One thing we’d love to see more of is renewable natural gas (RNG). RNG, also known as biomethane or biogas, is another type of natural gas emerging in some markets that reduces greenhouse gas emissions more than any other known transportation fuel alternative, including electricity. RNG is made by capturing methane emissions that escape into the atmosphere primarily from landfills, wastewater treatment plants and livestock manure. This gas can be cleaned up and used in any application that conventional natural gas is used for, including as a transportation fuel. So while natural gas from fracking is associated with little or no net greenhouse gas reduction, and electricity from renewable sources like wind and solar can at best be “carbon neutral,” renewable natural gas in some cases can actually be “carbon negative.” This means that burning the RNG for energy creates less greenhouse gases than simply releasing it into the atmosphere.  

Renewable propane is also a viable alternative fuel with an extremely low carbon footprint. Just as conventional propane is made as a byproduct of the natural gas refining process, renewable propane is produced as a natural byproduct of renewable natural gas refinement. RNG and renewable propane as transportation fuels aren’t yet widely available in Western Washington, but keep an eye out for more information from us soon about the potential of these exciting and highly beneficial alternative fuels.

Together, let’s keep on kickin’ gas!

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