Meeting the Need
By the Numbers:
- 90
- Percent of the universe by weight that‘s made of hydrogen (source: National Hydrogen Association)
Cleaner Fuels FAQs
ULSD | Biodiesel | GTL Diesel | Hydrogen
ULSD
What is ULSD?
ULSD (Ultra Low Sulfur Diesel) is a cleaner-burning diesel fuel, which contains a maximum of 15 ppm (parts-per-million) sulfur content.
Why is ULSD being tested?
AC Transit has been using California ULSD in all of its buses since 2002. ULSD is part of the Cleaner Fuels test as the baseline standard, against which Biodiesel and GTL are being compared.
How does ULSD fuel affect air quality?
Newer diesel vehicles equipped with advanced emissions control technology and running on ULSD will significantly improve air quality. Annual emission reductions could be equivalent to removing 90% of the pollution from today‘s older technology trucks and buses.
Where can I purchase ULSD?
In California, ULSD has become the standard diesel fuel. Outside California, the EPA does not yet require all retailers to sell only ULSD fuel. Although this doesn‘t affect most diesel vehicles, it is imperative that consumers outside California with 2007 model year and newer diesel vehicles check their owner‘s manuals and pump labels before fueling. Putting Low Sulfur Diesel in an engine designed to run only ULSD can result in costly emissions control system damage. Starting December 1, 2010, only ULSD fuel will be available for highway use throughout the U.S.
Can I use Low Sulfur diesel instead of ULSD in my older diesel car or truck?
Yes, owners of 2006 and earlier model year diesel-powered engines and vehicles may use either ULSD or Low Sulfur Diesel fuel, but ULSD is clearly better for the environment.
Biodiesel
What is biodiesel?
Biodiesel is a cleaner-burning alternative fuel produced from renewable resources, such as vegetable oils and animal fat. It must be properly processed into its fatty acid methyl ester (FAME) and must meet ASTM D6751 standards in order to be safe for use. Stringent product quality standards are critical to ensure good performance and to protect engines from fuel-related problems.
Why use biodiesel?
Compared to diesel from petroleum:
- Biodiesel diversifies our energy supply.
- Biodiesel has greater biodegradability.
- Biodiesel is renewable. It can be produced from a variety of plant materials or animal fats.
- Biodiesel reduces greenhouse gas emissions. Depending on how the fuel is made, processed and transported, using 100% biodiesel (B100) can potentially result in significantly less overall carbon dioxide emissions.
- Biodiesel has very low sulfur and aromatics levels and can help reduce emissions in some engines. While NOx (nitrogen oxides) emissions may increase slightly with biodiesel, particulate pollution can be significantly reduced in vehicles without advanced emissions technology.
Where does biodiesel come from?
The bad news is, you can‘t just use pure vegetable oil as a safe, clean fuel. The good news is, biodiesel can be made relatively simply from a wide variety of oil-producing crops or animal fats. Currently in the U.S., the most cost-effective method starts with soybean oil. Through a chemical process known as transesterification, the oil is reacted with an alcohol such as methanol or ethanol at a processing plant to produce biodiesel and glycerol (which can then be used in a variety of household products).
What is biodiesel blending?
Biodiesel blending refers to mixing biodiesel (B100) with petroleum diesel to create a variety of biodiesel blends ranging from B1 (1% biodiesel) to B99 (99% biodiesel). However, at this time, most engine manufacturers have only approved blends of up to 5% (B5).
Is it safe?
In its unblended form (B100), biodiesel has greater biodegradability than petroleum diesel, which makes any spills less damaging to the environment. However, biodiesel has greater solvency, can be less stable, and can be more aggressive on certain engine parts at high blend levels — generally, greater than 20% — requiring special handling and engine maintenance precautions. Always check your vehicle or equipment owner‘s manual, or contact your engine manufacturer, for proper guidance before using biodiesel at any level.
Is testing biodiesel going to affect AC Transit fares?
No. Cost is always a concern that AC Transit takes into account. For this test program, Chevron is providing AC Transit with biodiesel at regular diesel prices.
Why doesn‘t AC Transit use 100% biodiesel in all its buses?
AC Transit‘s primary mission is to provide the best possible service for its riders. We are testing B20 (20% biodiesel blend) to make sure there are no adverse effects on the engines. Currently, the manufacturer of AC Transit‘s engines will not warranty the engines for biodiesel blends above 20%.
Why is AC Transit testing biodiesel?
By testing biodiesel in the real world, AC Transit gains invaluable fuel handling and vehicle operational experience. Proving efficacy, reliability and cost effectiveness are critical first steps in encouraging further development of alternative fuels.
Where can I buy biodiesel?
Currently, unblended biodiesel (B100) or biodiesel blends are available at a small but growing number of stations. Chevron offers B5 at its retail stations in Portland, Oregon.
What types of vehicles can use biodiesel?
Biodiesel blends up to B5 can generally be used in any diesel-powered vehicle without modification. However, the greater the concentration of biodiesel, the more consumers should monitor the performance of their engines. Biodiesel has strong solvency and can degrade more rapidly than petroleum diesel. These factors can lead to clogged fuel filters and injector fouling. Use of biodiesel blends like B5 and B10 are not normally strong enough in concentration to cause these types of problems. Consumers who use B20 or greater blends up to B100 should monitor performance closely, especially during the early stages of use. Always check your owner‘s manual or with your engine manufacturer for guidance prior to using biodiesel at any level and take all appropriate precautions.
Will using biodiesel void my engine warranty?
Check your owner‘s manual or with the engine manufacturer. According to the U.S. Department of Energy's National Renewable Energy Laboratory (NREL), most engine manufacturers currently allow the use of up to 5% biodiesel (B5), so long as the unblended biodiesel fuel used in the blended product meets the quality standards specified by ASTM D6751. Many engine manufacturers publish their guidelines for biodiesel use on their websites.
GTL Diesel
What is GTL diesel?
GTL stands for gas-to-liquid. GTL diesel is a liquid fuel made from natural gas, rather than from crude oil.
Why use GTL diesel?
Natural gas is more abundant than conventional petroleum, but more difficult to store and transport, simply because it‘s a gas. Converting the gas to liquid near the source makes it easier to transport and use in our current liquid fuel-based transportation system. The primary reason to use GTL diesel is to broaden the range of potential fuel options.
Is it safe?
GTL diesel meets the safety standards for California diesel fuel.
Where can I buy GTL diesel?
GTL diesel is not generally available at stations in the U.S. However, Chevron is conducting a demonstration program at a retail station in Sacramento where a blend of GTL diesel and Ultra Low Sulfur Diesel is being sold. You can visit the station yourself at 201 Richards Blvd., Sacramento, California.
Where does GTL diesel come from?
GTL diesel is currently only produced on a large scale at a few refineries, mainly in Qatar and Malaysia. The GTL diesel used in the AC Transit trial is provided by Sasol Chevron from their facility in South Africa.
Hydrogen
What is hydrogen?
It‘s the most common element in the universe. Here on Earth, hydrogen combines easily with other elements. It's 14 times lighter than air, and when hydrogen combines with oxygen, it makes the water that covers 70% of our planet.
Why use hydrogen?
It‘s cleaner than diesel or gasoline. Hydrogen use in fuel cell vehicles eliminates tailpipe emissions of toxic compounds. In a hydrogen fuel cell vehicle, hydrogen (H2) combines with oxygen (O) to make water and electricity. While hydrogen is flammable, it is non-toxic and emits zero pollutants when used in a fuel cell. And if there's ever a leak in a hydrogen tank, the hydrogen dissipates quickly into the surrounding air, decreasing fire hazard and pollution risk.
How does a fuel cell work?
When hydrogen and oxygen combine, they create water and electricity. In a fuel cell, the protons from hydrogen pass through a membrane to the other side of the cell. The electrons from the hydrogen can't pass through the membrane, so they reach the other side of the cell through a wire, producing electricity. The protons, electrons and oxygen from the air then combine to form water.
What are the environmental benefits of hydrogen fuel cell vehicles?
Hydrogen fuel cell vehicles are quiet, zero-emission vehicles. The only thing coming out of the tailpipe is water vapor. There are no particulates, no carbon dioxide and no smog-forming nitrogen oxides, which means cleaner air and a healthier environment.
Is it safe?
Hydrogen is non-toxic and doesn't pollute. It‘s also 14 times lighter than air and dissipates rapidly. So if there's ever a leak, hydrogen doesn't pool on the ground, creating a fire hazard, or seep into the soil like liquid fuels. It dissipates very quickly — without polluting. Like many fuels, hydrogen is very flammable and must be handled and stored carefully.
Does producing hydrogen emit pollutants?
It depends. When hydrogen is produced from natural gas, some carbon dioxide is released, but smog-forming nitrogen oxides are negligible. Overall, reforming natural gas is a cleaner process than burning natural gas or diesel. When hydrogen is produced from water, the electricity might originate from a generator that creates some emissions. Ideally, in the future, the energy to produce hydrogen might come from clean, renewable solar or wind power.
Why not just have battery-powered electric vehicles instead of hydrogen?
Hydrogen is more versatile. It can be stored for long periods and used for longer-distance travel. The AC Transit fuel cell buses, for example, have a range of 300 miles — far greater than most electric vehicles today. Also, hydrogen-powered vehicles can be refueled in a matter of minutes, rather than the many hours it takes to recharge the batteries in battery-powered electric vehicles.
