Most fuel experts agree that the ideal alternative fuel for the future is hydrogen. It’s clean and abundant. But, unfortunately, it’s also a long way off thanks to problems with storage and refueling.
Still automakers and government officials do not want to be dependent on gasoline for the next 10 to 15 years. They, instead, are looking to several alternative fuels that can help not only with emissions but also with what many call national energy security.
The fuels range from biodiesel to propane. Most are renewable but most are also more expensive than gasoline.
“Biodiesel is coming on very strong,” says Richard Parish, senior project leader at the Center for Transportation Technology and Systems at the National Renewable Energy Laboratory.
Use of this fuel has grown dramatically over the last several years and is the alternative fuel receiving the most attention right now says Melissa Howell, executive director of the Kentucky Clean Fuels Coalition. Biodiesel is a diesel replacement or additive made from vegetable oils and animal fats. It comes from two primary and plentiful sources — soybean oil and yellow grease from restaurants, says Howell.
It can be blended with petroleum diesel fuels or used as pure biodiesel. Blends traditionally start at five percent biodiesel and 95 percent petroleum (B5). Blends less than 20 percent (B20) can be used in existing diesel engines without any engine alterations, Howell says.
Several equipment makers including Detroit Diesel, Cummins and Caterpillar have even endorsed the use of biodiesel in their products. “They said if you use our products we will not void the warranty but only to a B5 blend,” Howell says.
Higher blends can be used in engines built since 1994 with a few modifications but transportation and storage need special management. Biodiesel reduces emissions of unburned hydrocarbons, carbon monoxide, sulfates, polycyclic aromatic hydrocarbons, nitrated polycyclic aromatic hydrocarbons and particulates. While it reduces emissions it does not reduce nitrogen oxide, Parish says. Additionally, the higher the biodiesel content (B5 vs. B20) the larger the environmental impact.
“The emissions benefit greatly improvess between 2 percent and 20 percent,” Howell says. It also does not reduce a vehicle’s performance and can be used in virtually any type of vehicle on or off road. “Anybody who has a diesel vehicle can use biodiesel,” Howell says. Since biodiesel is made from soybean, U.S. farmers can grow as much as needed reducing the U.S. dependency on foreign oil, Howell says.
One of the drawbacks is that the fuel is not readily available. It is also more expensive than diesel. A B2 blend costs 3 cents more per gallon than diesel while a B20 blend costs 18 cents to 25 cents more than diesel. Another problem is that the two largest consumers of petroleum diesel are the United States Navy and the railroad industry. With the tremendous amount of diesel they use a switch to biodiesel would be extremely costly.
But the government is looking at legislation for incentives on renewable fuels and that would help biodiesel sales.
While the biodiesel industry has already started heavy marketing of the fuel to fleet owners, the average person is not aware of this fuel. If automakers decide to bring more diesel sedans and SUVs to the U.S. consumers will need to be well-informed about this alternative fuel.
Additionally, says Parish, the petroleum industry will need to be educated about biodiesel. To this point it has not shown must interest in the fuel since it offsets petroleum and is made from a biological process much different oil.
It is a foreign concept to them, he says.
With several million ethanol vehicles on the road today, the use of ethanol as a fuel should be higher. But unfortunately, the ethanol industry is not behind the use of the substance as a fuel which subsequently has driven up the price of ethanol.
Ethanol is an alcohol based fuel. It can be made from any biological feedstock that contains substantial amounts of sugar or materials that can be converted into sugar. Sugar beets and sugar cane contain sugar while corn can be converted into sugar.
Additionally, trees and grasses can be converted to sugar since they are made up of cellulose.
“We can grow more,” Howell says. “We can make more. We don’t have to import it.” There is an unbelievable number of ethanol plants in the U.S., Howell says. There are even more plants coming, Parish says. “There is something driving that,” Howell says. But it’s not E85 (85 percent ethanol and 15 percent petroleum) — the ideal fuel for the flex-fuel vehicles already on the road. Instead, ethanol is being used as an oxygenate blended with gasoline. According to the Alternative Fuel Data Center (AFDC), more than 1.5 billion gallons of ethanol are added to gasoline each year. This increases octane and improves the quality of emissions.
Used in this way, ethanol companies can get a higher price for the fuel. Ethanol costs about 20 cents to 50 cents more per gallon than gasoline.
“If it’s about the economy John Q. Public won’t pull up and put ethanol in,” Howell says. Unlike biodiesel, vehicles must be produced to be ethanol compatible since ethanol cannot come into contact with aluminum. While ethanol doesn’t look any different than gas it must be dispensed differently and requires a different pump.
Ethanol helps with national energy security since it can be grown and processed in the U.S., say government officials. It is also a good thing for farmers who can grow as much as needed and for the environment since it is cleaner than gasoline and has much lower carbon dioxide emissions.
“It does have some drawbacks,” Howell says. It is not as efficient as gasoline. Customers would pay more but would lose 25 percent of range, she says.
It also is not readily available as a fuel. For example, say Howell, Kentucky has only one E85 retail site.
Because it needs to be dispensed differently and it costs more for consumers, most retailers are hesitant to even make the investment to add it to their lineup.
“It’s a hard sell to make with the E85,” she says.
Parish agrees saying, “if there were more stations around it would be easier to use.”
In the late ‘80s and early ‘90s methanol was the alternative fuel of choice. California alone had more than 20,000 methanol fuel compatible vehicles on its roads, says Louis Browning, principal in the transportation practice at ICF consulting and a 30-year expert in alternative fuels and alternative fuel technology. But when methanol producers discovered there was a larger market for methanol as a gasoline oxygenate, prices rose and methanol stopped being used as a fuel. “It basically become cost prohibitive to drive vehicles on methanol because of this market shift,” he says. “Slowly but surely people stopped using it and the stations dried up.”
Methanol is an alcohol fuel, says the AFDC. It is produced by steam reforming natural gas to create a synthesis gas. It is fed into a reactor vessel in the presence of a catalyst to produce methanol and water vapor.
Biomass or coal can also be used instead of natural gas giving it the designation of renewable fuel.
It is easy to dispense but has no cost advantage over gasoline.
Methanol’s future in the auto industry now relies on hydrogen.
“Methanol is still a good carrier of hydrogen for fuel cell use,” Browning says. “Some manufacturers are looking at methanol as a way to carry hydrogen.”
It is very simple to convert methanol to hydrogen on a vehicle where converting other fuels is more difficult, he says. “The conversion efficiency is very good compared to converting something like gasoline, ethanol or natural gas,” he says.
Compressed Natural Gas
Compressed natural gas (CNG) has developed a following in California and Texas but hasn’t caught on in much of the rest of the U.S. Still, says Parish, it’s the fuel that has the best possibility of replacing diesel. Natural gas is a mixture of hydrocarbons — mainly methane — and is produced either from gas wells or in conjunction with crude oil production, according to the AFDC.
It is a gaseous fuel and is stored onboard a vehicle as CNG or liquefied natural gas (LNG). CNG is made when gas is separated from petroleum liquids and contaminants are removed. The gas is then separated from free liquids such as crude oil, hydrocarbon condensate water and entrained solids. It is then processed further to meet specified requirements.
Much like biodiesel and ethanol, CNG is domestically produced.
CNG also is more environmental friendly and safer than gasoline, Howell says. Because it rises faster than air, fires are virtually impossible.
“It’s very safe to use and very clean,” she says.
Distribution may also get easier as companies move to supplying home refueling technology for CNG vehicles, which are mostly being used in large fleets. But experts say CNG use won’t increase unless prices come down and it becomes more affordable.
Propane has been used for years for home heating but hasn’t found much popularity as an alternative vehicle fuel. “We have a lot of opportunity for propane in transportation,” Howell says. Propane is a byproduct of natural gas processing and petroleum refining.
There are some 350,000 vehicles using propane on the road today. They are mostly in fleets since OEMs do not build many propane-powered vehicles. Conversion kits are available.
Propane requires a different fueling that includes training on how to dispense it. On the plus side, propane vehicles have less carbon buildup and propane engines last two or three time longer than gas or diesel engines.
Electricity seems to have fallen out of favor with most automakers who are now turning their attention to hydrogen or hybrid vehicles. General Motors has even said it is taking its electric vehicles off the road when leases expire because it can’t supply the parts to repair them.
For the most part, automakers have stopped building electric vehicles and are not expected to restart any time soon.