Feb. 17 2011 12:00 AM

IN THE LATE 19TH CENTURY, when the very first enginepowered lawn mowers were introduced, the only fuel needed to run them was gasoline. Although some early mowers were powered by small steam engines, gasoline engines were installed in nearly all of the power lawn mowers built. Back then, no one bothered to look for alternative fuels, because there wasn’t any need. Gasoline was readily available, relatively inexpensive, and the Environmental Protection Agency had not as yet been born.

My, how times have changed.

Compressed natural gas (CNG) Photo courtesy: Dixie Chopper

With ever-restrictive emissions control standards, soaring gasoline prices, and increased pressure from environmental groups, the challenges facing lawn mower manufacturers have never been greater.

Fortunately for the landscape industry, these companies have discovered ways to turn these challenges into golden opportunities by using new and innovative technology to provide solutions that satisfy all sides.

This is why landscape contractors in the 21st century have an expanding range of options to choose from, as manufacturers search for alternative fuels that meet the demands related to regulations, emissions, cost and performance.

Let’s take a look at some alternative fuels that are available now, and a sneak preview of fuels yet to come.


Over the past number of years, with the rising cost of gasoline, gov ernmental agencies were seeking ways of mixing additives with gasoline so consumers would use less gasoline. Ethanol, which can be derived from sugar cane, soybeans, corn—to name a few—became accepted as an alternative, mixed with gasoline.

Until now, the government allowed a maximum of 10 percent ethanol to be blended with gasoline. Recently, the EPA approved a 50 percent increase in the ethanol/ gasoline mix. Thus, 15 percent of ethanol can now be blended with gasoline, creating an uproar with manufacturers of small engines. They claim that their engines, especially those made before 2006 were not manufactured with ethanol in mind, and could cause damage to the engine. Still, E-10, as it is known (10 percent ethanol blended with gasoline) is considered an acceptable alternative fuel.


The first alternative fuel engine to go head-to-head with gasoline was diesel. Both diesel fuel and gasoline come from the same source—fossil fuel. Both are subject to similar regulations, price fluctuations and supply shortages.

The difference is in how the engines operate. While gasoline engines use a spark to ignite the fuel, diesel engines control ignition by injection of the fuel, using either mechanical injectors or, more recently, by electronically-controlled fuel distributors and individual injectors. Also, because diesel fuel has a higher energy density than standard gasoline, it takes less fuel to provide the same amount of power.

“Diesel reduces fuel consumption, reduces emissions and, at the same time, increases productivity,” says Ray Garvey with The Grasshopper Company, Moundridge, Kansas. “Diesel packs about 12 percent more power than gasoline. With the new clean diesel technology, diesel engines emit lower levels of smog-forming pollutants such as carbon monoxide, hydrocarbons and oxides of nitrogen versus comparable gasoline.”

In addition to environmental concerns, there are also energy regulations that are causing modifications to diesel fuel composition.

The 2005 Energy Policy Act requires that an ever-increasing amount of the nation’s transportation fuel supply come from renewable sources, such as ethanol and biodiesel.

Both products are made from natural sources, such as corn or soy. The difference between them is that ethanol is an alcohol product to be added to gasoline, to increase octane levels while also promoting more complete fuel burning and reducing harmful emissions, while biodiesel is a domestic, renewable fuel for diesel engines, derived from natural oils.


“Biodiesel is an alternative fuel source derived from biological sources that are completely biodegradable and nontoxic,” says Scott Wozniak, senior marketing manager at The Toro Company, Bloomington, Minnesota. “Emissions from bio-fuels and biodiesel blends are lower than petroleumbased diesel fuels, making them more environmentally friendly.”

Biodiesel is produced from a wide range of vegetable oils and animal fats. It can reduce pollutant emissions, compared with petroleum diesel.

It also improves engine operation by raising diesel fuel’s lubricity and combustion quality.

When diesel and biodiesel mowers were first introduced, the landscape industry was very excited. The new engines offered more power than gasoline, and diesel fuel was much less expensive. Then gasoline engines began to offer increased horsepower, and the price of diesel fuel rose to the point where the only advantage over gasoline was the lower emissions.

So manufacturers began looking for other alternatives to gasoline, diesel and even biodiesel fuels, not because of the increased benefits to the environment, but because of their rising costs.

“Alternative fuel discussions start happening when the price of gas at the local stations head toward $3.50 and higher,” says John Cloutier, senior marketing manager with Exmark, Beatrice, Nebraska. “In the past few years, the price of diesel has not only caught up to that of gasoline, but it has surpassed it at a faster rate.”

According to the U.S. Energy Information Administration, Cloutier is correct. Recent reports state that the average price of a gallon of gasoline in January of 2011 was $3.070, while a gallon of diesel was $3.331.

As fuel prices increase, the cost of running a business increases as well. In the highly competitive landscape industry, a few cents can mean the difference between your company’s success or failure, if you have to increase your prices.


Also known as liquefied petroleum gas, LPG or autogas, propane is the most widely available alternative transportation fuel in the United States.

“Based on our studies, on average, propane-powered mowers result in 48 percent less greenhouse gas emissions than gasoline, and reduce carbon monoxide emissions by more than 80 percent,” s a i d P r o p a n e E d u c a t i o n & Research Council (PERC) Vice President Brian Feehan. “Propane is a widely available alternative fuel that is naturally stable and can be stored for a long period without going stale or varnishing within a carburetor.”

“Propane is stored as a liquid under relatively low pressure and becomes a gas at normal pressure,” Feehan explains. “The liquid storage gives it a high energy density, so a mower can run a long time on a tank of fuel, while the sealed and pressurized storage has the advantage of eliminating evaporative emissions and spillage, and poten tial fuel theft.”

“In the last year or so, we’ve had more people asking us about propane than we’ve had in the past five years or more,” Cloutier said. “Propane engines can generate 10 to 20 percent of torque at lower cost with fewer toxic emissions than either gasoline or diesel,” he said.

The cleaner-burning nature of propane also results in reduced maintenance requirements, such as less-frequent oil changes, and extended mower life. In addition, propane does not spoil or clog fuel systems in lawn equipment during seasonal storage, which can be the case with liquid fuels.

While propane conversion kits have been around for awhile, propane-dedicated production models began rolling off manufacturer’s assembly lines only a few y e a r s a g o . D i x i e C h o p p e r, Coatesville, Indiana, was the first commercial lawn mower manufacturer to produce an engine designed to run on propane. Others quickly followed, and now there are more than a dozen manufacturers of propane-powered zero-turn mowers who sell their mowers around the world.

Emission controls continue to be highly regulated in certain states. In California, propane-powered mowers must be certified by the California Air Resource Board (CARB). If your business is in California, and you’re looking to purchase a propane-powered mower, be sure the model is CARB-certified.

Compressed Natural Gas (CNG)

Virtually all natural gas consumed in the United States is produced in North America, and, compared with gasoline and diesel engines, natural gas engines are environmentally the cleanest. The cleaner-burning nature of natural gas may also result in reduced maintenance requirements. Like propane, natural gas does not spoil or clog fuel systems in lawn equipment during seasonal storage— again, unlike liquid fuels.

“Natural gas is the cleanest fuel available,” says Gary Morgan, president and CEO of Dixie Chopper. “Another advantage of CNG is that, because it is so clean, the downtime for maintenance is a lot less. There are longer intervals between oil changes, and the mower engines themselves last much longer with CNG than either gas or diesel.”

Natural gas must be compressed and stored at high pressure to enable adequate mowing time. Similar to propane, the sealed and pressurized fuel-storage system eliminates evaporative emissions and spillage, as well as the potential fuel theft sometimes associated with liquid-fueled lawn equipment.

“Another advantage of CNGpowered mowers is that natural gas disperses quickly when released, so if there was a leak, unlike with gasoline or diesel, the fuel won’t run all over the garage floor or get on the crew,” said Morgan.

With more municipalities converting to CNG to run their trucks and buses, fueling stations are becoming more accessible. A CNG website shows prices ranging from $1.82 to $2.59.

Electric battery-operated

The biggest advantage to battery-operated electric mowers is that they have zero emissions, no engine noise and relatively low maintenance. Because the engine is not fueled by any type of liquid or gas, there is also no need for oil, filters, spark plugs, fan belts, or Fuel cells any of the normal paraphernalia associated with lawn mower engines.

The major drawback is that the batteries in these mowers only last for about an hour of running time. They have been found to be insufficient for most commercial landscape jobs. However, mower manufacturers are continuing to work on improvements in the design that would extend the battery’s charge. But battery technology is up to the manufacturers of these batteries. They too are working diligently to develop new technology for longer times between charging.

A glimpse into the future shows promise of some new potential alternatives to fuel. These alternatives offer great opportunities, but again, we’re waiting for the technology to develop these products at a reasonable cost. Until then, it’s still only an idea.

Hydrogen mower manufacturers and engine designers are constantly on the lookout for new sources of fuel to keep their engines running, meet EPA standards and keep costs low. One alternative that is being talked about is hydrogen.

Hydrogen is prepared without using fossil fuel inputs and doesn’t produce carbon dioxide emissions. However, there are drawbacks of hydrogen use to make it a viable alternative for the commercial market at the present time. The first is the enormous cost to produce a hydrogen engine.

Algae—the newest energy source

Dozens of companies, especially in Europe, as well as many academic laboratories here in the U.S. are pursuing the possible use of algae as a source of green energy. Algae are attracting attention because the strains can potentially produce ten or more times more fuel per acre than the corn used to make ethanol or the soybeans used to make biodiesel. Moreover, algae can be grown on arid land and brackish water, so that fuel production would not compete with food production. And algae are voracious consumers of carbon dioxide, potentially helping to keep some of this greenhouse gas from contributing to global warming.

Other alternative products made from algae that are being investigated are biobutanol and biogasoline.

With so many different options from which to choose, and with new alternatives just over the horizon, there may come a time when gasoline and diesel-powered lawn mowers will become as extinct as the dinosaurs whose remains are being used for the fuel to power them.