Farm tractors traditionally use diesel engines. But, even though today’s diesels are cleaner than ever, agricultural engineers are scrambling to find alternative power sources. Batteries, hydrogen, natural gas and the sun may play an important role in the future.

Engineers are CNH recently developed a hydrogen-powered tractor. The New Holland NH2 is a working prototype able to perform all traditional tractor tasks while operating virtually silent and emitting zero pollutants.

Based on the popular New Holland T6000 Series tractor, the experimental NH2 replaces the traditional combustion engine with hydrogen fuel cells to generate electricity. Compressed hydrogen drawn from a tank on the tractor reacts in the fuel cell with oxygen, drawn from the air, to produce water and electrons. The electrons are harnessed in the form of an electric current, which drives electric motors to power the tractor's drive train and auxiliary systems.

The NH2's fuel cell generates 106 hp and emits only heat, vapor and water. The tractor has zero emissions because it does not produce polluting nitrogen oxides, soot particles or carbon dioxide. And, because the NH2 is virtually silent, there's no noise pollution.

Steyr, a Fiat brand popular in Europe, has unveiled a tractor powered by natural gas. The Profi 4135 Natural Power is equipped with a turbocharged four-cylinder engine that runs on ompressed natural gas (CNG). Nine fuel tanks, which hold 300 liters of gas, are integrated into the tractor's bodywork.

According to Steyr engineers, natural gas produces 25 percent lower CO₂ emissions and 95 percent less nitrous oxide when compared with diesel combustion.

At last year’s Agritechnica show in Hanover, Germany, Claas (an AGCO brand) displayed a concept tractor called the ETRION. It features “ecologically generated electricity [that is] converted into electromobility by eight power heads with wheel hub electric motors.”

Engineers at Valtra (another AGCO brand), recently created a concept tractor of their own called ANTS that features a modular design. It is powered by electricity produced in various ways, including batteries, fuel cells and turbo generators, or through a highly efficient internal combustion engine that can exploit biogas or bio diesel produced on farms. According to Valtra, “the power source will have the potential to be changed in a modular way as the need arises.” The company envisions both a 100- and a 200-kilowatt version of the futuristic tractor.

Farmers will operator the ANTS vehicle via speech recognition technology. All information will appear on window surfaces using a heads-up display.

Deere engineers have been exploring various diesel engine alternatives for the past decade. For instance, they’ve worked with Hydrogenics Corp. to develop fuel cells, Phoenix International to develop electronics and UQM Technologies to develop electric motors.

Engineers around the world are also working on solar-powered tractors. Although solar panels may not generate enough electricity to provide the high torque that tractors demand, the technology holds promise for running air conditioners, lights and other low-power applications.