A recent report on the BBC website outlined the intention of farmers in the U.K. to take advantage of new government schemes relating to rewards for those that generate solar power. Cow sheds, said the story, offered a prime opportunity for solar arrays to be stored and more earning potential than the livestock.
However, this is not the only solar power development to be seen in the agricultural industry in recent times. The end of September saw the conclusion of a European Commission project called RAMseS, the main part of which was the development of a tractor that operates on solar power.
The project featured seven countries—Italy, U.K., Jordan, Morocco, Lebanon, Poland, and Spain—and was coordinated by Toufic El Asmar from the University of Florence in Italy. One of the major benefits cited from the development of the tractor was its ability to eliminate 23.3 t (25.7 ton) of greenhouse gases every year, compared to a conventional vehicle.
There were three main goals for the vehicle. In addition to running independently of fossil fuels and emitting the least amount of pollution possible, all the components had to have the potential to be re-used.
“The multipurpose truck/tractor has the ability to do everything that a conventional tractor could do,” said El Asmar. “It can be compared to a 40-bhp John Deere or Massey Ferguson and is designed to be used on small- and medium-sized farms—between 5 and 50 hectares.”
The project involved a bank of 10-kWp photovoltaic modules that provided renewable energy, a multipurpose battery-powered tractor capable of doing the work of a conventional light tractor, and a set of 16 lead-acid batteries charged by the photovoltaic modules to store energy on the vehicle. As well as powering the tractor, the energy could be used around the farm or sold to the electricity grid.
The tractor takes a maximum of 8 h to charge and when fully charged can operate for 4 h. It has a maximum speed of 45 km/h (35 mph), and there are two 12-kW electrical motors generating 200 N·m (148 lb·ft). One motor is used for traction; the other for PTO implements. It is especially suitable for work in large greenhouses where exhaust fumes from a standard combustion vehicle are a problem.
Using life-cycle analysis, researchers compared the environmental impact of the RAMseS system with that of a commonly used light tractor with an internal-combustion engine of 29.5 bhp (30 kW). The results suggest that the system will release 57.16 t (63 ton) of CO2 during an assumed life span of 30 years. In comparison, the standard tractor would emit 757 t (834 ton) over the same period. The electric vehicle was also cleaner, producing 2.6 times fewer of the other pollutants. However, lead emissions are a problem. Overall, 73% of all emissions from the RAMseS system relate to the batteries, which emit about 20 t (22 ton) of lead.
When converted into monetary terms, the lifetime cost of pollution from the internal-combustion engine vehicle is 4.7 times greater than from the RAMseS system.
The EC project may have finished, but while the prototype remains in active service in Lebanon, El Asmar has realized the potential and is looking at independent, privately funded research into solar powered agricultural machines.
“We are currently looking for finance as we would like to upgrade the vehicle, especially the design, to make it more attractive to farmers,” he said. “We would also like to consider use of more efficient and more durable batteries, such as lithium-based products. We are looking at different routes to go down.”
He noted that lead-acid batteries still remain a popular choice as they add the desired weight needed for agricultural vehicles.
El Asmar believes there is plenty of potential for the solar-powered tractor to fulfill a number of other tasks.
“The vehicle could also be used for forestry management, as well as in public parks. It could even be used as a snowplow,” he said, adding that there would be enough power to undertake such tasks as an additional engine could be accommodated at the front of the vehicle, as well as another 16 batteries, which would provide 400 N·m (295 lb·ft) of traction power.
Away from solar power, New Holland has recently debuted its zero-emissions tractor, the NH2, in North America. Based on the New Holland T6000 Series tractor, the experimental NH2 sees hydrogen fuel cells replacing the traditional combustion engine 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 drivetrain and auxiliary systems.
The NH2’s fuel cell generates 106 bhp (70 kW) and emits only heat, vapor, and water, not producing nitrogen oxides, soot particles, or carbon dioxide. And because the NH2 is virtually silent, there’s also no noise pollution.
New Holland’s experimental hydrogen-powered tractor is a key element in a project that hopes to free farmers from the cost of purchased fossil fuel and that allows them to achieve fuel autonomy while meeting increasingly stringent emissions standards. The company will not confirm exact details on when a production version of the tractor will be available.