April 14, 2014

Biomass Promoted as Alternative Energy Source in Brazil

Researchers from Embrapa have been searching for renewable sources of energy to use on Brazilian farms and in grain facilities primarily for use in grain dryers. Currently the main source of energy used in grain dryers is eucalyptus firewood, which is generally grown on-site. They have found that tall-stature forage sorghum or elephant grass may be a better alternative than eucalyptus firewood. Twelve different types of forage sorghum are being tested in northern Mato Grosso and the first commercial variety is expected to be available in 2015.

Biomass from forage sorghum offers several advantages over eucalyptus. First, it has a shorter growth cycle of 5-8 months depending on location compared to 3-4 years for eucalyptus. This shorter growth cycle allows for greater flexibility in land use. It can grow as tall as 5 meters and produce as much as 60 tons of dry matter per hectare. Eucalyptus for its part produces approximately 20 tons of firewood per hectare per year.

The sorghum material does not contain quite as much energy potential as eucalyptus, 4,000 kcal/kg vs. 4,500 kcal/kg, but the increased tonnage more than makes up for the difference in energy content.

Research on forage sorghum continues in northern Mato Grosso looking at plant populations, fertilizer requirement, and disease and pest resistance.

Elephant grass is also being tested as another alternative to producing huge amounts of biomass in a short period of time. Research in Mato Grosso with ten different varieties of elephant grass indicates that the grass can be harvested every six months, but more work needs to be done on fertility rates. If elephant grass continues to receive nitrogen fertilizer it just keeps growing and never matures. Therefore, tests are underway to determine the amount and the timing of nitrogen fertilizer applications to achieve a desired amount of biomass production.