After Gutenberg

Biopact informs, Pennisetum purpureum is “a cane-like species of grass which utilizes the efficient C4 carbon fixation path.”

This blog Biopact about the first project to use elephant grass for combined heat and power now underway in Brazil.

Sykue Bioenergia, has already commissioned a thermoelectric power plant that will be fueled by elephant grass. The thermoelectric station will be built in Sao Desiderio in the state of Bahia in northeastern Brazil, by Dedini, an industrial company better known for building sugar mills and distilleries.

As previously noted by Biopact, coal is fetching record prices in Brazil, so the energy company may be smart to explore alternatives. “As a solid biofuel it [elephant grass] can be burned either in dedicated, highly efficient biomass power plants, in blast furnaces as an alternative to coal, or co-fired with coal in existing power plants.”

Image: Mississippi State University

A team at the University of Minnesota, that focused on long term ecological research has estimated that growing mixed [not monculture] prairie grasses “on all of the world’s degraded land could produce enough bioenergy to replace 13 percent of global petroleum consumption and 19 percent of global electricity consumption.”

Aye, but the rub may be turning the cane-like perennial — native to the tropical grasslands of Africa — into a solid biofuel. “It must be cut up into small pieces, and some heat energy applied” for drying. “Green elephant grass is 80 percent water, and it does not dry out in the sun, …but rots if left in piles.”

Elephant grass yields 30 to 40 tons of dry biomass per hectare a year, which is the reason that the Agrobiology Centre at the state Brazilian Agricultural Research Corporation (Embrapa) has expressed interest in development. However, this is a good / bad problem. If stored and / or transported, the dry grass must be compacted. Certainly, where people used wood stoves for heat, there is a potential market for biomass pellets. However, these would have to compete with various local biomass resources.

Heating with biomass results in a carbon neutral cycle.

In LAC (Latin America and Caribbean) sugar cane is a primary cash and fuel crop. With government intervention, Brazil has switched; Brazilian transportation now consumes more ethanol than petrol. In Cuba, which has faced the challenge of an energy crisis that few other countries have yet to see, the Sugar Ministry continues to reduce dependence on imported oil.

Aside from bagasse, there are other by-products that can be used for energy production and further processing. Each year almost three million tons of “cachaza” accumulates. This is the residue, which accrues when filtering the pressed sugar juice. It can be used for the production of methane in biogas plants. According to the plans of the Ministry for Science, Technology and Environment, 25 % of the sugar industry turnover should be generated through by-products of the sugar production by the year 2010.

“The Structure and Situation of the Cuban Power Industry: Supply Situations and Development of the Energy Sector“

Bagasse 1850 kcal PCI per Kg

Since bagasse is the waste biomass from sugar cane and elephant grass a cane-like species, the U.S. project that comes closest to the first Sykue Bioenergia project is a Florida Crystals co-generation plant that gets electric power from sugar cane fiber. Like its many counterparts in Brazil, Florida Crystals is a sugar company.

No one-size-fits-all solution will work to clean up and supply the world’s energy demands. “Brazil can use sugar cane, but North Americans will have to figure out something else — something home grown,” observes Eric de Pace. There has been considerable research with switchgrass, a warm season perennial grass, native to the Great Plains and eastern North America that easily adapts to marginal soils and arid climates with minimal fertility and management requirements. In forested areas, there also has been limited research with fast-growing trees such as coppiced willow or poplar; and, in agricultural areas, research using crop waste, e.g., stover, chaff, etc.

Yet, while there has been research with switchgrass alone, the push is for relatively small amounts of cellulosic feedstock mixed with a coal slurry. Instead of a biomass fueled thermoelectric power plant, biomass is added to coal and fed into an entrained flow gasifier. “Increasing Security and Reducing Carbon Emissions of the US Transportation Sector: A Transformational Role for Coal with Biomass” is a report produced by Nobilis for NETL / USAF that advocates mixing coal with relatively small amounts of lignocellulosic crops, sp., woody biomass, switchgrass or corn stover.