Sugarcane is gradually being edged out of pole position for biofuel efficiency, as studies at the state-owned EMBRAPA are finding that Napier grass or Elephant grass has a much greater potential. Its dry biomass, burned in ovens, can generate

25 times as much energy as the amount of fossil fuel used to produce it, while sugarcane converted into ethanol only produces 9 times as much.

Napier grass belongs to the sugarcane family. In South Malaysia, close to the equator, in the state of Johor, 50 km north from Singapore, I walked along dense Napier grass fields, where Napier grass grows 3 meters every 45 days. This means the farmers harvest the grass 6 times a year with a yield of 40 tonnes per hectare or 240 tonnes per year. I have pictures of Napier grass fields, after 1 week of har­vesting, already 30 cm high again! I do not know any other kind of energy crop that grows so fast with such a high bulk density as Napier grass.

Napier grass has a high cellulosic fiber content and is therefore an excellent cheap feedstock for ethanol production. Several kinds of Napier grass do not need nitro­genous fertilizers to grow fast. For use as a biofuel, the least nutritious varieties are sought, in contrast to its traditional use as animal feed. Nitrogenous fertilizers require the greatest amount of fossil fuel energy to produce them chemically and, by avoiding their use, greenhouse gas emissions are also avoided. In Malaysia, Napier grass is mostly fed by rainwater. Green Elephant grass is 80% water anyway and it does not dry out in the sun, as eucalyptus does, but rots if left in piles. To dry, it must be cut up into small pieces and some heat energy applied. Compacting is necessary for storage and transport because of the great bulk of the dry grass.

The potential demand for this alternative energy source is huge. Biomass energy implies a key saving for electricity companies because it can supply extra electricity at times of peak demand. The cement and mining industry, which imports coal to process iron ore into iron and steel for export, could use Elephant grass com­pressed into pellets, similar to woodpellets, in its blast furnaces as an economical and environmentally friendly solution. Pelletized, Elephant grass could open up export markets for Malaysia.

Advantages

1. Napier grass is propagated easily.

2. It has a soft stem that is easy to cut.

3. It has deep roots, so is fairly drought resistant.

4. The tender, young leaves are an excellent animal feed.

5. Napier grass grows very fast.

Disadvantages

1. Napier grass is an aggressive plant and if it is not controlled it can invade crop fields and become a weed.

Napier grass can reach 4 meters in height and reaches a very high productivity up to 150 tonnes per hectare per year. It can capture 40 tonnes of carbon dioxide. Napier grass is easy to maintain, permitting total mechanization. Napier grass can also clean up contaminated sites. It has the ability to pull a number of pollutants out of the soil, including heavy metals. Growing on poor soils, the grass is able to pump oxygen back into the soil. There is evidence that the grass draws the toxic materials out of the soil and improves its condition as a result.

Napier grass has a much higher productivity than switchgrass, Miscanthus, or food crops. Napier grass provides fuel and animal feed. Napier grass is becoming extremely interesting, since the costs of enzymes necessary to convert cellulosic fibers into sugars has come down by about 80% in the past 3 years. It is now commercially possible to produce ethanol out of Napier grass at a cost price 50% below gasoline with a depreciation time of the refinery of 10 years. The falling enzyme costs mean they will only account for 25% of the overall production costs. The improvements come as the enzyme makers have optimized and fine-tuned the exact cocktail needed at each stage of the process.