Miscanthus is a perennial grass, research in the UK and Europe and particularly Illinois in the USA, investigated the criteria for the ideal energy crop for combustion to generate heat electricity and ethanol. It has an estimated productive lifetime of at least 20–25 years, and both the stems and leaves of the crop can be harvested annually. Miscanthus is a promising non-food crop, yielding high quality lignocellulosic material for both energy, bio fuel/ethanol and fibre production. It is characterised by relatively high yields, low moisture content at harvest, high water and nitrogen use efficiencies and an apparently low susceptibility to pests and diseases. Rainfall required is between 500mm and 750mm per annum. Much Miscanthus work in Europe has been carried out under the umbrella of the Miscanthus Productivity Network . Its main objective was to generate information on the potential of Miscanthus as a non-food crop in Europe. Whilst water-use efficiency of Miscanthus is high, it nevertheless requires irrigation at most sites during the initial stabilisation of the crop. The first phase of Miscanthus production, planting, is potentially the most capital intensive one. The high investment required for planting arises from the inability to propagate by seed, and the need to purchase the rhizome, these are not readily available. We have now imported and produced rhizomes in South Africa alleviating the expense of import from overseas and agricultural cross border problems within the SADC region. In South Africa it has been classified by the Center for Invasive Biology in Cape Town as non-invasive.
The crop in South Africa was planted in May 2009. It has reached a height of 2.2 m in the first year as against 1.5 m in Europe,UK and USA. The yield for the first year is 7 tons dry mass per hectare as against 2 tons overseas. Judging by the first years growth we expect the crop to reach maturity in its third year as against 5 years overseas.
The criteria for the ideal energy crop are:
· High dry matter yield,
· Perennial growth,
· Efficient use of nitrogen, water, other resources and
· Resistance to pests and diseases.
Miscanthus satisfies all these criteria, and the result is a crop that is both profitable and environmentally friendly. It is a non-invasive perennial grass and excellent for carbon sequestration and soil building. The establishment of the energy crop Miscanthus offers significant benefits for farmers and landowners as a low input crop offering high returns.
Listed below are some of the benefits to using Miscanthus:
· The crop, once established needs no pesticide or fertiliser treatments, and offers biodiversity and additional carbon sequestration benefits. Miscanthus is one of the most efficient and environmentally friendly means of producing sustainable biomass for renewable energy markets.
· The crop produces biomass 3 times more efficiently than conventional agricultural crops such as wheat or maize. Approximately 15647 tons of Miscanthus can be grown on 350 hectares of land. Trials in Northern KZN are returning approx 60 tons per hectare.
· One of its uses in the UK is for the remediation of soils against nematodes, particularly potato soils. Miscanthus is said to be resistant to nematodes. It was tested to see if it would remediate soils contaminated with cadmium, the cadmium killed the rhizomes.
· Once established very little or no irrigation is required, minimal amounts of nitrogen fertiliser (50 kg of fertiliser per ha per year is needed), and can be grown on marginal land.
· The crop will yield annually for up to 25 years without replanting and is non-evasive.
· Miscanthus can be used in co-generation with coal fired power stations to generate electricity and as ethanol.
· The ethanol emissions are not unsafe for human health as is ethanol from sugar cane. The first ethanol extractions done here in SA have been sent to Indiana in the USA for further treatment in order to apply new fermentation techniques to ferment the xylose. The initial laboratory extractions showed a potential of 7900 liters per 40 ton dry mass before the xylose fermentation.
· It is estimated that the ethanol returns are 16000 liters per hectare, 2.5 times that of sugar cane and 6000 liters more than casava.
· Concerning biomass for power, studies done on the dry mass from eucalyptus x grandis have shown that the average yield, including waste, cut after a 7 year growing period yields approximately 110 tons per hectare. This equates to approximately 15,5 tons per hectare per annum. Miscanthus dry mass in South Africa is showing a return of 50 tons per hectare per annum.
· There is much talk at the moment with regards to bamboo for energy. Bamboo requires a minimum of 1000mm of rain per annum….not feasible in South African conditions. Optimum rainfall to obtain an optimum crop is 2000mm of rainfall per annum. Furthermore the yields are similar to that of eucalyptus x grandis and the energy balance due to harvesting is not as good as that of Miscanthus X Giganteus.
Miscanthus also is a very efficient fuel, because the energy ratio of input to output is less than 0.2. In contrast, the ratios exceed 0.8 for ethanol and biodiesel from canola, which are other plant-derived energy sources. A 70 ton sugar cane yield will give approximately 29 tons dry mass per hectare. Dry mass yields achieved in SA for Miscanthus are showing 50 tons per hectare, calorific value at 15% moisture is 19MJ/kg. Miscanthus to coal ratio is 12 tons coal to 20 tons Miscanthus – this assessment was done in the UK at the Drax Power Station.
POWER : Energy demand and CO-emissions are compared with those of the provision
and combustion of hard coal. The energy content of Miscanthus biomass harvested from one hectare,
about 20 t of dry matter, corresponds to the energy content of 12 t hard coal. For each gigajoule of hard coal, 96.6 kg COZ are emitted during provision and combustion. By combusting Miscanthus instead of hard coal 90% of CO*-emissions can be saved.
FARMERS AND LOCAL COMMUNITIES : Farmers and local communities could grow small hectares of
M x G in order to provide their own personal/village power via gasifiers.
Companies using the Product
Our South African member have Approx 200,000 rhizomes for sale.