Miscanthus x giganteus (MxG) is one of the leading candidate biomass crops and has the advantage that it can also grow under marginal site conditions. MxG biomass can be used in several different utilization pathways. When harvested green in the period September to October, it can be used as a biogas substrate. When harvested in early spring, it is suitable for combustion as a late harvest leads to lower water and mineral content. In addition, MxG biomass can be fermented to ethanol or used as a raw material to produce insulation material, pulp or bio-composites.
“Energy grass” Miscanthus x giganteus can be used for:
- Combustion for electricity and heat production in either biomass-dedicated plants or by being co-fired in more traditional coal plants.
- Construction — incorporation in the manufacture of medium density fibreboard (MDF) and isolation materials.
- Conversion to liquid fuels, in cellulosic fuel processes MxG is a stable and cost-effective feedstock.
- Paper, cellulosic fibre production and fibre-based materials (sustainable pulp and packaging)
- Chemical applications like renewable plastics and additives, in place of petroleum-based ingredients.
- Animal bedding and agricultural mulch.
Miscanthus Giganteus represents a key candidate energy crop for use in biomass-to-liquid fuel-conversion processes and biorefineries to produce a range of liquid fuels and chemicals; it has recently attracted considerable attention. Its yield, elemental composition, carbohydrate and lignin content and composition are of high importance for future biofuel production and development. Starting from Miscanthus, various pre-treatment technologies have recently been developed to break down the lignin structure, disrupt the crystalline structure of cellulose, and enhance its enzyme digestibility. These technologies included chemical, physicochemical, and biological pre-treatments. Due to its significantly lower concentrations of moisture and ash, Miscanthus also represents a key candidate crop for use in biomass-to-liquid conversion processes to produce a range of liquid fuels and chemicals by thermochemical conversion.
At present, the primary market for MxG is the energy market. MxG biomass can be used to produce heat, CHP or electricity power on a range of scales from large power stations (30MW+) requiring hundreds of thousands of tonnes of biomass annually, to small-scale systems (on-farm or single building) requiring just a few dozen tonnes during winter months. MG biomass can be pressed into fuel pellets / briggets or chipped and can be burned when needed — in the same way as oil, gas or coal.
If we assume an average yield figure of harvested miscanthus at 25 tonnes per hectare at 15% moisture and the energy per tonne at 19 GJ, one hectare will produce approximately 400 GJ at this yield level. At the time of harvest, miscanthus biomass has a water content of around 15%. A further drying process is therefore not necessary. A mean calorific value is around 4.3 kWh kg−1 in fresh biomass. More conservative scenario with 20% average moisture content is giving for MxG chips the calorific value of 3,805 kWh/tonne.
| Fuel – 20% MC | kWh per ton | Price per ton | Cent per kWh | Value per GJ |
| Miscanthus chips | 3.805 | 60 € | 0.016 € | 4.36 € |
*€4.36 per Gigajoule is equivalent to €0.16 cent per litre of home heating oil.
1,000 litres of oil contains 36.68 GJ of energy. The price of oil continues to fluctuate; however, it is possible to benchmark the price of biomass to that of the well-established supply chain of home heating oil. One litre of home heating oil contains approximately 10.5 kiloWatt hours (kWh) of energy. The table below shows that the value of home heating oil at €0.90 per litre is €23.61 per GigaJoule (GJ) of energy. To calculate the value per GJ, multiply the cent / kWh by 277.78.
| Cost per litre (€) | €/kWh | Value per GJ |
| 1.10 | 0.104 | 28.89 |
| 1.00 | 0.095 | 26.39 |
| 0.90 | 0.085 | 23.61 |
| 0.80 | 0.076 | 21.11 |
| 0.70 | 0.066 | 18.33 |
| 0.60 | 0.056 | 15.56 |
| 0.50 | 0.047 | 13.05 |
You can find ”Miscanthus Best Practice Manual” bellow, with its markets and economics info, or download it following this link:
MiscanthusBestPracticeManual190913
The return is very sensitive to:
- Site selection & soil fertility
- Crop establishment (rhizomes quality & generation, planting density, weed control etc.)
- Crop yield and price per tonne of harvested miscanthus
From year 2 onwards the MxG crop is harvested annually. The second-year harvestable yields may range from 8-12 t/ha, and those in the third year may achieve between 18-25 t/ha or more at 20% moisture content. Harvestable yields reach a plateau after 3-4 years. The reasons for the variation in the yield building phase duration and yield in the plateau phase depends on planting material, planting density, soil type, climate.