JSC Renergija - Willows Used for Biomass

Our cultured willows are mainly used for biofuel. Specific species of willows are used for biomass growing because of its ability to grow rapidly. Once implemented, the plantation yields for 25 years with a growing rate of 45 – 50 tons of green biomass per one hectare every rotation, i.e. every 3-4 years. Wood chips are the final product of willow plantations, burned in solid fuel boiler-houses. Energetic willow (Salix L) is considered as a new energy source in Lithuania, while in other countries it has been already tested as an alternative energy source to oil and gas. There are a lot gas-based boiler-houses and since it’s becoming more and more expensive, considerable number of that kind of boiler-houses are being adapted in order to burn wood.

This kind of conversion is mainly promoted by the ...

This kind of conversion is mainly promoted by the local authority in order to improve the usage of this green fuel. Our heating system is lacking for biomass wood, thus the considerable amount of wood chips is being imported from other countries. There are just about 1000 ha of willow plantations implemented and to provide the necessary amount of wood chips for the boiler-houses it should be a lot more than that.

Conventional reforestation would increase biofuel supply certainly. However, tangible economic benefits would be materialized within the decades. It would me much faster and more economical to meet the required quantity by planting short rotation fast-growing willows. These kinds of willows are growing on average 8 times faster than conventional trees. It means that the first biomass yield would be attained in four years. Considering willow plantations, the quantity of biomass is concentrated (comparing with the wood wastes). The yield is harvested quickly in the winter time and delivered straight to boiler-houses. The cultivation itself of energy willow (Salix L) plantations is quite easy and it‘s not requiring considerable investments.

Willow business is suitable for those land owners who do wish to engage in agriculture just during their free time. And for the professional farmers this is a new opportunity to establish oneself in the expanding biofuel market.

Technological Chain of Willow Plantations

Major stages of energy willow plantations:

Soil selection. Required rich soils that could accumulate greater amounts of water.
Cultivation. As plantations are mostly reared in agricultural areas, therefore conventional tillage methods are applied. In the degraded soils it is needed to increase the amount of humus, lime and fertilizer.
Preparation of planting material. Planting material consists of different genus of Salix L willow clones cuttings (20-25 cm long stem sections). Selectively enhanced clones (genetically identical individuals) are much more productive and more resistant to diseases and pests, comparing to naturally occurring willows’ varieties.
Planting. It is performed with the specialized mechanical planting unit in spring, with the density of 20,000 seedlings per hectare.
Agro technical supervision. The plantation should be protected from any weed competition during its’ first years. Mechanical and chemical protection is being used.
Fertilization. It’s being made on the basis of agrochemical soil analysis. Fertilizer types and quantities depend on the soil itself and plantations operating time.
Harvesting and chipping. Energy plantations are being harvested in the wintertime every 3-4 years. Willow stems are being cut down and crushed at the same time with the special harvesting unit, while the willow chips are falling in to the trailer that moves alongside the tractor.

Willows for Biofuel: Facts and Figures

20 tons of willow chips (green mass) are equivalent to 5 tons of coal.
1 ton of willow chips (green mass) gives 8,9 GJ of energy, which is about as much as 1 ton of peat briquettes. For comparison, 1 ton of fuel oil – 38,5 GJ of energy.
There are over 200 wood-waste-fired boiler-houses that operate now in Lithuania, which could use the green willow fuel.
The first yield of willows is attained 4-5 years. Afterwards, it is harvested every three years. Yield is about 45-50 tons (green mass) of wood from 1 ha.
Willows earn the growers an average of 1000 Lt annual income per ha.
1 square meter of willows evaporates 1 ton of water every year.
Within 3 years, willows produce about as much oxygen as is consumed while burning it.