More fuel from wood

The research cooperative "Biomass for SunFuel®", founded in 2003 by the states of Lower Saxony, Brandenburg and Hesse together with Volkswagen, is set to continue in the future. The purpose of the cooperative is to obtain new findings on the development and introduction of synthetic fuels in the context of Volkswagen's fuel and drive strategy, thus forming the basis for the production of biogenic fuels such as SunDiesel®. At a meeting in Wolfsburg in June 2009, the participants discussed new projects primarily involving the development of various types of woody biomass to generate energy (Presentations from 17th June 2009).

While the first phase of the research cooperative concentrated on the agricultural production of annual crops such as corn, rye, wheat, millet and sunflower (Results of 1st phase), in the future the focus will be on the production of "fast-growing energy wood" and other woody residues, which to date have been subjected to less testing. Biofuels, which are said to compete with food plants for land, could benefit from these raw materials since the plants in question are not edible. Furthermore, the term "residue" encompasses previously unusable material found in forest and landscape conservation, for example. Biomass from grasslands contaminated with heavy metal, which are increasingly more difficult to cultivate because of this contamination, could also be potential raw materials for energy generation.

Better exploitation of wood potential
One starting point for this second cooperation phase is continuing to have enough raw timber for material and energy use despite the rising demand for wood in industrial nations and the increasing demand for energy in Europe. In order for this to take place, production and use of raw timber must be intensified on existing land. In other words, existing stocks of timber that have been unexploited until now must be made available for efficient use from an economic perspective.

The current market for raw timber focuses on types of wood that have been traditionally used, such as beech, spruce, pine and larch, as they are particularly advantageous for forestry with regard to cost and revenue. Smallwood such as birch, alder, willow, poplar and rowan are considered to be wood species of little added value and have thus far been hardly used if at all. Therefore, resources exist that are available for immediate use and that, in terms of energy generation, can be beneficial from an ecological standpoint and profitable from a business perspective. Unlike the cultivation of trees in short rotation plantations, no additional land is needed, which is why they do not compete with the agricultural production of food either.

Opportunities for forestry
Compared with short-rotation plantations, another positive aspect of using existing raw materials is that it is not necessary to make investments in energy, fertiliser or workers. In Germany, the timber stock from these trees is about 180 million cubic metres, which corresponds to approx. 15% of the overall stock of deciduous wood. In the states of Brandenburg, Saxony and Mecklenburg-Western Pomerania, the stock of deciduous wood accounts for 30%. And this stock is hardly used, thus staying in the forest. For example, although growth of 32 million cubic metres was recorded between 1987 and 2004 in former West Germany, only about 1.2 million was actually used.

The planned project therefore seeks to estimate the actual potential available and then develop and use it in an environmentally friendly way. The task will be investigating which types of wood are to be used for which purposes in order to achieve the greatest yield. The use of the types of trees mentioned above could be an important contribution to supplying the energy sector and improving the economic situation of forestry at the same time.

Using our cultural landscape sustainably
There is also raw material potential for energy use that should not be underestimated in the areas of landscape conservation, roadside vegetation, strips of trees and hedges as well as growth on land that can no longer be used for agriculture due to the size structure. Current findings give a rough estimate of up to 1.2 million tons per year. Targeting this land for cultivation could increase the potential even more. Such biomass has the advantage that it has adapted to its location over many generations by means of natural selection and does not require fertiliser, plant protection, etc. However, there is still a lack of cost-effective, preferably fully mechanised, harvesting techniques suitable for inhomogeneous, naturally occurring biomass and the wide variety of soil conditions. Consequently, a further project will be investigating not only the identification of potential land fit for development from an ecological and business perspective but also the technical options for profitable harvesting.

Short-rotation forestry as wind protection
Fast-growing trees can not only be used in short-rotation plantations, they can also be planted in strips for wind protection on land at risk of erosion. A demonstration project is meant to investigate the effectiveness of wind protection for intensively cultivated farmlands larger than 25 ha and whether humus content, biodiversity and natural scenery can be improved. In addition, it should also be examined whether profitability can be attained by increasing agricultural yields and selling energy wood.

And what comes after the plantation?
Short-rotation plantations distinguish themselves from an ecological perspective because they are capable of storing large amounts of carbon and nitrogen in the soil over the course of their lives by forming roots, just to name one reason. If a short-rotation plantation is reconverted to traditional farming after twenty years or more, intensive tillage is usually required involving deep cutting, soil loosening and breaking up of roots. This procedure releases or mineralises a large amount of carbon and nitrogen that had previously been organically bound, meaning that it is no longer available for subsequent plants.
To avoid just this, a project at the University of Kassel is investigating which reduced tillage techniques allow the greatest possible amount of organically bound carbon and nitrogen to remain in the soil.
 
Read about the energy potential of fallow land and flotsam in Part 2.