Wald & Energie

1. Introduction – What role can forestry and agriculture play in energy production?

As the global demand for energy is soaring, high fossil fuel prices, increasing greenhouse gas emissions and concerns over energy import dependence are prompting a major shift in the sources from which energy is derived. Alternative forms of energy are receiving considerable interest as a means to reduce fossil fuel consumption and limit greenhouse gas emissions. For instance, biomass such as wood, crops and agricultural by-products can be used as a renewable source of energy, known as bioenergy. This bioenergy could help reduce dependence on fossil fuel imports and lower energy price while emitting less greenhouse gases than fossil fuels.

Energy sources in which new plants replace those harvested are only considered renewable if biomass growth equals or exceeds harvest. The net benefit in terms of CO₂ emissions depends on the balance between CO₂ captured during plant growth and CO₂ released when producing, processing, transporting and burning the fuel. Bioenergy can contribute to climate change mitigation if the net CO₂ releases are lower than those from the energy form it replaces, notably fossil fuels. Some countries have large forested areas which, if sustainably managed, can be used as a source of bioenergy. In developing countries, traditional bioenergy such as fuelwood, charcoal, dung etc. are still widely harvested and used in an unsustainable and unsafe way for cooking and heating purposes. However, large-scale modern facilities now exist that can effectively convert wood and forest residues to heat and power.

Recently, first-generation liquid biofuels made from oil-palm, sugar cane, maize, rapeseed, soybeans, wheat and other agricultural products have gained popularity as alternative ways to power vehicles. The expansion of agricultural production for bioenergy will very likely increase pressure on land and result in increased deforestation and associated carbon emissions; these arguments are used to question the actual role of liquid biofuels in mitigating climate change. Furthermore, because fossil fuel energy is usually used to grow, harvest, process and transport crops and biofuels, the net carbon benefit may be small – even negative – in some cases. In addition, there is evidence that the use of these crops for biofuels instead of food has contributed to increased food prices. Yet, it is expected that technology will soon become available for the production of wood-based second-generation liquid biofuels that would not compete with food crops and would be much more efficient both in terms of energy conversion and greenhouse gas emissions.

In coming years, global energy use is set to climb steeply and fossil fuels are likely to remain the most economically viable sources of energy. The extent to which energy sources are likely to change in the future depends, among other things, on energy prices and dependence on fossil fuel imports, the cost and mitigation potential of alternative energy sources and the degree of commitment to climate change mitigation. More...