Biofuels appeared to be such a nice way of reducing the climate change challenge: it reduces political dependence on fossil fuel supply, can be done with minimal change to existing engines and modes of transport, and provides new sources of income for rural economies. Calculations of the area needed to make a dent into current fossil fuel use quickly showed that it cannot be a substantial contribution to energy issues without requiring large areas and interfering with markets for food crops. If biofuel production extends beyond current agriculture, it will often increase emissions of carbondioxide. The net effect will be often a lower estimate of emission reduction than expected, but if high C-stock land is cleared, biofuel use can also increase net emissions. The debate on such emission enhancement has focussed on oil palm in the humid tropics of SE Asia, where forest and peatland conversion currently lead to large emissions – with or without a specific role for oil palm expansion. The public debate, however, has linked the two issues. The EU provided guidance to countries on minimum standards that should be used when biofuels are included in national renewable energy plans. Until 2017, a minimum emission reduction of 35% has to be achieved for any fuel included in the scheme, shifting to 50% by 2017 and 60% beyond. Default estimates are given for major current or potential sources of biofuel. A procedure was established to calculate emission reduction factors, using a lifecycle approach. Specific market flows of biofuels can apply for exception from the 'default' for the commodity. These procedures create the need for exporting countries and entities to understand the steps in calculation and to do the research needed to get reliable data.

 

 

 

Land cover change often involves multiple steps between 'natural forest' and 'biofuel feedstock plantation'. The first challenge is to reconstruct what happened by analysis of remote sensing imagery (time-series) combined with interviews with local witnesses. The second step is to negotiate the 'attribution' of this change to multiple actors and agents (e.g. legal, government sanctioned and illegal logging, natural and human-induced fire). See RASA for details on the methods for reconstructing land cover change.

 

 

 

The average over a production cycle of the sum of 5 C pools (aboveground biomass, understorey vegetation, surface necromass, soil organic matter and roots) is called 'time-averaged C stock'. When the preceding vegetation has a higher time-averaged C stock, the plantation starts with a 'Carbon Debt' with a 'pay back time' or annualized draw on the biofuel C accounting. If it is lower, the el term can reflect a net emission saving for the first production cycle. Methods for measurement of the pools where described in RACSA methodology and technical manuals.

 

 

 

Plantation management includes use of cover crops, recycling of dead leaves and litter, recycling of organic wastes from the factory. Rather than having to trace all these flows, we focus on the end result. Appropriate sampling scheme for soil C can compare actual to what would be expected under forest soil conditions ('C/Cref' ratio). Sampling depths is an issue. For peat soils a separate calculation scheme is needed, as the whole profile can change.

 

 

IPCC National Greenhouse Gas inventory guidelines suggest that 1% of N fertilizer is lost as N₂O from agricultural systems. Other literature suggests this can be 4%. In the absence of site-specific measurements, both assumptions can be compared for impact on the end result.

 

 

Emission factors for transport and mill are based on fossil fuel use and technical design of mill and processing steps before the product reaches the end-user.

 

Current 'default' value refers to knowledge at inception stage and will be modified by the full-scale assessment:

 

 

The net result is very sensitive to the preceding vegetation. For the oil palm example, a minimum emission reduction efficiency of 35% can only be reached in a 2nd production cycle, or when oil palm replaced vegetation of less than 40 t C/ha. Investment in CH4 capture at the mill can improve the situation. Where peat soils are used, the effects of drainage on emissions usually means the target efficiency can not be met. A third factor with considerable influence is the use of N fertilizer in relation to yield. Increase in N use efficiency can lower costs as well as help reaching the fossil fuel substitution efficiency.

 

 

 

 

Crutzen PJ, Mosier AR, Smith KA, and Winiwarter W. 2008. N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels. Atmos. Chem. Phys., 8, 389–395, 2008

 

Dewi S, Khasanah N, Rahayu S, Ekadinata A and van Noordwijk M. 2009. Carbon Footprint of Indonesian Palm Oil Production: a Pilot Study. Bogor, Indonesia. World Agroforestry Centre - ICRAF SEA Regional Office. http://www.worldagroforestry.org/sea/publication?do=view_pub_detail&pub_no=LE0153-09

 

DIRECTIVE 2009/28/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC. Official Journal of the European Union 5.6.2009: 16-62.

 

Hairiah K and Rahayu S. 2007. Pengukuran karbon tersimpan di berbagai macam penggunaan lahan. Bogor, Indonesia. World Agroforestry Centre - ICRAF, SEA Regional Office. 77p. http://www.worldagroforestry.org/sea/publication?do=view_pub_detail&pub_no=MN0035-07

 

IPCC. 1996. Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories. Intergovernmental Panel on Climate Change (IPCC). Geneva, Switzerland.