03.08.2015   ADVANCES IN

SUSTAINABILITY OF BIOENERGY: AGRICULTURAL AND PROCESSING INPUTS

To guarantee sustainable agriculture and processing of energy crops, we included a sustainable framework for the inputs required for them.

The yield projections for energy crops in this study are based on rain — fed agricultural systems where nutrients are added to the land.

3.3.2.1 AGRICULTURAL WATER USE

Regarding agricultural water use, this means that no irrigation is used for the energy crops in this study. Energy crop yields are scaled in accor­dance with the land’s suitability for rain-fed agriculture to reflect this. This means that most of the yields in this work are at around 50-70% of the maximum yield currently obtained in high input agricultural systems.

Table 3 gives ranges for these yields, as they differ per region. The number given in Table 3 is in primary biomass yield of the main product.

TABLE 3: Yields of energy crops used in this study in primary biomass yield of the main product.

Crop type

Range of yields across the regions (GJ ha-1)

Comments

Oils + fats

25-35 (-0.5-1 tonne ha-1 of oil)

Equates to -22-31 GJ ha-1 of transport fuel

Number includes only primary oil yields; agricultural and fuel processing residues are included elsewhere

Marker crops: rapeseed, soybeans and oil palm

Sugar + starch

62-121 (-4-7 tonne ha-1 of starch or sugar)

Equates to -49-95 GJ ha-1 of transport fuel

Number includes only primary starch/sugar yields; agricultural and fuel processing resi­dues are included elsewhere

Marker crops: sugar cane and maize

Highest yields in South America due to suit­ability for sugar cane

(Ligno) cellulosic

160-230 (-8-12 tonne ha-1

Equates to -61-88 GJ ha-1 of transport fuel

crops

of dry matter)

Number includes all primary biomass yields; fuel processing residues are included elsewhere