**1.2. Life cycle assessment**

significant challenges from the perspective of soil and water quality. At the same time, bioenergy systems present new opportunities to improve land and water sustainability and productivity,

In the search to develop renewable energy, woody and agricultural crops are being considered as an important source of low environmental impact feedstocks for electrical generation and biofuels production [4–7]. In countries like the USA, the bioenergy feedstock potential is dominated by agriculture (73%) [8]. In others like Finland, the largest feedstock source comes from forest resources. Forest bioenergy operational activities encompass activities of a continuing and cyclical nature such as stand establishment, mid-rotation silviculture, harvesting, product transportation, wood storage, energy production, ash recycling, and then back to stand establishment [8]. All of these have the potential to produce disturbance that might affect site quality and water resources, but the frequency for any given site is low [9– 12]. Agricultural production of feedstocks involves annual activities that have a much higher potential to affect soils and water resources. Since the rotational cycle for forestry is much less

frequent, the potential for disturbance to water and soil resources is greatly reduced.

The way forward relative to assessing the soil and water impacts of bioenergy systems and the sustainability of biomass production rests with three approaches that could be used individually but are more likely to be employed in some combination [12]. These approaches are: (1) Utilizing characteristics that can be quantified in Life Cycle Assessment (LCA) studies by

as well as addressing soil and water impacts produced by current land use.

**Figure 1.** Linkages between bioenergy systems, soils, and water in an agroforestry landscape (From [2]).

**1.1. Background**

114 Energy Systems and Environment

Life Cycle Assessment has been used to estimate the environmental impacts of biomass energy uses. Typically they examine greenhouse gas (GHG) emissions, CO2 emissions, energy balance, and some indirect effects. A review of published LCAs, revealed that more than half of the studies were from North America and Europe, and that most are found in papers published in scientific journals [9–11]. Increased numbers of South Asia, Africa, and South America can be found. About 50% of the studies limited the LCA to GHG and energy balances without considering contributions of bioenergy programs to other impact categories such as soils and water. The published studies concluded that there are a number of problems in currently used LCA approaches that make it impossible to quantify environmental impacts from bioenergy programs. Some of the key indirect effects issues strongly depend on local operations, vegetation, soil, and climate conditions that tend to make accurate assessment of environmental effects very problematic.

Although politicians and upper level managers claim that methods exist for assessing environmental impacts on soil and water, the scientific foundation for estimating indirect effects of bioenergy programs is constrained by the lack of adequate validation research, accurate assessment methods, and the relative infancy of the LCA process. It was clearly pointed out that determination of environmental outcomes of bioenergy production is complex and can lead to a wide range of results [11, 12]. This review clearly stated that the inclusion of indirect environmental effects in LCA represents the next research challenge and not the immediate incorporation into the assessment methodology.
