Finnveden et al. (2009) distinguish between two types of LCAs: attributional and consequential LCAs. The attributional LCA is defined by its focus on describing the

environmentally relevant physical flows to and from a life cycle and its subsystems. The consequential LCA is defined by its aim of describing how environmentally relevant flows will change in response to possible decisions (Curran et al. 2005). Similar distinctions have been made in several other publications, but often using other terms to denote the two types of LCA, and sometimes including further distinctions of subcategories within the two main types of LCA (Guinee et al. 2002). Baumann and Tillman (2004), for instance, distinguish at least three types of LCAs, namely LCAs of the accounting type, LCAs of the change-oriented type and standalone LCAs.

LCA studies of the accounting type are comparative and retrospective. This type of LCA is well suited to different types of eco-labelling and can be used in purchasing or procurement situations, since these applications involve a comparison of existing products. LCA studies of the change-oriented type are comparative and prospective. This makes them useful in product development, building design and process choices, since decision-making involves a comparison of options that may be implemented or produced in the future. A standalone LCA is used to describe a single product, often in an exploratory way in order to get acquainted with some important environmental characteristics of that product, identifying the ‘hot spots’ in the life-cycle, i. e. which activities cause the greatest environmental impact (Baumann and Tillman 2004).

In general, the attributional method is the most used in LCA, but in LCA of bioenergy systems the consequential methods appears as the most broadly applied. Almost 75 % of relevant studies reviewed by Cherubini and Str0mman (2011) compare the environmental impacts with those of a fossil reference system, as they are aimed at addressing the needs of policy makers, since consequential LCA is more relevant for decision-making.