Assessing environmental impacts of renewable power

• Electrical power systems based on renewable energy sources are often intuitivelyperceived as environmentally benign. This may be true at least for comparisonsbetween electricity generated by combustion of fossil fuels and non-combustionbasedrenewable sources, at least in terms of contributions to greenhouse gas(GHG) emissions (Chapter 7) and other air polluting gases. However, there existsno system generating electric power for applications on commercially relevantscales that is completely without unwanted environmental side effects; it is morea question of which environmental effects and their severity. Given the seriousimplications of climate change, the motivation to find substitutes for fossil-basedenergy systems is strong, but it is likewise important to not solve one environmentalproblem by creating another, although of a different type. In order to preventthat, systematic investigations and assessments of the environmental performanceof different renewable electricity sources become crucially important.The methods applied for environmental assessments of renewable energy sourcesneed to be applicable to a number of fundamentally different energy systems,spanning from the construction of offshore wind power farms to hydroelectricpower dams. These different energy sources provide a set of very differentenvironmental impacts occurring in many different ecosystems. The challenge ofthe environmental assessment methods is to deliver assessment results that arefair and encompass the various significant environmental impacts under different conditions. Particularly when seen from a life-cycle perspective, encompassingthe raw material extraction, production and use of the energy, a number of environmentalimpacts in terms of both resource extraction and emissions becomeapparent, even for renewable energy systems. Therefore, careful consideration ofenvironmental impacts of renewable energy systems along the entire life-cycle ofthe energy systems is important to avoid serious environmental repercussions (seealso Chapter 8).In addition, based on earlier experiences, it is apparent that the specific design,location and scale of e.g. hydro and wind power installations are factors thatto a large extent determine their environmental impacts (see also Chapter 9). Asmaller installation will often result in less environmental impact than a large-scale.These factors are so-called site-dependent and cannot easily be assessed in astandardised manner, which calls for flexible and adjustable assessment methodsthat can be adapted to the specific case. An unfortunate location of a hydropowerdam does not mean that the entire technology carry unacceptable environmentalimpacts, just that the specific location or design in the specific case is unfortunate.This chapter aims at a general description of the challenges posed when tryingto assess environmental impacts of renewable energy technologies and to, withlimited technical detail, introduce the ways environmental impacts are assessed.Furthermore, a few specific examples will be employed to exemplify environmentalimpacts of renewable power systems.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Naturresursteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Engineering (hsv//eng)

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