Experts from SLR discuss the role of environmental impact assessment (EIA) in developing sustainable development policies and environmental best practice for onshore wind farms
The topography and meteorology of the UK mean that the areas with the most reliable wind resources and the greatest potential for onshore wind farm developments are usually located on elevated ground.
Typically, preferred sites are also in areas that have seen limited development. These areas can be environmentally-sensitive locations and include areas with recognised landscape value, peatlands, headwaters of important river catchments and water-dependent habitats. They can also provide habitats for sensitive ecology and ornithology, and may be used by protected species.
The need for detailed, robust and comprehensive EIA, to inform development and decision making, in these situations is clear.
Improving best practice
The need for a comprehensive EIA in sensitive locations is not a new concept, however, onshore wind farm development has a number of key aspects which differentiate it from other forms of development.
As a result, best practice guidance and protocols for the development of onshore wind farms has been developed, and is being used, to ensure that rigorous assessment is undertaken of such developments.
Regulators across the UK, including Scottish Natural Heritage, the Scottish Environment Protection Agency and the Countryside Council for Wales (which was replaced by Natural Resources Wales on 1 April 2013), have worked with wind-energy industry groups (including Scottish Renewables and RenewablesUK) and developers to create guidance documents and best practice principles to be used when assessing the impacts of onshore wind farms.
Recent examples include:
- guidance for landscape assessment;
- tools for assessing carbon balance;
- habitat restoration guidance; and
- peat-slide risk assessment.
There have been few other examples where the need for rigorous EIA has led to the development of standards and best practice on such a scale for a specific form of development.
Integrated EIA
In sensitive environments integrated EIA is paramount regardless of the form of development. Various technical specialists have a role to play in assessing potential impacts, identifying appropriate mitigation measures and achieving a sustainable form of development.
In the case of an onshore wind farm it is especially important for the hydrology, ecology and geology teams to work together, because the three disciplines are interlinked and inter-dependant. For example, peatlands can provide complex habitats for protected species and potential dewatering could cause significant effects.
It is important that a design-led approach is used for the development of onshore wind farms. This should commence with a comprehensive constraints-mapping exercise.
The process can be used to guide discussions on design and, as the constraints-map is refined and the visual impacts of the development are understood, the design can be developed in a way that ensures the most appropriate design is achieved.
For a successful onshore wind farm development, specialists are required to work together. Many onshore wind farms require a habitat management plan, and they are particularly important in areas that have a legacy associated with previous development – for example, where there has been artificial drainage of peat, associated with commercial land management practices for forestry or peat cutting.
At such sites it is possible to provide positive and tangible benefits, across several technical areas, through managed ditch blocking and habitat restoration.
Ditch blocking is another example of a specialist area that has been subject to much recent research and the publication of best practice guidance.
Whole life-cycle assessment
Many onshore wind farm EIAs consider the potential impacts associated with the construction and operation of the wind farm. It is, however, usual practice to refer only briefly to the likely method of decommissioning.
This is owing to the fact that it is generally considered that the regulatory regimes are likely to be different in 25 years’ time and it is most appropriate to consider the method of decommissioning at that time.
However, following a commission from Scottish Natural Heritage, SLR is currently examining onshore wind farm decommissioning with the aim of publishing best practice guidance.
To summarise, onshore wind farm sites are often found in sensitive environmental locations, where it can be challenging to characterise baseline conditions.
Such developments are subject to thorough consultee, local authority and third-party review, and it is not usual for them to be the subject of appeal or for environmental statements to be considered at hearings and public inquires.
As such, onshore developments , perhaps more than many other area of development, have been the catalyst for much of the recent best practice guidance and developing survey and assessment approaches to promote the rigorous application of EIA.
This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.
