Harnessing geography for European wind

Justin Saunders

What's the best place for a wind farm? Not just any old hillside or "somewhere offshore". Deciding where to site a wind farm involves a range of criteria that can be termed “location intelligence”. This concept is playing a growing role in the planning, design and siting of European wind farms, says Justin Saunders.

When the UK government approved the giant 750 MW Gwynt y Mor wind farm off the coast of Llandudno, North Wales, in December 2008, key considerations about the exact location included the distance from the shore and how the visual impact from points along the coast could be minimised.

The developers had worked within a Government-set “strategic area”, carrying out studies and consultations to map the precise positions of turbines, and to show how they would affect visibility, marine navigation, ecology and fishing activities.

Similarly, the environmental statement behind plans for the forthcoming 152-turbine onshore farm at Clyde in south Lanarkshire, Scotland, involved the graphical representation of physical survey results shown against customised map data. Consultants created a series of 3D visualisations, photomontages, ZTVs (zones of theoretical visibility) and digital terrain and elevation models that accurately predicted how the farm would appear.

And another example can be seen in northwest Portugal, where the December 2008 commissioning of the 240MW farm at Ventominho, also required a wide array of geographic assessments to be carried out during design and construction. Complex logistical issues had to be tackled to connect five sub-farms across a 30km zone with a single point of connection to the electricity grid.

Location intelligence

Deciding where to site a wind farm involves a range of criteria that can be termed “location intelligence”. More than simply a map, location intelligence concerns the ability to process, manage and share different kinds of information relating to a particular point or wider geographic area. The concept has evolved from the rather specialist preserve known as geographic information systems or GIS. These are essentially sets of software tools working together to create, manipulate and present digital map data on screen.
Commercial grid operator seizes the moment

Meanwhile Imera Ltd, a Dublin-based asset development company specialising in subsea power interconnectors and power transmission grids, has received EU approval for its first interconnectors linking Ireland and the UK.

The EU approval came in January 2009 as an EU Exemption for Third Party Access on Imera's East West Interconnector (Ireland -UK). According to Grace Samodal, senior VP, commercial and trading, at Imera, “This exemption allows us to operate on a merchant basis.”

At present, Imera holds five licences to build, own, and operate interconnectors and is actively developing interconnectors between Ireland and the UK, France and the UK, and Belgium and the UK. These projects form the foundation for EuropaGrid.

The company is now set to build the North Sea and Atlantic electricity grids, connecting key markets and offshore wind farms as the foundation of a pan-European offshore electricity network. The company claims that EuropaGrid will enable the development of a true European integrated power market and greatly enhance security of electricity supply.

Once installed, EuropaGrid will consist of a large grid of sub-sea AC and DC cables. These will connect Ireland with the UK and France and the UK with France and Belgium. Future interconnector projects will connect other countries in Europe and interconnectors will be linked to form a “mesh” or a grid.

Connections to this grid for large offshore wind projects will be provided in order to connect all major wind projects and national transmission systems in Europe.

Rory O'Neill, Imera's ceo, said, “there are two main factors driving the development of the North Sea Grid – the EU's call for increased interconnection across Europe as a priority issue, and its target of 20% of its required energy from renewable sources by 2020. Imera's EuropaGrid will not only fast-track increased cross-border interconnection in Europe, but also enable enormous growth in renewable generation developments.”

Imera's approach is expected to allow electricity produced from offshore wind generation to be traded in the single electricity market. It is also said to be the most efficient way of building interconnectors and transmission connections for offshore generators as it eliminates duplication and unused capacity on sub-sea cables.

And O'Neill added, “because we are a private company, we can build networks faster and cheaper than most regulated organisations. We also have access to the largest fleet of specialised cable-laying vessels and marine engineering expertise through our parent company, Oceanteam.”

Imera is currently raising over €100M in investment to finance the development of the first phase of EuropaGrid.

In a GIS that supports a site location map for a proposed wind farm, additional statistical data will typically be imported as files from a spreadsheet to a server-based database system. A statistical program then helps to categorise data inputs and define the geographic area parameters. This can help developers compare different turbine positions in relation to wind speed, grid capacity, power lines, visual intrusion and other factors. Finding the optimum position for a turbine can improve the efficiency of energy production and protect against unnecessary costs. That goes for both single turbines and industrial-scale farms whether on- or offshore.

Onshore, mapping at a scale of 1:50,000 is ideal for looking at the surrounding geographic context of a proposed development, including road infrastructure. Closer in, scales higher than 1:25,000 offer more detail, with individual building outlines, critical access routes and field boundaries coming into view. Preliminary site investigation must then take into account even more local factors such as slopes, lines of sight, ridge lines and gradients. These are contained in digital surface and terrain models, 3D elevation data and high-resolution aerial imagery that matches underlying mapping through a process called orthorectification.

Precise geographic data can be used to:

  •  Help develop accurate analyses;
  •  Present site plans for the official planning approval process;
  •  Deliver ongoing project management;
  •  Provide contextual information to enable insurers to assess risk and provide cover for the turbine   machinery, connections and cabling;
  •  Mapping can also show noise contours around a potential site to help influence design and address any abatement needs.

Bespoke web services are enabling users to embed mapping components directly into their database applications, thus replacing shipments of off-the-shelf data stacks that require onward processing.

This trend towards web-based location intelligence is opening up engineering-grade data for mainstream use that was once the sole domain of geographic technologists.

Benefits of GIS

GIS as a technical subject, far from being the preserve of experts, is easy-to-use, and its practical applications are likely to benefit sectors such as the wind power industry.

In the construction phase of an offshore farm, for example, GIS can help engineers and project managers to monitor and track activities as they happen on and under the sea. This can be vital for ensuring the health and safety of personnel and the protection of kit and infrastructure assets.

And combining GIS and the internet allows different layers of information to be fed in to multiple workstations and mobile units, giving different users an up-to-date picture of weather conditions, wind speed, boat movements, wave heights and so on. All the information is captured, referenced, connected, analysed and stored online.

In Germany, the renewables industry has long recognised the importance of location to the viability and efficiency of wind farms. The push to offshore generation is in part down to a lack of suitable land for onshore developments and the influence of stricter planning requirements.

On the research side, the Deutsche Energie-Agentur (dena), has used geographic information in a study of how best to integrate on- and off-shore grid capacity. One of the considerations was the need to compensate for the sizeable extra cost of laying foundations and grid connections for the growing number of offshore turbines.

Dena believes it is necessary to identify pilot zones in relatively shallow waters within 50km of the coast and to lay bundled cables into an expanded onshore grid. The agency says laying many parallel cables through sensitive ecological areas such as the Wadden Sea would create a serious risk to the undersea environment.

Belgium provides another national case study of the use of location intelligence. There, successive Government directives on wind farming have also laid down criteria for the selection of zoning, and hence emphasised the benefits of accurate geographic information.

The European Wind Atlas – and beyond

As with other EU countries, Belgium looked to the European Wind Atlas as a starting point for assessing wind energy applications. This atlas was first published in hard copy in 1989. It was intended as a comprehensive data bank of the wind climate across Europe, containing statistics from more than 200 weather stations and a software pack for producing regional charts of wind speed and directions.

Researchers at the University of Brussels, acting on their agreed national criteria, then published an inventory of suitable locations based on regional zoning maps. This phase considered issues such as planning and building regulations and further investigations into topographic and environmental issues. The next step was to work with utility companies to examine the capacity of the grid and cost of connecting with preferred locations. The study produced a “capacity map” to help compute the bulk cost of wind-generated electricity.

The growth of professional standard mapping in the wind farm sector has now been strengthened by advances in surveying that make it possible to measure and portray the lay of the land in centimetric detail so that the most optimal positions for power facilities can be found. Laser-driven airborne techniques, aerial photography and satellite imagery are central to the mix, along with ground-based data capture fixed with GPS. All of this can sit within a common geographic reference framework for ease of sharing and associating data. An example of such a framework is OS MasterMap in Great Britain.

At the same time, the trend towards online delivery and web services means developers can have a fully hosted “location solution” brought direct to the desktop rather than just a data feed. This has benefits in data storage, copyright management and time and cost savings. Hosted services such as eMapSite provide multiple search criteria and the means of exporting data in different formats for CAD, GIS and graphics software.

Looking ahead, it is likely that more and more site projects will be managed through dedicated web resources, just as in other land and property sectors that use advanced mapping solutions. In larger wind energy construction projects, for example, authorised consultants and contractors will increasingly be given appropriate tiers of access to site plans and other map data through secure log-ins to assist with asset management, health and safety, information storage and analysis.

One of the core considerations going forward will be the need to strike the right balance between cutting carbon emissions overall and sustaining biodiversity around specific site locations. In the UK, guidance produced by the British Wind Energy Association and nature conservation bodies recognises the potential benefits of wind energy as long as the “right development is in the right location”. In this regard, geographic boundary analysis can help to ensure wind farms do not cause adverse effects on the integrity of nature reserves, Special Areas of Conservation or Sites of Special Scientific interest.

European and national legislation also governs the protection of plants and animal species through the mapping of bird migration routes, local flight paths, foraging areas and cliff, headland, valley, ridge and other habitats. When adjacent wind farms are proposed, geographic information can help to show the wider cumulative impacts on biodiversity through scenario models.

Return on investment

Essentially, whether you call it a map or a “spatial context”, the point of using geographic information is to help extract value from data and provide a tangible return on investment. A mapping interface can inform vital decisions by showing information in a graphical form that can never be achieved by tables of figures or text alone. For example, viewing a fly-around animation built with geographic co-ordinates, 3D visualisation tools and topographic and elevation mapping can help bring a proposed development to life on screen – ideal for presentations, planning applications and reports. The geographic context can help clarify the development proposition to stakeholders and allow engineers to iterate turbine position in response to wind models, accessibility, surface geology and visual impact.

A key challenge for map data providers: to work with consultancies and wind energy companies to continue to enhance data quality and functionality.

Solutions should be available in industry-standard development environments such as Javascript and use internationally recognised protocols such as XML (eXtensible Markup Language), WMS (Web Map Service) and WFS (Web Feature Service). The requirements of application developers and solution providers are best served through a suite of accessible, interoperable web services that adhere to these standards. For the end user, the watchwords are accuracy, cost-effectiveness and ease-of-use.

About the author
Justin Saunders is co-founder and technical director of the UK mapping provider, eMapSite, and a member of the British Wind Energy Association


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