A method for EIA scoping of wave energy converters—based on classification of the used technology
Introduction
Wave Energy Converters (WECs) have been undergoing a significant development since the oil crisis in the 1970s, and have been subject to extensive studies. The technologies have been optimized, extensively tested and pilot wave energy projects have been realized. The knowledge and experiences gained lead to a development status that is ready for the market. The growth and interest in expanding the wave energy sector are based on its potential estimated to be up to 10 TW. Depending on what is considered to be exploitable, this covers from 15% to 66% of the total world energy consumption referred to 2006 (Engineering Committee on Oceanic Resources — Working Group on Wave Energy Conversion, 2003, Cruz et al., 2008).
WECs vary in technological concept and design. A total of 96 companies and energy concepts worldwide are listed by European Marine Equipment Council (EMEC) today; more than 56% of the WECs are located in Europe. Forty-nine different wave energy concepts are under development today only within Europe (Fig. 1). In order to gain permit from the related planning authorities to place a full scale WEC at a specific site, an Environmental Impact Assessment (EIA) is an administrative procedure that a project will usually have to pass (Zubiate et al., 2005). As WECs deployed in full scale is an early practice, only few EIAs of WECs have been carried out. It is argued by the developers, that only minor environmental impacts can be expected by deployment of WECs, and that most impacts are associated with the installation and decommissioning phase. (Sørensen and Russel, 2008). Never the less a European Directive requires that the European countries at least conduct an initial EIA screening to investigate whether or not a WEC is mandatory to conduct a full EIA.
Today Environmental Impact Assessments have been carried out for the following wave energy devices:
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AquaBuOY based on the deployment September 2007, Oregon, US (Weinstein et al., 2007) (Fig. 2).
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Wave Dragon 1:4½ prototype deployed by 2003 in Nissum Bredning, Denmark (Hansen et al., 2003) (Fig. 2).
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Wave Dragon based on the expected deployment off the west coast of Wales, UK by 2010 (Russell and Wave, 2007).
The deployment of the AWS west of Portugal in 2005 (Beirão at al. 2007) was established without any accessible EIA. So was the case with the deployment of Pelamis in Portugal, 2008 (Fig. 2) and a number of prototype shoreline devices of the OWC kind that have already been constructed and operated with varying degrees of success over the last 30 years around the World.
Further information on EIA exists for:
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The EMEC test center in Orkney, UK.
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The Wave Hub project north of Cornwall, UK established in 2008 (Harrington and Andina-Pendás 2007).
The EMEC test center has been created for the purpose of testing full scale grid connected prototype devices in a limited amount of time (Fig. 3). Being a test site, the devices are not required to be subjects of full EIAs, but an Environmental Statement demonstrating that the developers are aware of the issues and potential environmental impacts of their devices. Wave Hub is an innovative demonstration site for wave energy generation located in the South West of England, north coast of Cornwall (Harrington and Andina-Pendás, 2007). It consists of an offshore electrical “socket” to connect arrays of wave energy converters to the national grid via under-sea cables (Fig. 3).
In European EIA systems, the involvement of the public, as well as the competent authority and other responsible government agencies, is an integral part of the process. Normally it is the competent authorities together with the developer of the project and his consultants in cooperation that carry out the first two steps of an EIA, namely the screening and the scoping, and sets the plan for the following process (Kørnøv et al., 2007). The organization and quality of the communication between the developer and the authorities depend on the national legislation in the actual country as well as on the administrative body. As implementation of full scale WECs is still at an early stage, the planning authorities in the European context have in general not a specific frame or body in place to handle the applications. This increases the risk that conflicts arise from the communication and thereby the risk that there will be a lack of coordination among developer, consenting bodies, authorities and statutory consultees (Kørnøv et al., 2007, Cashmore, 2004). In the worst case scenario this may translate into a delay that may eventually jeopardize the outcome of the project. At the present time Denmark is the only European country that has an administrative body in place to coordinate the planning and implementation of offshore wind and WECs: the Danish Energy Agency. Before 2009 the Danish Energy Agency allowed the deployment of 4 wave energy converters as demonstration plants and prototypes: (Wave Dragon, Wave Star, Wave Plane and Poseidon Organ) with very smooth procedures demonstrating an efficient frame work: for the development projects EIA screenings were carried out with the conclusion that it was not necessary to conduct EIAs for the projects. The conclusion was submitted for consulting to the statutory consultees who gave 3 positive responses, for which the project could then continue its implementation with no more environmental investigations. For one of the four demonstration projects the affected municipality asked for investigation of the impact of a specific duck species, and when this was conducted and showed that the ducks would not be impacted, no further investigations were demanded and no EIA was carried out. In the UK an administrative body similar to the Danish is under construction. At European level so far activities in the maritime environment have been managed by separate policies but the EU is rapidly calling for more integrated approach with a maritime spatial planning. Offshore energy production, including wave energy, seats within the list of main activities to be coordinated. The program also foresees coordination between Member States that will lead to less bulky procedures and lower administrative costs.
It is Authors' belief that a new classification based on the expected environmental impact of the devices will make it easier for developers and authorities to carry out the scoping of this type of projects. Indeed, the high variety of existing wave energy technologies challenges the understanding of the issues involved in the process therefore preventing a slim and efficient consenting process that is desirable for a renewable energy project. As the focus of this paper is on the technical aspect of EIA regarding the delimitation and the coverage of EIAs in relation to ocean energy devices, the first two steps, Screening and Scoping of the EIA process, are of main interest.
Section snippets
Methods and materials
To identify which receptors are important to EIA of WECs, this paper takes its point of departure in the legislative context. The first part of this paper, Section 3, investigates the demands to EIA with focus on WECs within the EU. The related EU directive which is the basic EIA frame for all European Countries, is presented and the demands to the content of EIAs are described with special focus on the first two steps of the process where the scope and content of EIA is decided upon. Section 4
EU directive on EIA
EIA is an environmental management instrument implemented worldwide. EIA was introduced in The Council of the European Union, 1985 via the directive: “Council Directive 85/337/EEC—on the assessment of the effects of certain public and private projects on the environment” (85/332/EEC) and later with an amending directive in 1997 (97/11/EEC). The European Directive describes the aim of EIA as: “…providing the competent authorities with relevant information to enable them to take a decision on a
Development of an impact matrix from the EMEC EIA guidance
EMEC presented a very detailed list of information that developers must provide with respective key impact issues associated with different aspects of the device (EMEC EIA Guidance for WECs).
The proposed criteria to assess the environmental impact of wave energy converters is based on the exposure, defined as “the contact or co-occurrence of a stressor with a receptor”, and the effects describing the ability of a stressor to cause adverse consequences. The criteria for the EIA can hence be
Relevant parameters for EIA of wave energy converters
Different wave energy technologies have few things in common, one with the other, that can be listed as follows: electrical transmission infrastructure, electrical system, subsea conversion station/system and energy storage. Unless the device is onshore, these installations may be responsible for electromagnetic fields and for the impact on benthic habitats. Other common features are: shore connection, shore facilities and in most cases use of antifouling; the latter could be responsible for
D: distance from shore
It is possible to classify the devices by location (Fig. 6):
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Onshore devices. All the devices installed on land, in harbors or any device installed within the swash and surf zone.
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Intermediate water devices. All the devices installed further than the surfzone or in any case within 5 km from land.
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Offshore devices. All the devices installed further than 5 km from land.
The D parameter has direct consequences on the following receptors:
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Local communities (visual impact and recreational use of the sea).
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S: stability elements
It has been stated that most impacts are associated with establishment and decommission phase of WECs. Considerable impact can be attributed to the installation of stability elements. Four elements can provide stability to WECs depending on the device. For floating devices, anchors/moorings that allow different degrees of movements are used. Mooring lines can be
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simple mooring lines,
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complex mooring lines.
In case of wave energy parks they can form intriguing underwater patterns (Fig. 7). Simple
z/d: obstruction to water column
d being the water depth at location and z the draft of the wave energy device if floating or the extension from the sea bottom if bottom based (Folley et al. 2007), the |z/d| parameter expresses the relative obstruction of the water column (vertical) by the device. z is positive for floating devices and negative for bottom based devices (Fig. 8). The absolute value of the obstruction parameter is included between 0 and 1, assuming it is never equal to 0 and equal to 1 for total obstruction of
w/a: obstruction to sea surface
It is important to remember that the final goal of the sector is to realize wave energy farms and extract bigger quantities of energy. In this prospective the EIA must take into account impacts related to its extension, like conflict of utilization of the sea resources with other sectors, the hydrodynamic processes, sediment distribution and movement, routes of large sea species, such as mammal.
z/d being a parameter that refers to two dimensional conditions, it seems important to mention the
P: power takeoff system
The power take off systems in wave energy involve moving parts, either directly activated by wave motion (hydraulic ram, elastomeric hose pump and air turbines) or by wave energy potential (hydroelectric turbines) and a system to convert the mechanical energy into electricity (generators). The stage of conversion is obviously technology dependent and so is their expected impact on receptors; nevertheless the power take off system also allow some device classification (Drew et al., 2009).
The
Validation of assessment method
As already mentioned, because of the early stage of wave energy devices, not many technologies underwent a full EIA. In the following section the EIA of AquaBuOY and Wave Dragon is used to validate the assessment method presented in this paper. The validation is summarized and presented in Table 6, Table 7 (Weinstein et al., 2007, Russell et al., 2007).
It emerges that the assessment method succeeds in addressing the relevant parameters for the environmental impact of WECs. Also the
Suggestion for the EIA process
No clear indication from the Authorities exists on what to provide for the EIA of wave energy devices, as for them it is difficult to spot common approaches to such an enormous variety of technologies. For this reason the risk is that WE companies are dragged into a time consuming and too expensive process for the EIA and Consents process that may kill the project and consequently the technology. The case of Wave Dragon is eloquent: the developer had to take care of communication to the public,
Conclusions
Selection of relevant parameters for EIA of wave energy converters has been made. Those are:
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D parameter, indicating the distance of the installation from shore.
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S parameter, indicating the kind of element used for stabilizing the device.
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z/d parameter, indicating the relative water column obstruction (vertical) caused by the presence of the device.
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w/a parameter, indicating the relative horizontal obstruction of a wave energy farm.
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P parameter, indicating the kind of power takeoff utilized in the
Lucia Margheritini has a Master of Science in Environmental Engineering from the University of Bologna (2005), Italy. She has been working for 3 years as research assistant on wave energy at the Department of Civil Engineering at Aalborg University. Lucia Margheritini concluded her PhD titled “R&D towards commercialization of Sea wave Slot cone Generator (SSG) overtopping wave energy converter” the 4th of December 2009 and has now a PostDoc position at the Civil Engineering department of
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2020, Renewable EnergyCitation Excerpt :On the other hand, Floating Oscillating Water Column (FOWC) converters are designed to operate in deeper waters, where the wave energy resource is higher. They also present a smaller visual disturbance, and have the distinct advantage of decreased competition for marine space compared to nearshore or coastal sites [10]. For these reasons, the Spar-buoy OWC has been the subject of many recent theoretical and experimental studies [11–17].
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2020, Renewable and Sustainable Energy ReviewsThe effect of arrays of wave energy converters on the nearshore wave climate
2019, Ocean EngineeringCitation Excerpt :Therefore, a further investigation using SWAN version 41.10A and SNL-SWAN will be progressed in the future, as well as progressing the CFD NWT model to calculate WEC power matrix to be used in SNL-SWAN. Another important aspect in a wave farm study is environmental impact assessment (EIA) where a proposed wave farm should be screened for an EIA due to the uncertainty effect to the environment (O'Hagan et al., 2016) depending on devices classification define as onshore devices, intermediate water devices and offshore devices (Margheritini et al., 2012). As the focus of this present study is the impact of arrays of WECs on the nearshore wave climate, only the effect on coastal processes was evaluated.
Lucia Margheritini has a Master of Science in Environmental Engineering from the University of Bologna (2005), Italy. She has been working for 3 years as research assistant on wave energy at the Department of Civil Engineering at Aalborg University. Lucia Margheritini concluded her PhD titled “R&D towards commercialization of Sea wave Slot cone Generator (SSG) overtopping wave energy converter” the 4th of December 2009 and has now a PostDoc position at the Civil Engineering department of Aalborg University.
AMH has a Master of Science in Engineering from Aalborg University, DK (2002). She worked for five years in the administration of a Greenlandic Municipality, Qaqortup Kommunia first as a planner and later as the head of department of business and labour (2002–2007). AMH is presently writing a PhD at Aalborg University regarding strategic environmental assessment of aluminium industry in Greenland (2007–present).
Peter Frigaard Head of the Department of Civil Engineering, Aalborg University, Denmark and has a PhD in Civil Engineering. He is Member of Danish Society of Hydraulic Engineering and Member of the Society of Danish Engineers.
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