Contents

1.0 Introduction 4
2.0 Wave Energy Technologies – Spill Over /Overtopping Devices 5 2.1 Wave Capture Systems 5 2.2 Wave Dragon (Offshore) 6 2.3 Point Absorbers (Near/Offshore) 7 2.4 Oscillating Water Column (Nearshore) 7 2.5 Hinged Contour Devices (Near/Offshore) 8 2.6 Case Study – Pelamis DeviceI 9 2.7 Economic Appraisal 9 2.6 Non Technological Barriers - Environmental Impacts: 13 2.7 Non Technological Barriers - Social Impacts: 16 2.8 Miscellaneous Non Technological Barriers 16 2.9 Technological Barriers that impact the deployment of wave energy 17
3.0 Tidal Stream Technologies 21 3.1 Horizontal Axis Turbines 21 3.2 Vertical Axis Turbines 22 3.3 Reciprocating devices (oscillating hydrofoils) 22 3.4 Venturi Effect Tidal Stream Devices 23 3.5 Economic Appraisal: 24 3.6 Non Technological Barriers – Socio-Economic & Environmental Impacts: 27 3.7 Technological Barriers that impact the deployment of Tidal Stream energy. 29 3.8 Grid Integration: 30 3.8.1 Grid connection charges 30 3.8.2 Connection Charges. 30 3.9 Grid Connection. 30 3.9.1 Technological Barriers for Tidal Stream 31 3.10 Research and Development for future Irish Energy Strategies:. 37
4.0 Summary 41
5.0 Conclusion 41 5.1 Wave Energy: 42 5.2 Tidal Stream: 42
Bibliography 46

1.0 Introduction

The aim of this report is to critically review the socio-economic and environmental impacts associated with Ocean Energy Technologies. The author begins the review by providing some examples of Wave Energy Conversion devices and then selects one type in which the impacts are discussed and critically examined in an Irish context. An economic appraisal is provided on the WEC and then the technical and non-technical barriers to the development of WEC’s are provided, using Irish, British and international experiences as examples. The author will examine a pilot programme which is being developed off Co. Mayo relating to wave energy. A detailed environmental impact assessment is provided showing both positive and negative impacts associated with the use of WEC devices. The next section details the issues pertaining to grid integration for the WEC. This provides details on grid capacity, interconnections, smart grids and energy storage options. In the next part of the report, the author provides information on research, design and development options for WEC.

The next section of the report, examining Tidal Stream devices, follows the same approach as for the WEC. A brief overview of some of the technologies available for Tidal Energy Devices (TED’s) is provided. A combined socio-economic and environmental assessment is provided which shows the non-technological barriers associated with the TED under review (the SeaGen device) in Strangford Lough, County Down.

The author then examines the issues pertaining to the integration of the TED into existing electricity grids for Northern Ireland and the Republic of Ireland. While the technological barriers are not significant, the barriers for integration are and the author explores these in detail. Part of the review takes into account the economics surrounding the implementation of TED’s in the UK and Ireland. The report finishes by providing examples of where further Research and Development projects are to take place to help further the introduction of TED’s in Ireland, the UK and the rest of the world.

2.0 Wave Energy Technologies – Spill Over /Overtopping Devices

2.1 Wave Capture Systems - potential for Energy extraction and integration with grid systems: The Tapchan (on shore) system is an example of this type of technology which was piloted in Norway in 1985. Waves break over a sea wall and water is impounded or dammed at a head height greater than sea level. The seawater then returns to sea through a low head generator. As the larger waves overtop the structure, smaller waves increase in height within the channel providing water in the reservoir.
[pic]
Figure 3: Schematic Diagram of the Tapchan Wave Capture System (Twidell and Weir 2006 p.419)

According to Twidell and Weir (ibid) the concept was used in a rock shore environment which helped to prolong the system’s life span. Various other test cases were deployed in the near shore environments and did not survive the severe conditions presented to them during storm events.

According to the Oxford University Press (OUP, 2012) website, shore-based TAPCHAN (TAPered CHANnel) schemes have a relatively low power output and are only suitable for sites where there is a deep water shoreline and a low tidal range of less than a metre. To overcome these limitations, a floating offshore version of TAPCHAN called Wave Dragon is under development, with an inlet span of around 200 m, to generate about 4 MW.

2.2 Wave Dragon (Offshore) - potential for Energy extraction and integration with grid systems: This device is another Power Take Off device similar to the Pelamis device discussed later in the report. A pilot study of the device was used in Nissum Bredning, Denmark.

[pic]
Figure 4: Power Take-offs and Generator Systems (Ahmed 2010 p. 322)

The Wave Dragon is an overtopping device which uses a pair of curved wave reflectors to force ocean waves up a ramp and into a reservoir above sea level where water is let out through a number of turbines. With its doubly curved ramp and wave reflectors, Wave Dragon is designed to maximise the amount of water that overtops it as the waves reach it the device prevents the waves from breaking and this holds the energy stored in the water. The current pilot programme in Denmark could produce 7MW for 10,000 homes. On a larger scale, it could provide sufficient energy for cities such as Brest in France (Wave Dragon 2012). In an Irish context, ESB International (Ireland) is supporting this technology. According to Ahmed (2010), the integration of technologies whether from ocean or wind technologies could offset one another during down time of periods where wind, sea fluctuations are low.

2.3 Point Absorbers (Near/Offshore) - potential for Energy extraction and integration with grid systems: As the device floats in the ocean, the vertical motion of the buoy is transmitted to the piston (by the hose pumps) causing the disk to oscillate up and down in the acceleration tube. The movement of this disk alternately stretches and compresses the hose pumps on either side of the disk.

[pic]
Figure 6: Point Absorber Technology (Scottish Enterprise, 2005)

As each hose pump is stretched, its internal volume is reduced, forcing water out of the hose into a high-pressure accumulator. The water is then fed to a turbine which drives a generator. This type of device has been tested in Makah Bay, U.S.A with a power output between 80 KW and 250 KW expected from the technology at the current developmental scale. As discussed in the previous section, a number of factors require attention in order for it to become a viable option for the electrical grid. These include viability in loading, power quality as well as the potential to impact on the ecology of the marine environment.

2.4 Oscillating Water Column (Nearshore) - potential for Energy extraction and integration with grid systems: These devices use wave motion in a cavern which while oscillating forces air pressure to oscillate in the column above the water level in the cavern.

This in turn drives a Well turbine which rotates in the same direction regardless of the axial movement of the air column in the cavern. These devices are producing electricity for the Scottish markets.
[pic]
Figure 8: On-shore wave power system using an oscillating water column
(Twidell and Weir 2006 p.419)

2.5 Hinged Contour Devices (Near/Offshore) - potential for Energy extraction and integration with grid systems: These devices use the relative motion of a series of floating structures to generate electricity. The vertical and/or horizontal movement between the floats can be captured using either hydraulic or mechanical couplings.

[pic]
Figure 7: Hinged Contour Device (Scottish Enterprise, 2005)

This device is located on or near the sea surface and moves in response to the shape of the wave. The Pelamis, as shown in Figure 7 is a semi-submerged articulated structure, which sits as a ‘snake’ aligned approximately head-on to the oncoming waves.

It moves in both the horizontal and vertical directions simultaneously. Each Pelamis is moored in place and this also allows movement which drives hydraulic rams which power the electrical generators. These supply underwater cables to the wave farms located on shore.

2.6 Case Study – Pelamis Device: The Author selects the Pelamis device given the availability of economic information available on this technology. The Pelamis device is currently being used off the west coast of Ireland in Belmullet, County Mayo as part of the Atlantic Marine Energy Test Site project.

[pic]
Figure 9: Pelamis Device (Offshore) like those used in Mayo, Ireland (Dalton, 2012)

In the next section of the report, the author provides information on the socio-economic and environmental considerations to be considered as part of the particular project. The device itself is 120m long, 3.5m in diameter, 750kW, 700 tonnes in weight.

7. Economic Appraisal: The information obtained for the assessment of this case study originated from work conducted through research studies in University College Cork (UCC). A number of key factors that affect the profit and cost of electricity were identified and they include:

• Cost of materials and initial cost (IC); • Size/Number of the WEC farm;

• Cable size and rating; • Feed-in tariff.

IC for the Pelamis had to take into account the cost of steel, given its structure and materials of construction. The graph in Figure 10 shows the variability of the price of steel. The cost increased 3 fold from 2002 to 2008 inclusive from €50/tonne to €350/tonne. However, it dropped again to less than €150/tonne in the late 2000’s.
[pic]
Figure 10: Variability in Steel costs from 2002 to 2009 (Dalton, 2012)

Dalton goes onto suggest that the costs for the technology are also dependent on production discounts and wave farm size. Cabling costs are another major expenditure associated with the implementation of the Pelamis device. The breakdown in costs associated with power output, voltage and the cost per km are provided in Figure 11. [pic]
Figure 11: Cable Costs for the Pelamis Device used in Mayo (ibid)

As can be seen in Figure 11, the cable cost per km is optimised when using a 38kV electrical network, which can be transformed at the near-shore sub-station.

[pic]
Figure 12: Additional IC Costs associated with the Pelamis Project (ibid)

Figure 12 shows that 90% of the initial costs are associated with replacement costs. While expected, given the energy and forces typical for sea conditions, it is very large when compared to other operational and maintenance costs for the project. According to Dalton, the typical discount factor equates to 10%, this is the percentage rate required to calculate the present value of a future cash flow. Dalton goes onto to identify Key Economic Indicators that require evaluation during the design, construction, commissioning, operation and maintenance as well as end of life for the project, they include:

i. Cost of Electricity (COE) (€/kWh) ii. Net present value (NPV) € where: a. NPV = ∑ total net cash * discount factor b. Discount factor = 1/(1-r)^years c. Where r is the discount rate iii. Internal rate of return (IRR) %

The economic indicators are briefly outlined for the Pelamis project. While the economic viability of a single device is not a realistic option, a combination of wave energy convertors i.e. from the Pelamis or combined energy convertors in a wave farm will ensure that that cost of electricity will reduce with a larger Wave Farm array.

[pic]
Figure 13: Cost of Electricity associated with the Pelamis Project (ibid)

Using 2010 as a baseline, the NPV provides a profitability value, it can be seen that the project is economically viable using wave energy conversion technologies greater than 50MW as illustrated in Figure 14. [pic]

Figure 14: NPV Calculations for Pelamis Technology in Mayo (ibid)

Next the author examines the Internal Rate of Return (IRR) for the project. As the rate is internal, the author eliminates externalities such as rates of inflation or interest rate variation. The higher the IRR the more viable the project becomes. According to Dalton, winter use of the technology is a good option to run with. However, the use of other renewables is advised for summer months as wave potential decreases during this period off the shores of Ireland. In terms of economic viability it is concluded that:

i. At 2010 costs of steel and 100MW, COE = €0.12/kWh. ii. At 2010 costs and 100MW, with a tariff of €0.22/kWh, NPV was viable. iii. €0.10/kWh is not viable. iv. IRR at 2010 costs is viable at €0.22/kWh tariff for large wave farms only.

6. Non Technological Barriers - Environmental Impacts: Some of the barriers to the implementation of wave energy technologies in particular are derived from licensing constraints (Waveplam, 2012). These can take time, especially due to the public consultation process, which is a pre-requisite for the completion of Strategic Environmental Assessments (SEA) for policies and development plans. This is also true during the compilation of Environmental Impact Assessments (EIA) for projects. The author identified the environmental impacts associated with the programme proposed for in Co. Mayo. These are broadly outlined in the following scoping report issued by the ESB to the local authority i.e. Mayo County Council (ESB, 2012). These documents are required as part of the planning process in the Republic of Ireland for projects that may impact on either terrestrial or marine environments.

As with any EIA process, the negative, positive and neutral impacts need to be determined as part of the impact assessment process. While all impacts are to be identified, those that fall under the term of a significant impact will require remediation measures by the developer in this instance the ESB.

The areas that require an evaluation in the EIA procedure are outlined below:

▪ the character, sensitivity and current use of the environment; ▪ the nature, magnitude and scale of the proposal; ▪ the likely nature, magnitude and duration of the impact; ▪ the resilience/sensitivity of the affected environment; ▪ the confidence in the predicted impacts; ▪ the offshore marine environment; ▪ the onshore intertidal environment where relevant; ▪ the level of public concern and knowledge of the issue; and ▪ The potential for mitigation.

The author provides the main environmental impacts associated with the projects as outlined by the ESB in Table 1 and information gained from previously studied Environmental Science programmes have been included to provide specific examples of environmental impacts associated with new projects.

|Environmental Aspect |Environmental Impact |Mitigation Measures |
|Land and Sea Scape |Construction activity on and offshore |License requirements met |
| |Visual Impact | |
|Physical Environment |Impact on coastal processes i.e. |Marine geologists to be hired, other |
| |sedimentation processes |competent personnel to assist in the |
| |WEC could impact bathymetry as energy |hazard identification for submarine |
| |absorbed in the WEC |environmental impacts. |
|Biological Environment |Benthic Habitat loss through drilling for |Land and marine mapping exercises using |
| |moorings |ecological risk assessment tools e.g. use|
| |Habitat and Species loss: |of quadrats. |

|Environmental Aspect |Environmental Impact |Mitigation Measures |
|Cultural |construction impacts upon previously |Detailed review of the area to determine |
| |recorded archaeological sites or features|shipwreck sites or other areas of |
| |offshore and onshore |importance |
|Socio-economic |Direct and indirect employment attributed|Habitat introduction for new species to the|
| |to the project works |areas |
| |No take areas for fishing could enhance | |
| |lobster fishing rights in the area |New employment opportunities and fish |
| | |market for the local area |
|Transport |New road networks required, vibration |Air/water quality stations established, |
| |noise, dust generation |noise barriers in place where construction |
| |Job creation |activities occur |
|Navigation |Fishing vessel routes affected? |Specific risk assessments required to |
| |Collision potential for WEC and fishing |determine risk controls with local |
| |vessels |community representatives |
|Ornithology |Above water collisions |Establish man made habitats conducive to |
| |Disturbance of habitats |species in the area, risk of collision (low|
| |Construction noise affecting breeding, |in terms of protected species) |
| |feeding grounds | |
|Noise |Underwater and surface noise impact on |License requirements agreed during planning|
| |marine life |application and monitored |

7. Non Technological Barriers - Social Impacts: While the project will bring new employment to the area, the established fishing grounds will be impacted upon as a result of the project and it will have a negative effect on those engaged in the fishing industry in this region of Mayo. While there will be a visual impact associated with the installation, it is perceived as “low” in impact terms. The “noise” impact for humans, given the location at sea is deemed to be an insignificant impact.

8. Miscellaneous Non Technological Barriers: Other areas that can impede access to this energy resources include:

1. Regulatory – According to Dalton & Rousseau (2012), a four staged comprehensive document has been developed as part of the Irish Ocean Energy Strategy. Dalton et al state that Ireland is one of the only countries in the EU to have such a programme in place. The strategy provides grants to indigenous and foreign companies who wish to develop ocean energy in Irish waters. Test sites could be improved if barriers such as those listed below are addressed before test sites are established:

• Approved sites with existing licensing; • Environment impact assessment waiver; • Free cable connection; • Free data collection; • Adjacent service facilities.

2. Logistical – Access to manufacturing areas such as shipyards and skilled workforce may prove to be a limiting factor. Energy strategies will play a pivotal role in moving towards renewable energy technologies over the coming 10 to 20 years. However and as an example, if Ireland is to reach its ocean energy target of 500MW by 2020, the Irish need to manufacture one Pelamis per week to meet this demand. Access to raw materials and sites to achieve these targets may prove challenging.

3. Financial - The potential barriers were discussed in Section 2.7. At present, there are no grant schemes in place to help investors implement projects on a commercial scale and it can take investors many years to get licensing/permits for wave energy projects. Systems such as “One stop shops” for these projects could help investors move more readily into this energy market. Ireland is looking at this option under the guise of the Ocean Energy Development Unit (OEDU), a sub set of the SEAI.

9. Technological Barriers that impact the deployment of wave energy: Are divided into the following sections:

1. Mooring Systems: These are required to keep the WEC in place and positioned to the sea bed in the case of Pelamis. Further RD&D is required here.?? However according to the manufacturers of the Ocean Energy Buoy mooring devices have survived the high energy conditions that the WEC they produce are exposed to (Ocean Energy 2012).

2. Power Take Off Systems: This is where kinetic energy is converted into electrical energy and it is the most critical part of the machine. Optimisation of the engineering devices used is under review at present and environmental noise is an area that requires particular attention according to the IEA (2006, p. 177). According to the IEA further work is required in this area (ibid).

3. Deployment Methodology and Decommissioning: The cost effectiveness of deploying these devices pose an economic and technological barrier to larger scale deployment of the devices. Insurance premiums and improvements in health and safety requirements for personnel involved in the installation works and the potential for damage to equipment pose other challenges similar to non-technical barriers. If deployment and end of life techniques for WEC’s can be optimised, then the barriers for deployment and end of life can be reduced in terms of cost.

10. Grid Integration:

1. Grid Connection Charges

1. Deep Connection Charges: These require the developer to cover the cost for the connection fees and include grid reinforcement charges.

2. Shallow Connection Charges: These include costs for the developer for connection to the grid only and all costs associated with the grid thereafter. Integration and reinforcement costs are covered by the end user. In Ireland and the UK, deep connection charges apply when connecting to the distribution network and shallow connection costs apply when connecting to the transmission network.

2. Grid Capacity: Countries like Ireland and the UK have relatively isolated grids when compared to mainland Europe, therefore, this makes increased capacity from renewables more difficult. However, the uptake and future proposal for Irish/UK interconnectors tie-in connection or hub to hub like those being developed for Wind energy projects may help to offset this particular barrier as set out by Dalton et al. (2012). The main issues associated with grid integration are as follows:

3. New Interconnections: The main challenges here for Renewable Energy (RE) relates to the intermittent nature of power derived from RE. The geographical location of the hot spots, for Ireland, to the West and North West have relatively poor gird infrastructure at present and will require additional expenditure to upgrade the grid to facilitate access to the source. This as a result provides technological barriers to assist RE integration into the Irish Electricity market.

4. Energy Storage Investment: Wave energy is driven largely by wind energy due to temperature variations between the Polar Regions and the equator. As these temperatures vary over the seasons, so too will the stored energy held within the waves.

To compensate for this, a combination of stored energy systems such as “pumped hydro” (e.g. ‘Spirit of Ireland’ project) or demand side management can be utilised to offset times where variability impacts supply and demand requirements.

5. Smart Grids: These will support grids at a local/regional level separate to the traditional centralised grid system seen in Ireland and elsewhere and according to the Euractiv website (2012) they will “increase its capacity to host renewable and distributed electricity sources”. The smart grid approach will also allow for consumers to shift demand to off-peak times which could reduce or minimise the need to re-invest in the upgrade of some of the national grid network throughout Ireland and the rest of NW Europe. In the next section of the report, the author briefly examines Research and Development options as they apply to Ireland.

6. Research and Development for future Irish Energy Strategies: In an Irish context, the main areas of research for wave energy started in Queen's University, Belfast (QUB) in 1975 following the invention by Professor Alan Wells of a Self-Rectifying Turbine. Wells produced the Wells turbine which can produce energy from oscillating flows like the OWC technology discussed earlier. UCC commenced studies in 1979, supported from UCG and the University of Limerick.

In Belfast, interest in wave energy increased after the 1970’s oil shock and the UK government provided finances to support further research. In 1982 funding ceased in the UK and a focus on smaller scale technologies was adopted by the UK authorities. In 1985 the Belfast team produced a medium sized wave power unit intended for use for a local island community in Scotland. The turbine was a 75kW machine and it was connected to the grid in the early 1990’s. A joint research project between the Belfast University and the Cork based Hydraulics and Maritime Research Centre (HMRC) Cork looked at installing a 500 kW pilot plant in the Isle of Islay.

However, the U.K. funding for this venture ceased and the research studies have been hampered as a result. In Cork, the HMRC are using a number of methods to research the technologies for wave energy conversion including:

• Mathematically modelling the Wave Energy converters; • Laboratory research and field trials in Cork, Galway and Mayo.

“Other research works held in Cork include field trials which were carried out at Bull Rock, an island off the Beara Peninsula which holds a lighthouse. In 1982, the Commissioner of Irish Lights decided to cap a blow hole on the Rock due to the corrosive sea-water spray. As blow holes are naturally formed oscillating water columns, HMRC inserted steel pipes into the concrete slab to monitor the air flow. Another blow hole was developed in 1984 and following strengthening work in 1985 measurements were made and this continued until November 1986” (Ó Gallachóir 2012)

In relation to developmental works for Irish wave energy technologies, Ó Gallachóir (2012) believes “small wave energy conversion is an ideal source of energy for small island communities”. Ó Gallachóir suggests that large scale commercial use of the technologies in an Irish context may take several years. On-shore and near-shore OWC devices are at an advanced stage of prototype development with device teams in Japan, Portugal and the UK. Ireland is playing a part in these developments which are funded through the EU renewable energy programme.

3.0 Tidal Stream Technologies

The author outlines some of the Tidal Stream technologies that could be used to extract energy from tidal flow. Tidal stream technologies are designed to harness the kinetic energy of the fast flowing water in tidal areas.

[pic] Figure 15: Horiontal Axis Turbine & right a SeaGen Device (Aquaret 2012)

Research and development in this emerging field has led to the design of several types of devices to capture this energy. The diagram in Figure 15 illustrates the concept.

3.1 Horizontal Axis Turbines - potential for Energy extraction and integration with grid systems: These devices act in the same manner as a wind turbine. The blades of the machine are place in the tidal stream and rotate by 180 degrees in either direction which allows the generator to produce electricity. This particular technology has been adopted for the SeaGen project in Strangford Lough, County Down, Ireland and it forms the basis of the Author’s case study for tidal stream energy potential.

3.2 Vertical Axis Turbines - potential for Energy extraction and integration with grid systems: These devices use the same principle as the horizontal axis turbines only with a different direction of rotation. A turbine is placed in a tidal stream which causes the turbine to rotate and produce power.

[pic]
Figure 16: Vertical Axis Turbine (Aquaret 2012)

The blades rotate around the axis of the hub of the machine as the tide passes by the turbine. As with the Vertical blade design, it can generate electricity regardless of the direction of the tidal stream.

3.3 Reciprocating devices (oscillating hydrofoils) - potential for Energy extraction and integration with grid systems: These devices have hydrofoils which move up and down in a plane normal to the tidal stream, instead of rotating blades. The oscillations are used to produce electricity and can operate regardless of the direction of the tidal stream.

According to Aquaret, one design uses pistons to feed a hydraulic circuit, which turns a hydraulic motor and generator to produce power (ibid). An example of this type of technology is shown in Figure 17.

[pic]
Figure 17: Vertical Axis Turbine (Aquaret 2012)

The blades rotate around the axis of the hub of the machine as the tide passes by the turbine and the Vertical blade design enables it to generate electricity regardless of the direction of the tidal stream. This technology is being used by Engineering Business Ltd. Their device is called the Active Water Column Generator (AWCG) and it works in much the same as the ‘Stingray’ device also designed by the same company. As it moves, air is drawn in and expelled from the top of chamber powering an air-based turbine. A scaled model of this concept was built and tested in dry dock in 1999 but only limited research has been carried out into the concept since (ibid).

3.4 Venturi Effect Tidal Stream Devices - potential for Energy extraction and integration with grid systems: With this system, the tidal flow is directed through a duct, which concentrates the flow and produces a pressure difference causing a secondary fluid flow through a turbine.

The resultant flow can drive a turbine directly or the induced pressure differential in the system can drive an air-turbine. The venturi draws the tidal currents into the turbine in order to capture and convert energy into electricity. At the rated speed of 3.1 m/s, the power will be 1.5 MW. The use of a gravity foundation will allow the turbine to be deployed quickly and with little or no seabed preparation.

[pic]
Figure 18: Vertical Axis Turbine (Aquaret 2012)

The design is load bearing and self-supporting without the need for extensive sea-bed preparations which allows for a rapid installation process. While there are other types of tidal stream technologies, these will not be reviewed within the scope of the report. As discussed in section 3.1, the author will examine the SeaGen model as it is currently in commercial use and it is an example of Tidal Stream technology which is already in use in Ireland. In the next part of the report, the author will examine the costs associated with the project as it applied to the County Down project.

5. Economic Appraisal: In order to determine the economic benefits, a number of factors require review including:

• Efficacy of the device to capture kinetic energy from the tidal stream; • Capital cost for the installed device, this includes e.g. foundations, cabling, installation, and grid connection; • Operating and maintenance costs associated with the device.

The pie chart in Figure 19 provides a typical percentage breakdown of costs for the Tidal Stream projects but it can vary from project to project. What is clear however is, the significant costs incurred for the rotor and power train assembly. This is followed closely by the structural costs, most likely for the steel as discussed in the previous sections for the wave energy technologies.

[pic]
Figure 19: Capital Cost Breakdown for a Tidal Stream Energy Device (Aquaret 2012)

In a DTI report from 2007, a comparison was made between the overall economics of two horizontal axis tidal turbine devices: a fixed pitch, bi-directional, variable speed turbine generator device with a variable pitch and a variable speed turbine generator device that rotates to face into the tidal flow. The SeaGen device used in County Down has rotating blades to allow it to face the tidal flow. The report found that a fixed pitch was more economically viable than the one used in Strangford Lough. However, from an energy engineering perspective, the fixed blade could only deliver electricity in a mono-directional flow. Based on this, the author does not agree with the conclusions of the report as the overall and full life cycle costs could be offset by the rotational blades as it can deliver energy in both directions relative to the tidal stream. The economics will be presented in the following pages.

A breakdown of how the DTI report assessed costs for the SeaGen and fixed blade devices are calculated and are shown in Figure 20.

[pic]
Figure 20: Major Categories to which costs were allocated in the DTI Report (Aquaret 2012)

Table 2 illusrates the costs associated with various sections of the project. The DTI report used a number of assumtions to calculate the viability of both types of devices. [pic]
Table 2: Major Categories to which Costs were allocated in the DTI Report (DTI, 2007)

The DTI report assumed a tidal stream farm of 30 devices, each rated at 1MW, having a 20m diameter rotor, and operating in a tidal stream with a maximum flow speed of 2.5 m/s were entered into the DTI reports calculations.

The costs based on the DTI model from 2007 showed that the cost per MW was 5% less if a fixed pitch was to be used using the assumptions outlined earlier. Based on other sources of information, costs per MW equated to 3 Million just over double the predicted costs identifed in the DTI report (Their Earth, 2012). This is largely due to current production methods, volumes and technologies. The cost of such a turbine is circa. 30% more than a conventional offshore wind turbine (ibid). The overall cost/MW is expected to fall with continued R&D efforts.

3.6 Non Technological Barriers – Socio-Economic & Environmental Impacts: The author presents the socio-economic and environmental impacts in the next two tables. They examine the associated impacts including preparatory, construction, installation, commissioning, operational, maintenance and decommissioning for the project cycle associated with a Tidal stream project.

[pic]
Table 3: Preparatory, Construction and Installation Impacts (Aquaret, 2012)

Next the author presents information on operational & maintenance impacts in Table 4.
[pic][pic]
Table 4: Operational, Maintenance, Accidental and Decommisioning Impacts (Aquaret, 2012)

There will be some environmental impact associated with a project and the significance of the impact will vary and is determined by an EIA. The EIA for a project can determine the significant effects and will be required especially for areas protected under the Wild Bids and or Habitats Directives. Where the impacts are deemed significant, mitigation measures are required and environmental monitoring programmes are needed to verify the efficacy of the mitigation measures. These are typically issued with environmental licensing requirements. According to the non-Technical Summary of the EIA issued in 2005, potential impacts on marine animals and basking sharks were unknown at the time. However, SeaGen put in place measures to detect marine organisms in close proximity to the turbines and these can be slowed down/shutdown where there is a risk to marine animals (SeaGen, 2005).

7. Technological Barriers that impact the deployment of Tidal Stream energy: “Tidal current energy technology is relatively well developed. At present, most barriers seem to be predominantly institutional, rather than for any other reason” The main barriers according to Dacre (2007) are illustrated in Figure 21.

[pic]
Figure 21: Major Barriers for Tidal Stream Development (Dacre, 2007, p 206)

Dacre is of the opinion that the main barriers relate to institutional and regulatory but acknowledges that access to the grid and the ability of the grid capacity to cope with RE is a barrier that requires attention by Policy Makers. Other non-technical barriers include insurance premiums for Public and Employer Liabilities and the administration burden associated with Health and Safety Legal compliance which is required but places additional costs on the project teams.

3.8 Grid Integration:

3.8.1 Grid connection charges

3.8.2 Connection Charges: These were discussed earlier in the report and are the same as those imposed for wave energy devices.

9. Grid Connection: According to Bryan (2006) a number of locations around Ireland have been marked as plausible locations for the introduction of Tidal Stream Energy into the existing grid. They are shown in Figure 22 and are located in sites in the Republic and Northern Ireland. The introduction of interconnectors can also help alleviate issues with variability and grid capacity. They will be improved with the introduction of further interconnectors between the North and South of Ireland. [pic]

Figure 22: Location of the 110 kV+ Buses where Viable Tidal Sites could connect (Bryans, 2006, p 146)

1. Technological Barriers for Tidal Stream: These can be outlined under the following areas:

1. Transmission Losses – As with any electrical systems power or (I2R), losses will result especially if the distance between the consumer and the source (Tidal Stream Devices) are significant. This can be reduced if the source can be located as closely as possible to the main users. In an Irish context, the main areas of population are Dublin, Belfast and Cork, so losses can be expected from the locations identified in Figure 22 and this is especially true for the Author’s home city of Cork.

Transmission Loss Adjustment Factors (TLAF’s) are used to help predict and offset such losses and these vary depending on seasonal factors. There are a number of methods in which to counter these losses, for example, the inclusion of additional generators and power booster stations. These have two main effects, increasing reactive power in the grid and/or increase power factor correction to unity. The lower the PF, the more losses will occur.

Additional Energy is introduced into the generator to allow it to increase reactive power, the benefit to losses was reduced for the Coleraine and Larne sites, see Figure 23 and Figure 24.

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Figure 23: The Reduction in Losses resulting from Increased Generation at Coleraine (Bryans, 2006, p 149)

Under all cases, a greater reduction in losses was offered through adding generation at Coleraine as opposed to Larne. Larne is electrically closer to large generators, therefore, losses there would have been acceptable and did would not impact on power quality.
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Figure 23: The Reduction in Losses resulting from Increased Generation at Larne (Bryans, 2006, p 149)

Looking at the average TLAFs for the year see, Figure 24, it is possible to see that if tidal generation were to develop at Shannon or Arklow they would be penalised for causing transmission system losses to increase, whilst those developed on the North Coast, the Maiden Islands or Malin Head would be rewarded for reducing system losses.

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Figure 24: The Reduction in Losses resulting from Increased Generation at Larne (Bryans, 2006, p 150)

2. Short Circuit Level – Bryan identified that for fault conditions, the impedance to earth is reduced therefore the reactive power flowing through the grid is increased. As a result, larger switchgear maybe required to interrupt the fault current, therefore, bringing additional costs to the project team. Importantly, the Root Mean Square (RMS) and the residual DC voltage that decays when interrupted must be designed into any switchgear being used to control fault and operating conditions for Tidal Energy Devices (TED’s).

3. Connection Capacity and Cost – There are two types of connection offers presented by the Transmission System Operator (TSO) to a TED developer. A firm connection offer is what the TSO is prepared to guarantee that the transmission system can accept at any time. The TSO can also offer a ‘non-firm’ connection which will enable the generator to produce above the firm connection offer, as long as it does not exceed the transmission system rating.

Currently in areas where a low firm connection is made, it may change over time as the grid is re-enforced and where new additions to the grid are made e.g. through other renewables mainly from wind generation devices and wind farms. The costs for the implementation of new installations and overhead, subsea cables are outlined in Figure 25.

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Figure 25: Potential Costs for Grid Connection Works and Various Cable Sizes (Bryans, 2006, p 160)

Other costs associated with grid integration in Northern Ireland were deducted by Bryan (2006, p 164). The firm connection costs in GBP/MW for the North coast of Ireland are outlined in Figure 26 over for the North coast of Ireland. For single TED the costs are quite low, however, for large scale commercial use the costs increase significantly at 80MW but tapers off again above this value.
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Figure 26: Approximation of the Grid Connection Cost off the North Coast (Bryans, 2006, p 164)

In the Republic, Arkow at present is not a viable options for TED however with grid re-enfocement in time this could be faciliated. According to Bryan (ibid), other renewable sources namely from wind generation present competition for grid connections off the Codling Bank. .
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Figure 27: Approximation of the Grid Connection Cost off the North Coast (Bryans, 2006, p 164)

An interconnetor from Wales to Arklow also provides another competitior for grid connections for TED. Costs associated with the implementation of TED from the Colding Bank are shown in Figure 28. These show the cost for the connection point as well as the projected cost/MW.

Based on the figures, Scenario A, a connection point at Kilcoole would provide the most cost effective solution, however, the capacity is reduced by 50% if this option was selected. Given the proximity to Dublin, the Ballybeg option could be justifed and power losses addressed as discussed earlier.

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Figure 28: Approximation of the Grid Connection Cost off the East Coast (Bryans, 2006, p 168)

Looking at Strangford Lough, the costs associated are identified. Further development of TED’s in the Strangford narrows is limited as the current gird infrastructure capability is not sufficient for additional TED’s. Further MCT’s would require an upgrade of the existing Bishopscourt Sub-station. The impact on voltage is the main concern with any of the sites discussed herein. The costs associated with gird integration for the optimal sites discussed earlier are presented in Figure 29.

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Figure 29: Approximation of the Grid Connection Cost for Tidal Generation at Each Site (Bryans, 2006, p 176)

Based on the data presented the costs for firm connections vary significantly between the Northern Irish sites at the Maidens and the North Coast.

For example, at 20MW the cost/MW for the connection at the Maidens equates to £200, 000 against the North Coast which equates to about a quarter of this. As discussed previously, the proximity to generating stations, as well as the distance from source to the consumer have a distinct bearing on the overheads associated with the projects.

10. Research and Development for future Irish Energy Strategies: Tidal Stream energy would only account for 2% of the total electricity requirements for Ireland, as discussed earlier, some of the technological barriers can be overcome at a cost to the State. Tidal generation is more efficient in terms of reducing CO2 and NOx emissions than wind generation and will offer similar savings in SO2 as wind generation (Bryans, 2012). The main challenges at a ‘Macro Level’ that require further research and development are provided in Figure 30.

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Figure 30: Generic Challenges involved in Marine Energy Development (UK Gov, 2010, p 24)

In terms of Scalability, the SeaGen is the only full scale operational TED in Ireland at present. The reliability was called into question after technical issues with one of the turbines was repaired after a number of years remaining idle. Predictability issues for tidal energy at least are consistent versus that of wave enery, i.e. Spring and neap tides are easily forecasted. The challanges on the diagram for TED at least still require substantial RD&D. In terms of ‘Micro Level’ improvements, the author outlines these in Figure 31.

The systems and components outlined below may not be improved much more that what is seen today but the components and systems may have room for further optimisation with RD&D efforts, which, will require investment from public and private partnerships to expand the potential that TED’s have.

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Figure 31: Generic Subsystems (capitalised) and Components (lower case) in a Tidal Stream
Energy Conversion Device (DECC, 2008, p 7)

The main systems and component parts that require further RD&D to optimise the systems further are outlined (in capitalised words) below and include:

• Hydrodynamic Subsystems; • Reaction Systems; • Power Take Subsystem; • Control Subsystem.

A scale model of the system or a subsystem is a physical model produced to test specific aspects of the design.

A prototype is a functioning, full-scale system but subject to significant further design changes, whereas, the commercial demonstrator is a device approaching readiness for production, with only minor changes. The SeaGen TED fits into this category of development as it is already providing eletcricity to the Bishopscourt Subtation in County Down.

A number of new and developing TED’s are being worked on at present. These include:

2 Tidal Generation Ltd. successfully re-deploys 500kW machine in Orkney (July 2010: TGL has re-deployed the 500kW tidal stream turbine on Friday 24th June 2011. After a few days to complete commissioning and safety checks, the machine is now generating at full rated power.

1. Meygen to further Tidal Development in Pentland Firth, Scotland (November 2010): This development is looking to fit circa 400 underwater turbines capable of producing 400MW between the Caithness coast and the Island of Stroma.

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Figure 31: Example of the Turbine to be used in Pentland Firth, Scotland (Tidal Generation, 2012)

The project will be introduced over 6 stages and is expected to be completed by 2020. Phase 1 is looking at the potential for environmental impact.

2. Next Iteration of the SeaGen Device – Plans are already underway by Marine Current Turbines for the next generation of the SeaGen device as used in Strangford Lough. This device will be designed for use in deeper waters, therefore, greater potential to abstract energy from tidal flows.

It will comprise of three power trains, given the depth of water in which it will be deployed, a surface piercing pile will not be used for this design. SeaGen will make use of a structure pivoted on the seabed that retains the MCT philosophy of raising the turbines out of the water for onsite maintenance (MCT, 2012).

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Figure 32: Design Concept for the SeaGen (U) Planned by MCT (MCT, 2012)

The author now concludes the report by providing views on which options may be more cost effective in an Irish context. In the next section of the report the author summarises the areas discussed within the report and from there provides conclusuons and recommendations based on the information studied in order to produce the report.

4.0 Summary

The aim of this report was to critically review the socio-economic and environmental impacts associated with Ocean Energy Technologies. The author provided examples of Wave Energy Conversion devices and selected the Pelamis device as their case study. An economic appraisal was provided from there and the technical and non-technical barriers to the development of WEC’s were provided. A detailed environmental impact assessment was produced by the Author showing the positive and negative impacts. The next section detailed the issues pertaining to grid integration for a WEC and provided details on grid capacity, interconnections, smart grids and energy storage options. Then the author discussed research, design and development options for WEC.

Tidal Stream Devices (TEDs) were examined and a brief overview of some of the technologies available for TED’s were provided. A combined socio-economic and environmental assessment was presented which provided some of the key non-technological barriers associated with the SeaGen device used in Strangford Lough, County Down. The author then examined the issues pertaining to the integration of the SeaGen device into existing electricity grids in Northern Ireland and possible constraints for the Republic of Ireland. The author provided possible options for further Research and Development projects which are planned for in the UK.

5.0 Conclusion

Interestingly, the author noted during a review of the “Renewables 2010 Global Status Report” that Ocean Energy in general is the least well developed of all the Renewables (REN 21, 2010, p. 28) and efforts are focusing on other RE projects such as Wind, Solar and Biofuels.

Based on the author’s review of Ocean Energy for the report, the pros and cons for Wave Energy and Tidal Stream Energy can be broadly outlined as follows:

5.1 Wave Energy:

The advantages of this technology are that Ireland has significant resource availability at its doorstep. In terms of visual impact it’s negligible to nil, however, an environmental impact will occur on the seabed for moorings and fixings to ensure the equipment is not lost at sea. There is a lead–lag relationship between Wind and Wave energy; therefore, this could result in reduced reserved power requirements. In terms of potential impact to migratory birds, especially, those protected by the Wild Birds Directive and the Habitats Directives, impacts in this regards are nil. Importantly, in the current economic climate, the introduction of ocean energy devices whether wave or tidal bring potential for job growth. This can include construction work and fulltime work opportunities for personnel maintaining and operating the devices. Other support services and contracts works could develop from the implementation of the technology.

The disadvantages of wave energy are that the technology is not operating in full scale at present in Ireland. Therefore, the challenges presented earlier, i.e. affordability, scalability, survivability still require developers trust in this technology. Whilst some of the systems and sub systems have improved through continued RD&D, issues still occur at sea. For example, the Pelamis device used off the coast of Portugal showed signs of leaking in three of the floating structures. Other key disadvantages include non-technological barriers such as access to safely maintained the equipment. Insurance cover for Employers liability and Environmental Impact Statements which require significant costs to produce may not always receive planning. If they do it can place significant burdens on developers.

5.2 Tidal Stream:

Advantages include the fact that the spring and neap tides are predictable and make this type of technology more attractive to developers. From an operational and maintenance perspective access to the devices is much more accessible than to that of WEC devices.

In terms of economic benefits proximity to the shoreline makes infrastructural costs less than that of WEC, therefore, power losses and cable costs are reduced significantly. Like WEC, the TEDs provide little to no impact on bird species feeding and roosting grounds. Importantly for TEDs, the technology is producing electricity at a commercial level in County Down with new iterations of the devices already being researched and developed in the UK. Like WEC employment, is an important factor that TEDs could bring to a local community. For TEDs these could also attract environmental and energy management tourists to learn from the experiences gained from the TED and help improve newer technologies for future projects.

The disadvantages in terms of environmental impact on bird species are low and the potential impact on marine life is increased. For example, in the Strangford narrows, Basking Sharks and cetaceans could be exposed to the rotating blades of the turbines. Potential impacts associated with the removal of energy from the tidal flow are not really known at this stage. This could have an adverse and unknown effect on sedimentation and other non-biotic relationships for the areas that use TEDs. As with ships and boats in marine environments, the build-up of aquatic organisms on equipment may affect the operational efficacy of equipment over time, resulting in increased maintenance costs for a TED. Another potential disadvantage associated with the use of TEDs is the societal impact associated with the loss of water ways for tourism and water sports.

Common disadvantages to both WECs and TEDs are the issues pertaining to licensing requirements as discussed above. These are a key barrier that can hinder progress for both national and international developers and the author believes that this process requires a review. The author recognised that the projects must take account of social, economic and environmental considerations, however, the overall benefits to society and the global environment would be better served if society placed a higher reliance on renewable sources of energy. This brings the author on to discuss the benefits of wave versus tidal taking into account the economics of both options.

By 2030 the NPV per technology of the Ocean Energy market could be worth >€1.5bn to both the Republic of Ireland and Northern Ireland and provide more than 20,000 jobs. While definite costs and development potential are not yet transparent as the Ocean Energy industry is immature, there is huge market potential available to Ireland, North and South. Also learning rates which describe the rate of cost reductions during commercial deployment are expected to rapidly increase with relatively significant levels of support in the short term. This will help to optimise the technologies by adopting a ‘learn by doing’ and improving the efficiency of the technologies which can only be achieved through further Research and Development.

In conclusion, with supporting data obtained from Ernst & Young (2010), the levelised costs are presented in Table 5 for Tidal Stream Shallow and Deep Water scenarios as well as Wave Energy.

| |Pre-demonstration |Demonstration |2020 |2035 |2050 |
|Tidal Stream Deep |539 |247 |203 |126 |101 |
|(£/MWh) | | | | | |
|Wave Energy |551 |403 |214 |118 |86 |
|(£/MWh) | | | | | |

Table 5: Showing Comparative Costs between Tidal and Wave Energy (Ernst & Young, 2010 p.10-23)

At present, the most expensive option/MWh is Wave Energy technology, the cheapest is Tidal Stream used in shallow waters for pre-demonstration or developmental scale projects.

During pilot scale projects, the costs change as learning curves increase. Again shallow Tidal Stream remains the cheaper option in terms of RD&D. However, for commercial scale technologies, the costs for Wave Energy decrease significantly and according to Ernst & Young by 2020, it will be nearly on par with tidal stream. With further RD&D and increased learning rates, wave energy technology are forecasted to become the cheapest option from 2035 onwards (based on levelised costs). So how could this be realised in an Irish/UK and International context? The author provides a macro level strategy which could be implemented to help facilitate the realisation of these predicted figures.

5.3 Macro and National Level Recommendations: The author recommends a Macro and National Level Strategy adopting the following recommendations which will further enable an All-Ireland breakthrough of Ocean Energy to meet the cost projections set out by Ernst & Young in their 2010 Report. This could be facilitated by:

➢ Investigating and improving REFIT to enable early development, this could expedite the RD&D in Wave Energy in particular; ➢ Enabling further capital grant funding for promising technologies; ➢ Continuing strong RD&D Funding and Programmes to attract and retain the best talent and develop and attract high value companies through talent pooling; ➢ Reviewing progress - This requires continuous engagement with the public, private and academic sectors; ➢ Optimising the interconnections between the Republic of Ireland and Northern Ireland and UK jurisdictions; ➢ Market integration; ➢ Development of Smart Grids; ➢ Extensions and re-enforcement of the existing networks; ➢ Enhanced storage of the supply to enhance energy security; ➢ Meeting Ireland’s obligations with regard to climate change by reducing GHG emissions as well as NOX, SOX and particulate matter emissions associated with fossil fuel combustion; ➢ Increased efficiencies in the Electricity Grid.

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Index

Energy Storage, 19
Environmental Impact Assessments, 14
Grid Capacity, 19
Grid Connection, 31
Grid Integration, 18 interconnetor, 37
Internal Rate of Return, 13
Key Economic Indicators, 11
Mooring Systems, 17
Pelamis, 3, 6, 9, 10, 11, 12, 13, 17, 43, 44, 48
Power Take Off, 6, 18
SeaGen, 4, 22, 25, 26, 27, 30, 39, 40, 41, 42, 43, 49, 50 smart grid, 19
Strangford Lough, 4, 22, 26, 38, 41, 43, 50
Strategic Environmental Assessments, 13
Tapchan, 5
Tidal stream technologies, 22
Transmission System Operator, 35
Well turbine, 8

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