EMBS 2010 Susana Baston

EMBS – Edinburgh, 25th August 2010

Towards understanding the Environmental Consequences of

Marine Renewable EnergyConfrontation vs Mitigation


Dr. Susana Bastón Meira

Research associate in theICIT- International Centre for Island Technology


Contents

1. Motivation

2. Confrontation vs Mitigation

3. Monitoring techniques

4. Capabilities of numerical models

5. SUNTANS model

6. Conclusions


Motivation

The first Marine Energy Converters (MECs) have been tested at EMEC’s site (European Marine Energy Centre) Several developers are located in Orkney The Pentland Firth and Orkney waters have been recently provided licences by Crown Estate for ‘Round 1’ development sites. The ICIT, part of Heriot-Watt University, is involved in a MRE research programme


Motivation

• Coastal physical processes

• Hydrodynamics and water column processes

• Pelagic and benthic dynamics

• Ecosystem considerations and consequences

SRDG (Strategic Research Development Grant) funded by the Scottish Funding Council

WP 5: ENVIRONMENTAL AND ECOLOGICAL IMPACTS

www.mreds.co.uk

Marine Renewable Energy Development in Scotland (MREDS)


Confrontation vs MitigationMRE has the potential to cause conflict among interested parties:

a) Developers and energy companies

b) Fishing sector and

c) Environmental groups

Key points• Baseline before development takes place.• Need to model cumulative impacts• Monitoring and predicting environmental effects• Common standards• Time pressure


Confrontation vs Mitigation

Potential negative impacts

Species displacement

Environmental conditions

Colision risks

Noise


Confrontation vs Mitigation

How good is the energy resource?

How the energy is dissipated?

Long term and far-field effects

Scale up to arrays


Monitoring techniques

a) Acoustic Doppler Current Profilers (ADCPs)

Current profiles and sediment flux

c) Acoustic Backscatter Systems (ABS):

Suspended sediment profiles close to the sea bed

b) Wave buoys:

2D wave spectra at a point

Moorings and Buoys


Monitoring techniques

a) Satellite observations

Optical wavelengths: suspended sediment concentrations

Dopplerised SAR imagery: currents

b) High Frequency (HF) Radar: surface currents and wave spectra

Remote sensing

a) ROV (Remote Observation Vehicles)

b) Gliders

ROVs and Floats


Capabilities of numerical models

MRE development Environmental impacts

Availability Prediction tool

Efficiency Ecological models

Initial site selection, mitigate impact, maximise efficiency

Predict effects of installation of MECs and extraction of energy from a flow field

Near and far field spatial information

Long term temporal modelling

Accurate predictions of nutrients and sediment transport in coastal waters


SUNTANS model

u, v, w are Cartesian components of velocityu is the vector form of velocityq the non-hydrostatic component of pressureη is the free surface elevationf and b are the Coriolis terms υH and υV are the horizontal and vertical turbulent eddy viscosities

∇H the horizontal gradient operator:

SUNTANSSUNTANS is a numerical model designed for the simulation of complex, non-hydrostatic coastal, river and estuarine flows with high resolution on unstructured grids using parallel computers.


SUNTANS model

Resource: Dr Rob Harris1, Dr Karl Stephen2, Prof Margot Gerritsen3

1.- ICIT/HWU, 2.- IPE/HWU, 3.- Stanford University


SUNTANS model

SUNTANS is Non-hydrostatic:

When a fluid is in motion, the vertical pressure gradient is also influenced by the vertical acceleration and friction non-hydrostatic pressure effects

P = p + q

Static pressure + Dynamic pressure

• Bottom density currents at high latitudes• Super critical flows related to topography in fjords and inlets

Hydrostatic approximation: Equilibrium between pressure gradient and gravitational force


SUNTANS model


The developer and the environmentalist/ecologist must avoid

Confrontation and achieve Mitigation for successful growth of the

marine renewable industry

There is a common demand from all stakeholders: the definition of a

standard monitoring protocol and a clearer understanding of physical

conditions and environmental effects

There is a requirement for cost effective accurate long term spatial

modelling of the environment

The SUNTANS model is a valuable tool, capable of providing

information leading to a better understanding of the resource and

intervention effects at MEC sites. Reducing confrontation and

facilitating mitigation through improved understanding.

Conclusions


Towards understanding the Environmental Consequences of

Marine Renewable EnergyConfrontation vs Mitigation

Thanks for your attention!

Email: [email protected]

http://www.icit.org.uk/

EMBS 2010 Susana Baston

Education

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