Global resource is very large : 1-10 TW (World average consumption of electrical energy : 2 TW)
T otal usable resource comparable to the one of wind in coastal regions
( Portugal 2-4 GW versus 6-7 GW for onshore wind )
Resource more abundant in moderate to high latitudes (North and South)
From: Barstow, Mollison & Cruz.
Wave Energy can exhibit large seasonal variation In northerrn hemisphere resource is generally much,lower in summer than in winter In southern hemisfere summer –winter variations are much lower important advantage (Australia,NZ, South Africa, Chile, Argentina, Brasil)
SOUTH NORTH Average monthly mean lower in relation to annual average
Medium / high resource (30 kW/m, deep water); moderate extremes
Long west coast facing open ocean with majority population
Electrical grid, harbours, shipyards
RESOURCE ASSESSMENT & SITE SELECTION
RESOURCE ASSESSMENT (I) WERATLAS – Offshore European Wave Energy Atlas (1996)
Wave Climate &
Atlantic and Mediterranean coasts
www.ineti.pt/proj/weratlas European Wave Energy Atlas (INETI)
PORTUGAL - RESOURCE ASSESSMENT (II)
Nearshore Resource Atlas
Detailed statistics at 85 points
76 nearshore (30-50 km)
2 open ocean
Madeira Archipelago (www.aream.pt)
PEMAP - Potential of Marine Energies in Portugal
Evaluation of theoretical, technical and accessible resources
WAVE ENERGY TECHNOLOGIES Corpos oscilantes (com motor hidráulico, Turbina hidráulica, gera-dor eléctrico linear) Estrutura flutuante: Mighty Whale, OE-Buoy, Oceanlinx Coluna de água oscilante (com turbina de ar) Galgamento (com turbina hidráulica de baixa queda) Estrutura flutuante (com concentração): Wave Dragon Flutuante Submerso Essencialmente translação vertical: AquaBuoy, FO3, Wavebob, Power Buoy, Wave Star Essencialmente rotação: Pelamis, SEAREV Essencialmente translação vertical: AWS Rotação: WaveRoller, Oyster Estrutura fixa Isolado: Pico, LIMPET Em quebra-mar: Sakata, Foz do Douro Estrutura fixa Na costa (com concentração): TAPCHAN Em quebramar (sem concentração): SSG Pico Limpet Sakata Foz do Douro OE-Buoy Mighty Whale Energetech AquaBuoy FO3 Wavebob Power Buoy Wave Star Pelamis SEAREV Wave Roller Oyster AWS TAPCHAN SSG Wave Dragon
Present Situation 1
Co-existence of various basic concepts :
Oscilanting Water Column (OWC)
Small oscillating systems (“point absorbers”)
Large oscillating systems (multi-bodies)
Run-up systems, ...
Many projects (>50), of which a small number ( ≈ 15 ?) attained or is closed to protoitype . Opposite to wind energy, no dominating technology Slow convergence to a small number of basic concepts ? There area several modes of efficiently extracting wave energy.
As in life, the systems that will survive will be the most prone in a Darwinian fight for market survivability . How long this will take? Who will be the winners? ? Tempo geológico Floating bodies (with hidraulic motor, Hidraulic turbinehidráulica, linera electrical generator) Floating Submerged Essencialmente translação vertical: AquaBuoy, FO3, Wavebob, Power Buoy, Wave Star Essencialmente rotação: Pelamis, SEAREV Essentially vertical translation: AWS Rotação: WaveRoller, Oyster Floating structure : Mighty Whale, BBDB, Energetech/Oceanlinx Oscillating Water Column (air turbine) Fixed Structure Isolado: Pico, LIMPET Em quebra-mar: Sakata, Mutriku Run-up (with low head hidraulic turbine) Fixed Structure At coast (with concentração): TAPCHAN In breakwater (no concentration): SSG Floating structure (with concentration): Wave Dragon
Water Reservoir in run-up systems :
Tapchan, Wave Dragon, SSG.
Solar energy (24h period) and t ides (12h25m) intermitent sources. How to store energy? Wave energy is also intermitent, with much lower period (5-15 s). It is necessary to make regular the electrical produced power (electrical grid, electrical equipaments).
Kinetic energy in a inertia wheel :
Rotor of air turbines in the OWC sistems.
Oscillating bodies with hydraulic circuit.
Energy Conversion Systems (product: electrical energy)
Linear Electrical Generator (AWS, vertical oscilating buoys)
Good golab Efiiciency.
Prototype Phase . Not avilabale in market?
Energy storage ≈ 0 : necessary high relation maximum/mean power
Low head hidraulic turbines (Wave Dragon, run-up systems)
Energy storage in the water reservoir
Air Turbines ( OWC).
Several types (Wells, impulse, …).
Advanced prototype phase .
Efficiency (50-60%?) to be increased
Kinetic Energy storage in rotor (+ in Wells turbine).
Hidraulico motor in high pressure oil circuit ( floating bodies)
Conventional use of conventional equipment .
High efficiency (lower at partial load)
Gas Acumulators (expensive…) for energy storage.
High head hidraulicas turbines (Oyster, AquaBuoy).
Alternative to high pressure oil.
Conventional equipment, high efficiency.
Closed or open circuit (sea water).
Present situation 2 Technology is more difficult than that of wind energy. In technical and economic aspects, situation is similar to wind energy technology in the 1980s (?) Except in some Oscillating Water Columns (Pico 1999, Islay 2000), experience on maintenance, reliability and survivability is small or null, beyond few months. Information is scarce (and nor much reliable?) on costs and economic aspects. Often, what is publicised by teams is based on cenarios and projections assuming cost reduction.
Present situation 3 In general, capacity factor ( ratio of annual power/ nominal power) similar to wind energy (≈ 0.3). In the present technological development stage, electrical energy cost (€/kWh) is comprised between wind and large PV . To compete with wind energy, it is necessary 1/3 cost reduction for most advanced systems (1/2 if compared to offshore wind ). Relatively large investiments (especially in Europe) by private companies indicate that these cost reductions are believed to be possible (in 10+ years?).
PORTUGAL APPROACH 1970s
WHY SHORELINE OWC ?
Most developed type Europe (UK, Norway, Portugal, Spain)
Japan, India, China, Australia
Simple and robust
No submarine cable
Less available space
Conflicts of use
OWC - OSCILLATING WATER COLUMN OWC AIR TURBINE WAVES
Air Turbine (several types)
Other electrical equipment
and for Control
Air Valves (protection, control)
OWC Pico Island, Azores 12m
( concrete , …)
OWC Air Chamber
TECHNOLOGY DEVELOPMENT (I)
OSCILLATING WATER COLUMN
R&D – OWC + Air turbines
Mathematical modelling and tank testing
Wells Air Turbine
Electrical and control equipment
Impulse Air Turbine
OWC Pico island - 400 kW (1999) – 1st grid connected in the world
Renewable electricity 45% by 2010 (EC Directive 39%)
Scenario for energy: waves 50 MW by 2015 (2005)
Feed-in Tariff & PPA - Decree-Law 225/2007:
- 260 €/MWh for first 20MW, then decreases
MARKET DEPLOYMENT POLICIES
Pilot Zone for Wave Energy Exploitation - Decree-Law 5/2008 - 150 km North of Lisbon, best resource (30 + kW/m pa) - 320 km 2 , 30<h< 80m - Prototypes, pre-commercial and commercial - Capacity: 250 MW - Infrastructures, licensing MARKET DEPLOYMENT POLICIES PILOT ZONE