20 January 2009 I Mech E Manchester Marine Current Turbines TM Ltd Coastal Marine Power and the Role of Marine Current Turbine’s technology
by Peter Fraenkel, BSc(Eng), CEng, FIMechE, FIE Technical Director
Marine Current Turbines Ltd The Court, The Green, SkGiffdBilBSStoke Gifford, Bristol BS34 8PD, UK . www.marineturbines.com 1 Marine Current Turbines TM Ltd
Climate change - CO2 last 1000 years
Start of industrial revolution
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Peak Oil - the Supply-Demand Gap
Source: Dick Lawrence, The Case for Modeling World Energy Flow, World Energy Modelling, Berlin 2004
BB
100
80 ? gap World Conservation ? Renewables ? 60 Lifestyle change ? Substitution ? Deprivation ? Conflict ? 40 OPEC
20
USA 0
1920 1940 1960 1980 2000 2020 2040 3 Marine Current Turbines TM Ltd
Most renewables are diffuse
Source: Prof. David MacKay Sustainable Energy Without the Hot air 2008 4 Marine Current Turbines TM Ltd
Marine Energy - the options
Technology Status Load Installed Unit cost Size of UK factor Capital cost electricity resource (%) (£/kW) (p/kWh) (TWh/yr) Offshore wind commercial 25 to 40% 1300 – 2000 5 to 7p over 100 ☯☯ Tidal barrage uneconomical 20 to 25% 1500 - 3000 >9p ~50 ☯ Tidal & marine current pilot projects 30 to 45% 1500 - 2500 3 to 9p * >20 ? turbines ☯ Wave – shoreline OWC experimental 20 to 30% 1500 - 3000 5 to 10p ~2 Wave - nearshore OWC experimental 25 to 35% 1500 - 3000 5 to 12p ~50 ☯? Wave - offshore – point pilot projects 20 to 50% 1500 - 2500 ? 4 to 12p * >100 or line absorber or ☯? OWC OTEC experimental 80% + ? ? ? n/a to UK Salt gradient laboratory 80% + ? ? ? ? ? * Carbon Trust “Future Marine Energy: The Results of the Marine Energy Challenge”, Jan 2006 figures apply for 1GW installed
Highlighted rows show technologies most likely to be cost-effective for use off the UK Marine Current Turbines TM Ltd Wind - the big one for the UK?
23,000 offshore 5MW widtbiind turbines wou lddlild deliver on average more than the entire present UK domestic electricity demand Marine Current Turbines TM Ltd
UK Offshore Wind
Gross usable Sea-Space = 76,000km2 Typical power capture = 3MW/km2 Gross energy capture = 3,200 TWh/yr DTI projection (2002) = 100 TWh/yr implies th e gov ernm en t onl y ex pects to use 3% of gross at approx 7GW A total of approx 390TWh of eltiitlectricity was genera tdithUKted in the UK in 2004. Marine Current Turbines TM Ltd
La Rance Tidal Power Barrage the exception that proves the rule the only large tidal barrage in the world Rance River estuary, Brittany (France) 24×10 MW bulb turbines (240 MW) Built 1966
http://www.stacey.peak-media.co.uk/Brittany2003/Rance/Rance.htm Marine Current Turbines TM Ltd
Severn Barrage - coming up for its 4th review
• Severn River estuary • 8,640 MW total capacity • 17 TWh average energy output • Ebb generation with flow pumping • 16 km (9.6 mi) total barrage length • £14 billion estimated cost • 27% Capacity Factor (2 x 4hr in 24hr) unlikely to be economically competitive Marine Current Turbines TM Ltd
Comparison: Severn tidal barrage v tidal stream Marine Current Turbines TM Ltd
Severn Barrage - coming up for its 4th review
Proposed Cardiff Weston Barrage silt Marine Current Turbines TM Ltd
Excellent Reference Marine Current Turbines TM Ltd
What could be possible Marine Current Turbines TM Ltd
Where we seem to be heading? Marine Current Turbines TM Ltd
State Sector Energy R&D spending 1974-2005
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Structural: the reaction to power generation
~100t per MW at 2.5m/s ~170t per MW at 1.5m/s Marine Current Turbines TM Ltd
Decentralised Marine RE Systems*: What do we need for commercial success?
1. Scale – must be 1MW or more to be economic
2. Access – safe, affordable, reliable access for servicing
3. Reliability – need to minimise costly intervention
4. Life – several decades; otherwise not economic
… fthldlfew technology developers are anywhere near to delivering technology to fit these criteria
* i.e. wave and tidal stream energy systems 17 TM Marine Current TurbinesWave Ltd Energy UK Resource water depth mean power annual (()m) (GW) energy (TWh) 40 10 87 20 7 61 shoreline 0.2 1.75 Marine Current Turbines TM Ltd
Shoreline Wave Energy Converters: Wavegen’s Limpet Oscillating Water Column Marine Current Turbines TM Ltd
Near-shore - Aquamarine “Oyster” Marine Current Turbines TM Ltd
Pelamis Wave Power
Pitching segments react against each other - hydraulic rams drive hydraulic motor and hence an electrical generator Marine Current Turbines TM Ltd
Ocean Power Technology - 40kW Powerbuoy
Heaving buoy with internal reaction Marine Current Turbines TM Ltd
Wave Dragon - overtopping wave collector Marine Current Turbines TM Ltd Tidal Stream Energy
1. Large resource - too big to be neglected or ignored 2. Technical feasibility - rapid development is possible 3. Predictability - driven by gravity - not weather 4. Minimal environmental impact - and favourable ERoEI - <12mths San Bernardino Straits - The Philippines
shown running at 3.5m/s or 7 knots 24 Marine Current Turbines TM Ltd
Marine currents = High energy intensity A tidal current turbine gains over 4x as much energy per Size Comparison 2 m of rotor as a wind turbine 1MW wind turbine compared with 1MW tidal turbine 1 x 55m dia
Outline of 1MW solar array 70m x 70m
2 x 16m dia
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The Effect of Velocity Shear
Velocity Power / Energy Sea Level
75% of the Energy is in the upper 50% of the water column
25% of the Energy is in the lower 50%
Sea Bed Marine Current Turbines TM Ltd Hammerfest Strøm 300kW - (2003 - ?)
Hammerfest Strøm 300kW axial flow ((y)Norway) Marine Current Turbines TM Ltd Ponte di Archimede “Kobold” Turbine - (2004) - 20kW Marine Current Turbines TM Ltd North American experimental devices
UEK - 30kW?
Verdant Power (35kW) (6 units in East River NY) Marine Current Turbines TM Ltd Recent experimental devices in 2007
Open Hydro - 50kW?
Clean Current - 50 to 100kW? Marine Current Turbines TM Ltd Marine Current Turbines: SeaGen
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MCT responsible for 3 out of 5 tidal turbines tested so far in the UK
at least 300m2 rotor area needed for economic viability because of high fixed cost overheads of off-shore projects MCT MCT MCT
2 10m 150m2 95m2 28m2 402m2
note that SeaGen is the first large enough for commercial viability - 4x the size of even Seaflow 32 rotor area TM sq.m. Marine Current Turbines Ltd 410 400 390 380 370 360 350 340 330 Square metres of 320 310 300 sq.m. gives about 1000kW at 2.5m/s 300 290 nominal minimum size for commercial scale generation tidal turbines in the 280 270 260 sea so far…. 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Rotor Area 10 24 95 113 28 20 28 28 48 28 402 sq.m. Rotor Size 3.5 2 x 4 11 12 6 5 6 6 4 x 12 6 2 x 16 metres
f t i t K w r o s n n o p m d e r n u o e f e E lo e e d e e l c U f o w r r o G o r m o y r a o n a t i H u e S r o e h P N e P S S c t n c R S C t r n T s e n R A T T A a p a A C C fe i d e C r d r O l M M e e C M e m t V n m o a P H Date 1994 2002 2003 2003 2004 2006 2006 2006 2007 2008 2008 Marine Current Turbines TM Ltd
Background: 15kW Tidal Current Turbine (1994-5) PROOF OF CONCEPT PROJECT (IT Power. Scottish Nuclear & NEL) Loch Linnhe, Scotland World’s first tidal current turbine
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Seaflow installed operational rotor raised for access 30 May 2003 rotor dia. 11m (= 95 sq.m.) rated power 300kW @ 2.5m/s pile dia. 2. 1m mass 130t water depth 24m ± 5m
Low cost access from a RIB
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SeaGen Prototype Some key features:- 2 x 600kW rotors:16m diameter