Ocean Wave Energy

Lilian Busse

What we agree on: That we need more renewable energyWhat we dont agree on:That Ocean Energy is a good renewable energy source, and its worth spending money in research and development

OutlineComparison to other renewable energiesBasics of ocean wave energyTechnological statusPossible locations for ocean wave energyFunding issues for ocean wave energyBenefits of ocean wave energyNeeds in R&D for ocean wave energy devices

Renewable Energy Sources

Ocean energy wave energy is behind wind and solar energy developments 85% fossil based8% nuclear4% hydroLess than 4% is Solar, Wind, Geothermal8%44%48%(6% geothermal, 2% solar and wind)(Source: POEMS)

Potential for Ocean Wave EnergyPotential world wide: 2,000 TWh/year (10% of the world electricity consumption)(Clement et al. 2002)

Comparisons to other renewable energy sourcesNorthern CA: 30 kilowatt per m wave crest (with storms 1 Megawatt per m)Solar energy: 300 watts per m2Wind energy: 800 watts per m2

Types of Ocean EnergyThermal energyMechanical energyFrom tidesFrom waves

3 basic systems for ocean wave energy devices1. Channel systems that funnel waves into reservoirs2. Float systems that drive hydraulic pumps3. Oscillating water column systems that use waves to compress air within a container mechanical power either directly activates a generator, or transfers to a working fluid, water or air, which then drives a turbine/generator

Technological statusof wave energyOcean energy today is where wind energy was in 1974 Many devices have been invented, only some tested and evaluated, only a few tested at sea (most in wave tanks)Since 1855: 1000 patentsSome are already tested in the field (e.g. Island of Islay in Scotland, LIMPET (Land-Installed Marine Powered Energy Transformer) 500 kW sufficient for 400 homes)

Locations of ocean wave energy devicesThe western coastline has the highest wave potential in the US (Northern CA)Floating or completely submergedOffshore or onshore, on the seabedMost of prototypes have been places at or near shoreWave power at deep sea ocean sites have 3-8 times more the wave power than coastal sites (but more expensive)

Global Coastal Wave Power Estimates(POEMS)Europe: Denmark, Norway, Sweden, Ireland, UK, Portugal

Funding for Ocean Wave Energylimited research due to the lack of federal fundingEuropean Union funds Ocean wave energy since 1992 with a total Euro 9.5 for 9 yearsInvestment by both public and private sectors is essentialinvestment costs of 820 billion Euro

(Clement et al. 2002)

Benefits of Ocean Wave EnergyWhy better than other renewable energiesAvailable 24/7 on 365 days - therefore power produced from them is much steadier and more predictable waves can be accurately predicted 48 hours in advance and therefore forecast energy output (BUT irregularity in wave ampitude, and direction)Good data on waves from wave monitoring bouysWave energy contains 1000 times the kinetic energy of wind (can produce the same amount of power in less space)

Benefits of Ocean Wave Energy cont.General benefits of Ocean wave energyReduce dependence on a specific sourceEnergy security for USNew business development in local geographic regionCan provide many coastal locations with energyIn remote areas (islands) wave energy is an attractive energy because of high energy import costs

$ 0.12/kW min. cost for wave energy conversion -Baltimore: $ 0.06/kW -San Diego $ 0.13/kW -Australian Island: $ 0.45/kW

Benefits of Ocean Wave Energy cont.Impact on the environmentpollution-freeLess infrastructure (no access roads), and less spaceQuieter and less visual obtrusive than wind devices

Needs in research and development of ocean wave energy devicesCost reductionEfficiency and reliability improvementsIdentification of sitesBetter understanding of the impacts of marine life and shorelineWeather effects over the life of the facility and the ability to survive in the marine environment (e.g. hurricanes)Therefore more research and development money is needed to make ocean wave energy competitive!

SourcesPOEMS: Practical Ocean Energy Management Systems, Inc.ENR: Engineering News-RecordPrevisic, M. 2003: The state of the Art in Wave Energy Conversion. Sea Technology 44 (7), 15-18. Feasibility of developing wave power as a renewable energy source for Hawaii. Department of Business, Economic Development and Tourism, Jan. 2002.Clement et al 2002: Wave energy in Europe: current status and perspectives. Renewable and Sustainable Energy Reviews 6, 405-431.