Ocean Wave Energy

Lilian Busse

What we agree on:

• That we need more renewable energy

What we don’t agree on:

• That Ocean Energy is a good renewable energy source, and it’s worth spending money in research and development

Outline

• Comparison to other renewable energies• Basics of ocean wave energy• Technological status• Possible locations for ocean wave energy• Funding issues for ocean wave energy• Benefits of ocean wave energy• Needs 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, Geothermal

8%

44%

48%

(6% geothermal, 2% solar and wind)

(Source: POEMS)

Potential for Ocean Wave Energy

• Potential world wide: 2,000 TWh/year (10% of the world electricity consumption)

(Clement et al. 2002)

Comparisons to other renewable energy sources

• Northern CA: 30 kilowatt per m wave crest(with storms 1 Megawatt per m)

• Solar energy: 300 watts per m2

• Wind energy: 800 watts per m2

Types of Ocean Energy

• Thermal energy• Mechanical energy

From tides From waves

3 basic systems for ocean wave energy devices

• 1. Channel systems that funnel waves into reservoirs

• 2. Float systems that drive hydraulic pumps• 3. 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 energy

• Ocean 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 patents• Some 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 devices

• The western coastline has the highest wave potential in the US (Northern CA)

• Floating or completely submerged• Offshore or onshore, on the seabed• Most of prototypes have been places at or near

shore• Wave 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 Energy

• limited research due to the lack of federal funding

• European Union funds Ocean wave energy since 1992 with a total Euro 9.5 for 9 years

• Investment by both public and private sectors is essential

• investment costs of 820 billion Euro

(Clement et al. 2002)

Benefits of Ocean Wave Energy

Why better than other renewable energies• Available 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 bouys

• Wave 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 energy• Reduce dependence on a specific source• Energy security for US• New business development in local geographic

region• Can provide many coastal locations with energy• In 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 environment•“pollution-free”•Less infrastructure (no access roads), and less space•Quieter and less visual obtrusive than wind devices

Needs in research and development of ocean wave energy devices

• Cost reduction• Efficiency and reliability improvements• Identification of sites• Better understanding of the impacts of marine

life and shoreline• Weather 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!

• POEMS: Practical Ocean Energy Management Systems, Inc.• ENR: Engineering News-Record• Previsic, 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.

Sources