Tidal and Wave Energy By: Patrick Blomberg Adam Womack

How it Works – Tidal Barrages Tidal Barrages Dam an estuary As water flows out or in, a turbine is spun Electricity is generated by the turbine

How it Works – Tidal Barrages

from How it Works – Tidal Barrages

How it Works - Wave Energy Many experimental technologies Example: Pelamis Project from

How it Works - Wave Energy Offshore Turbines Have gearboxes, anchored by a monopile from

How it Works - Wave Energy Swanturbines No gearboxes, anchored by concrete from

How it Works - Wave Energy from

Environmental – Tidal Barrages Under Construction – –Essentially the barrage is a dam –Stagnating water –Increase in pollutants –Given time, returns to normal

Environmental – Tidal Barrages After Construction –Tidal height changed Decrease in mud flats area during low tide Unpredictable effect on bird migration (30-50%) Outside high tide increase; excess flow –Turbidity decreases Increase in phytoplankton Unpredictable changes to food chain –Sediment gradient altered Severn Estuary Solution

Environmental – Wave Energy Blade Speed rpm –Boat propeller up to 10x faster Monopile/Concrete –Easily Avoided Other Designs –Stationary, surface Vortex –Unsure, expected to be avoided Image from:

Economic – Tidal Barrages Historical Example – Rance Estuary –Cost about 530 Million Euros in today’s costs, not including inflation in mid 60’s –240 MW output –Estimated energy cost (Not including startup) 18 cents Euro / kW Nuklear estimated similarly at 25/kW

Economic – Tidal Barrages Severn Estuary –Estimated $12-16 million construction About 3 Nuclear plants –8640 MW Output About 8 Nucler plants –Running costs about 1.5x Nuclear –Estimated lifespan – 120 years Nuclear is about 60 Alternate Design - Lifts

Economic – Wave Energy MCT – About $16 million US –Plotted Velocities –300 kW design –1 MW design Other Estimates –‘Cheaper than tidal’ –‘About the same as wind’

Conclusions Wave Energy –More area for utilization –Promising research –Potential for higher than 10% of world need Tidal Barrages –Widely varying environmental impact –Expensive, but long lasting –Very placement specific

Questions?