Aller au contenu
EDF France
Accédez à tous les sites EDF depuis ce menu
EDF France

Return to home The EDF Group

  • Supporting our clients on a daily basis
  • Producing a climate-friendly energy
  • Inventing the future of energy
  • Dedicated sections

    • Investors & Shareholders
    • Journalists
    • Applicants
    • Suppliers
    • Our scientific community
    • EDF Pulse

    Financial information at 30 September 2020

    Follow the Group's Financial information at 30 September 2020 - On Friday, November 13th 2020 from 9:00 am (Paris time).

    Subscription to the webcast
  • EDF at a Glance

You are :

Residential
Businesses
Local authorities
EDF join us Join us
The EDF Group Discover our activities

Dedicated sections

  • Investors & Shareholders
  • Journalists
  • Applicants
  • Suppliers
  • Our scientific community
  • EDF Pulse

Financial information at 30 September 2020

Follow the Group's Financial information at 30 September 2020 - On Friday, November 13th 2020 from 9:00 am (Paris time).

Subscription to the webcast

Sites in France

  • Corsica
  • French Guiana
  • Guadeloupe
  • Martinique
  • Réunion
  • Saint-Pierre and Miquelon

Sites worldwide

  • Africa
  • Asia
  • Belgium
  • Germany
  • Italia
  • Middle East
  • North and South America
  • Russia
  • United Kingdom
  • FR
  • Press contact
  • Investors contact
Contact information

I already have an account

Register

I do not have an account

Create my Account
Back to Marine Energy
You are here :
  1. EDF.fr
  2. The EDF Group
  3. Our energies
  4. Renewable Energies
  5. Marine Energy
  6. Tidal Power

Tidal Power

  • Partager cette page par email

Tidal power: EDF a precursor

Tidal power uses the differential between low and high tides to generate electricity. A precursor in this field, EDF has been harnessing this energy since 1966 at its plant built across the estuary of the La Rance River in Brittany, France. In a world first for this source of renewable energy, it produces around 500 GWh/year.

Tidal Energy: renewable and low environmental impact

Tidal energy seeks to harness the differential between low and high tides. There are many advantages in using tides to generate electricity: tides are a perfectly predicable phenomenon (unique for a renewable energy source), they are inexhaustible and carbon-free, and they have low environmental impact.

The principle involves building a barrage to create an artificial reservoir and so a differential in water levels to drive the turbines and alternators that will generate electricity. A tidal power plant uses the rising and falling movement of tides to create the level differential needed to produce energy.

La Rance tidal power plant: a world first

EDF was a precursor with this technology when, in 1966, it built the tidal power plant on the mouth of the La Rance River in Brittany, France. It is one of just two such plants in the world along with Sihwa in South Korea. The La Rance plant has an installed capacity of 240 MW distributed between 24 bulb-type turbine generators, each with a capacity of 10 MW. For almost 50 years, it has been producing around 500 GWh/year, equivalent to the consumption of a city the size of Rennes, France.

The La Rance plant is one of just two such plants in the world along with Sihwa in South Korea.

The La Rance plant operates according to two different modes: ebb only generation or flood and ebb generation.

  • ebb generation: the barrage’s six valves are opened until high tide is reached to fill the reservoir. As the tide recedes, the differential created between the impounded water and the sea is sufficient to drive the turbines and alternators to generate electricity
  • flood and ebb generation: during spring tides, electricity is also produced on the incoming as well as on the outgoing tides. The differential between the low tide and the level upstream from the barrage is sufficient to drive the bulb-type turbines and generate electricity on the flood tide. The turbines and alternators were specifically designed to be able to operate in both directions.

Lastly, the La Rance plant’s turbines can also pump water. At the end of the incoming tide, the generator operates in reverse mode and pumps seawater in order to further raise the level behind the barrage before slack water is reached (the short period when there is no movement either way in the tidal stream). This enables production to start up sooner and so maximise output.

A precursor in tidal power, EDF is currently involved in detailed research on mechanisms to harness marine energy. The Group is working with partners like IFREMER (French Research Institute for Exploitation of the Sea) to expand its expertise in this field.

Back to top
EDF
  • Sitemap
  • Legal notices
  • Cookies
  • Credits

Energy is our future, save it !
©2021 EDF