Tidal Energy

BUILDING ENERGY MANAGEMENT

TIDAL ENERGY K. VINEETHA - 19171NB003

Topics to be Covered Introduction What is Tidal Energy?

History of Tidal Enegry Types of Energy generation Examples around the World Advantages & Disadvantages Inferences

How are TIDES formed?

THE RISE AND FALL OF OCEAN TIDES RESULT FROM THE COMBINED GRAVITATIONAL PULL ON WATER BY THE MOON AND, TO A LESSER EXTENT BY THE SUN, WHICH EXERTS A FORCE ON WATER DIRECTED TOWARDS THE TWO ASTRONOMICAL BODIES. THESE GRAVITATIONAL EFFECTS COMBINE WITH CENTRIFUGAL FORCES THAT RESULT FROM THE EARTH AND THE MOON ORBITING EACH OTHER TO MAKE THE DETAILS OF TIDAL CHANGES COMPLEX. - ENERGY RESOURCES: TIDAL ENERGY

19171NB003 | www.nationalgeographic.org/encyclopedia/tidal-energy, www.studentenergy.org/topics/tidal-power

Tidal Energy

An example for Tidal energy as an renewable energy powered by the tidal generators to mimic the natural rise and fall of ocean tides and currents so that it helps marine life avoid getting caught in the system.

An Introduction Tidal energy is one of the oldest forms of energy generation. It is a renewable form of energy that converts the natural rise and fall of the tides into electricity.

Tidal energy presents an evolving technology with tremendous potential.

However, it can only be installed along coastlines.

Coastlines often experience two high tides and two low tides on a daily basis. The difference in water levels must be at least 5 meters high to produce electricity.

19171NB003 | www.tidalelectric.com/history-of-tidal-power

History of Tidal Energy

The earliest evidence of the use of the oceans’ tides for power conversion dates back to about 900 A.D., but it is likely that there were predecessors lost in the anonymity of prehistory.

Early tidal power plants utilized naturallyoccurring tidal basins by building a barrage (dam) across the opening of the basin and allowing the basin to fill on the rising tide, impounding the water as the tide fell, and then releasing the impounded water through a waterwheel, paddle wheel or similar energy-conversion device.

The power was typically used for grinding grains into flour.

Power was available for about two to three hours, usually twice a day.

19171NB003 | www.tidalelectric.com/history-of-tidal-power

Historical Tidal Barrage Technology

In Hayle, England, tidal power was used to “dredge” a shipping channel by flushing it regularly with a pulse of stored tidallyimpounded water.

Types of Technologies used to create Tidal Energy TIDAL BARRAGES: They are the most efficient tidal energy sources.

A tidal barrage is a dam that utilizes the potential energy generated by the change in height between high and low tides.

This energy turns a turbine or compresses air, which generates electricity.

19171NB003 | www.studentenergy.org/topics/tidal-power, www.britannica.com/science/tidal-power

TIDAL FENCES They are turbines that operate like giant turnstiles.

19171NB003 | www.studentenergy.org/topics/tidal-power, prezi.com/bj-x-ouc7tqx/tidal-energy/

TIDAL TURBINES It is similar to wind turbines only under water. In both cases, electricity is generated when the mechanical energy of tidal currents turns turbines connected to a generator.

In the 1960’s the first commercial-scale modernera tidal power plant was built, near St. Malo, France.

The hydro mechanical devices such as the paddle wheel and the overshot waterwheel have given way to highly-efficient bulb-type hydroelectric turbine/generator sets.

The tidal barrage at St. Malo uses twenty-four 10megawatt low-head bulb-type turbine generator sets.

Installed in 1965, the barrage has been functioning without missing a tide for more than 37 years.

St. Malo, France

19171NB003 | www.tidalelectric.com/history-of-tidal-power, www.thegreenage.co.uk/cos/rance-tidal-power/

Existing Tidal Power Plants

The second commercial-scale tidal barrage was put in service at in 1982 in order to demonstrate the functioning of the STRAFLO turbine.

There are approximately 10 small barrages scattered throughout the world, but they are not intended for commercial power generation. For example, there is a 200 kw tidal barrage on the River Tawe in Swansea Bay, Wales that operates the gates of a lock.

China has several tidal barrages of 400 kw and less in size.

Annapolis Royale, Nova Scotia, Canada 19171NB003 | www.tidalelectric.com/history-of-tidal-power, marinas.com/

It is renewable.

Ocean currents generate relatively more energy than air currents because ocean water is 832 times more dense than air and therefore applies greater force on the turbines.

It is simple and easy to create station to harness the power.

It is very cheap to maintain.

There is no waste or pollution.

Very reliable.

The tides can be predictable.

Tidal power is renewable as the tide will continue to come inwards. The water is not used up, it stays in the water cycle, and can therefore be used over and over again without the need for replenishment.

19171NB003 | https://prezi.com/bj-x-ouc7tqx/tidal-energy/

ADVANTAGES:

The process from turning the water power into electrical power can be tricky and time consuming.

It changes the coastline completely.

Habitats that birds or animals live on are destroyed.

Building costs are very expensive.

Disrupts creatures’ migration in the oceans.

Needs a very big piece of sea to be effective.

The tide difference needs to be minimum of 5mts.

Adoption of tidal technologies has been slow and the amount of power generated from tidal power plants is very small [about 10 hours of the day]. This is largely due to the very specific site requirements necessary to produce tidal electricity.

Tide cycles do not always match the daily consumption patterns of electricity and therefore do not provide sufficient capacity to satisfy demand.

19171NB003 | https://prezi.com/bj-x-ouc7tqx/tidal-energy/, www.studentenergy.org/topics/tidal-power

DISADVANTAGES:

INFERENCES Tidal energy is a kind of renewable energy with large potential & with no direct greenhouse gas emissions and a low environmental impact.

It has many advantages over solar and wind energy because the ocean’s tidal patterns are well understood, tidal energy is a very predictable energy source making it a highly attractive for electrical grid management.

The energy density of tides is also higher than solar and wind energy.

However, the high demand in technology and capital investment has hindered the development of tidal energy so that the tidal energy projects are much less than those of solar and wind energy.

With the development of innovative tidal turbine system and coastal infrastructure, the popularization of tidal energy worldwide can be expected.