ENERGÍA MAREOMOTRIZ

La energía mareomotriz es la que se obtiene aprovechando las mareas, mediante su empalme a un alternador se puede utilizar el sistema para lageneración de electricidad, transformando así la energía mareomotriz en energía eléctrica, una forma energética más segura y aprovechable. Es un tipo de energía renovable, en tanto que la fuente de energía primaria no se agota por su explotación, y es limpia ya que en la transformación energética no se producen subproductos contaminantes gaseosos, líquidos o sólidos. Sin embargo, la relación entre la cantidad de energía que se puede obtener con los medios actuales y el coste económico y ambiental de instalar los dispositivos para su proceso han impedido una penetración notable de este tipo de energía.

Antiguo molino de mareas en Isla Cristina (Huelva).

Otras formas de extraer energía del mar son: las olas (energía undimotriz), de la diferencia de temperatura entre la superficie y las aguas profundas del océano, el gradiente térmico oceánico; de la salinidad, de las corrientes marinas o la energía eólica marina.

En España, el Gobierno de Cantabria y el Instituto para la Diversificación y Ahorro Energético (IDAE) quieren crear un centro de I+D+ien la costa de Santoña. La planta podría atender al consumo doméstico anual de unos 2.500 hogares.

                                                                        Generador axial en Reino Unido.

MÉTODOS DE GENERACIÓN 

Los métodos de generación mediante energía de marea pueden clasificarse en estas tres:

Generador de la corriente de marea

Los generadores de corriente de marea Tidal Stream Generators (o TSG por sus iniciales inglés) hacen uso de la energía cinética del agua en movimiento a las turbinas de la energía, de manera similar al viento (aire en movimiento) que utilizan las turbinas eólicas. Este método está ganando popularidad debido a costos más bajos y a un menor impacto ecológico en comparación con las presas de marea, ya que esto ocasiona que el agua suba 10 mt. a nivel del mar sobre lo normal.

Presa de marea

Las presas de marea hacen uso de la energía potencial que existe en la diferencia de altura (o pérdida de carga) entre las mareas altas y bajas. Las presas son esencialmente los diques en todo el ancho de un estuario, y sufren los altos costes de la infraestructura civil, la escasez mundial de sitios viables y las cuestiones ambientales.

Energía mareomotriz dinámica

La energía mareomotriz dinámica (Dynamic tidal power o DTP) es una tecnología de generación teórica que explota la interacción entre las energías cinética y potencial en las corrientes de marea. Se propone que las presas muy largas (por ejemplo: 30 a 50 km de longitud) se construyan desde las costas hacia afuera en el mar o el océano, sin encerrar un área. Se introducen por la presa diferencias de fase de mareas, lo que lleva a un diferencial de nivel de agua importante (por lo menos 2.3 metros) en aguas marinas ribereñas poco profundas con corrientes de mareas que oscilan paralelas a la costa, como las que encontramos en el Reino Unido, China y Corea. Cada represa genera energía en una escala de 6 a 17 GW.

LA RANCE EN FRANCIA

En el estuario del río Rance, EDF instaló una central eléctrica con energía mareomotriz. Funciona desde el año 1967, produciendo electricidad para cubrir las necesidades de una ciudad como Rennes (el 9% de las necesidades de Bretaña). El coste del kwh resultó similar o más barato que el de una central eléctrica convencional, sin el coste de emisiones de gases de efecto invernadero a la atmósfera ni consumo de combustibles fósiles ni los riesgos de las centrales nucleares (13 metros de diferencia de marea).

Los problemas medio ambientale fueron bastante graves, como aterramiento del río, cambios de salinidad en el estuario en sus proximidades y cambio del ecosistema antes y después de las instalaciones.

Otros proyectos exactamente iguales, como el de una central mucho mayor prevista en Francia en la zona del Mont Saint Michel, o el de la bahía de Fundy, en Canadá, donde se dan hasta 15 metros de diferencia de marea, o el del estuario del río Severn, en el Reino Unido, entre Gales e Inglaterra, no han llegado a ejecutarse por el riesgo de un fuerte impacto ambiental.

                                               Central eléctrica mareomotriz en el estuario del río Rance.

ventajas y desventaja de la energia mareomotriz

ventajas

• Auto renovable
• No contaminante
• Silenciosa
• Bajo costo de materia prima
• No concentra población
• Disponible en cualquier clima y época del año

Desventajas

• Impacto visual y estructural sobre el paisaje costero
• Localización puntual
• Dependiente de la amplitud de mareas
• Traslado de energía muy costoso
• Efecto negativo sobre la flora y la fauna
• Limitada

now in english

Tidal energy is obtained taking advantage of the tide, by fitting an alternator can use the system to lageneración electricity, transforming wave energy into electrical energy, a more secure form usable energy. It is a type of renewable energy, while the primary energy source is not exhausted by its operation, and is clean and in energy transformation occur no polluting byproducts gaseous, liquid or solid. However, the relationship between the amount of energy that can be obtained with today's media and the economic and environmental cost of installing the devices for processing have prevented significant penetration of this type of energy.


Other ways to extract energy from the sea are the waves (wave power), the temperature difference between surface and deep waters of the ocean, the ocean thermal gradient, salinity, ocean currents or offshore wind.

In Spain, the Government of Cantabria and the Institute for Energy Diversification and Saving (IDEA) want to create an R + D + ien Santoña coast. The plant would cater to the average consumption of 2,500 homes.



Generation methods


The methods of tidal power generation means can be classified into three:
Generator tidal current
The tidal power generators Tidal Stream Generators (or English initials TSG) use the kinetic energy of flowing water to power turbines, similar to the wind (air movement) using wind turbines. This method is gaining popularity due to lower costs and reduced environmental impact compared to tidal dams, as this causes the water to rise 10 mt. at sea level above normal.

Dam tide

Dams make use of tidal energy potential in the difference in height (or head loss) between the high and low tides. Dams are essentially dams across the full width of an estuary, and suffer high civil infrastructure costs, a worldwide shortage of viable sites, and environmental issues.

Tidal dynamics

Dynamic tidal power (or DTP Dynamic tidal power) is a theoretical generation technology that exploits the interaction between the kinetic and potential tidal currents. It proposes that very long dams (for example: 30-50 km length) be built from the coast out into the sea or ocean, without enclosing an area. Are introduced by the dam tidal phase differences, leading to a differential water level important (at least 2.3 meters) in shallow coastal marine waters with varying tidal currents parallel to the coast, as we find in the UK, China and Korea. Each dam generates power on a scale of 6-17 GW.

THE RANCE IN FRANCE

In the Rance River estuary, EDF installed a tidal energy power plant. Operation since 1967, producing electricity to meet the needs of a city like Rennes (9% of Britain's needs). The cost of kwh was similar or cheaper than a conventional power plant, without the cost of emissions of greenhouse gases to the atmosphere and fossil fuel consumption and the risks of nuclear power plants (13 meter tidal difference) .
The problems were quite serious ambientale half as river siltation, changes in salinity in the estuary in its vicinity and ecosystem change before and after the installations.
Other projects are exactly alike, as the core of a much larger planned in France in the Mont Saint Michel, or the Bay of Fundy in Canada, where there are up to 15 meters apart tidal estuary or River Severn in the UK, Wales and England, have failed to run the risk of a serious environmental harm.


advantages and disadvantages of tidal energy

advantage

Auto renewable
non-polluting
silent
Lower raw material costs
No population concentrated
Available in any weather and time of year

disadvantages

Visual and structural impact on the coastal landscape
pinpointing
Dependent tidal range
Expensive energy transfer
Negative impact on flora and fauna
limited

Internet, the last battle of neoliberalism
Internet, not being covered by the International Telecommunication Regulations adopted in 1988 has not been subject to any regulations, only the law of the market and stronger
The International Telecommunication Union opened this week in Dubai, United Arab Emirates, the World Conference on International Telecommunications, which will meet for 15 days in order to revise the International Telecommunication Regulations.
The celebration of this event was preceded by a negative media campaign funded and organized from the United States and that has resonated in many media around the world.
But before going into details, we
A little history
In 1865 he founded the International Telegraph Union (ICU) for 20 states. That same year, under the International Telegraph Convention establishing the first telegraph service regulations.
In 1932 the International Telegraph Union changed its name to the International Telecommunication Union (ITU), and later, in 1948, under an agreement with the newly formed United Nations, ITU became his agency specialized in the field of telecommunications.
For its part, the International Telecommunication Regulations (ITRs) has its genesis in the telegraph service regulations of 1865 and the Telegraph and Telephone Regulations 1932.
It arises from the need for a matter of treaty provisions applicable to services and international telecommunication networks to, among other things, establish the general principles of service delivery and operations, set the rules of global interconnection and interoperability and provide a basis for development of the sector in all countries.
The current version of RTI is a treaty signed by 178 countries in 1988 and implemented worldwide since it came into force in 1990.
So, why the fuss now?
Internet is the culprit
In 1988, when the RTI was last revised, internet was not widespread, so it is not mentioned in the Regulations.
However, today internet and its associated technologies are a vital and growing part of international telecommunications.
Therefore, one of the issues discussed at the Conference held in Dubai is the modification and extension of the International Telecommunication Regulations to include the topic of internet.
Indeed, during the preparatory process of the event many ITU Member States have submitted proposals on the internet, most on two issues of concern to many countries: its economics and security.
However, the campaign orchestrated by the U.S. ITU and accuses the UN of wanting to "control", "restrict access" or "impose censorship" internet.
Double standards and interests
But the United States is precisely who controls the Internet critical resources through the Internet Corporation for Assigned Names and Numbers (ICANN), who restricts access to websites to countries like Cuba, which applied unilateral measures that violate international law, and who imposes censorship of Internet content that affect their interests, such as the Wikileaks site.
In addition, major U.S. companies are content and infrastructure that control and receive most of the money flows on the Internet. And U.S. is one of the countries that consider Internet as a theater of military operations.
Therefore, the attempt to discredit the ITU and the World Conference on International Telecommunications aims to avoid any change to International Telecommunication Regulations that may affect this domain facto they have on the internet.
But also pursues more fundamental purposes.
Scheduled or unscheduled, that is the question
Internet, not being covered by the International Telecommunication Regulations adopted in 1988 has not been subject to any regulations, only the law of the market and stronger.
Therefore, one of the primary issues are discussed in Dubai is internet considering a telecommunications service and therefore susceptible to being regulated.
This is not a purely technical discussion, as it has important implications for people receiving telecommunications services.
For example, one of the regulations of the telecommunications sector is the "universal service obligation" under which operators must provide telecommunications service everywhere and not only in those where a profit. This regulation is what has allowed rural or urban low-income phone service there. However there is no equivalent regulation for the internet service.
Another example is the regulation which requires telephone service providers to have their own power source in order to ensure the availability of emergency services. Internet providers are not required to comply with this regulation although internet telephony is a service that is replacing traditional telephony. The negative effect of this regulation have not revealed during the recent storm Sandy where network outage brought down electricity service internet telephony leaving thousands of people cut off in an emergency situation.
Despite these examples, and others who demonstrate the need for regulations to correct the "mistakes" of the market as the sole regulatory agency, the United States and its allies will battle in Dubai so that the regulations do not reach internet , and consequently, so that within a short time all telecommunications are deregulated.
This battle is one more than the advocates of neoliberalism are fighting to try to impose their vision of a world where markets prevail without restrictions and where states and intergovernmental institutions such as the United Nations system, fail to meet their roles as guarantors of public interest.

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