Forces of nature

WIND ENERGY

Wind energy is one of the most advanced renewable energies. Based on the use of wind power to generate mainly electricity, this clean inexhaustible energy helps reduce the emission of harmful gases and fully protects the environment.

  • The power of the wind: Wind is the driving force of this energy. Through modern turbines, wind power is converted into electricity. As with all other renewable energies, wind energy does not produce environmentally-harmful emissions. As it is an alternative energy to fossil fuels, it helps avoid the emission of tonnes of CO2 into the atmosphere. In fact, each kilowatt-hour (kWh) produced by wind energy has 21 times less environmental impact than one kWh of oil -produced energy, 10 times less than nuclear energy and 5 times less than gas.
  • How it works: The sun, responsible for wind, heats up the atmosphere unevenly, creating an air mass with different temperatures and, therefore, pressures. This difference in pressure forces air to move from high-pressure zones to low-pressure zones, so creating wind. The tower of the wind turbine, usually between 40 and 60 metres high (like a 15-storey building), supports the generating structure (nacelle) and the rotor. The energy created by the movement of the rotor blades moves through the bush inside the nacelle. The bush is the only exterior element which rotates and is joined to the blades. The measuring tower calculates the wind power that the wind farm receives. The electrical energy produced in the generator goes through some cables until reaching the generator, where it is transformed and sent to the electricity network in an optimum condition without irregularities. And with just one click, it reaches your home.
  • Strength in numbers: Usually, wind turbines are grouped together on a wind farm. That way, the best use is made of the site's energy-generating possibilities. This also means lower costs due to fewer electrical transmission lines and avoids further environmental impact. Each wind farm has a central operations centre which controls the operation of turbines, energy generated, etc. When locating a new wind farm, several aspects must be taken into account, such as wind speed and air turbulence in the area, and an environmental study must be successfully approved.
  • The modern giants of Don Quixote: Since the first wind turbines were made at the turn of the 20th century, wind technology has advanced at an electrifying speed and production of this type of energy has multiplied a hundredfold in the last 15 years. Although the windmills Don Quixote encountered on his travels had four blades, the majority of today's wind turbines have three blades and a horizontal axis. It has been scientifically proven that three is the ideal number of blades and if there are more, output is actually less. This is due to the turbulence from one blade affecting the following one. Modern wind turbines have a life cycle of at least 20 years. If we compare this to a car engine (a life cycle of around 5,000 hours), we can easily see the extent to which turbines optimise the wind found on-site.
  • IBERDROLA RENOVABLES ON WIND ENERGY:
    • Onshore (land-based wind farms): IBERDROLA RENOVABLES consolidates its global leadership in the wind energy business with a total capacity, at the end of the first half of 2010, of 11,010 MW. The geographical breakdown follows: 5.194 MW in Spain, 3.877 MW in the US, 816 MW in the UK and 1.123 MW in other countries worldwide.
    • Offshore (sea-based wind farms): IBERDROLA RENOVABLES is leader in offshore wind development, with the company currently developing projects amounting to 12,000 MW all over the world. The company has recently been awarded, together with Vattenfall, the construction rights to build one of the largest offshore wind farms in the world in the United Kingdom. The North Sea zone, known as East Anglia Array, has the potential to develop up to 7,200 MW, with construction is expected to begin in 2015. This initiative is in addition to others already under development in various areas of Europe (Germany, Spain and the United Kingdom), amounting up to an additional 4,800 MW. In Spain, IBERDROLA RENOVABLES has requested areas to be reserved for conducting preliminary studies before seeking authorization for six projects, which will be located on the coasts of Cadiz, Castellón and Huelva, with a total of 1,500 MW.

SOLAR ENERGY

The sun, the planet's main source of life, is also one of the most important energy sources.

  • The power of sunlight

Solar radiation is collected by panels and then transferred to a heat collector, usually a fluid. 

Solar energy is the top priority of many governments thanks to its numerous environmental and economic benefits: It provides high-quality energy, thermal solar energy is produced exactly where it is then used, it fully adapts to the end-user's needs, given the life expectancy of the sun, it is inexhaustible on a human scale, maintenance of solar cells is minimal, it reduces emissions of gases produced by fossil fuels and is an alternative to these.

  • How thermal solar energy works

The sun, the planet's main source of life, is also one of the most important energy sources.

Solar radiation is collected by panels and then transferred to a heat collector, usually a fluid.

Of all the collection systems in use, the cylindro-parabolic is the most widespread. It was launched in the 1980s and today there are solar fields across Europe and the USA.

Solar panels consist of: Support structure, Cylindro-parabolic reflector, Absorber tube.

Reflectors concentrate sunlight on a tube at the focal point of a parabolic dish, where incoming radiation is between 30 and 80 times greater.

A thermal fluid (oil) flows inside the tube to a vapour generator, and later to a turbine.

Future developments of this technology will include direct vapour production in the absorber tubes.

Reflectors work in the following way: The solar field heats the oils. Vapour is generated by the hot oil. The vapour powers a turbine, generating electricity. The refrigeration tower cools down the vapour and returns water to the circuit. The electricity generated is sent to the distribution network. And with just one click, it reaches your home.

  • How photovoltaic solar energy works

The sun is our planet's main source of life.

Sunlight is absorbed by photovoltaic solar panels.

To take maximum advantage of the sunlight, several solar panels are grouped together. These are called solar fields.

The main material used to make solar panels is silicon, one of the most abundant materials on our planet.

Photovoltaic solar panels consist of: Panel of photovoltaic cells, Transparent glass panel.

Photovoltaic cells of a solar panel also consist of: Upper metal layer, Silicon panels, Electrons, Lower metal layer.

When sunlight hits the photovoltaic cell, electrons inside the silicon panel are released and regrouped on the surface.

On one side positive, and on the other negative.

If this electrical circuit is closed, electrons are released from the cell and electrical current is produced.

The electrical energy generated in the photovoltaic solar panels is continuous current which is transformed into alternative current and is distributed through the electricity network. And with just one click, it reaches your home.

  • Lighting up your home: The possible applications of solar energy are countless. 
  • Thermal Solar Energy: Thermal solar systems can be used for domestic hot water systems (DHW), central heating and for drying, although the first use is by far the most widespread. DHW systems are designed to cover 100% of the demand for hot water in summer and between 50% and 80% in winter.

In 2007, IBERDROLA RENOVABLES began works on the first 50 MW field in Puertollano, which opened on May 2009. Eleven 50 MW projects of thermoelectric solar energy with cylindro-parabolic collectors are currently under development, as is one 3 MW Direct Vapour Generation (DVG) R&D project in the Almería Solar Field.

This portfolio of 13 projects totals an output of over 600 MW. 

  • Photovoltaic Solar Energy: Electricity generated by photovoltaic solar systems has a wide variety of applications. Photovoltaic solar panels can be found in artificial satellites, solar fields, on rooftops and in buildings, as well as on bicycles, watches and calculators. IBERDROLA RENOVABLES currently runs two photovoltaic solar fields, one in Spain (Castile-La Mancha) and another in Greece.

MINI-HIDRAULIC ENERGY

Mini-hydraulic power stations use the force of falling water to generate electricity. The output they generate (10 MW) and their size are both less than hydroelectric power stations, as is their impact on ecosystems.

  • In full flow: Like other renewable energies, mini-hydraulic reduces the CO2 emissions caused by the use of fossil fuels; and the benefits for the environment are numerous. Mini-hydraulic is a clean energy with no pollutants (except in the construction stage, when environmental impact must be strictly controlled) and respects the environment because of easily-avoidable impacts. It is inexhaustible thanks to the natural water cycle, which it also fully respects. Mini-hydraulic power stations do not use up river water: they only collect a certain amount at one point and return it further down the river.
  • How it works

Water is the source of life.

Water is also a source of electricity

Mini-hydraulic stations use the force of a flowing river to obtain electricity.

These stations retain part of the flow of a river in a storage reservoir or a diversion dam, which divert water from its natural course.

The diversion channel transports water to a surge tank, where some of it is stored, so that when water falls from a certain height through a penstock, it does so with greater force.

The process is as follows: The storage reservoir diverts water to a diversion dam. Water falls from the surge tank to the turbine through a penstock. At the end of the penstock the water reaches a turbine, situated in the plant building. Water used in the process is returned to the river through a water discharge channel. The electricity generated by the plant is transferred to the distribution network and with just one click, it reaches your home.

  • Not all rivers are the same: Neither are all minihydraulic power stations. Depending on their location along the river, different types of generating stations can be identified: Depending on their location, there are high-mountain and low-course stations. The former have a low volume but high drop, whereas medium- and low-course ones have a large volume but little drop. The amount or variability of river volume also influences the type of mini-hydroelectric power station. Different river characteristics imply the selection of one type of machinery or another for each station.
  • Let the rivers run: The high output achieved by minihydraulic power stations means this energy source is almost exclusively used for electricity production to be sold to the general network.  As a result, two types of systems can be identified depending on their connection with the electricity network: 
    • Isolated systems: They are usually micro stations (with an output of under 5 kW) and are used for private low-consumption supply.
    • Connected systems: Are connected to the general electricity network with the output of at least one micro station and unused energy is supplied to the network.
  • IBERDROLA RENOVABLES, Spain, at the close of the 3rd quarter 2008, had minihydraulic installations with an output of over 340 MW and a total of 135 stations, the most important ones being La Loriguilla (Valencia), Talavera (Toledo), Los Gavilanes (Ávila) and La Fuensanta (Albacete).

BIOMASS ENERGY

Organic waste from agricultural, livestock and forestry activities, as well as agri-food by-products and wood, can be used to produce heat, electricity and biofuels for vehicles.

  • What exactly is biomass?
    • It does not contaminate because: Carbon is photosynthesised by biological materials (agricultural waste, trees...) which release oxygen into the atmosphere.  The power station burns biomass, returning the CO2 which plants captured at the start of the photosynthesis process. Therefore, CO2 emissions are zero. 
    • It removes splinters, dry branches etc. from forests, therefore reducing the risk of fire. 
    • Installations hardly have an impact on the environment.
  • How it works: Biomass installations can use both animal and plant waste as a source of energy. Forest biomass installations use plant waste to generate energy. This waste is usually obtained following the pruning and cleaning of nearby woodland, which also helps avoid fires and diseases. The process is as follows: Stored biomass is sent to a burner, where it is burnt, and water vapour is obtained. The vapour reaches a turbine, making it rotate and producing mechanical energy. A condenser which cools down the vapour speeds up the turbine, so generating more energy. This powers the generator, which converts the mechanical energy from the turbine rotation into electrical energy and the transformer increases the voltage of the electrical current produced in the generator. Energy is then ready to be distributed on the electricity network and consumed. Biomass can be used to generate different types of energy:
    • Thermal
    • Electrical
    • Mechanical
  • A burning issue: Biomass is a source of renewable energy which uses biological matter to generate energy. Processes generally depend on the type of matter used: 
    • Combustion: When source materials are firewood, wood, sawdust or solid waste, in other words, mainly dry biomass. This process, as opposed to that of solid fuels, does not produce sulphur dioxide, the cause of acid rain.
    • Chemical method: With raw materials such as pig excrement, manure, animal remains, waste water or methane-fermented cultures, a process which produces the anaerobic digestion of humid biomass.
  • Making the most of leftovers: The use of biomass dates back to our forefathers, when they discovered fire and how to produce heat by burning wood. Today, the idea remains the same but production processes have advanced, and we can use this energy in our everyday lives to:
    • Generate heat with individual heaters, boilers and central heating systems in places with sufficient space to house the silos and combustion units needed.
    • Generate electricity, usually combining this energy with another.
    • Produce clean fuels such as biodiesel and bioethanol, more and more commonly used in means of transport like buses.
    • Independently supply certain industries and electricity power stations.
    • Eliminate waste productively and in a clean way.
  • IBERDROLA RENOVABLES plans to launch a power station in Corduente (Guadalajara), the Company's first in Spain to use forest residues, with an output of 2 MW and a forecast use of 26,000 tonnes of residues per year. The Guadalajara plant is in addition to other forest biomass installations being developed in Spain: one in Archidona (Malaga), with an output of 15 MW and another in Somozas (La Coruña), with 7.7 MW.


MARINE ENERGY

Over 70% of the earth's surface is water. The sea is the planet's number one absorber of sunlight and therefore is a vital source of energy. The force of waves and tides is an inexhaustible natural resource, which provides clean energy that fully respects the environment.

  • Deep down...The sea provides a natural way of collecting and concentrating energy through, mainly, waves and tides. To achieve this, various devices are being developed to convert this energy into electricity for its use on the earth. The principle of wave energy systems basically lies in exposing waves to a floating device, in a wide range of frequencies and directions, which would be subject to three-dimensional movements. These movements use a hydraulic system to transform them into a rotational movement, which is later converted into electricity by an electrical generator.
  • How it works:Wind passes over the sea and creates a series of rhythmic waves; by using wave surge, electricity can be generated. To obtain this, a special technology is used called IPS devices. These devices are buoys which transform wave surge into a rotational movement which generates electricity. IPS devices consist of:
    • Collector body
    • Connection to the generating system
    • Steel pile, which also consists of an electricity generator and hydraulic system
    • Floating anchor

Operation of IPS devices: Electricity produced in generators is transferred along an underwater cable in which voltage is increased. The electricity is sent from the substation to the electricity network. Another technological breakthrough with widespread use in wave power is the Pelamis converter, so called for its similarity to a tropical sea snake of the same name. 

How the Pelamis converter works: The Pelamis device consists of a series of semi-submerged cylindrical sections linked by hinged joints. The oscillation of waves causes a zigzag movement in the various cylinders. Through a series of hydraulic rams and motors, this snake-like movement drives electrical generators which produce low-voltage electricity. Power is fed down a single umbilical cable to a junction on the sea bed, where voltage is increased and the electricity is distributed on the standard electricity network and with just one click, it reaches your home.

  • As green as the see: Though still not widely used, marine energy is clean and fully respects the environment. It has hardly any environmental impact and does not produce any contaminating waste.  The future of this renewable energy is highly-promising: experts estimate that the energy generated by 30 of these systems would supply around 20,000 homes with the average European electricity consumption.
  • On the crest of a wave...IBERDROLA RENOVABLES ON MARINE ENERGY. IBERDROLA RENOVABLES is a pioneer in the development of marine energy projects. 
  • Wave Power: IBERDROLA RENOVABLES has installed the first 40 KW buoy in the pilot wave field of Santoña (Cantabria), the first of its kind in Europe. The second phase will see the installation of 9 more buoys, giving a total output of 1.35 MW. Its UK sister company, SCOTTISH POWER RENEWABLES , is also developing a wave field off the coast of the Orkney Islands with Pelamis generators, which will become the wave field with the highest output (3 MW) in the world.
  • Tidal Power: SCOTTISH POWER RENEWABLES is studying three coastal locations in Scotland and Northern Ireland to develop the largest tidal power plants in the world. Each plant will have between 5 and 20 turbines, giving a total output of 60 MW, enough to supply 40,000 homes.