Introduction

As sources of non-renewable energy like oil and gas become more scarce, we need to develop new forms of energy. Renewable energy resources are sustainable, meaning that they can be replaced and will not run out.

As well as being an alternative to fuel sources which are less sustainable, renewable energy can help us cut CO2 emissions and reduce the impact of climate change. The wind and marine energy sector has seen huge growth over the last few years, mainly due to the Government’s commitment to reduce carbon emissions.


The UK Industry

By 2020, 15% of the UK’s
electricity must come from
renewable energy sources
UK Government

Onshore wind technology has been used on a commercial scale in the UK since the early 1990s and the industry now provides the majority of the country’s renewable energy. The UK leads the world in the offshore wind sector. It is a global centre for small wind technology and a leader in the research and development of marine energy.


Wind energy

People have used wind energy for a very long time. The first windmills were built over 5,000 years ago, some were used for grinding stones that crushed grain into flour and others were used to pump water out of wells. Wind energy has been the world’s fastest growing renewable energy source in recent years. As Europe’s windiest country, wind energy is an important resource for the UK.

Wind turbines produce no harmful solids, liquids or gases and no fuel needs to be transported to them. At the end of their useful life (typically 25 years) they can be taken down and the parts can be recycled.

Wind turbines harvest the kinetic energy of the wind and use it to generate mechanical power which is converted into electricity. Wind farms, which are made up of lots of turbines, can be located onshore or offshore. One wind turbine can generate up to 6.5 million units of electricity each year, which is enough to run a computer for 2,250 years!

Turbine blades capture the wind and turn the rotor which they are joined to. The rotor turns a shaft which is connected to a set of cogs called a gear box inside the nacelle, which houses all the workings for the turbine. The gear box is connected to a generator which makes electricity when it turns.

Each turn of the rotor is called a revolution. The rotor turns about 22 revolutions per minute (RPM). But in order to generate electricity the generator has to turn 1500 RPM. The gear box converts the 22 revolutions to 1500 revolutions. The electricity generated is sent down cables which run down the tower to the ground or under the sea. The cables take the electricity to the National Grid which distributes across the UK.

Marine energy

The movement of wave and tidal flows can be harnessed to generate electricity. Wave and tidal power is more consistent and predictable than wind power and it increases in the winter, when demand for electricity is at its highest. It is estimated that around 50% of Europe’s tidal energy resource can be found in the UK.

The UK is one of the principal centres for wave and tidal research, with many of the country’s top universities and research institutions working with technology developers.

There are a number of dedicated test facilities for wave and tidal research in the UK, including the New and Renewable Energy Centre (NaREC) in North East England, the Wave Hub in Cornwall, and the European Marine Energy Centre (EMEC) in Orkney which is the world’s first fully-accredited, grid-connected wave and tidal test facility.

Given the wealth of wave and tidal resources around our shores and our history of natural resource exploration, this is a fantastic opportunity to lead the world in wave and tidal power. The industry is still young though, and research is needed to ensure its future development.


Companies

Aquamarine Power

Edinburgh-based Aquamarine Power is developing Oyster wave-power technology. The Oyster wave power device is a buoyant, hinged flap which is attached to the seabed at around ten metres depth, around half a kilometre from shore.

Pelamis Wave Power

Pelamis Wave Power designs, manufactures and operates wave-power equipment. They are specialists in hydraulic, electrical, structural and offshore engineering, software and electronic design and project development.


Careers

The rapid growth of the renewables sector means more and more skilled workers will be needed in the wind and marine industries in the coming years. This will cover a variety of roles including opportunities to work on global projects and travel the world.

With enough skilled workers, the UK is set to become a world leader in renewable energy and the sector will offer thousands of exciting, dynamic career opportunities across the UK for decades to come.

There were around 21,000 people directly and indirectly employed in the wind and marine industries in 2010 – approximately 88,000 will be needed by 2021.

Renewable technologies

Cable Systems

Ultimately, the power produced by wind and marine energy systems needs to reach consumers. This means that electrical cables are needed to connect each array of turbines, wave or tidal units to substations which, in turn, connect to the National Grid.

These cable systems allow power to be transferred to and from remote areas, meaning that energy can be traded across the UK.

Offshore service vessels

It is vital to keep everything running reliably and efficiently on wind farms and marine energy installations and to fix problems quickly. This means that operational and maintenance activities are an ongoing part of running an installation to ensure that it maximises the amount of power generated .

This includes monitoring the condition of the turbines and responding to unexpected faults and failures. The Service Vessel takes construction and service engineers to offshore sites for maintenance and resourcing.

Photo credit: The Crown Estate and RenewableUK

Substation

Offshore substations collect the electrical power from the turbines and transform it to a higher voltage for transmission back to shore. Substations, also known as topsides, resemble North Sea oil platforms. They contain high voltage electrical equipment and are supported by foundations similar to those used for turbines.

Wind farms usually have one substation for every 100 or so turbines. Substation platforms can weigh over 1,000 tonnes and some of the largest floating cranes in the world are required for their installation.

Photo credit: The Crown Estate and RenewableUK

Helicopters

Boats are usually used to transfer maintenance crew to turbines, where they climb the turbine tower to access the components housed in the nacelle at the top. However, when the sea is too dangerous, helicopters are used to transfer maintenance crew directly to the nacelle platform with winch mechanisms.

Photo credit: RenewableUK

Wind Turbine Control System

Wind turbines are fitted with sensors that are used as part of a control system to check the turbine is working correctly and to protect it from operating in hazardous conditions. The control systems also monitor the frequency, current, and voltage of the power generated to ensure it is at the correct level for supply to the grid.

Performance measurements include wind speed and direction, blade pitch angle, rotor speed, and the amount of power generated. These measurements are used to normalise turbine operations by regulating its speed, power and load. An additional safety system can override the control system in emergencies.

Control functions can be divided into two areas:

  • Generator Torque Control – regulates the power generator via a power electronics converter;
  • Blade Pitch Control – regulates generator speed by changing the orientation of the blades to change the aerodynamic forces.

Photo credit: RenewableUK

Nacelle

A wind turbine nacelle is the box-shaped component on top of the tower. It is connected to the rotor and houses hundreds of generating components, protecting them from environmental forces so they can work reliably in harsh offshore conditions for many years. The components assembled in the nacelle include the gearbox, main frame, generators, brake, heating and cooling systems, drive train, and control systems. Wind turbine nacelles can be 150 feet above sea level.

Photo credit: RenewableUK

Tower

A wind turbine tower supports the nacelle and rotor. The tower is a steel cylinder usually around 60-100 metres tall , made of three or four tubular steel sections. Each section contains cables to transfer the electricity generated at the top to the grid connection point. Many towers also have load lifting systems with load-bearing capability of over 400 pounds and lifts and ladders to allow access to the nacelle for maintenance.

Photo credit: RenewableUK