In electricity generation, a generator is a device that converts motion-based power or fuel-based power into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all the power for electrical grids.
Dynamic braking is the use of an electric traction motor as a generator when slowing a vehicle such as an electric or diesel-electric locomotive. It is termed "rheostatic" if the generated electrical power is dissipated as heat in brake grid resistors, and "regenerative" if the power is returned to the supply line. Dynamic braking reduces wear on friction-based braking components, and regeneration lowers net energy consumption. Dynamic braking may also be used on railcars with multiple units, light rail vehicles, electric trams, trolleybuses, and electric and hybrid electric automobiles.
Fluid power is the use of fluids under pressure to generate, control, and transmit power. Fluid power is conventionally subdivided into hydraulics and pneumatics. Although steam is also a fluid, steam power is usually classified separately from fluid power. Compressed-air and water-pressure systems were once used to transmit power from a central source to industrial users over extended geographic areas; fluid power systems today are usually within a single building or mobile machine.
Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC).
Wave Dragon is a concept wave energy converter of the overtopping type, developed by the Danish company Wave Dragon Aps. Incoming waves flow up a ramp into a reservoir, the water the drains back to sea level though a hydro-electric turbine, generating electricity. "Reflector arms" are used to focus incoming waves, to channel the waves towards the ramp, increasing the energy captured.
The Pelamis Wave Energy Converter was a technology that used the motion of ocean surface waves to create electricity. The machine was made up of connected sections which flex and bend as waves pass; it is this motion which is used to generate electricity.
Hybrid vehicle drivetrains transmit power to the driving wheels for hybrid vehicles. A hybrid vehicle has multiple forms of motive power.
Oceanlinx was a company established in 1997 which specialised in the research and development of ocean-based renewable energy technology. The company's central technology was based on the Wave Energy Converter "WEC" which converts wave energy into electrical energy. Oceanlinx technology focused on the oscillating water column principle, and developed several prototype generators which were deployed and tested in Port Kembla, New South Wales. In 2014, Oceanlinx entered receivership and its technology, intellectual property, brand and trademark were sold to Wave Power Renewables Limited in Hong Kong. Wave Power Renewables Limited has continued to develop the technology, and Oceanlinx's founding director, Tom Denniss has further developed the technology since 2016 as a director of Wave Swell Energy.
CETO is a wave-energy technology that converts kinetic energy from ocean swell into electrical power and directly desalinates freshwater through reverse osmosis. The technology was developed and tested onshore and offshore in Fremantle, Western Australia. In early 2015 a CETO 5 production installation was commissioned and connected to the grid. As of January 2016 all the electricity generated is being purchased to contribute towards the power requirements of HMAS Stirling naval base at Garden Island, Western Australia. Some of the energy will also be used directly to desalinate water.
A free-piston engine is a linear, 'crankless' internal combustion engine, in which the piston motion is not controlled by a crankshaft but determined by the interaction of forces from the combustion chamber gases, a rebound device and a load device.
Evopod is a unique tidal energy device being developed by a UK-based company Oceanflow Energy Ltd for generating electricity from tidal streams and ocean currents. It can operate in exposed deep water sites where severe wind and waves also make up the environment.
The Oyster was a hydro-electric wave energy device that used the motion of ocean waves to generate electricity. It was made up of a Power Connector Frame (PCF), which is bolted to the seabed, and a Power Capture Unit (PCU). The PCU is a hinged buoyant flap that moves back and forth with movement of the waves. The movement of the flap drives two hydraulic pistons that feed high-pressured water to an onshore hydro-electric turbine, which drives a generator to make electricity. Oyster was stationed at the European Marine Energy Centre (EMEC) at its Billia Croo site in Orkney, Scotland until the company ceased trading in 2015.
A tidal stream generator, often referred to as a tidal energy converter (TEC), is a machine that extracts energy from moving masses of water, in particular tides, although the term is often used in reference to machines designed to extract energy from the run of a river or tidal estuarine sites. Certain types of these machines function very much like underwater wind turbines and are thus often referred to as tidal turbines. They were first conceived in the 1970s during the oil crisis.
PowerBuoy is a series of low-carbon emission marine power stations manufactured by Ocean Power Technologies (OPT), a renewable energy company located in New Jersey. PowerBuoys are most commonly used to provide power to offshore payloads generated through eco-friendly means. The PowerBuoy is designed to act as an Uninterruptible power supply. It stores energy in onboard batteries so that it can still provide continuous power through low generation periods.
Oscillating water columns (OWCs) are a type of wave energy converter that harness energy from the oscillation of the seawater inside a chamber or hollow caused by the action of waves. OWCs have shown promise as a renewable energy source with low environmental impact. Because of this, multiple companies have been working to design increasingly efficient OWC models. OWC are devices with a semi-submerged chamber or hollow open to the sea below, keeping a trapped air pocket above a water column. Waves force the column to act like a piston, moving up and down, forcing the air out of the chamber and back into it. This continuous movement forces a bidirectional stream of high-velocity air, which is channeled through a power take-off (PTO). The PTO system converts the airflow into energy. In models that convert airflow to electricity, the PTO system consists of a bidirectional turbine. This means that the turbine always spins the same direction regardless of the direction of airflow, allowing for energy to be continuously generated. Both the collecting chamber and PTO systems will be explained further under "Basic OWC Components."
Azura is a wave power device developed by Azura Wave Power in New Plymouth. A version was tested in Hawaii from 2015 for several years, with the aim of scaling up to create utility scale power for the grid. This was found to be too expensive, so Azura are now working on a smaller-scale device to produce both electricity and potable water. Two devices have been tested, which can generate 20 kilowatts of power.
Located on the east side of Gibraltar, on a former World War II ammunition jetty, the Gibraltar Wave Farm is the first commercial, grid-connected wave energy power station in all of Europe. The project utilizes the devices of Eco Wave Power Ltd, an Israel-based wave energy company. The wave farm was initially launched with an estimated peak capacity of 100 kW in April 2016 and plans for expansion to 5 MW within the next years. The project is operating through a 25-year PPA between Eco Wave Power, the Government of Gibraltar, and the Gibraltar Electricity Authority. Upon completion, it is expected generate 15% of the total electricity consumption of Gibraltar. The project is funded, in part, by the 2014-2020 European Regional Development Fund, in order to put the country in line with the EU's renewable energy goal: 20% energy generated from renewable power by 2020. The project is also funded by private investment groups. As of February 2018, the Gibraltar Wave Farm accrued 15,000 grid connected hours, a new world record for wave energy plant.
The Ocean Grazer is a conceptual energy collection platform, projected to house several renewable energy generation modules, including wave energy, solar energy and wind energy. The development of the Ocean Grazer platform has been carried out by the University of Groningen in the Netherlands, since 2014, and now by a spin-out company Ocean Grazer BV.
AWS Ocean Energy Ltd is a Scottish wave energy device developer, based in Dochfour near Inverness, Highland. The company has developed and tested several concepts, primarily the Archimedes Waveswing (AWS) after which the company is named.
