Hydroelectric power has been harnessed in varying forms for well over a century on a commercial/industrial level. On a smaller scale, the use of water power may date as far back as the ancient Greeks, who used it to power mills. Modern large-scale water-power owes its development to the British civil engineer John Smeaton, who first built large waterwheels out of cast iron. In the UK, large scale hydroelectric power schemes were implemented in the 1950s and 1960s.

Water-power played an important part in the Industrial Revolution. It gave impetus to the growth of the textile, leather, and machine-shop industries in the early 19th century. Although the steam engine had already been developed, coal was scarce and wood unsatisfactory as a fuel. Water-power helped to develop early industrial cities in Europe and the United States until the opening of the canals provided cheap coal by the middle of the 19th century.

The earliest hydroelectric plant was constructed in 1880 in Cragside, Northumberland, England. The rebirth of water-power came with the development of the electric generator, further improvement of the hydraulic turbine, and the growing demand for electricity by the turn of the 20th century. By 1920 hydroelectric plants already accounted for 40 per cent of the electric power produced in the United States.

Today, hydro power supplies one quarter of the world's electricity, and 5% of its overall energy requirements. Hydro power is seen as a sustainable renewable resource, and is therefore being promoted, especially in the developing world as the demand for energy increases very rapidly.


Hydropower is the renewable energy contained in flowing water. Electricity generated using hydropower is known as hydroelectricity and is generally considered to be reliable.

A hydroelectric power station converts the kinetic, or movement, energy in flowing or falling water into electrical energy that can be used in homes and businesses. Hydroelectric power can be generated on a small scale with a 'run-of-river' installation, which uses naturally flowing river water to turn one or more turbines, or on a large scale with a hydroelectric dam.

A hydroelectric dam straddles a river, blocking the water's progress downstream. Water collects on the upstream side of the dam, forming an artificial lake known as a reservoir. Damming the river converts the water's kinetic energy into potential energy: the reservoir becomes a sort of battery, storing energy that can be released a little at a time. As well as being a source of energy, some reservoirs are used as boating lakes or drinking water supplies.

The reservoir's potential energy is converted back into kinetic energy by opening underwater gates, or intakes, in the dam. When an intake opens, the immense weight of the reservoir forces water through a channel called the penstock towards a turbine. The water rushes past the turbine, hitting its blades and causing it to spin, converting some of the water's kinetic energy into mechanical energy. The water then finally flows out of the dam and continues its journey downstream.

A shaft connects the turbine to a generator, so when the turbine spins, so does the generator. The generator uses an electromagnetic field to convert this mechanical energy into electrical energy.

As long as there is plenty of water in the reservoir, a hydroelectric dam can respond quickly to changes in demand for electricity. Opening and closing the intakes directly controls the amount of water flowing through the penstock, which determines the amount of electricity the dam is generating.


  • Once a dam is constructed, electricity can be produced at a constant rate.
  • If electricity is not needed, the sluice gates can be shut, stopping electricity generation. The water can be saved for use another time when electricity demand is high
  • Dams are designed to last many decades and so can contribute to the generation of electricity for many years / decades.
  • The lake that forms behind the dam can be used for water sports and leisure / pleasure activities. Often large dams become tourist attractions in their own right
  • The build-up of water in the lake means that energy can be stored until needed, when the water is released to produce electricity.
  • When in use, electricity produced by dam systems do not produce greenhouse gases. They do not pollute the atmosphere.


Hydroelectric power comes from flowing water. Water, when it is falling by the force of gravity, can be used to turn turbines and generators that produce electricity.

In the UK there are three main methods for generating hydroelectricity:

  • Storage:¬†where a dam collects water in a reservoir, then releases it to drive turbines, producing electricity
  • Pumped Storage: where water is pumped to a higher reservoir, usually during times of low-priced electricity, then released to a lower reservoir, again driving a turbine, usually when the electricity price is higher
  • Run-of-river: where the natural flow of a river or stream is used to drive a turbine.


Hydropower is used in 30 countries around the world. The countries that generate the most electricity from hydropower are China, Canada, Brazil and the USA. Africa and South East Asia are not able to produce much hydroelectricity, likely due to a lack of money and technology.
Why choose a career in Hydro?

Hydropower is a renewable resource and an environmentally friendly way to generate electricity, therefore jobs associated with the field are considered "green." There are a wide range of jobs in the hydropower industry, from dealing with the qualities of the water to designing, constructing and maintaining hydroelectric plants. Reasons to join the industry include:

  • As the UK's hydropower capacity has escalated, so has the industry size and this has left us with a skills gap.
  • Efforts to attract more people with practical, technical and academic skills are high on the agenda.
  • A third of Britain's electricity plant will be retired by 2025.
  • The UK is committed to increasing renewable generation to 15% by 2020.
  • At present 40% of the UK's renewable generation is provided by hydropower.
  • Less than one third of the world's practical hydro capacity has been developed
  • Hydropower has a prominent role to play in the future energy mix.


The development of hydropower projects requires a variety of skills to understand both the technical aspects of the individual plants and also understand the social, political, environmental, financial and economic aspects. As with many of the other renewable energy technologies, the design, construction, and maintenance of hydropower plants requires electrical and mechanical engineers, technicians, and skilled workers. You should contact us if you believe you would like to transfer to this industry to see what type of roles are currently available.

Typically the following personnel can transfer with ease:

Project Managers, Project Engineers, Civil engineers, construction managers, electrical engineers and designers, mechanical engineers and designers, environmental specialists (biologists, hydrologists, ecologists etc.), recreation planners, resource managers, commercial officers, document controllers, HR personnel, admin personnel.

Hydro-electric output continues to grow across the globe. It is considered to be a clean, renewable source of energy, releasing a very low level of greenhouse gases when compared to fossil fuels. It also costs far less to produce and operate than fossil fuels, making it an exciting, growing sector of the renewable energy industry.


  • In most instances no training will be required prior to placement; we will put you in touch with employers happy to engage you with your current skills and qualifications.
  • We can advise on training and assist with placing you on a relevant course should training be required.