To read the previous article in our renewable energy series, click here.

Our continued use of renewable energy processes will hopefully be the key to saying goodbye to fossil fuels forever.

The major types of renewable energy in use today include:

With all of these options for clean energy and so much promise for further technological advancements, it is quite easy to imagine a world fully sustained by renewable energy processes in the future.

Hydropower-Dam

Image courtesy of renewableenergymexico

What is Hydropower?

Hydropower, sometimes refered to as Hydraulic power or water power, is power created from the energy of falling and running water, which can be harnessed for useful purposes, including creating electricity. It is also widely used for irrigation and operating mechanical devices like water mills, textile mills, power houses and even paint making. Hydropower lends itself directly to the development of hydroelectricity, which is the electricity generated by the hydropower process.

This form of renewable energy is in fact the most widely used, accounting for 16% of electricity generation across the globe.

How does it work?

There are a few different types of energy-producing hydropower, including but not limited to:

  • Conventional hydroelectric
  • Run-of-the-river
  • Pumped-storage

Conventional hydroelectric is the technique most commonly used for dams. In this case, dammed water drives a water turbine and a generator. Energy created from this cycle travels from the generator along power lines to be transformed into useable energy. The Three Gorges Dam in China uses this method.

575px-Hydroelectric_dam.svg

A conventional hydroelectric dam facility diagram. This is the most common type of hydro energy generation. Image courtesy of Wikipedia

 

Run-of-the-river hydroelectricity captures kinetic energy produced by running rivers or streams, without the need for a dam. This method of harnessing energy is reliant on seasonal river flows and so is not a completely reliable source of renewable energy. However, this type of hydropower can act as an intermittent source of energy. The Chief Joseph Dam in the US is an example of this type.

Chief Joseph Dam

“Chief Joseph Dam” courtesy of U.S. Army Corps of Engineers, photographer unknown.

 

Pumped-storage hydroelectricity (PSH) is an energy storage technique used for load balancing. This method stores potential energy in the form of the gravitational energy of water which is pumped from a low elevation reservoir to a higher elevation. The Bath County Pumped-Storage facility currently holds the grestest capacity out of all other facilities of this kind.

pumped storage diagram

Pumped-storage diagram courtesy of Wikipedia.

Despite being the most widely used form of renewable energy today, hydropower has it’s disadvantages as well as its advantages.

Advantages:

  • Reliability and Flexibility: The turbines used in hydroelectric facilities have a very short start up and shut down time. Therefore, if hydropower is needed in an emergency as a backup, this can be done quickly and efficiently. On the other hand, if a facility is generating surplus power, generation can be decreased to the desired level so as not to overrun the turbines and to save potential power for when it might be needed down the track.
  • No fuel or extra costs: Hydroelectric plants do not need fossil fuels such as gas, oil, coal or any other imports to function. This makes it a cheap source of renewable energy. A facility could last for up to 100 years and possibly longer, and without the need for high numbers of personnel (automated plants), labor costs are usually low.
  • Reduced carbon dioxide emissions: This is an important factor in deciding whether or not a particular energy-harvesting technology is renewable as opposed to fossil fuel practices which obviously emmit high levels of CO2.
  • Reservoirs can provide other uses: They can be transformed into facilities for water sports and can be tourist attractions. Just take a look at the photos featured in this article; hydroelectric facilities are certainly a sight to see. Large dams can also be used as a flood-preventative technique; those living downstream of the facility can be protected from flooding.

Disadvantages:

  • Loss of land, Ecosystem problems: The generation of hydroelectric power changes downstream river environments. Water exiting a turbine usually contains very little sediment, which leads to scouring of river beds and loss of riverbanks downstream. The natural processes of river environments are disrupted and large amounts of land are used for the facility, putting a strain on already established ecosystems and animal habitats.
  • Relocation: The building of large hydropower facilities means the possible need for relocation of existing inhabitants, whether it be a small community or a town. Even if nearby towns do not need to be relocated, lives can be affected by the lengthy (and loud) process of constructing a large facility.
  • Facility Risks: Faliures due to poor construction, natural disasters or sabotage can have catastrophic effects on downriver settlements and infrastructure. Past dam failures have been some of the worst man-made disasters in history.
Panorama of Itaipu hydroelectric dam from Brasilian side. Courtesy of St-Amant, Wikipedia.

Panorama of Itaipu hydroelectric dam from Brasilian side. Courtesy of St-Amant, Wikipedia.

Innovations in Hydropower

The technology that makes hydropower possible is constantly being developed, tested and taken to the next level to reach new standards of renewable energy efficiency. Here are some of the promising hydropower innovations around today:

1. Wave-powered electricity generators

Although some technical failures forced this innovation to go offline after only 2 months, it is a promising idea that, with further development, could become a valuable source of alternative energy. This technology uses floating tube structures which pump hydraulic fluids when the tubes bob up and down in the ocean waves. This hydro-kinetic energy then drives generators.

Photo by JOAO ABREU MIRANDA/AFP/Getty Images. Courtesy of Chron.

Photo by JOAO ABREU MIRANDA/AFP/Getty Images. Courtesy of Chron.

2. Tidal energy turbines

This technology harnesses the power of tides to generate energy. The already-developed technology is described as an underwater turbine. The turbine is currently located off the coast of Maine in the US, where the tides are some of the most powerful in the area. Tides can reach 6 meters and the turbines generate enough electricity to power up to 30 homes.

ORPC's TidGen® turbine generator unit being readied for installation at Cobscook Bay Tidal Energy Project site. Photo courtesy of Ocean Renewable Power Company.

ORPC’s TidGen® turbine generator unit being readied for installation at Cobscook Bay Tidal Energy Project site. Photo courtesy of Ocean Renewable Power Company.

3. RiverStar systems by Bourne Energy

The Bourne Energy Co. describes their RiverStar system as “a self-contained energy module composed of a stabilizer, energy absorber,
energy transmission and mooring system and energy conversion and control system. It is designed to be sited in-river in interconnected arrays. RiverStar does not require a dam and reservoir; instead it harvests hydropower along a section of a river.”

This is a very exciting innovation, as some of the major problems associated with hydropower facilities (especially dams) at the moment include their massive scale, the space they take up and the devastating effects on the environment around them should their construction fail. The RiverStar system might one day elminate the need for dams all together, and might even be more efficient technology in capturing hydroelectricity.

RS2

 

Featured image (Three Gorges Dam panorama) courtesy of Wikipedia.

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