Hydraulic energy

Rotor of shovels in a small water course.

Hydraulic energy, hydric energy or hydroenergy is that which is obtained from the use of the kinetic and potential energies of the current of the water, waterfalls or tides. It can be transformed to different scales. There have been, for centuries, small farms in which the current of a river, with a small dam, moves a wheel of blades or horns and generates a movement generally applied to mills or fulling mills.

It was generally considered a type of renewable energy since it does not emit polluting products. Others consider that it produces a great environmental impact due to the construction of the dams, which flood large areas of land and modify the flow of the river and the quality of the water.

History

A water piston Nongshu of Wang Zhen (fl. 1290-1333)

Saint Anthony Falls, United States; hydraulic energy was used here to grind flour.

Water-driven mineral mill, end of the centuryXIX.

Evidence suggests that the foundations of water power date back to ancient Greek civilization. Other evidence indicates that the waterwheel arose independently in China around the same period. Evidence for waterwheels and watermills they date back to the ancient Near East in the IV century BCE. In addition, some evidence indicates the use of water power by irrigation machines in the ancient civilizations of Sumer and Babylonia. Studies indicate that the waterwheel was the earliest form of water power and that it was powered by humans or animals..

In the Roman Empire, water-powered mills were described by Vitruvius in the I century BCE. The Barbegal mill, located in present-day France, had 16 waterwheels that processed up to 28 tons of grain per day. Roman waterwheels were also used to saw marble, such as the Hierapolis sawmill of the late 19th century III d. C. These sawmills had a waterwheel that powered two cranks and connecting rods to drive two saws. It also appears in two excavations from the 6th century century of the Byzantine Empire uncovered sawmills at Ephesus and Gerasa. The crank and connecting rod mechanism of these Roman watermills converted the rotary motion of the waterwheel into the linear motion of saw blades.

In China, during the Han dynasty (202 BC - 220 AD), water-powered hammers and bellows are believed to have been powered by water spoons. However, some historians suggested that they were powered by water wheels. This is because it has been theorized that the water blades would not have had sufficient motive power to drive the bellows of a blast furnace. Many texts describe the Hunnic waterwheel; some of the oldest are the Jijiupian dictionary from 40 B.C. C., Yang Xiong's text known as the Fangyan of the year 15 B.C. C., as well as the Xin Lun, written by Huan Tan around the year 20 AD. It was also during this time that the engineer Du Shi (c. AD 31) applied the force of water wheels to piston-bellows to forge cast iron.

Another example of the early use of hydraulic power is seen in the erodo. Eroding is the use of the force of a wave of water released from a tank in the extraction of metallic ores. The method was first used in the Dolaucothi gold mines in Wales beginning in AD 75. This method was later developed in Spain in mines such as Las Médulas. Deheading was also widely used in Britain in the Medieval and later periods to extract lead and tin ores. It later evolved into hydraulic mining when it was used during the California Gold Rush in the 19th century.

The Islamic Empire covered a large region, mainly in Asia and Africa, along with other surrounding areas. During the Golden Age of Islam and the Agricultural Revolution of medieval Islam (VIII-XIII), hydroelectric power was widely used and developed. The first uses of tidal power arose in conjunction with large hydraulic factory complexes. A wide range of water-powered industrial mills were used in the region, including fulling mills, meat mills, paper mills, de-hullers, sawmills, mills, etc. ships, stamp factory, steel factory, sugar factory and tidal mill. In the XI century, all the provinces of the Islamic empire had these industrial mills, from Al-Andalus and North Africa to the Middle East and Central Asia. Muslim engineers also used water turbines as well as gears in water mills and water hoisting machines. They also pioneered the use of dams as a source of hydraulic power, used to provide additional power to water mills and water-lifting machines.

In addition, the Muslim mechanical engineer Al-Jazari (1136-1206) described in his book The Book of Knowledge of Mechanical Devices the design of 50 devices. Many of these devices were powered by water, including clocks, a device for serving wine, and five devices for raising water from rivers or ponds, where three of them are powered by animals and one may be powered by animals or by water. In addition, they included an endless belt with attached pitchers, a cow-powered shadoof (a crane-like watering tool), and an alternate device with flip-up valves.

Benoît Fourneyron, the French engineer who developed the first hydroelectric turbine

In the 19th century, French engineer Benoît Fourneyron developed the first hydroelectric turbine. This device was installed in the commercial center of Niagara Falls in 1895 and is still in use. Early 20th century 20th, English engineer William Armstrong built and operated the first private power station which was located at his home in Cragside in Northumberland, England. In 1753, French engineer Bernard Forest de Bélidor published his book, Architecture Hydraulique , which described vertical and horizontal axis hydraulic machines.

Increasing demand from the Industrial Revolution would also fuel development. At the start of the Industrial Revolution in Britain, water was the main source of energy for new inventions such as Richard Arkwright's water frame. Although hydropower gave way to steam power in many of the largest mills and factories, it continued to be used through the 18th and centuries. span style="font-variant:small-caps;text-transform:lowercase">XIX for many minor operations, such as driving the bellows in small blast furnaces (for example, the Dyfi furnace). For example, the Dyfi kiln and the mills, such as those built at the San Antonio Falls, which take advantage of the 15-meter drop in the Mississippi River.

Technological advances have moved the open water wheel to a closed turbine, or water motor. In 1848, British-American engineer James B. Francis, chief engineer of Lowell's Locks and Canals Company, improved these designs to create a turbine with 90% efficiency. He applied scientific principles and test methods to the Turbine design problem. His mathematical and graphical calculation methods allowed him to safely design high-performance turbines that were exactly matched to site-specific flow conditions. The Francis reaction turbine is still in use. In the 1870s, stemming from uses in the California mining industry, Lester Allan Pelton developed the high-efficiency impulse turbine Pelton wheel, which used hydraulic power from the high-altitude currents characteristic of the Sierra Nevada.

Transformation of hydraulic energy

The main application of hydropower today is to obtain electricity. Hydroelectric plants are generally located in regions where there is an adequate combination of rainfall and geological slopes favorable to the construction of dams. Hydraulic energy is obtained from the potential and kinetic energy of the masses of water transported by rivers, coming from rain and snowmelt. In its fall between two levels of the channel, the water is passed through a hydraulic turbine, which transmits the energy to an alternator that converts it into electrical energy.

Another system that is used is to conduct the water from a stream with a great unevenness, through a closed pipe, at the base of which there is a turbine. The water is collected in a small dam and the difference in height provides the necessary potential energy.

Another one consists of making a small dam in the river and diverting part of the flow through a channel with a lesser slope than the river, so that a few kilometers later it will have gained a certain difference in level with the channel and it is made to fall the water to it through a pipe, with a special turbine.

Advantages and disadvantages

Advantages

• High energy efficiency.
• Because of the water cycle it is almost inexhaustible.
• It is a clean energy since it does not produce toxic emissions during its operation.

In addition, the reservoirs that are built to generate hydraulic energy:

• They allow water storage for recreational activities and supply of irrigation systems. And most importantly, they allow to laminate the grown in times of torrential rains, regulating the flow of the river downstream.

Economic advantages

The great advantage of hydraulic or hydroelectric power is the elimination of fuels. The cost of operating a hydraulic plant is almost immune to the volatility of the prices of fossil fuels such as oil, coal or natural gas. Also, there is no need to import fuels from other countries.

Hydropower plants also tend to have longer economic lives than fuel-burning power plants. There are hydraulic plants that continue to operate after 50 to 99 years. Operating costs are low because the plants are automated and require few people for normal operation.

Since hydro plants don't burn fuel, they don't directly produce carbon dioxide. Very little carbon dioxide is produced during the construction period of the plants, but it is little, especially in comparison to the emissions of an equivalent plant that burns fuels.

Presa de las Tres Gargantas (in the course of the Yangtse River in China), the world's largest hydroelectric plant. It generates a power of 22.5 GW, but it affected more than 1 900 000 people and flooded 630 km2.

Disadvantages

• The construction of large reservoirs can flood important tracts of land, obviously depending on the topography of the land upstream of the dam, which could mean loss of fertile land and damage to the ecosystem, depending on where they are built.
• Destruction of nature. Dams and reservoirs can be destructive to aquatic ecosystems. For example, studies have shown that dams on the coast of North America have reduced the common northern trout populations that need to migrate to certain places to reproduce. There are studies looking for solutions to this type of problem. An example is the invention of a type of ladder for fish.
• When the gates open and close repeatedly, the flow of the river can be drastically modified causing an alteration in ecosystems.
• They can be affected by cases of climate phenomena.

Mitigation measures

Throughout the second half of the XX century, environmental awareness, of people, governments and international credit institutions, which are ultimately those who finance large hydroelectric projects.

Currently, environmental mitigation measures are an integral part of all projects financed by multilateral lending institutions, and the costs of mitigation measures have to be included in the project cost.

World hydroelectric capacity

Global share of renewable energy (2008)

Trends in the top five hydroelectricity producing countries

The classification of the hydroelectric capacity is by the actual annual energy production or by the nominal power of the installed capacity. In 2015, hydropower generated 16.6% of the world's total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries and the Asia-Pacific region generated 32% of hydroelectricity in 2010. China is the largest producer of hydropower, with 721 terawatt-hours of production in 2010, accounting for about 17% of household electricity use. Brazil, Canada, New Zealand, Norway, Paraguay, Austria, Switzerland, and Venezuela have a majority of domestic electricity production from hydroelectric power. Paraguay produces 100% of its electricity from hydroelectric dams and exports 90% of its production to Brazil and Argentina. Norway produces 98-99% of its electricity from hydroelectric sources.

A hydroelectric station rarely operates at full power for a full year; The relationship between the annual average power and the capacity of installed capacity is the capacity factor. Installed capacity is the sum of all generator nameplate power ratings.

The ten largest hydroelectric producing countries in 2020.

Country	Hydroelectric production annual (TWh)	Installed capacity (GW)	Capacity factor	% of the global production	%% generation domestic electricity
ChinaChina	1232	352	0.37	28.5 %	17.2%
BrazilBrazil	389	105	0.56	9.0 %	64.7 %
CanadaCanada	386	81	0.59	8.9 %	59.0 %
United States	317	103	0.42	7.3 %	7.1 %
Russia Russia	193	91	0.42	4.5 %	17.3%
India	151	49	0.43	3.5 %	9.6 %
Norway Norway	140	33	0.49	3.2 %	95.0 %
JapanJapan	88	50	0.37	2.0 %	8.4 %
VietnamVietnam	84	18	0.67	1.9 %	34.9 %
France	71	26	0.46	1.6 %	12.1 %

Water power installed capacity (MW)

#	Country	2020
1	China	370 160
2	Brazil	109 318
3	United States	103 058
4	Canada	81 058
5	Russia	51 811
6	India	50 680
7	Japan	50 016
8	Norway	33 003
9	Turkey	30 984
10	France	25 897
11	Italy	22 448
12	Spain	20 114
13	Vietnam	18 165
14	Venezuela	16 521
15	Sweden	16 479
16	Switzerland	15 571
17	Austria	15 147
18	Iran	13 233
19	Mexico	12 671
20	Colombia	12 611
21	Argentina	11 348
22	Germany	10 720
23	Pakistan	10 002
24	Paraguay	8 810
25	Australia	8 528
26	Laos	7 376
27	Portugal	7 262
28	Chile	6 934
29	Romania	6 684
30	South Korea	6 506
31	Ukraine	6 329
32	Malaysia	6 275
33	Indonesia	6 210
34	Peru	5 735
35	New Zealand	5 389
36	Tajikistan	5 273
37	Ecuador	5 098