Hydro-powered energy

I represents coal, El hydro power and other energy sources. Data from Reference 2. 

Micro-hydro systems use the natural flow of water to yield up to 100 kW output of electrical energy [22]. Simplicity, efficiency, longevity, reliability, and low maintenance costs make these systems attractive for mral development [23]. Like solar and wind, the fuel source for microhydro power is free, and the use of hydro-powered turbines to generate electricity produces no on-site air pollution. 

Alternative Energy News Network. Micro Hydro Power- Pros and Cons [Internet]. Available at www. alternative-energy-news, info/micro-hydro-power-pros-and-cons [Accessed 2012-03]. 

Hydroelectricity, at present the most important of the clean, econonucally feasible, renewable energy options, can benefit from a water resources development project however, that is seldom the only benefit. It is clear, therefore, that hydro-power has an important role to play in the future, both in terms of energy supply and water resources development. 

As Table 1 illustrates, Switzerland exhibits an extremely high specific aimual production of electrical energy from hydro power - by far the largest compared to other countries within Europe. This reflects the high level of water utilization, efficient production facilities, and a high density of power stations more than 90% of suitable rivers and streams are harnessed in Switzerland for this purpose [13]. 

With more than 1,200 power stations, the country generates around 57% (=35,000 GWh per year) of electrical energy from hydro power [15]. These power stations are supported by around 1,400 water intake structures [16] and some 200 reservoirs [17]. These artificial storage basins store a total usable volume of almost 4,000 million cubic meters, and are theoretically capable of temporarily retaining around 7% of annual precipitation. 

Where inexpensive electric power is available, for example off-peak hydro-power or nuclear power, hydrogen can be produced by electrolysis of water. Another approach is to use solar energy to "split" water into H2 and 02. The feasibility of this scheme depends on the development of catalysts that absorb sunlight and then use the energy to reduce water to hydrogen. 

Armenia has hydro energy resources that can cover up to 35% of country s energy demand, but according to above mentioned, hydropower development has no much perspective in the country due to limitations of hydro-power resources and this could result environmental degradation, particularly lose of environmental quality of the Lake Sevan. However, the system of small hydropower plants on mountainous rivers could be developed as a support to Armenian energy grid. 

Autonomous power systems can be based on renewable energy (RE) units, such as wind turbines, photovoltaic systems or small hydro power stations and fossil-fuel generators. Due to the intermittent nature of renewable energy, storage devices and/or appropriate demand management strategies are necessary when conventional generators are not included in the system. 

Hydro power systems utilise the energy of flowing water for the production of electricity. A general consensus for the definition of small hydro power plants does not exist. The upper power limit varies from 2.5 to 25 MW, depending on the country, but 10 MW is the most acceptable one and has been proposed by the European Small Hydro Association (Thematic Network on Small Hydro Power, 2005). 

Stavrakakis GS, Kariniotakis GN, (1995). A general simulation algorithm for the accurate assessment of isolated diesel-wind turbines system interaction, Parts I, II. IEEE Transactions on Energy Conversion, 10 577-590 Thematic Network on Small Hydro Power, (2005). Proposal for a European strategy of research, development and demonstration for renewable energy from small hydropower. http //www.esha.be... 

Fourth, electrolysis presents a path to hydrogen production from renewably generated electrical power. From an energy perspective, electrolysis is literally a way to transform electricity into fuel. Electrolysis is thus the means of linking renewably generated power to transport fuels markets. Currently, renewable solar, wind, and hydro power, by themselves, produce only electricity. 

Figure 5.54. Electric energy derived from nuclear energy (delivered as electricity or used to produce hydrogen, and including transmission losses). The figure shows average flows in each country. Note that countries with large hydro power production need no or little nuclear energy, as hydro is given first priority (Sorensen, 1999).

Serensen, B. (1981). A combined wind and hydro power system. Energy Policy, March, pp. 51-55. 

It is of interest to refer to the article by H. Blix (1997) who was director general of IAEA for many years until 1997. Presently, oil, gas, and coal—the fossil fuels— provide nearly 85% of the commercial energy that the world uses close to 37% for oil, 25% for coal, and more than 21% for gas, with nuclear power and hydro power providing around 7% each, and commercial renewables such as solar, wind and biomass nearly 2.5%. (Noncommercial uses of renewable energy are estimated to provide another 10% of world energy consumption). In China, coal presently supplies 75% of energy consumption, oil about 17%, nuclear and hydro 5%, and gas 2%. 

Norwegian University of Science and Technology, Department of Thermal Energy and Hydro Power, 7491 Trondheim, Norway... 

It is obvious that the production efficiency of the methanol vectors is lower than gasoline production efficiency, due to the conversion of the primary energy (hydro)electric power to a completely different energy carrier. As shown in Fig.l the primary energy demand for the production of methanol is 9.5 (conc.-C02) and 11.4 kWh/1 methanol (air-C02). This is corresponding to an efficiency for the fuel generation of 45.8 and 38.1%, respectively... 

On the energy supply side the early penetration of gas in the first half of the 1990s, the limited use of coal and the full exploitation of existing hydro power have resulted in an electricity generation system... 

Information on wind and hydro power programs and systems, www.eere.energy.gov/windandhydro/... 

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