Hydraulic Energy and Small Hydroelectric Systems
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Questions and Answers

What percentage of the total electricity generated in the European Union is represented by hydropower electricity?

13%

How many tons of CO2 emissions are reduced annually by hydropower electricity in the European Union?

67 million

Conventional hydropower schemes are known for their minimal environmental impact.

False

Properly designed small hydro schemes can be easily integrated into local ecosystems.

<p>True</p> Signup and view all the answers

What was the total capacity of hydro energy produced in the European Union in 2001?

<p>118 GW</p> Signup and view all the answers

What percentage of the installed capacity in 2001 was attributed to small hydro plants?

<p>8.4%</p> Signup and view all the answers

What was the objective set by the European Commission for small hydro power generation by 2010?

<p>14,000 MW</p> Signup and view all the answers

Most small hydro plants are classified as 'run-of-river' schemes.

<p>True</p> Signup and view all the answers

Run-of-river schemes require extensive water storage capabilities.

<p>False</p> Signup and view all the answers

The turbine in a run-of-river scheme operates even when the river flow falls below a predetermined value.

<p>False</p> Signup and view all the answers

Which of these countries set the border line for small hydroelectricity at 10 MW?

<p>Belgium</p> Signup and view all the answers

What is the limit for small hydroelectricity in Italy?

<p>3 MW</p> Signup and view all the answers

What is the limit for small hydroelectricity in Great Britain?

<p>5 MW</p> Signup and view all the answers

What two forms of energy are harnessed by hydroelectric plants?

<p>potential and kinetic energy</p> Signup and view all the answers

What is the formula for calculating the power produced by a hydroelectric system?

<p>P = η γQH</p> Signup and view all the answers

What does Q represent in the power formula?

<p>Volumetric flow rate</p> Signup and view all the answers

What is the formula for calculating the electricity produced by a hydroelectric plant?

<p>E = P × n</p> Signup and view all the answers

What does P represent in the electricity formula?

<p>Net power at given flow rate</p> Signup and view all the answers

Which of these classifications is NOT based on the nominal power installed in the plant?

<p>Run-of-the-river systems</p> Signup and view all the answers

What is the nominal power range for micro-plants?

<p>less than 100 kW</p> Signup and view all the answers

Which of these classifications for hydroelectric plants is NOT based on the available head?

<p>Run-of-the-river systems</p> Signup and view all the answers

What is the head range for low head plants?

<p>less than 50 m</p> Signup and view all the answers

What is the head range for medium head plants?

<p>between 50 m and 250 m</p> Signup and view all the answers

What is the head range for very high head plants?

<p>greater than 1000 m</p> Signup and view all the answers

Which of these classifications is NOT based on the flow rate used?

<p>Basin Systems</p> Signup and view all the answers

What is the flow rate range for low flowrate plants?

<p>less than 10 m³/s</p> Signup and view all the answers

What is the flow rate range for medium flowrate plants?

<p>between 10 m³/s and 100 m³/s</p> Signup and view all the answers

What is the flow rate range for very large flowrate plants?

<p>greater than 1000 m³/s</p> Signup and view all the answers

Which of these is NOT one of the three main categories of hydroelectric plants based on water storage duration?

<p>Pumped Storage</p> Signup and view all the answers

What is the storage duration range for seasonal reservoirs?

<p>greater than or equal to 400 hours</p> Signup and view all the answers

What is the storage duration range for weekly or daily modulation basins?

<p>less than 400 hours but greater than 2 hours</p> Signup and view all the answers

Run-of-the-river systems are characterized by the absence of water storage or storage lasting less than two hours.

<p>True</p> Signup and view all the answers

What is the average annual yield in Italy from natural contributions?

<p>47,003 GWh/year</p> Signup and view all the answers

What is the average annual yield from pumping inlets in Italy?

<p>6654.8 GWh/year</p> Signup and view all the answers

What is the average annual yield from other pumping sources in Italy?

<p>183.6 GWh/year</p> Signup and view all the answers

Which of these is NOT a component of a high head scheme?

<p>Fish Ladder</p> Signup and view all the answers

Penstocks are typically considered an economical design option for diverting water to the turbine.

<p>False</p> Signup and view all the answers

Low head schemes can be constructed in river valleys.

<p>True</p> Signup and view all the answers

Low head schemes can utilize either a short penstock or an integrated intake with a small dam.

<p>True</p> Signup and view all the answers

Which of these is NOT a component of a low head scheme with an integrated intake?

<p>Penstock</p> Signup and view all the answers

Small hydropower schemes are often able to afford the cost of large reservoirs for their operation.

<p>False</p> Signup and view all the answers

Which of these is NOT a common alternative use for a reservoir that may allow for hydroelectric generation?

<p>Mineral Extraction</p> Signup and view all the answers

Connecting headwater and tailwater in a waterway is a significant challenge in small hydropower schemes.

<p>True</p> Signup and view all the answers

A siphon intake can be installed in a small hydropower scheme when the dam is not too high.

<p>True</p> Signup and view all the answers

Integral siphon intakes are a common solution for schemes with heads above 10 m.

<p>False</p> Signup and view all the answers

The turbine in a small hydropower scheme can be located either on top of the dam or downstream.

<p>True</p> Signup and view all the answers

Small hydropower units often require significant modifications to existing dams during installation.

<p>False</p> Signup and view all the answers

The concept of 'minimum constant flow' was introduced in the Italian Law 183/1989 to ensure a balance between human needs and the environment.

<p>True</p> Signup and view all the answers

The 'Minimum Vital Flow' (MVF) concept, introduced later, focused primarily on maintaining the physical characteristics of river ecosystems.

<p>False</p> Signup and view all the answers

Hydrological formulas used by River Basin Authorities in Italy are based on complex models incorporating a wide range of environmental factors.

<p>False</p> Signup and view all the answers

The MVF formula for the Po River Basin Authority incorporates factors related to the hydrological regime, morphology, naturalness, quality of water, and human impact.

<p>True</p> Signup and view all the answers

Which of these factors is NOT included in the MVF formula?

<p>Climate change</p> Signup and view all the answers

The Italian law 'Legge Galli' aims to protect river ecosystems by ensuring a minimum vital flow.

<p>True</p> Signup and view all the answers

Flow duration curves depict the relationship between flow rate and the frequency of occurrence.

<p>True</p> Signup and view all the answers

The 'cut-off' flow rate refers to the minimum flow rate at which the hydroelectric plant can efficiently operate.

<p>True</p> Signup and view all the answers

The 'unusable area' in a flow duration curve represents the portion of time when the flow rate is above the cut-off rate.

<p>False</p> Signup and view all the answers

The area beneath the flow duration curve represents the total amount of water passing a point in a given period.

<p>True</p> Signup and view all the answers

The operating ranges of different turbine types are fixed and do not vary between manufacturers.

<p>False</p> Signup and view all the answers

Which type of turbine is generally suitable for high head applications?

<p>Pelton</p> Signup and view all the answers

Study Notes

Hydraulic Energy

  • Hydropower in the EU accounts for 13% of total electricity generation, reducing CO2 emissions by over 67 million tons annually.
  • Small hydro schemes integrate easily into local ecosystems, unlike conventional hydro that floods large areas.
  • In 2001, the EU produced approximately 365 TWh of hydro energy with an installed capacity of 118 GW.
  • Small hydro plants contributed 8.4% of installed capacity (9.9 GW) and generated 39 TWh (about 11%).
  • The EU Commission aimed for 14,000 MW of small hydro capacity by 2010.
  • Most small hydro plants are "run-of-river" schemes, meaning they rely on natural river flow without significant water storage.

Small Hydroelectric Systems

  • Confusion exists regarding the definition of a "small" hydroelectric plant.
  • No universally agreed EU definition exists for small plants, potentially hindering their development.
  • Various EU countries have different power limits for qualifying as a small plant (e.g., Italy - 3 MW, France - 8 MW, Great Britain - 5 MW).
  • Power output is calculated using the formula: P = ηγQH, where:
    • Q = volumetric flow rate (m³/s)
    • H = head (m)
    • γ = specific weight of the liquid (N/m³)
    • η = global system efficiency (unitless).

Classification of Hydroelectric Plants

  • Plants are categorized by nominal power (Pn):
    • Micro-plants: Pn < 100 kW
    • Mini-plants: 100 < Pn < 1000 kW
    • Small-plants: 1000 < Pn < 10,000 kW
    • Large-plants: Pn > 10,000 kW
  • Plants are further classified by hydraulic scheme:
    • Run-of-the-river systems
    • Plants with storage and regulation basin
  • Plants are further classified by available head:
    • Low head (H < 50 m)
    • Medium head (H = 50 - 250 m)
    • High head (H = 250 - 1000 m)
    • Very high head (H > 1000 m)
  • Plants are further classified by flow rate:
    • Low flow rate (Q < 10 m³/s)
    • Medium flow rate (Q = 10 - 100 m³/s)
    • Large flow rate (Q = 100 - 1000 m³/s)
    • Very large flow rate (Q > 1000 m³/s)

Hydroelectric Storage

  • Hydroelectric plants are classified into three categories based on storage duration:
    • Reservoir systems: >400 hours of storage
    • Basin systems: 2 - 400 hours of storage
    • Run-of-the-river systems: less than 2 hours

Hydropower in Italy

  • In 2009, Italy had approximately 152 reservoir systems
  • Including 177 basin and 1927 run-of-the-river plants.
  • Average annual yield from natural contributions was 47,003 GWh/yr
  • Additional production was from pumping inlets.

Possible Hydraulic Schemes

  • Various schemes exist for diverting and conveying water to generate electricity including medium and high-head schemes.
  • Low-head options use river valleys with either diversions to a power intake or with dam-integrated intakes.

Minimum Vital Flow (DMV)

  • Operators of hydroelectric power plants are required to release minimum water flows (DMV) to protect river ecosystems.
  • The flow rate must be sufficient to maintain vital river conditions beyond hydropower diversions and downstream water quality and the biodiversity.

National and Regional Laws

  • National Laws govern minimum vital flows for river preservation under the principles of water quality, naturalness and water management for the Italian regions.
  • Regional Laws specify further requirements.

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Small Hydroelectric Power Plants PDF

Description

Explore the role of hydraulic energy in the EU's electricity generation, focusing on the significance of small hydro systems. Learn about their environmental benefits, contribution to CO2 reduction, and the challenges regarding definitions and classifications in different EU countries.

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