Hydropower Flashcards
What are the three main types of power generation from water?
- Hydro
- Tidal
- Wave
Give an example of an impulse turbine and suggest the situation its best used in
Pelton turbines/Pelton wheel - Suitable for large heads and ‘small’ flow rates
Give an example of an reaction turbine and suggest the situation its best used in
Kaplan turbine - For low head conditions and large flowrates, high efficiency, blades fully emerged in water using thrust from reaction forces.
Give an example of a mixed regime turbine and suggest the situation its best used in
Francis turbine - moderate flow rate and moderate head. e.g dams
What is the equation for available power of hydropower plan based on potential energy?
P=kphrg
- k is a coefficient of efficiency, ~0.9 at the right conditions
- ρ is the density of water (~1000 kg/m³)
- h is head in meters
- r is flow rate in m³/s
- g is acceleration due to gravity: 9.8 m/s²
What is the equation for available power of hydropower plan based on kinetic energy (for ROR is you know v)?
P=1/2 kpAv^3
What are the summary of pros for hydropower?
Well-established technology
Low operating cost
Minimal impact on the atmosphere
don’t forget the CO2 to make the cement in the dam…
Base load power generation, unlike wind, solar
Quick response to changes in electricity demand (stored)
Long plant life (typically over 40yr before major refurbishment)
Tourism honeypot
What are the summary of cons for hydropower?
Large capital cost; hence long payback period
Possible displacement of population
Changes in sediment transport (with reservoirs possibly silting up)
Impact on fish and ecosystem
Dam failures can have catastrophic consequences
Location dependent
High maintenance (but infrequently needed)
High decommissioning costs
What is the time between low and high tide that is used in tidal calculations
6.2 hours for a two way turbine or 12.4 for a one way turbine
