Part B2: Hydro power

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Part B2 Hydro power B2.1 Fundamentals of Hydro
power
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B1.2 ReservoirsSeminars Monday A206a
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B2.1 Hydro powerTopics Fundamentals

• Power available
• The energy equation, quick and dirty power
  estimation
• Hydro systems
• Parts of a hydro system, types of hydro system
• power needs
• Load curves, load factors, methods of smoothing
  system demand
• yields and economics
• Use of flow-duration curves, efficiency methods
  of estimating yields, estimating economic
  viability, other factors effecting viability

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B2.1.1 Fundamentals of Hydro power The energy
equation
Shaft work
Heat energy
Friction losses
p Pressure (Pa) g Gravity (m s2) r
fluid density (kg m-3) v velocity (m s-1) z t
Elevation (m) h energy (meters)
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B2.1.1 Fundamentals of Hydro power The energy
equation ImplicationsFlow in pipes No
friction, no shaft work
v1
p1
Energy line
h
z1
v2
p2
z2
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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction,
no shaft work
v1
p1
Energy line
h
z1
v2
p2
z2
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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction
Equations

• Darcys formula

Hf Friction head loss (m) f Friction
factor L Pipe length (m) D Pipe diameter
(m) v velocity (m s-1) g Gravity (m s2)
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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction
Moody diagram
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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction
Nomogram
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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction
Equations

• Blasius equation
• For hydraulically smooth pipe (Re 4,000
  100,000)

f Friction factor k Surface roughness D
Pipe diameter (m) Re Reynolds number g
Gravity (m s2)

• Swamee-Jain equation
• 10-6 lt k/D lt 0.01 (Re 5,000 3x108)

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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction
and shaft work
v1
p1
Energy line
v2
h
z1
so
p2
v3
p3
z2
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B2.1.1 Fundamentals of Hydro power The energy
equation Implications Flow in pipes Friction
and shaft work
v1
p1
Energy line
Extracting pressure energy
v2
h
z1
So
p2
v3
p3
z2
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B2.1.2 Fundamentals of Hydro power Types of
hydro system
Low head (run of the river only)
Medium head (stored only)
High head (run of the river or stored)
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B2.1.2 Fundamentals of Hydro power Types of
hydro system
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B2.1.2 Fundamentals of Hydro power Parts of a
hydro system
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B2.1.2 Hydro powerParts of a hydro system
Ideals

• Intake and power canal
• See section 1.3
• Forebay
• Must be able to cope with largest flow required
  by turbine
• Penstock
• Keep as short as possible?
• Powerhouse
• Should be close to settlement (reduces
  transmission costs) or easily accessible (for
  maintenance)
• Tailrace
• Should empty into natural water course

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B2.1.2 Fundamentals of Hydro power Parts of a
hydro system The powerhouse
Turbine
Coupling
generator
Control
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B2.1.2 Fundamentals of Hydro power Parts of a
hydro system The powerhouse
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B2.1.3 Fundamentals of Hydro power Power needs
Load curves
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B2.1.3 Fundamentals of Hydro power Power needs
Load curves
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B2.1.3 Fundamentals of Hydro power Power needs
Load curves
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B2.1.3 Fundamentals of Hydro power Power needs
Load and plant factors

• Load factor
• Plant factor

Aim for more than 0.6
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B2.1.3 Fundamentals of Hydro power Power needs
Calculating load and plant factors
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B2.1.3 Fundamentals of Hydro power Power needs
Calculating load and plant factors
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B2.1.3 Fundamentals of Hydro power Power needs
Calculating load and plant factors

• Load factor, 0.15
• Plant factor, 0.13

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B2.1.3 Fundamentals of Hydro power Power needs
Improving load and plant factors
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B2.1.3 Fundamentals of Hydro power Power needs
Improving load and plant factors

• Load factor, 0.45
• Plant factor, 0.42

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B2.1.3 Fundamentals of Hydro power Power needs
Improving load and plant factors
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B2.1.3 Fundamentals of Hydro power Power needs
Improving load and plant factors

• Load factor, 0.64
• Plant factor, 0.64

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B2.1.3 Fundamentals of Hydro power Power needs
Improving load and plant factors

• Battery storage
• Slow cookers
• Water heating
• Water pumping
• Divert water to other uses
• Short term (lt24 hour) water storage at weir

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B2.1.3 Fundamentals of Hydro power Power needs
Improving load and plant factors How to
encourage off-peak use

• Subsidy
• Tariffs

This must be discussed and agreed before work
commences
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B2.1.4 Fundamentals of Hydro power Yields and
economics
So losses overall are about 50
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B2.1.4 Fundamentals of Hydro power Yields and
economics Quick and dirty yield

• Power delivered
• per square kilometre of catchment
• per meter of annual rainfall
• per meter of head

Which is pretty close to 100W/km2/mrain/mhead
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B2.1.4 Fundamentals of Hydro power Yields and
economics Flow-duration curve
http//www.geocities.com/jonpeltier/Excel/Charts/P
robabilityChart.html
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B2.1.4 Fundamentals of Hydro power Yields and
economics Flow-duration curve
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B2.1.4 Fundamentals of Hydro power Yields and
economics Flow-duration curve
Worth about 4-500 in the UK wholesale market
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B2.1.4 Fundamentals of Hydro power Yields and
economics Flow-duration curve
14,000 kWh/mhead
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B2.1.4 Fundamentals of Hydro power Yields and
economics Flow-duration curve
17,000 kWh/mhead
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B2.1.3 Fundamentals of Hydro power Power needs
Plant factors
fplant Plant factor Etotal demand Surface
roughness Einstalled Pipe diameter (m) Edaily
demand Reynolds number fexceedence fraction
of time that demand is exceeded
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B2.1.4 Fundamentals of Hydro power Yields and
economics Unit energy cost
Cunit energy Unit energy cost Cannual
Annualised cost COM Operation and maintenance
cost Pinstalled Installed power fplant
Plant factor
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B2.1.4 Fundamentals of Hydro power Yields and
economics Interest
Cannual Annualised cost Ccapital Capital cost
i Interest rate n number of years
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B2.1.4 Fundamentals of Hydro power Yields and
economics Economies of scale
target cost 1000/kW
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B2.1.4 Fundamentals of Hydro power Yields and
economics Cost breakdown
Civil works 13
Electromechanical 27
Electromechanical 48
Civil works 19
Penstock 21
Penstock 12
Engineering 12
Engineering 12
Distribution 14
Distribution 6
Nepal
Sri Lanka
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B2.1.4 Fundamentals of Hydro power Yields and
economics Cost breakdown (60kW scheme)
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B2.1.4 Fundamentals of Hydro power Yields and
economics Environmental impact Potential
benefits

• Prevention of deforestation
• Reduced pollution
• Reduced erosion of roads/paths from carrying
• Environmental protection/Flood control

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B2.1.4 Fundamentals of Hydro power Yields and
economics Environmental impact Potential costs

• Stream diversion
• Changes to aquatic ecosystem (impact on Fishing)
• Changes to bank ecosystem
• Changes to drinking animals
• Possible erosion at tailrace
• Water storage
• Mosquito breeding
• Drinking animals

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B2.1.4 Fundamentals of Hydro power Yields and
economics Social impact Potential benefits

• Better education/health
• Increased earning potential from powered industry
• Self reliance local capacity building
• Reduction of limited ownership/control of power
  sources
• More comfort
• Recreation
• Reduction of urbanisation as rural life improves
• Community building

Who benefits?
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B2.1.4 Fundamentals of Hydro power Yields and
economics Social impact Potential costs

• Existing energy/fuel suppliers
• Existing stream users
• Potential for unrest if benefits are distributed
  unequally (or unexpectedly)
• Use of sweat equity may cause problems

Who loses?
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B2.1.4 Fundamentals of Hydro power Yields and
economics Social impact Assessment Things to
check

• Types of people
• Institutions
• Energy sources
• Village organisations
• Household and individuals
• Entrepreneurs and officials
• Other villages and model schemes

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B2.1.4 Hydro powerYields and economics Social
impact Sustainable livelihoods

• " A livelihood comprises the capabilities, assets
  (including both material and social resources)
  and activities required for a means of living. A
  livelihood is sustainable when it can cope with
  and recover from stresses and shocks and
  maintains or enhances its capabilities and assets
  both now and in the future, while not undermining
  the natural resource base."

Hydro is not the end it is the means
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B2.1.4 Fundamentals of Hydro power Yields and
economics When is hydro viable

• When there is a need for power
• schools, hospitals, unrealised potential for
  local industry
• When alternatives are unavailable or difficult
• Diesel generators fuel cost (including
  transport), individual ownership
• Grid extension expense(?), uncertainty of
  future tariffs
• When there is the ability in the community to
  manage the system

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B2.1.4 Fundamentals of Hydro power Yields and
economics When is hydro viable