HydroelectricityHydroelectricitySolar Power From WaterSolar Power From Water

Andrea JoyAndrea Joy

What is Hydroelectricity?What is Hydroelectricity?

Hydroelectricity is an electrical Hydroelectricity is an electrical generation system that creates generation system that creates electrical current from the movement electrical current from the movement of water through turbines. of water through turbines.

A Little HistoryA Little History• Since ancient times humans have used moving Since ancient times humans have used moving

water as an energy source. At least 5000 years water as an energy source. At least 5000 years ago simple water wheels were being used for ago simple water wheels were being used for irrigation and water distribution. irrigation and water distribution.

• Development created increasingly efficient designs Development created increasingly efficient designs until Benoit Fourneyron invented the first water until Benoit Fourneyron invented the first water turbine in 1832, with an efficiency of 80%.turbine in 1832, with an efficiency of 80%.

• A few years later James Francis began A few years later James Francis began experimenting with inward flow radial turbines and experimenting with inward flow radial turbines and these led to the modern turbine most commonly these led to the modern turbine most commonly used today called the Francis turbine.used today called the Francis turbine.

• In the last quarter of the nineteenth century, hydro In the last quarter of the nineteenth century, hydro technology proceeded to develop exponentially.technology proceeded to develop exponentially.

How much Power?How much Power?

• How much power a hydroelectric system How much power a hydroelectric system generates depends on input:generates depends on input:

• Effective headEffective head (height through which (height through which water falls) water falls) HH

• Flow rateFlow rate (cubic meters of water per (cubic meters of water per second) second) QQ

INPUT : P(kW) = 10 × INPUT : P(kW) = 10 × QQ × × H H

Stored Energy and Available Stored Energy and Available PowerPower

Potential energyPotential energy = MgH = MgH

M = mass of water in kilogramsM = mass of water in kilograms

g = acceleration due to gravity (g = acceleration due to gravity (9.81 9.81 msms-2-2))

H = head (height)H = head (height)

Output Power :Output Power : P(kW) = 9.81 P(kW) = 9.81ηηQHQH

ηη = Turbo-generator efficiency = Turbo-generator efficiency

Q = Flow rateQ = Flow rate

H = HeadH = Head

Key ComponentsKey Components• Dam or Barrage (a solid wall to back up the water Dam or Barrage (a solid wall to back up the water

creating a reservoir)creating a reservoir)

• Reservoir (created by the dam or barrage)Reservoir (created by the dam or barrage)

• Penstock (for medium or high head systems, to Penstock (for medium or high head systems, to transport water from reservoir to turbine) transport water from reservoir to turbine)

• A turbine runner (a set of curved blades on a radial A turbine runner (a set of curved blades on a radial frame through which water flows and creates direct frame through which water flows and creates direct power) power)

• Generator (converts the direct (kinetic) power into Generator (converts the direct (kinetic) power into electric current)electric current)

Types of Modern Hydroelectric Types of Modern Hydroelectric PlantsPlants

• Low Head (small height of drop)Low Head (small height of drop)

• Medium Head (medium drop)Medium Head (medium drop)

• High head (high drop)High head (high drop)

Low HeadLow Head

Medium HeadMedium Head

High HeadHigh Head

Types of TurbineTypes of Turbine

ImpactsImpacts

BenefitsBenefits• Clean renewable Clean renewable

sustainable energysustainable energy

• Creation of Creation of ‘waterfront ‘waterfront property’property’

• Can aid in flood Can aid in flood control and control and irrigationirrigation

InsultsInsults• Disturbance of natural Disturbance of natural

habitatshabitats

• Potential catastrophes Potential catastrophes from a breech in the from a breech in the damdam

• Relocation of Relocation of communitiescommunities

• Aesthetic implicationsAesthetic implications

• Power storage Power storage difficultiesdifficulties

BenefitsBenefits

• The energy produced by hydroelectric generation The energy produced by hydroelectric generation systems is clean, creating little to no atmospheric systems is clean, creating little to no atmospheric pollution, no radioactive compounds, and no pollution, no radioactive compounds, and no particulates or chemical compounds that are particulates or chemical compounds that are harmful to human health. harmful to human health.

• It is renewable, and can function for as long as It is renewable, and can function for as long as the structures themselves are maintained.the structures themselves are maintained.

• It is sustainable and can be depended on by It is sustainable and can be depended on by future generationsfuture generations

• Artificial reservoirs create waterfront property Artificial reservoirs create waterfront property which has economic and aesthetic value.which has economic and aesthetic value.

• Reservoirs can aid in irrigation and flood control. Reservoirs can aid in irrigation and flood control.

InsultsInsults• Often, large scale projects require deforestation, Often, large scale projects require deforestation,

flooding of riparian areas, and disturbance in fish flooding of riparian areas, and disturbance in fish spawning and breeding behaviors, and if the spawning and breeding behaviors, and if the trees are not cut and removed they rot at the trees are not cut and removed they rot at the bottom of the reservoir creating methane, a bottom of the reservoir creating methane, a potent greenhouse gas.potent greenhouse gas.

• Creation of reservoirs and diversion or piping Creation of reservoirs and diversion or piping water can result in increased evaporation leading water can result in increased evaporation leading to a fall in the water table.to a fall in the water table.

• It can threaten and kill flora and fauna that It can threaten and kill flora and fauna that depended on the natural flow such as fish who depended on the natural flow such as fish who must swim up river to spawn. must swim up river to spawn.

• Construction can cause major disturbances Construction can cause major disturbances pollution and alteration of land. pollution and alteration of land.

• Silt accumulation reduces the useful volume and Silt accumulation reduces the useful volume and thus output capacity of the reservoir and it does thus output capacity of the reservoir and it does not make it down stream to areas that really not make it down stream to areas that really need it for soil building.need it for soil building.

Insults continued…Insults continued…

• Dam failure can kill thousands of humans as well Dam failure can kill thousands of humans as well as other species downriver by creating a surge as other species downriver by creating a surge that devastates the land much like a Tsumani.that devastates the land much like a Tsumani.

• Relocation of communities in reservoir areas is Relocation of communities in reservoir areas is difficult for people who have lived in these areas difficult for people who have lived in these areas and established their communities there.and established their communities there.

• Aesthetic value of the Dam itself is usually Aesthetic value of the Dam itself is usually negative. negative.

• Storage of Power to compensate for peak demand Storage of Power to compensate for peak demand or generator failure is difficult, although pumped or generator failure is difficult, although pumped storage offers a viable option in certain instances.storage offers a viable option in certain instances.

Scale and NeedScale and Need

• In considering the cost/benefit analysis for In considering the cost/benefit analysis for a hydro system it is important to consider a hydro system it is important to consider the scale as many of the potential insults the scale as many of the potential insults can be avoided in the creation of small can be avoided in the creation of small scale hydroelectric systems.scale hydroelectric systems.

• It is also important to consider that in It is also important to consider that in general if a hydro plant is being general if a hydro plant is being considered, it is necessary to generate considered, it is necessary to generate power for the region in some form, and power for the region in some form, and thus would be better than a more thus would be better than a more conventional fossil fuel based system, all conventional fossil fuel based system, all things considered.things considered.

SummarySummary

• Hydroelectric systems are not entirely free Hydroelectric systems are not entirely free of negative impacts, but all things of negative impacts, but all things considered they are often far better than considered they are often far better than non-renewable alternatives, but this non-renewable alternatives, but this depends heavily on the site.depends heavily on the site.

• Hydroelectricity is a well established Hydroelectricity is a well established technology that already accounts for about technology that already accounts for about 1/6 of world’s electrical output, and over 1/6 of world’s electrical output, and over 90% of electricity from renewable energy 90% of electricity from renewable energy sources.sources.

• Site, scale, and need are all important in Site, scale, and need are all important in deciding where and how to construct a dam.deciding where and how to construct a dam.

Hydroelectricity in BelizeHydroelectricity in Belize

• Mollejon Dam (on Macal)Mollejon Dam (on Macal)

• Challilo Dam (on Macal, downstream)Challilo Dam (on Macal, downstream)

The Chalillo DamThe Chalillo Dam

Challilo Dam Project

Specifications:

Will deliver 30 GWh of electricity and increase capacity of Mollejon by about 55 GWh annually.

49.5 m high storage Dam

7 MW power house at toe of Dam

Located on Macal River 18 kilometers upstream from existing 25 MW Mollejon plant

Will flood 9.5 sq km including 1.5 sq. km of existing river (2,800 acres of rainforest that is a home to jaguars, ocelots, Tapirs and some of the last known Scarlet Macaws)

Cost estimated at US $30 million

Insults of DamInsults of Dam

Destruction of habitats for already endangered species such as the Jaguar and Scarlet Macaws

Absence of promised economic benefits to Belizean people (Fortis raises light bills 12% in May 2005 and another 13% in January 2006.)

Being built near a fault line, so it is a very unstable and dangerous site

Loss of cultural heritage ("A total of 298 structures have been identified in the project area.  This is a very high density and is consistent with heavy settlement in other river valleys in Belize.” )

Methane emissions from rotting vegetation will contribute further to Global Warming.

Flooding behind Dam Feb. Flooding behind Dam Feb. 20062006

Before and after construction Before and after construction began….began….

But how much is Challillo really considering But how much is Challillo really considering the people of Belize’s desires…..the people of Belize’s desires…..

"This is the prettiest river in the country," says Mick Fleming, "This is the prettiest river in the country," says Mick Fleming, who owns the Chaa Creek Lodge, an ecotourism resort set who owns the Chaa Creek Lodge, an ecotourism resort set in the jungle 20 miles downstream from the dam site. in the jungle 20 miles downstream from the dam site. "We're going to lose something incredibly valuable in return "We're going to lose something incredibly valuable in return for an extremely small amount of power." for an extremely small amount of power."

Plenty of people in Cayo agree with Fleming's assessment. Plenty of people in Cayo agree with Fleming's assessment. The city council in the district capital, San Ignacio, opposes The city council in the district capital, San Ignacio, opposes the dam, and the vice mayor testified against the project the dam, and the vice mayor testified against the project during an unsuccessful attempt to block construction during an unsuccessful attempt to block construction brought before the Privy Council in London last year. T-brought before the Privy Council in London last year. T-shirts and banners bearing such slogans as "The Macal is shirts and banners bearing such slogans as "The Macal is Ours" are seen all over town. "We use the river for drinking Ours" are seen all over town. "We use the river for drinking and swimming and tourism and canoeing," explains San and swimming and tourism and canoeing," explains San Ignacio hotel owner Maria Preston. "The river is everything Ignacio hotel owner Maria Preston. "The river is everything for us.“for us.“

Is it really good for Belize?Is it really good for Belize?

While the dam will substantially boost domestic electricity While the dam will substantially boost domestic electricity production, most of the power will be generated at times of production, most of the power will be generated at times of day when it is more expensive than importing it from Mexico. day when it is more expensive than importing it from Mexico. A 2000 study by the California-based Conservation Strategy A 2000 study by the California-based Conservation Strategy Fund estimated the project would be a net drag on the Fund estimated the project would be a net drag on the Belizean economy. The dam is also being built near an active Belizean economy. The dam is also being built near an active fault line, and Fortis admitted that it mischaracterized the fault line, and Fortis admitted that it mischaracterized the geological properties of the site.geological properties of the site.

"This a bad project all the way around," says Grainne Ryder, "This a bad project all the way around," says Grainne Ryder,

policy director of Probe International in Toronto, which has led policy director of Probe International in Toronto, which has led a campaign against Chalillo in Canada. "Fortis may make a a campaign against Chalillo in Canada. "Fortis may make a quick profit out of it, but Belizeans will be left with the real quick profit out of it, but Belizeans will be left with the real costs for generations." costs for generations."

For more info on the Challilo Project check out: For more info on the Challilo Project check out: www.stopfortis.orgwww.stopfortis.org