HYDROELECTRIC POWER

HEP IS USUALLY OBTAINED THROUGH THE HARNESSING OF THE POTENTIAL ENERGY OF DAMMED WATER BEING CHANNELED THROUGH A WATER TURBINE WHICH IN TURN POWERS A GENERATOR AND CREATES USEFUL ENERGY

HEP IS ALSO OBTAINED THROUGH THE KINETIC ENERGY OF WATER, SUCH AS TIDAL ENERGY, CURRENTLY AROUND 20% OF THE TOTAL ENERGY PRODUCTION WORLDWIDE COMES FROM HEP

MANY HEP SOURCES ARE CONNECTED TO PUBLIC ENERGY GRIDS, HOWEVER MANY WERE ORIGINALLY CREATED TO POWER PRIVATE, ENERGY HUNGRY SITES SUCH AS ALUMINIUM PROCESSING

HOW DOES IT WORK?

• The amount of energy produced is dependant on the height distance from where the water starts and where it hits the turbine, as well as the actual amount of water

• The height distance between the source and the water’s outflow is called the ‘head’

• To obtain better head, the water may be run through a large pipe, called a penstock before it goes through the water turbine, to maximise the water’s potential energy

• The turbine then powers the generator, which in turn creates useful energy

LARGE-SCALE HEP

HOOVER DAM, USA•SITUATED ON THE COLORADO RIVER, BETWEEN THE AMERICAN STATES OF ARIZONA AND NEVADA•CONSTRUCTION COMPLETED IN 1936•LAKE MEAD CREATED AS A CONSEQUENCE•WATER TRAVELLING THROUGH THE PENSTOCKS TO THE TURBINES, REACHES SPEEDS OF UP TO 137 KPH AS THEY GRADUALLY GET NARROWER, THE WATER PRESSURE BUILDS TO MAXIMISE POTENTIAL ENERGY

•THE TURBINES CREATE 2,080 MEGAWATTS

•2ND HIGHEST DAM IN THE US, AT 221.4M HIGH

•LAKE MEAD BACKS UP 110 MILES BEHIND THE DAM, WITH AN

AREA OF 157,900 ACRES, AND VOLUME OF 28,537,000 ACRE

FEET

ADVANTAGES OF LARGE-SCALE HEP

1. HYDROELECTRIC POWER ELIMINATES THE NEED AND COST OF USING FUEL TO PRODUCE ELECTRICITY2. HEP STATIONS HAVE A MUCH LONGER LIFE-SPAN THAN FUEL POWERED POWERSTATIONS, WITH SOME HEP STATIONS BUILT 100 YEARS AGO AND STILL IN SERVICE TODAY3. HEP PLANTS CAN ALSO BE BUILT FROM DAMS THAT WERE ORIGINALLY INTRODUCED FOR IRRIGATION AND FLOOD CONTROL WITH RELATIVELY LOW COST4. MANY LAKES CREATED AS A RESULT OF HEP STATIONS, CAN BECOME TOURIST ATTRACTIONS AND WATER-SPORTS CENTRES

DISADVANTAGES OF LARGE-SCALE HEP

• HUGE AMOUNTS OF LAND NEED TO BE FLOODED, AS RESULT OF THE DAM BUILDING, DISPLACING MANY INDIGINOUS PEOPLE AND CREATURES

• AQUATIC ECOSYSTEMS ARE AFFECTED, AS FISH CANNOT REACH AREAS CRUCIAL FOR THEIR REPRODUCTION FOR EXAMPLE

• WHEN CREATURES TRAVEL THROUGH THE WATER TURBINES, THEY CAN GET INJURED OR KILLED

• WHEN WATER PASSES THROUGH THE TURBINES, IT OFTEN LOSES ALL OF ITS SEDIMENT CONTENT DUE TO LACK OF ENERGY, LEADING TO DEPLETED RIVER BANKS AND RIVER BED FURTHER DOWNSTREAM AND THEREFORE INCREASED EROSION

…more disadvantages

• PLANTS AND OTHER ORGANIC MATTER FLOODED BY THE RESEVOIRS CREATED, MAY IN TROPICAL AREAS CREATE LARGE AMOUNTS OF METHANE DUE TO RAPID DECOMPOSITION

• WHEN DAMS SUCH AS THE ‘VAJONT’ ARE BUILT IN GEOGRAPHICALLY INAPPROPRIATE LOCATIONS, DISASTERS CAN OCCUR, SUCH AS WHEN THE ‘VAJONT’ DAM IN ITALY WHERE ALMOST 2000 PEOPLE DIED IN 1963!

SUSTAINABILITY

• HYDROELECTRIC POWER IS ONE OF THE FEW NON-FUEL BASED POWER STATIONS THAT ARE ABLE TO PROVIDE SUBSTANTIAL AMOUNTS OF ELECTRICITY ALONE, TO POWER WHOLE CONURBATIONS OR LARGE INDUSTRIAL SITES

• HOWEVER THERE ARE SOME BY-PRODUCTS OF DAM CONSTRUCTION THAT ARE NOT IDEAL, AND CAN BE VERY DAMAGING TO THE ENVIRONMENT

FUTURITY

• HYDROELECTRIC POWERPLANTS ARE ABLE TO PRODUCE ELECTRICITY FOR LARGE AMOUNTS OF TIME IN COMPARISON TO OTHER (PARTICULARLY FUEL-POWERED) POWER STATIONS

• THEY DO NOT RELY ON FUEL AND ARE THEREFORE EXEMPT FROM PRICE DROPS AND RISES OR WORST CASE, THE EXHAUSTION OF THE EARTH’S FOSSIL FUELS

ENVIRONMENT

• ALTHOUGH THERE ARE SOME DAMAGING ELEMENTS TO THE ENVIRONMENT INVOLVED WITH HEP, OVERALL THE ENERGY SOURCE CAN BE CONSIDERED ENVIONMENTALLY FRIENDLY

• IN COMPARISON TO FUEL-POWERED POWER STATIONS THE ENVIRONMENTAL IMPACTS AND CONTRIBUTION TO GLOBAL WARMING CAN BE CONSIDERED MINOR

• HOWEVER THE PROJECTS DO NEED LARGE AREAS OF LAND TO BE EFFECTIVE

EQUITY AND SOCIAL JUSTICE

• PERHAPS THE LARGEST DOWNFALL OF HEP, IS THE HUGE SOCIAL INJUSTICE, WHEN THOUSANDS OF PEOPLE ARE FORCEFULLY REMOVED FROM THEIR HOMES SO IN ORDER TO BUILD A HEP PROJECT

• THESE PEOPLE TEND TO BE FROM RURAL AREAS, AND MANY HAVE ANCESTRAL ROOTS TO THESE PARTICULAR PLACES, AND THEIR REHOUSING IS OFTEN SUB-STANDARD TO THEIR HOMES, AND LEAVES THEM WITH NO MEANS OF SUPPORTING THEMSELVES

PUBLIC PARTICIPATION

• THE CONSTRUCTION OF LARGE-SCALE HEP PROJECTS PROVIDES MANY JOBS, BOTH IN CONSTRUCTION AND DESIGN, AS WELL AS THE HARVESTING OF THE LARGE AMOUNTS OF MATERIALS NEEDED FOR THE CONSTRUCTION

• HOWEVER, MOST THE PEOPLE WHO ARE DISPLACED WOULD NOT AGREE THAT THEY PARTICIPATED WITH THE PROJECT, THEY WOULD ARGUE THAT THEY WERE FORCIBLY REMOVED, AND IN SOME CASES PEOPLE ARE

HEP, GOOD OR BAD?

• ALTHOUGH MANY PEOPLE APPEAR TO BE TAKEN ADVANTAGE OF IN THE COURSE OF LARGE-SCALE HEP PROJECTS, IT SEEMS THAT HEP IS MUCH BETTER OVERALL THAN ANY OTHER MEANS OF GENERATING ENERGY, DUE TO THE BALANCE BETWEEN ENERGY PRODUCED AND ENVIRONMENTAL IMPACT

• HOWEVER IF IT WERE TESTED UNDER THE 4 QUARTILES OF SUSTAINABILITY, IT WOULD BE CONSIDERED ‘UNSUSTAINABLE’