“Men are only as good as their technical development allows them to be” - George Orwell CP551...

“Men are only as good as their technical development

allows them to be”- George Orwell

CP551 Sustainable Development

15 Feb 2008 R. Shanthini

Module 6:

Energy and Transport for economic and human

development, and their impact on

Sustainable Development.


Global energy consumption in 2004

≈ 15 TW = 15 x 1012 W

(86.5% of which comes from burning of fossil fuels)


Global population in 2004 ≈ 6.37 billion

Global energy consumption per person in 2004

≈ 15 x 1012 W / 6.37 x 109

≈ 2.4 kW


1.65

8.0

0.6

10.5

2.4

0

2

4

6

8

10

12

China Singapore Sri Lanka US World

Energy consumption per capita in 2004 (in kW)


Non-renewables

Renewables

???

Energy Options

Fossil fuels (oil, natural gas and coal)Nuclear (Uranium) power

HydropowerSolar energyWind energy

Geothermal energyOcean (wave, tidal and ocean thermal) energy

Biomass energyBiofuels (bioethanol or biodiesel) energy

Hydrogen (fuel-cell) economy


Renewable energy

are flows of energy that are regenerative or virtually inexhaustible.

- Dr. Raymond Wright

Sustainable energy

is energy which is replenishable within a human lifetime and causes no long-term

damages to the environment.

Source: http://www.jsdnp.org.jm/glossary.html


Sustainable Energy Options?






Energy Options


Non-sustainables

Are these sustainable?

?????







Hydropower- putting barriers in the natural flow of a river prevents fish from migration, alters ecosystems, and threatens the livelihoods of local communities

- the world's 52,000 largest dams release 104 million metric tons of methane annually, which is 4% of the total warming impact of human activities

- hydropower is not renewable, because reservoirs fill up with sediment and cost billions to dredge

- catastrophic failure (If dam breaks it would be a disaster and would kill many people)

- loss of land as well as flooding of areas such as natural habitats and existing settlements


Sustainable energy is replenishable within a human lifetime and causes no long-term damages to the environment.

Hydropower

The twin Aswan Dams of Nile river have plugged the flooding of the river, and much of the flood and its load of rich fertilizing silt are now deposited in reservoirs instead of the delta, thus heavily polluting the river and causing decline in soil fertility in the Nile Delta.



The Three Gorges Dam project in China will flood a

huge area, evacuate over a million people, wash away 13

major cities, and submerge thousands of archeological

and cultural sites.


Non-sustainables


?????








Source: http://en.wikipedia.org/wiki/Image:Available_Energy-2.jpg

Available Energy

in 2004

absorbed by land and ocean

Solar Energy



Solar panels heat up the water and they don’t generate electricity

Solar Energy

Photovoltaic (PV) cell turn light into electricity

Total of installed PV is around 6,000 MWp in 2006



Solar irradiance

PV module

Charge controller

DC loadsAC loads

Inverter

Battery

Stand Alone System


CIS Tower, Manchester, England

£5.5m solar project

- weatherproof cladding is provided by replacing the mosaic tiles around the tower by PV cells (alive & dummy cells).

- dummy cells were used to optimise the system’s electircal generation and minimise costs.

- generates total electricity for 61 average three-bed houses each year

Source: http://www.solarcentury.com/projects/commercial/cis_solar_tower

Solar Energy


Sustainable energy is replenishable within a human lifetime and causes no long-term damages to the environment.Inorganic Solar Cells

Bulk

Thin-film

Germanium Silicon

Mono-crystalline

Poly-crystalline

Ribbon

Silicon

AmorphousSilicon

NonocrystallineSilicon

3rd GenerationMaterials

CIS

CIGS

CdTe

GaAs

Light absorbing dyes

Solar Energy

- CdTe (cadmium telluride) is easier to deposit and more suitable for large-scale production. Cd is however toxic.

- Processing silica (SiO2) to produce silicon is a very high energy process, and it takes over two years for a conventional solar cell to generate as much energy as was used to make the silicon it contains.

- Silicon is produced by reacting carbon (charcoal) and silica at a temperature around 1700 deg C.

- And, 1.5 tonnes of CO2 is emitted for each tonne of silicon

(about 98% pure) produced.

- PV cells complete with biological plants.



Solar Energy

- Germanium is an “un-substitutable” industrial mineral.

- 75% of germanium is used in optical fibre systems, infrared optics, solar electrical applications, and other speciality glass uses.

- Germanium gives these glasses their desired optical properties.

- Germanium use will likely increase with solar-electric power becomes widely available and as optic cables continue to replace traditional copper wire.



Source: Graedel, T.E. and Klee, R.J., 2002. Getting serious about sustainability,Env. Sci. & Tech. 36(4): 523-9


Calculation of United States’ Sustainable Limiting Rate of Germanium Consumption:

Step 1: Virgin material supply limit

The reserve base for germanium in 1999 = 500 Mg

So the virgin material supply limit over the next 50 years

= 500 Mg / 50 years

= 10 Mg/yr




Step 2: Allocation of virgin material

Average U.S. population over the next 50 years

= 340 million

Equal allocation of germanium among the average U.S. population gives

(10 Mg/yr) / 340 million

= 29 mg / (person.yr)




Step 3: Regional “re-captureable” resource base

Worldwide germanium production from recycled material

≈ 25% of the total germanium consumed

Equal allocation of virgin germanium among the average U.S. population therefore becomes 1.25*29 mg / (person.yr)

= 36 mg / (person.yr)

The sustainable limiting rate of germanium consumption in U.S. is thus 36 mg / (person.yr)




Step 4: Current consumption rate vs. sustainable limiting rate

Germanium consumption in U.S. in 1999 = 28 Mg

Population in U.S. in 1999 = 275 million

So, germanium consumption rate in U.S. in 1999

= 28 Mg / 275 million = 102 mg / (person.yr)

which is about 2.8 times the sustainable limiting rate of germanium consumption in U.S.



Non-sustainables


?????







Hydrogen Energy (fuel cell)

How does a fuel cell works?

Go to http://www.fueleconomy.gov/feg/fuelcell8.swf




- Power is produced by an electrochemical process not by combustion

- Noiseless operation

- 50% hydrogen energy content to electrical energy conversion efficiency

- Multi-fuel (hydrocarbon and alcohols) capability

- Durability, reliability, scalability and ease of maintenance

- Only water and heat is emitted from a fuel cell (water is in fact a greenhouse gas)




- The electrodes are composed of platinum particles uniformly supported on carbon particles. The platinum acts as a catalyst.

- Polymer Electrolyte Membrane (Proton Exchange Membrane) is a thin, solid, organic compound.

- Hydrogen for the fuel cell is produced from fossil fuel at present (so CO2 emissions are part of hydrogen energy).

- Power-plant-to-wheel efficiency of 22% if the hydrogen is stored as high-pressure gas, and 17% if it is stored as liquid hydrogen

- Hydrogen transportation and refuelling




Non-sustainables


?????







“Men are only as good as their technical development allows them to be” - George Orwell CP551...

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