Chikuni Okoro Schumacher Cput

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10/19/2012 International Conference onDomestic Use of Energy 2006

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SUSTAINABLE ENERGY TECHNOLOGIES - REVIEW OF

CURRENT INTERNATIONAL TRENDS AND LESSONS FORSOUTHERN AFRICA

E. Chikuni,

Department of ElectricalEngineering

Polytechnic of Namibia


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Presenter Ed Chikuni

The presenter has worked on renewable R&D

project as well as conventional enterprises in the

transport & manufacturing sectors. For the past 10years he has been an academic.


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Introduction

The problems of waste, over-consumption and

inappropriate use of resources (especially energy)

and ramifications for future generations werehighlighted in E.F. Schumachers celebrated book,

Small is Beautiful [1] published 27 years ago .

In this book, the USA, for example with 6% of the

worlds population consumes 40% of its resources


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Dominance of Oil Coal & Natural Gas on the Energy Scene


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South African Scenario


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Who is polluting


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Sustainable Energy According to Davidson sustainable energy is

defined as energy that will provide affordable,accessible and reliable energy services that

meet economic, social and environmentalneeds within the overall developmental contextof the society for which the services areintended, while recognising equitable

distribution in meeting those needs (Davidson2002).


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About This Presentation

This presentation will cover the following:

Brief review of the global primary energy consumption

Wind Energy Biomass

Fuel Cells

Geothermal

Photovoltaics

Conclusion


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Wind Energy


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10/19/2012 International Conference onDomestic Use of Energy 2006 10

Wind: Germany

Current Installed Capacity: 4444 MW

Germany remains the largest wind energy market

in the world. In an average wind year, 31.6 billionkWh of electricity can be generated already

today reaching 6.2 % of the net power

consumption in Germany. The further expansion

of wind energy utilisation in Germany in future willno longer be confined to land, but will increasingly

be offshore.


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Germany

In Germany, the most successful sites are in the northern

coastal state of Lower Saxony. There are two techniquesused to connect the turbine system to the generator, direct

coupling or through a gearbox. Both systems have been

used successfully; the geared system represents a

traditional tried and tested approach while the directcoupling method with is multi-pole, ring generator, is

associated with revolutionary design which may well set

the direction for new large turbines. Figure 2 shows a large

wind turbine (2.5 MW) of a type seen in many locations inEurope. Figure 3 shows its power curve. Currently the

largest turbines are rated around 5MW


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ermany: nWind energy development has been boosted in Germany by the

Renewable Energy Feed in Law (REL) which obliges utilities to

purchase at a premium renewable energy produced byindependent power producers (IPP). The REL operates a

differential pricing system for each technology, with local

adjustments for energy resource availability and reducing

payments over the projects duration. For example, the overall

price for wind-power is set at DM 0.178/kWh during the first five

years of operation.Solar PV systems will now receive DM

0.45/kWh, with a degression of 5 % for new installations, starting

in 2002 - to reflect the expected costs reduction potential of a

technology which is still expensive. Renewable PortfolioStandards (RPS) are targets, for example 10% of electricity

supply from renewables by a certain date.


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Biomass: Resources, Applications


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Fuel Cells

A fuel cell can be described as a closed container towhich a fuel such as hydrogen and oxygen is addedand which generates electrical energy, heat and water.The cell contains two electrodes and one electrolyte,after which the fuel cell type is usually named. Theadvantages of the fuel cell, in addition to itscomparatively high electrical efficiency, are that ithas limited or zero local emissions, allows very

flexible operations, has a modular construction andproduces low noise emission.


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Geothermal Resource Geothermal energy comes from the structure of the earth and

its interior heat source and circulation. There is a continualflow of heat energy outwards towards the surface. SurfaceManifestations Include:

Volcanoes

Hot springs

Geysers

Strictly speaking Geothermal Energy is not renewable andshould be treated like fossil fuel. A study by the University of

Oregon [4] on one site estimated that at the design rate of theplant, the resource would last 26 years. Geothermal energy

applications include space heating and steam power plants


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Photovoltaics Photovoltaics (PV) is the direct conversion of sunlight

into electricity using devices made of thin semiconductorlayers. Silicon technology is the most mature and a

crystalline silicon cell can convert up to 23.5 % of the

sunlight in electricity. Cheaper cells made of amorphous

silicon actually have stable efficiencies of 7 %. Modules

including cells made with other materials are not yet in

market. A module is an aggregation of solar cells and it

produces power between 10 and 200 W/sqm. With the

best modules available in the market it is possible to

produce electricity at 0.14 ECU per kWh


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A Solar Tracking Photovoltaic Array at Gobabeb: Namibia


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Conclusions

The potentional of each of the renewable energy

technologies described above varies from country

to country. While solar-thermal energy potential

holds the most promise for most Southern Africancountries, there are some countries, in particular

those with costal boundaries, where there is good

wind and wave power prospects, for example

South Africa and Namibia. Currently there areprojects to promote and exploit these energy

resources.


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Conclusions

Africa is endowed with the renewable

energy resource, but is perhaps the

continent least aware of its potential.

There is a need to sensitize not only the decisionmakers but also the general population bout the

potential and desirability of sustainable Energy

Technologies.

f


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Chikuni Okoro Schumacher Cput

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