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Abstracts for research articles in the current volume: Volume 22
Volume 22 No 1
Volume 22 No 2
Volume 22 No
3
Volume 22 No
4
Volume 22 No 1:
February 2011
The impacts of biodiesel feedstock
production systems in South Africa: An application of a Partial
Equilibrium model to the Eastern Cape Social Accounting Matrix
O Adeyemo, Russell Wise and Alan Brent
In this paper the impacts of biodiesel
feedstock production in the Eastern Cape Province of South Africa is
assessed through the application of a Partial Equilibrium Model to
the Eastern Cape Social Accounting Matrix, using canola production
in the Province as an ‘external shock’. Six economic indicators were
estimated. The results show that investment in biodiesel production
in the Eastern Cape will generate, in 2007 terms, an additional GDP
of R18.1 million and 410 employment opportunities per annum, R24.3
million per annum over an assumed lifetime of 20 years in capital
formation, R2.1 million additional income generated in low income
households, increase in government revenue, and a positive balance
of payment. These indicators imply that, given the parameters that
are accounted for in a Partial Equilibrium Model, every Rand
invested in canola projects in the Eastern Cape will, overall, be of
socio-economic advantage to the Province. It is envisaged that
further applications of such models may lead to a better
understanding of the implications of biofuels in the South African
economy, and thereby inform decision- and policy-making in terms of
the sustainability of biofuels production systems in general.
Development of a universal DC power
supply using solar photovoltaic, utility and battery power sources
Joe Oladosu Oni and Bukola Olalekan Bolaji
In this paper, a universal direct
current (DC) power supply system was developed and tested in order
to provide uninterrupted power for DC appliances. The system employs
simple Diode OR logic for the three power sources (mains from
utility power supply, the solar photovoltaic and battery). The
parallel combination of the three diodes at the output functions
like a comparator circuit and compares the outputs voltage of the
three sources, so that the highest voltage at a particular time
feeds the DC output and supplies the charging current to the
battery. The universal DC power supply system was tested under
various operating conditions and the results obtained showed a good
performance of the system. The system outputs, when all the power
sources were available, during utility power failure and when only
the stored energy in the back-up battery was available were 13.8,
13.1 and 12.2V, respectively. The system guarantees an uninterrupted
power supply, which can be used to power telecommunication
equipment, audiovisual materials, computers, DC motor driven devices
and other DC appliances. A typical day solar radiation varied from
547 W/m2 to 865 W/m2 while the generated voltage from PV varied from
11.8 V to 13.7 V. The generated voltage from solar power source
increases with the increase in solar radiation.
White Certificates and White
Certificate Trading Schemes as greenhouse gas mitigation policy
options for South Africa
Emily Tyler, Michelle du Toit and Zelda Burchell
Energy efficiency activities driven by
White Certificate Trading schemes (WCT) achieve the objective of
conserving energy, and in most circumstances, also that of reducing
greenhouse gas (GHG) emissions. The potential therefore exists that
both objectives could be targeted by a single policy mechanism.
Energy efficiency activities are important from a GHG mitigation
perspective as they represent some of the least costly GHG
mitigation activities available to economies. However, there are
some significant differences between the use of a direct policy
instrument to target GHG emissions mitigation, and the use of an
indirect instrument such as WCT, whose direct policy objective is to
achieve energy efficiency. Most importantly, WCT utilises intensity
targets, whereas GHG mitigation is required by science to comprise
absolute reductions. International experience does however suggest
that white certificates can be fully fungible with a GHG mitigation
policy instrument such as an emissions trading scheme, as long as
double counting rules are firmly in place, and the design of the
schemes are compatible.Given that 80 percent of the South African
GHG emissions are energy related, with energy efficiency measures in
industry, commerce and the residential sector representing the bulk
of negative cost mitigation options available in the economy, energy
efficiency has an important role to play in the country’s mitigation
strategy. This paper presents results on research into WCT as a
policy option for South Africa conducted in 2008 and presented at
the Climate Change Summit 2009. It investigates in particular the
Electricity Conservation Scheme (ECS) as an option for incorporating
a WCT mechanism.There is limited experience and therefore analysis
on WCS available to date, and even less on the potential interaction
and linkages of WCS and emissions trading schemes. This paper
therefore identifies significant scope for future research on this
topic.
Emissions trading as a policy option
for greenhouse gas mitigation in South Africa
Emily Tyler, Michelle du Toit and Zelda Burchell
Emissions trading is fast becoming one
of the most popular policy instruments for reducing greenhouse gas
emissions internationally. This hybrid instrument combines the
certainty of mitigation volume delivered by regulation, whilst also
harnessing the power of the market through an economic approach to
deliver migitation price discovery and least cost mitigation
opportunities. Theoretically, this is a powerful combination.
However, the realities of uncertainty and lack of information result
in international emissions trading experience deviating
substantially from the instrument’s theoretical potential. This is
of particular relevance in a developing country context. Scheme
design is therefore very important to counter these market failures,
and policymakers are required to strike a balance between this and
introducing distortions. Given that the instrument is in its
infancy, performance of the various schemes up and running
internationally is inconclusive. Emissions trading proponents argue
that the benefits will be realised over time, once the initial
teething problems are overcome. The paper is the result of research
conducted in 2008 and presented at the South African Climate Policy
Summit in 2009. It considers theory and international experience in
application to the potential establishment of an emissions trading
scheme in South Africa. Lack of data, capacity and experience with
markets in the energy sector present complications in the use of the
instrument as a central part of the nation’s mitigation policy
suite, as do market concentration issues. Should an emissions
trading be proposed, the paper argues for ways in which its design
could address these complications, and align with the current energy
security imperative resulting from the electricity crisis in the
country, the twin political objectives of poverty reduction and
employment creation of the recently elected government, and the
timeframes proposed by the Long Term Mitigation Scenarios.
Green certificate trading
Kerri Brick and Martine Visser
Policies to promote renewable
electricity are increasingly seen as a way to reduce the negative
environmental impacts associated with electricity consumption and
meet growing electricity demand. This paper reviews the
international experience with one such policy, namely, renewable
energy certificates, and considers important design aspects of a
national green certificate system. Within a South African context, a
green certificate system would provide a mechanism with which to
verify compliance with any future renewable energy obligations, and
would encourage renewable electricity generation in the current
monopoly environment. In terms of a national green certificate
framework, international experience has shown that renewable energy
certificates must be both accredited and standardized, with
enforcement of penalties for non-compliance with renewable energy
quotas. Above all, a long-term and stable policy environment is
crucial for developing renewable energy markets.
Analysis of the economic implications of
a carbon tax
Harald Winkler and Andrew Marquard
A carbon tax should be considered among
the range of instruments available to the South African government,
economy and society, as part of a broad portfolio of mitigation
actions. A carbon tax was one of the most effective wedges or
mitigation options analysed for the Long-term mitigation scenarios (LTMS)
for South Africa. The LTMS strategic option ‘Using the market’
reduced emissions roughly as required by Science, for several
decades. The LTMS research indicated that the effectiveness
increases, up to certain tax levels. South Africa might consider a
tax starting around R100-200 / t CO2eq, escalating in future. Our
paper presents results on research on a carbon tax in South Africa
conducted in 2008 and was presented at the Climate Change Summit
2009. The efficiency with which a carbon tax achieves the goal of
reducing GHG emissions depends on responsiveness and
substitutability. This is shown more fully on the supply-side, while
further work will be needed to fully understand the response to a
carbon tax on the demand side. Careful design of a carbon tax (or
other economic instruments considered) will be important to ensure
that it is effective in meeting its objective – reducing GHG
emissions. We propose a price discovery and adjustment mechanism
that sets a band around the desired ‘peak, plateau and decline’
trajectory. Equity demands that poor households, in particular, be
shielded from any burden. Off-setting incentives, such as food
subsidies or reduced VAT on basic goods, should in finance measure
that which will ensure that the package of tax and incentives is a
net benefit to the poor – and not to treat the tax as a
revenue-raising instrument. With appropriate design, a carbon tax
can be a powerful instrument of mitigation in South Africa, and at
the same time, contribute to socio-economic objectives.
Volume 22 No
2:
May 2011
Carbon footprint of the University of
Cape Town
Thapelo C M Letete, Nothando Wandile
Mungwe, Mondli Guma and Andrew Marquard
Since signing the Talloires Declaration
in 1990, the University of Cape Town (UCT) has been striving to set
an example of environmental responsibility by establishing
environmentally sound policies and practices, and by developing
curricula and research initiatives to support an environmentally
sustainable future. One of the most recent efforts in this quest was
the release of a Green Campus Action Plan for the University of Cape
Town by the Properties and Services Department in 2008. While the
Plan proposed a number of carbon emission mitigation interventions
for the University, it also stressed the need to conduct a detailed
and comprehensive carbon footprint analysis for the whole
University. The aim of this analysis was to determine the carbon
footprint of UCT, not only to give a tangible number with which the
University’s carbon sustainability level can be compared with other
academic institutions, but also to provide the much needed baseline
against which future mitigation efforts on the university campus can
be measured. UCT’s carbon footprint for the year 2007 was found to
be about 83 400 tons CO2-eq, with campus energy consumption,
Transportation and Goods and Services contributing about 81%, 18%
and 1% the footprint respectively. Electricity consumption alone
contributes about 80% of all the emissions associated with
university activities. UCT’s per-capita emissions for 2007 amount to
about 4.0 tons CO2-eq emissions per student. For comparison only,
South Africa’s 2007 per capita emissions were estimated at 10.4 tons
CO2-eq.
In terms of energy consumption only,
UCT’s footprint is about 3.2 tons CO2-eq per student, higher than
the National University of Lesotho’s value of 0.1 and much lower
than Massachusetts Institute of Technology’s value of 33.1.
Enhancing consumers’ voluntary use of
small-scale wind turbines to generate their own electricity in South
Africa
Brendan Whelan and Edwin Muchapondwa
This paper investigates whether
households and small businesses can voluntarily take advantage of
the South Africa’s substantial wind resources to produce their own
power from small-scale wind turbines in a viable way. The viability
of small-scale wind turbines used to displace electricity
consumption from the grid is assessed by means of a financial
analysis based on the internal rate of return method. The benefits
of small-scale wind turbines output is valued at the grid power
tariff which is saved rather than at the wind feed-in tariff rate.
The analysis found the small-scale wind turbines to be robustly
viable in locations with a mean annual wind speed of at least 8m/s,
which is only a few of the windiest locations in South Africa. The
competiveness of the wind turbines is seriously challenged by the
relatively low coal-based electricity tariffs in South Africa. As
such, the financial analysis also considers alternative scenarios
where the turbines are supported by financial mechanisms, namely: a
tariff subsidy; a capital subsidy and revenue from carbon credits.
The analysis reveals that a tariff subsidy of between R1.00 and
R1.60/kWh or a capital subsidy of between R25.95 and R32.330/kW or a
carbon credit price of between R2.135 and R3.200 will be needed to
boost the viability of consumer-based small-scale wind turbines in
areas with a mean annual wind speed of at least 5m/s, which is
considered to be above average. Thus, there is a need for
subsidizing all producers of renewable energy including those who
produce it for their own consumption as they equally contribute to
renewable energy expansion in the country. A tariff subsidy is
however likely to be met with both political and public resistance
if it means that consumers have to cross-subsidize the tariff, while
the significant funds required for capital subsidies might not be
freely available. Carbon credit prices have yet to mature to the
required high levels. Thus, the removal of distortionary support to
coal-based electricity generation might be the only currently
available alternative of enhancing viability of consumer-based
small-scale wind turbines.
Analysis of the performance profile of
the NCERD thermosyphon solar water heater
Solomon Agbo
The work reported here is the
performance profile of a thermosyphon solar water heater developed
by the National Centre for Energy Research and Development (NCERD),
University of Nigeria, Nsukka. The performance evaluation was based
on the mathematical models that describe the test system and some
measured experimental data. The effect of some of the design and
operating parameters that have been shown to affect the system’s
performance was investigated. The parameters considered included the
number of glazing covers, glazing cover thickness, tube spacing and
the nature of absorber plate material. The performance results
indicate that the test system has a maximum average daily collector
efficiency of 0.658 and a mean system temperature of 81oC. The
efficiency of the collector drops to an average seasonal value of
0.54 with a negligible variation across the three climatic seasons
was covered in the study. With a tube spacing not exceeding 10 cm,
the performance of the system is optimized irrespective of the
nature of the absorber plate material. We found that the number of
glazing covers affects the top-loss coefficient of the system
depending on the type of absorber plate used. Multiple glazing shows
a negligible contribution especially for low temperature
application. The glazing cover thickness does not affect the
performance of the system significantly.
What contribution does the installation
of solar water heaters make towards the alleviation of energy
poverty in South Africa?
Holle Linnea Wlokas
The South African government has
publicized plans to install one million solar water heaters in
households throughout South Africa by the year 2014, with the goals
of reducing strain on existing electricity resources, mitigating
greenhouse gas emissions, creating employment and alleviating
poverty. This paper examines two existing solar water heater
installation projects with the aim of investigating the social
contribution of the installation of solar water heaters in
low-income households in South Africa. The Sustainable Urban
Livelihoods approach (SULA) was adjusted to provide an analytical
framework for the development of suitable indicators of social
change in the context of renewable energies and energy poverty.
Increases in household capital and the reduction of household
vulnerability to shocks, stressors and seasonal variability as the
result of solar water heater installation were investigated in
projects in low-income housing developments in the cities of Cape
Town and Port Elizabeth, South Africa. Data collected from paired
household surveys (before and after installation) in over 600
households and qualitative information (Most Significant Change
stories) show that the provision of a constant, cheap source of
heated water contributed positively to the alleviation of energy
poverty. Household capitals (categorised as Human, Social,
Financial, Physical, Natural and Gender capital), including aspects
such as health benefits and time and financial savings, were all
positively effected by the installation of solar water heaters. In
addition, improved energy security greatly reduced household
vulnerability to shocks, stressors and seasonal variability.
Comparison between the two projects revealed that the geographical
setting (climatic conditions in particular), and the approach and
strategies adopted by the implementers of the solar water heater
installation project, greatly determine the extent to which benefits
to the households are realised.
The effect of open sun and indoor forced
convection on heat transfer coefficients for the drying of papad
Mahesh Kumar, Pankaj Khatak, Ravinder
Kumar Sahdev and Om Prakash
In this research paper, a simulation
study has been carried out for the determination of convective heat
transfer coefficients of papad under open sun drying and indoor
forced convection drying modes. Experimental data obtained from open
sun and indoor forced convection drying modes for papad were used to
determine the values of the constants (C and n) in Nusselt number
expression by using linear regression analysis, and consequently
convective heat transfer coefficients were evaluated. The average
values of convective heat transfer coefficients were found to be
3.54 and 1.56 W/m2 oC under open sun drying and indoor forced
convection drying modes respectively. The experimental errors in
terms of percent uncertainty were also evaluated.
Volume 22 No
3:
August 2011
Dissemination of solar water heaters in
South Africa
Keh-Chin Chang, Wei-Min Lin, Greg Ross
and Kung-Ming Chung
Global concern over a looming energy
crisis, water scarcity and man-made climate change are driving a
huge demand for clean technologies, which focus on preserving the
earth’s resources. In South Africa, the economy is very
energy-intensive with coal being the main national energy supply. In
view of the growing depletion of fossil fuel, it is important for
South Africa to adopt a more sustainable energy mix. This study
examines the potential for widespread dissemination of solar water
heaters (SWHs) in South Africa. Barriers and constraints to market
expansion are analyzed to determine strategies for overcoming these
barriers. It is found that payback period of a SWH is shorter than
the life-span of the system itself, indicating that SWHs are
economically viable even with low production cost of electricity and
thus represent a profitable investment proposition for end users,
manufacturers and distributors. However, the subsidy programs
offered by the government of South Africa may not be sufficient to
facilitate diffusion. This is attributed to the high initial capital
cost of the system and low affordability of the majority of the
South Africa population with low income. Alternative financing
mechanisms are required.
The challenges and potential options to
meet the peak electricity demand in Mauritius
Khalil Elahee
This paper reviews the current
challenges facing Mauritius in terms of meeting peak electricity
demand. As a fast-developing island-economy with a very high
population density, this is a crucial issue. The more so that it
imports 80% of its energy requirements in terms of fossil fuels,
relies significantly on tourism and needs to protect its fragile
ecosystems. The nature of the peak electricity demand and its
evolution is firstly analysed. Reference is made to past scenarios
for electricity supply, the obstacles to their implementation and
their relevance in terms of sustainability. The forecasts
underpinning the latter scenarios are found to be over-estimated.
Demand-Side Management projects are discussed and their potential to
promote an alternative scenario based on revised forecasts are
discussed. Hence a new Maurice Ile Durable (Mauritius
Sustainable Island, MID) scenario is proposed in view of stabilising
the peak demand, reducing the rate of increase of total electricity
demand and making the capacity margin positive. The newly-devised
scenario is not only more sustainable but also addresses several
political and socio-economic issues to bring holistic win-win
solutions. Institutional and regulatory reforms as well as a
relevant Business Framework are also important in order to meet the
challenges of MID. The new scenario relies only on existing
technology with an excellent track-record and provides the
transition to a more sustainable future.
Outdoor testing of amorphous and
crystalline silicon solar panels at Thohoyandou
Eric Maluta and Vaithianathaswami
Sankaran
The use of solar panels is becoming one
of the options for some of the rural communities in Limpopo
Province, South Africa, to get electrical energy for their radio and
television sets as the national grid may not reach them in the near
future. Hence, dissemination of knowledge of how to use the solar
devices and their maintenance is crucial for these communities. This
will be possible only if there is appropriate information available
for the potential end-users, installers and extension workers. With
this in mind, an attempt has been made to evaluate the performance
of an amorphous and a crystalline solar panel at our experimental
site. Outdoor tests were conducted to measure solar radiation,
open-circuit voltage, short circuit current, current-voltage (I-V)
curve, fill-factor and conversion efficiency and hence to compare
the performance of the two types of panels. It was found that both
types give a satisfactory performance for the climate of this
region.
Renewable energy, poverty alleviation
and developing nations: Evidence from Senegal
Djiby Racine Thiam
The desire to increase energy access
remains a strong driving force for poverty alleviation in rural
areas of developing countries. The supply of modern energy
facilitates the improvement of human living conditions and the
productivity of sectors. It also contributes by reducing the time
spent, mainly for women and children, in collecting biomass and
therefore can provide an opportunity for an increase in the
education level of children and for women empowerment. This paper
shows how renewable energy facilitates the improvement of the
standard of living in a Sahelian developing country of Senegal.
Using a life-cycle-cost approach while integrating an assessment of
the environmental externalities, I argue that in remote rural areas
where grid-connection is non-existent, photovoltaic (PV) renewable
technologies provide suitable solutions for delivering energy
services although wind technology has been considered as well. In
this framework, policies promoting the adoption of clean
technologies in developing nations like Sen-egal could be considered
as being the main components on the agenda of poverty reduction.
The impact of health behaviour change
intervention on indoor air pollution indicators in the rural North
West Province, South Africa
Brendon Barnes, Angela Mathee and
Elizabeth Thomas
Indoor air pollution has been associated
with a number of health outcomes including child lower respiratory
infections such as pneumonia. Behavi-oural change has been promoted
as a potential intervention strategy but very little evidence exists
of the impact of such strategies on actual indoor air pollution
indicators particularly in poor rural contexts. The aim of this
study was to evaluate a community counselling intervention on
stationary levels of PM10 and carbon monoxide (CO) as well as CO
measured on children younger than five. Using a quasi-experimental
design, baseline data was collected in an intervention (n=36) and a
control (n=38) community; the intervention was implemented in the
intervention community only; and follow-up data was collected one
year later amongst the same households. Despite the fact that indoor
air pollution was reduced in both communities, the intervention
group performed significantly better than the control group when
stratified by burning location. The net median reductions associated
with the intervention were: PM10=57%, CO=31% and CO (child)=33%
amongst households that burned indoor fires. The study provides
tentative evidence that a health behaviour change is associated with
reductions in child indoor air pollution exposure. The intervention
is relatively inexpensive and easy to replicate. However, more
powerful epidemiological studies are needed to determine the impact
on health outcomes.
Experimental
study on heat and mass transfer for heating milk
Mahesh Kumar, K
S Kasana, Sudhir Kumar and Om Prakash
In this paper,
an attempt has been made to estimate the convective heat transfer
coefficient for sensible heating of milk in a stainless steel pot
during khoa, made by traditional method. Various indoor experiments
were performed for simulation of a developed thermal model for
maximum evaporation by varying heat inputs from 240 watts to 420
watts. The experimental data was used to determine values of
constants in the well known Nusselt expression by simple linear
regression analysis and, consequently, convective heat transfer
coefficients were determined. It is found that the convective heat
transfer coefficients decrease with an increase in rate of heating.
The experimental error in terms of percent uncertainty was also
evaluated.
Volume 22 No
4:
December 2011
The technical pre-feasibility to use
briquettes made from wood and agricultural waste for gasification in
a downdraft gasifier for electricity generation
Pholoso Malatji, Ntshengedzeni Sampson
Mamphweli and Martina Meincken
Biomass can be converted to energy
through various thermochemical and biological processes.
Gasification is one of the thermochemical processes that has
recently gained popularity, because it achieves higher conversion
efficiencies than, for example, incinerators, boilers or furnaces.
Fixed-bed downdraft gasifiers are preferred for electricity
generation, because they produce very little tar, but on the other
hand, they are limited with regard to biomass properties, such as
particle size, bulk density and moisture content. Biomass material
with a heterogeneous size is usually processed into pellets or
briquettes, which have to be mechanically strong enough to be
handled. Cohesive strength is provided by residual moisture and
lignin present in most biomass. However, the briquetting process
becomes more complicated if one wants to add agricultural waste
products that do not necessarily contain lignin as binders. The aim
of this work was to process wood chips, grape skins and chicken
litter into briquettes that are mechanically stable and have a
sufficiently high energy content, as well as adequate bulk density
for gasification. The performance of these briquettes in a downdraft
gasifier was simulated with a program developed for wood, which was
modified to optimise the briquette yield. The results showed a
gasification performance comparable to solid pine wood, implying
that the blended briquettes could be used as fuel for a downdraft
biomass gasifier. Unfortunately, the briquettes proved too instable
to experimentally verify the performance in a gasifier. This paper
describes the properties of the briquettes as well as the
gasification simulation results.
What is the carbon emission factor for
the South African electricity grid?
Randall Spalding-Fecher
One of the most important parameters for
developing Clean Development Mechanism (CDM) project proposals in
the electricity sector (both supply and efficiency) is the standard
electricity ‘grid emission factor’, which represents the carbon
dioxide related to a megawatt hour of electricity supplied or saved
on the grid. While there are detailed guidelines from the CDM
Executive Board on how to calculate this emission factor, the values
used in registered CDM projects in South Africa vary widely, both
due to changes in the rules over time and also to misapplication of
the rules. This paper shows how the application of the latest
guidelines gives a ‘combined margin emission factor’ for South
Africa of 0.957 tCO2/MWh in 2009/2010. The variation in emission
factors in the literature, as well as the importance of reducing the
transaction costs for South African project developers, points to
the need for an official published grid emission factor from the CDM
host country authority in South Africa, the Designated National
Authority (DNA), within the Department of Energy.
Industrial and commercial opportunities
to utilise concentrating solar thermal systems in South Africa
Alan Brent and Marthinus Pretorius
A solar energy technology roadmap has
been developed for South Africa. The roadmap lists a number of
technological systems that fulfil three requirements from a South
African perspective. First, they have clearly been demonstrated or
commercialised. Second, a local industry could be stimulated
including the potential to export, with associate socio-economic
growth; and the other requirements of government can be met in terms
of improving energy security and access, and addressing climate
change. Third, they have a medium to high R&D intensity, in terms of
available capacity and associate resources needed to support the
further development of the technological systems. Concentrated Solar
Thermal systems feature prominently in the list of technologies.
These systems can generate electrical power, then referred to as
Concentrating Solar Power systems, typically in the 1 to 100 MW
range for on- and off-grid applications. They can also simply
produce heat, typically in the 100 to 1000ºC range, primarily for
commercial and industrial process applications. This paper discusses
the international trends and drivers for these systems to generate
power and heat, and then focuses on the specific potential in the
South African context. A number of barriers to realizing the
potential are discussed and recommendations are made accordingly to
stimulate the growth of this industry sector in South Africa.
Energy demand projections and relevance
of income dynamics in Gauteng’s residential sector
Mamahloko Senatla
Energy modelling serves as a crucial
tool for informing both energy policy and strategy development. But
the modelling process is faced with both sectoral energy data and
structural challenges. Among all the sectors, the residential sector
usually presents a huge challenge to the modelling profession due to
the dynamic nature of the sector. The challenge is brought by the
fact that each an every household in a region may have different
energy consumption characteristics and the computing power of the
available models cannot incorporate all the details of individual
household characteristics. Even if there was enough computing power
within the models, energy consumption is collected through surveys
and as a result only a sample of a region is captured. These
challenges have forced energy modellers to categorise households
that have similar characteristics. Different researchers choose
different methods for categorising the households. Some researchers
choose to categorise households by location and climate, others
choose housing types while others choose quintiles. Currently, there
is no consensus on which categorisation method takes precedence over
others.
In these myriad ways of categorising
households, the determining factor employed in each method is what
is assumed to be the driver of energy demand in that particular area
of study. Many researchers acknowledge that households’ income,
preferences and access to certain fuels determine how households use
energy. Although many researchers recognise that income is the main
driver of energy demand in the residential sector, there has been no
energy modelling study that has tried to categorise households by
income in South Africa. This paper chose to categorise households by
income because income is taken to be the main driver of energy
demand in the urban residential sector. Gauteng province was chosen
as a case study area for this paper. The Long-range Energy
Alternatives Planning System (LEAP) is used as a tool for such
analysis.
This paper will further reveal how the
dynamics of differing income across the residential sector affects
total energy demand in the long run. The households in Gauteng are
classified into three income categories – high, middle and low
income households. In addition to different income categories, the
paper further investigates the energy demand of Gauteng’s
residential sector under three economic scenarios with five energy
demand scenarios. The three economic scenarios are first economic
scenario (ECO1), second economic scenario (ECO2) and third economic
scenario (ECO3). The most distinguishing factor between these
economic scenarios is the mobility of households from one income
band to the next.
The model results show that electricity
demand will be high in all the three economic scenarios. The reason
for such high electrical energy demand in all the economic scenarios
compared to other fuels is due to the fact that among all the
provinces, Gauteng households have one of the highest electricity
consumption profiles. ECO2 showed the highest energy demand in all
the five energy demand scenarios. This is due to the fact that the
share of high income households in ECO2 was very high, compared to
the other two economic scenarios. The favourable energy demand
scenarios will be the Energy Efficiency and MEPS scenarios due to
their ability to reduce more energy demand than other scenarios in
all the three economic scenarios.
Sustainable cooling alternatives for
buildings
Jaco Vorster and Robert Dobson
Four sustainable alternative-energy
cooling system options are investigated to quantify the actual
energy that may be saved when employed in conjunction with
conventional air conditioning systems. The four systems considered
are active mass cooling, night flushing, roof-spraying and a
roof-pond. A one-room building configuration is assumed of which the
hourly cooling load and temperature is modelled for both a base case
and different combinations of the four sustainable cooling
alternative systems. Active mass cooling, night flushing and the
roof-spray system proved to be viable options in which the cooling
load of an air conditioner may be reduced to maintain a constant
room temperature. The roof-spray system showed the most effective
results in limiting heat gains to the one-room building and keeping
peak room temperatures low.
Policy review and analysis: Energy
efficiency strategy for the Republic of South Africa
Shirene A Rosenberg and Harald Winkler
This paper aims
to draw attention to the complex landscape of translating policy
into implementation actions. It underscores the disjuncture between
a broad global response to climate change mitigation measures and
the requirements for national action in this regard. Individual
countries face this challenge of interpreting and translating the
cross-cutting response measures into local action. Climate change
mitigation and energy security are two themes that are growing in
importance in terms of its contribution towards South Africa’s
developmental agenda, thereby requiring an understanding of how
policies and strategies are geared towards supporting this
developmental agenda, in a way that does not compromise existing or
future growth and progress. An assessment of the implementation of
the South African energy efficiency strategy, demonstrates that the
translation of policy intent into implementation is not self evident
and associated with a number of prerequisites. These do not merely
relate to the competence or capacity of an institution to implement
the policy, but to a complex interrelationship of a number of
factors. This includes supporting legislation, institutional
arrangements, sources of finance and the need for co-operative
governance.
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