Power for Africa: solar hybrid systems for rural
electrification
Developing and third-world countries are the
losers of accelerated climate change. These countries that largely
rely
on agriculture are severely affected by extreme weather conditions
and changes in climate conditions. However, they do not have
the money to adapt accordingly. And the increasing scarceness
and rising prices of fossil fuel oil hamper their development.
It is against this background that rural electrification with
reasonable renewable energy becomes of particular importance,
because decentrally generated electricity allows access to
clean water, to health care services, education and economic
development.
Solar power system on the roof of a
church in Mbinga (Tanzania); Solar modules, inverters and batteries
ensure power supply far away from the electricity network. Photos:
Energiebau Solarstromsysteme GmbH
The Cologne-based company Energiebau Solarstromsysteme GmbH
and the development organisation Internationale Weiterbildung
und Entwicklung gGmbH (InWEnt, Bonn) developed a concept for
electricity supply with photovoltaic systems and vegetable oil
generators and successfully implemented this hybrid technology
in numerous reference projects. In January 2007 they received
the "Roy Family Award 2007" for their achievements.
This prize is awarded every two years by the Harvard University
(John F. Kennedy School of Government). The award recognises
successful public-private partnerships in the field of environmental
protection. As solar system of the month of February 2007, the
Solarserver presents the solar power system combined with a vegetable
oil generator operated by the Vincentian Sisters in Mbinga (Tanzania).
This solar hybrid system provides clean electricity day and night
to 140 people in various institutions run by these sisters.
Only a few rural regions in Africa and the Third
World are connected to the electricity network. Decentralised power
supply from solar and biological energy is an economically and
ecologically feasible alternative. Picture, right: nuts of the
oil-yielding jatropha plant. Photos: Energiebau Solarstromsysteme
GmbH
Many regions without electricity;
diesel for generators is expensive and uneconomical
Around the
world 1.5 billion people must live without electricity. In
the rural areas of Africa electricity, if generated at all, is
produced
with diesel generators, since the establishment of a central
power supply with a network of power lines is economically
not feasible and far too expensive. Self-sufficient solar power
systems
that do not depend on a grid offer a reliable alternative.
If, however, besides solar radiation diesel fuel is continued
to
be used as a second combustible, the people will remain dependent
on this fossil fuel that is generally transported over long
distances. The price for diesel in Tanzania amounts to approx.
one euro
per litre, i.e. a price that is comparable to that in Europe.
Income, however, is significantly lower. The dramatically increased
crude oil and diesel prices are an enormous burden for many
countries in Africa and Asia, particularly in the rural areas.
People living in developing countries
generally pay similar prices for imported crude oil products as
Europeans do, but earn significantly less. Picture, right: press
to manufacture vegetable oil from jatropha nuts. Photos: Energiebau
Solarstromsysteme GmbH
Jatropha plantations replace oil imports
The above reasons led
Energiebau Solarstromsysteme GmbH to develop a technology in
which generators can also be run on pure vegetable oil that
is won on site with a simple mechanical press from the oil-producing
jatropha plant. This plant originating from South America even
grows in very dry regions in barren soil. Jatropha nuts contain
high degrees of oil but are inedible for humans and animals.
Thus, neither on agricultural fields nor among fruits, competition
is created between the cultivation of food and these energy-yielding
plants. Jatropha oil not only solves the problem of high fuel
costs; also the inefficient transport of diesel fuels over
long
distances as well as the environmental hazards posed by diesel,
can be avoided. Furthermore, the rural population can generate
additional income from planting and selling jatropha. Thus,
on the basis of renewable energy, reliable and sustainable energy
supply can be established.
Electricity from sunlight and vegetable oil
The solar hybrid system of
the sisters consists of a photovoltaic system for the direct conversion
of solar energy to electricity in a generator that runs on pure vegetable
oil, as well as inverters and batteries. Since the end of August
2006 the solar vegetable oil system provides electricity to the
educational
centre of the Vincentian Sisters in Mbinga that consists of twelve
buildings. In their convent the “Good Vincentian Sisters” thus
lead the way for sustainable development, because they also do without
diesel and produce the oil required for the generator themselves from
jatropha nuts.
Schematic presentation of a solar hybrid system
for basic electricity supply with a (vegetable oil) generator for
peak loads. Graphics: Energiebau Solarstromsysteme GmbH
If the field of solar modules and the capacity
of the battery system are designed accordingly, maximum supply
security can be achieved even in times of less sunshine, which
however occur less frequently in Africa than in Central Europe.
81 ‘Schott ASE 100’ solar modules with a total peak
performance of 8.1 kW (kWpeak) supply solar direct current to
6 ‘SMA Technologie AG’ inverters. These three ‘SMA
SI 4248’ and three ‘Sunnyboy SB 3800’ convert
the solar power into alternating current, as we know it from
our sockets here at home too. The modules cover a surface of
approx. 80 m2 and were mounted on the roof with a ‘LORENZ
PLUS’ supporting structure manufactured by Energiebau Solarstromsysteme
GmbH. According to calculations by Energiebau the investment
in solar energy production under Africa’s sun will have
paid off after 10-15 years, so-called energetic amortisation
is achieved even faster: within two to five years, the solar
power system will have produced as much energy as was required
for its manufacturing.
A model for the whole of Africa
During
assembly of the solar power system, the sisters in Mbinga gained
some hands-on experience and acquired knowledge and skills to
conduct maintenance work on the existing and future smaller photovoltaic
systems in other institutions. They don’t want their pupils
to lag behind modern technology and unrestricted power supply
provides new perspectives in achieving this goal. For the Vincentian
Sisters, who are concerned about the economic and ecological
development of their country, reliable, economic and ecological
power supply is a big gain. "Generating electricity from
solar energy and jatropha will be a great help for Tanzania.
This can become a model for the whole of Africa,” Sister
Kaya says.
Sisters assembling solar modules on the church roof;
a practical introduction to solar technology. Photos: Energiebau Solarstromsysteme
GmbH
The vegetable oil generator by the manufacturer Kuboto
that is only switched on during particularly high power consumption peaks,
was adapted by Energiebau Solarstromsysteme GmbH to run on jatropha oil
rather than diesel. Its output is 30 kilowatt (kW) at 1 500 rotations
per minute and a consumption of 0.34 litres to produce one kilowatt hour
of electricity. The photovoltaics system alone produces a daily output
of 35-40 kWh of clean electricity. The vegetable oil generator thus only
runs for about 2.5 hours a day. The total solar hybrid system cost the
sisters approx. 100 000 euro. Every litre of jatropha oil saves almost
one euro in comparison to diesel.
Solar power covers base load, generator
covers peak loads
During times of low electricity consumption and high
solar radiation, the batteries are loaded. Thus the solar power system
was not designed to cover peak loads; it serves to cover the basic
electricity demand. Peakloads, for example when machines are operated,
are covered
by the generator.
Generator control panel (left foreground). About two dozen
batteries guarantee power supply around the clock. Photos: Energiebau Solarstromsysteme
GmbH
By combining a solar system with a photovoltaic system,
the photovoltaic system can be significantly smaller. The costs of the
overall system are thus lower than in a pure solar power system. And
the fuel costs are reduced to a minimum.
On the way to total independence
from crude oil
The list of institutions established in Tanzania by the
Vincentian Sisters in the past 40 years is long: it includes a maternity
ward, nursery schools, general schools, as well as schools of home
economics and agriculture. 18 of these institutions were successfully
built up
in Africa by sisters from the Swabian village Untermarchtal since
1960. Today seven German and 183 local sisters live and work here. The
convent
of sisters in Mbinga is fully self-sufficient. The sisters run numerous
workshops, e.g. a carpentry workshop, a metal workshop and a book-binding
workshop as well as a textile processing workshop in which local
sisters receive thorough training in the various trades.
Workshops and
schools
cannot be operated successfully without reliable power supply.
The Vincentian Sisters, however, were no longer prepared to spend an
ever
increasing
share of their financial menas for diesel fuel in order to be able
to run generators, particularly since this money, to the largest
degree, consists of donations. Eventually high fuel costs even led to
certain
machines and urgently required equipment only being run on an hourly
basis. Now the energy required comes from heaven – and from the
earth.
The future with renewable energy: nursery school
in Mbinga, jatropha plantation.
Photos: Energiebau Solarstromsysteme GmbH
Two years ago already the Vincentian Sisters started planting jatropha.
With the cultivation of the nut and the production of oil the sisters
initiated a local value-adding chain with additional income opportunities
for the people in and around Mbinga. In their agricultural school they
now teach their pupils about planting and cultivating this energy plant
and thereby make a contribution to the sustainable development of the
country. Up until today the sisters have planted about 30 000 bushes.
A further 30 000 bushes are to follow. “50 000 jatropha plants
will allow us to be fully independent from diesel fuel throughout the
year and we can then independently produce power for all institutions
here in our convent in Mbinga,” Sister Kaya explains.
Energy from
renewable sources: technically possible and economically feasible
"The
project in Mbinga shows that the use of renewable energy in African rural
areas that are far removed from the electricity network is technically
possible and economically feasible. In the long run the regenerative
energy supply systems will drive ahead sustainable and decentralised
energy supply in Africa,” Michael Schäfer, Managing Director
of Energiebau Solarstromsysteme GmbH, explains. In order to achieve this
goal, Energiebau and InWEnt organises training seminars on the cultivation
of jatropha in numerous regions of Africa.
Solar power system (close-up), Dusk in Mbinga. Photos: Energiebau
Solarstromsysteme GmbH
Other reference projects in Ghana, Tanzania and Indonesia
Specialists
from Energie Solarsysteme have already successfully put their concept
for decentralised electrification into practice in Ghana, Mali and
Tanzania. Furthermore, in co-operation with InWEnt and within the framework
of
development co-operation a network of partners was established in these
countries that can install and maintain such systems. The Federal Ministry
for Economics and Technology (BMWi) supported the project in Tanzania
through the Deutsche Energie-Agentur (dena) on the grounds of its referential
character.
In Ghana (Busunu) a solar hybrid system with a vegetable
oil generator supplies a village of 360 houses with electricity. In
Matemanga (Tanzania) a water pump is driven by a jatropha generator and
a solar
power system supplies the local clinic with electricity. In Indonesia
a solar hybrid system with a vegetable oil generator transformed
a training
centre on Sumba Island into an independent electricity producer.
