svoc 2009 - chavez fuentes. renewable energy resources and technologies – a perspective and...

SLOVAK UNIVERSITY OF TECHNOLOGY Faculty of Chemical and Food Technology

INSTITUTE OF CHEMICAL AND ENVIRONMENTAL ENGINEERING

ŠVOČ 2009 RENEWABLE ENERGY RESOURCES AND TECHNOLOGIES – A PERSPECTIVE

AND EXPERIENCE IN A RURAL COMMUNITY IN MOZAMBIQUE

BRATISLAVA 2009

Author: Juan José Chávez Fuentes

Adviser: Doc. Ing. Igor Bodik CSc.

Renewable energy resources and technologies - a perspective and experience in a

rural community in Mozambique ŠVOČ

1

ABSTRACT

Energy plays an important role in the socio-economic development of every country.

Economic growth and improvement of people's living standard are all directly or indirectly

related to the increasing utilization of energy, of which electricity is the most important. The

use of renewable energy is becoming an increasingly valuable part of the world's energy

development. Solar energy as off-grid systems brings new possibilities of development to

rural communities which are not connected to any electricity network; supplying its energy

needs by an effective and sustainable utilization of the inexhaustible resource.

Developing countries situated in zones where isolation is high throughout the year can widely

exploit solar technologies. Such is the case of Mozambique, a developing country located in

Sub-Saharan Africa. Its population is about 21.5 million, of which, in spite of the efforts of

the government to improve the electrical infrastructure, more than 90% of the households are

not connected to any electrical grid and the most of the people living in rural communities

will remain in the same conditions for the next 15 years.1 Off-grid solar systems are coming

to help to satisfy the most necessary needs of the communities in health, educational,

administrative and technological matters. Going beyond, one day renewable resources could

supply the energy demand in rural communities.

The purposes of this study are to show the benefits of using renewable energy, mainly solar

energy, in places without connection to the local power grid; and, based on the experience as

project manager in the assembly of off-grid solar systems in a rural community in

Mozambique, proportionate a roughly analyze of the project and its outcomes and give a

perspective of the application of renewable resources in the project Solar Energy for Meloco,

Mozambique.



2

AKNOWLEDGMENTS

Hereby, I would like to thank Ing. Zuzana Letkova for all her support and for giving

me the opportunity to participate in a project of this magnitude, to Jaroslav Korvín for

his valuable practical and technical knowledge, skills and experiences during the

execution of the project in Mozambique; to Doc. Ing. Igor Bodik CSc. for his support

while preparing this study.



3

CONTENTS

1. BACKGROUND ........................................................................................................... 4

Renewable energy resources .............................................................................................. 5

Importance of the renewable energies today ...................................................................... 6

2. SOLAR ENERGY ......................................................................................................... 8

Grid-connected and off- grid systems ................................................................................. 8

Applications of solar technologies ..................................................................................... 8

World insolation ................................................................................................................ 8

Disadvantages of the solar energy ................................................................................... 10

Photovoltaic systems (PV) ............................................................................................... 11

3. PROJECT: SOLAR ENERGY FOR MELOCO, MOZAMBIQUE ............................... 12

Aim of the project ............................................................................................................ 12

Situation of the locality .................................................................................................... 12

Phases of the Project ....................................................................................................... 12

Technical Characteristics of the Assembled Systems ........................................................ 13

Project Assumptions ........................................................................................................ 14

Evaluation of results ........................................................................................................ 15

4. CONCLUSION ............................................................................................................ 17

5. APPENDIX ................................................................................................................. 18

6. REFERENCES ............................................................................................................ 20



4

1. BACKGROUND

“Engineering is a great profession. There is the satisfaction of watching a figment of the imagination

emerge through the aid of science to a plan on paper. Then it moves to realisation in stone or metal or

energy. Then it brings homes to men or women. Then it elevates the standard of living and adds to the

comforts of life. This is the engineer's high privilege”

Herbert Hoover (1874 - 1964)

The world faces today the big challenge of holding a sustainable development. At energy matters,

this means the provision of energy to satisfy the needs of the present without compromising the

ability of future generations to meet their needs.

The two most common forms of energy we use are heat and electricity. Most of the machines

around us use either heat or electricity to do their work. Besides them, we use many other forms

of energy every day of our lives. Energy is easily converted from one form to another. This is an

important and very useful property, because we rarely produce energy using the same device, or

in the same form as what is needed for the task at hand. Since energy is often produced at some

distance from its end use, we also need to transmit it from its source location to where it is

needed. This is done by means of wires in the case of electricity, or pipelines or tank trucks in the

case of oil or natural gas. Not all forms of energy can be easily stored or transported. For

instance, light is impossible to store directly. It has to be converted to some other form, such as

chemical energy first.

Much of our energy supply comes from coal, oil, natural gas, or radioactive elements. They are

considered non-renewable because once they are removed from the ground and used, they are not

immediately replaced. Humans will have used up most of these deposits in less than 200 years.

Once they are gone, non-renewable energy supplies cannot be replaced. Renewable energy on the

other hand quickly replaces itself and is usually available in a never-ending supply. Renewable

energy comes mainly from the natural flow of sunlight, wind, or water around the Earth.

The image above compares the total electricity consumed in 2007, with the population in this

year and the electricity generated from renewable sources.2



5

Renewable energy resources

The most common definition is that renewable energy comes from an energy resource that is

replaced by a natural process at a rate, that is equal to or faster than the rate at which that

resource is being consumed. Renewable energy is a subset of sustainable energy and may be

used directly, or used to create other more convenient forms of energy. Some of them are

exposed below.

Solar Energy

Sunlight is an excellent source of heat and electricity. Solar collectors and modules are

designed to capture sun’s energy and change it from radiation into more usable forms such

as heat or electricity.

Solar energy is often called as the energy of the future, while is becoming increasingly

popular for remote power needs such as telecommunication towers, agricultural

applications, in tropical countries without access to an electrical grid, for heating water, and

many other applications around the world.

Wind Energy

Wind power is the conversion of wind energy into a useful form of energy, such as

electricity, using wind turbines. It is also widely used to move water and produce work,

using water-pumping windmills.

There are now many thousands of wind turbines operating. Nevertheless its huge potential

is reserved to locations where wind power density (WDP) is optimal (13% of the total global

land area). Isolated communities can use small-scale wind turbines to displace diesel fuel

consumption and other similar technologies.

Biomass

Energy

The term biomass refers to any form of plant or animal tissue. The energy stored in biomass

can be released by burning the material directly, or by feeding it to micro-organisms that

use it to make biogas, a form of natural gas.

In the energy industry, biomass refers to wood, straw, biological waste products such as

manure, and other natural materials that contain stored energy.

Energy from biomass is still used around the world, for everything from cooking and

heating to generating electricity.

Hydroelectric

energy

The energy of falling water is used mainly to drive electrical generators at hydroelectric

dams.

As long as rainfall and other precipitations can fill the streams and rivers, moving water can

be a renewable source of energy; nevertheless, they may not be sustainable in the long run

because of their impact on the environment.

Tidal power

Tidal stream systems make use of the kinetic energy of moving water to power turbines, in

a similar way to windmills that use moving air. It’s generated by the relative motion of the

Earth, Sun and the Moon, which interact via gravitational forces.

These systems need to be located in areas with fast currents where natural flows are

concentrated between obstructions, for example at the entrances to bays and rivers,

around rocky points, headlands, or between islands or other land masses.

Wave Energy

Wave power is the transport of energy by ocean surface waves, and the capture of that

energy to do useful work.

Wave height is determined by wind speed and blowing duration, fetch, depth and

topography of the seafloor. A variety of technologies have been proposed to capture the



6

energy from waves. Some of the more promising designs are undergoing demonstration

testing at commercial scales.

Geothermal

Heat

The hot water or steam is carried to communities in insulated pipes and used to heat

homes and businesses.

In some cases, the water is superheated. This water quickly turns to high-pressure steam,

which can turn high-speed turbines that drive electrical generators.

This energy is produce by taking advantage of naturally occurring geysers, hot springs, and

steam vents (called fumaroles) to gather hot water and steam for heating.

Ground

Source Heat

Pumps

A ground source heat pump works the same way every refrigerator does; using a

compressor, lengths of sealed tubing for gathering and dispersing heat (heat exchangers),

and a gas called the refrigerant.

The temperature of the soil below about 2 metres remains constant regardless of the

weather or season. The difference between air and deep soil temperatures can be used for

heating and cooling in a very efficient manner.

Importance of the renewable energies today

Energy Price Stability

In the last years, we have seen large fluctuations in the cost of natural gas, oil, and electricity

due to global economics, market deregulation, and political events in some parts of the world.

Renewable energy is not subject to sharp price changes because it comes from sources such

as sunshine, flowing water, wind, and biological waste, all of which are free.

Protecting Global Climates

When fossil fuels are burned, they release carbon dioxide. This gas acts like an invisible

blanket, trapping more of the sun's energy in the atmosphere, causing the Earth to warm up

little by little. Carbon dioxide is building up in the atmosphere as more and more fossil fuels

are used in homes, factories, and automobiles. If this continues, most scientists think our

planet is likely to become significantly warmer, which could cause many serious problems

around the world. These problems could include melting of arctic ice, increased forest fires,

rising sea levels, loss of animal habitat, damage to coral reefs, the spreading of tropical

diseases, expanding deserts, and more frequent and severe storms.

Protecting Landscapes and Watersheds

Some energy projects, particularly big coalmines, hydro dams, and oil and gas activities, can

have a large impact on lands and watersheds. Damage or loss of natural lands and watersheds

is likely to affect humans and animals. For example, wilderness areas could be lost for when

energy resources are extracted. Hydro dams can flood large areas, while the facilities

associated with oil sands development can affect forests and disrupt animal movements and

migrations. On the other hand, solar energy can provide a continuous supply of energy, which

is integrated directly into buildings so that it has very little impact on land use. Run-of-river

hydro plants can be designed to allow for free flow of existing streams.



7

Unlimited Supplies

Renewable energy supplies will never run out. While the supplies of coal, oil, and natural gas

are limited, sunshine, wind, biomass, and water power are considered almost limitless

resources.

Jobs and the Economy

Renewable energy can be developed in such a way that every household or neighbourhood

could have its own renewable power generating equipment. This would create many new jobs

for people involved in setting up and maintaining this energy supply, and in manufacturing

the equipment. It is also more efficient to produce renewable energy in small amounts right

where it is needed. The energy losses and equipment needed to transmit power over long

distances can also be minimized in this way.



8

2. SOLAR ENERGY

Solar power is the conversion of sunlight to electricity or heat. It can be converted directly

into electricity using photovoltaics (PV), or indirectly with concentrating solar power (CSP). The solar power generation is either stored or instantly used to provide

continuous power.

Grid-connected and off- grid systems

More developed countries have started to build solar power plants grid-connected, replacing

other sources of energy generation for their daily demand and offering special stimulations to

spread the consume of this illimitable resource, often combined with other renewable

technologies and with public network.

On the other hand, solar energy has the enormous potential to also cover places which have

no access to electricity network or where building a system of wires or pipelines to carry

energy is relatively expensive.

Off-grid means supplying your own power, having no connection to any network of energy

distribution. For many rural communities, solar technologies off-grid have several advantages

over grid extension. They can be located closer to the demand, therefore distribution and

transmission cost and consequently energy and capacity loss are reduced. Systems become

independent from the electricity networks policies and supplies. Peak electricity consumption

in rural communities can be satisfied, while solar systems have their highest efficiency during

the day. From a social point of view, they can create more employment, in particular for the

local workforce, among the installation, operation of the equipment in different sectors and

giving maintenance; strengthening the economy by an effective and sustainable utilization of

the local resource. In environmental terms, they will provide benefits reducing emissions of

air pollutants, offsetting greenhouse gases, decreasing the usage of fossil fuels and protecting

the natural biomass reserves around the region.

For some communities in developing countries off-grid systems represent the only alternative

to satisfy their most basic electrical needs. Solar energy used in a bigger scale plays an

important role for their development. 3

Applications of solar technologies

Solar technologies roughly consist in converting sunlight into heat or electricity. The most

typical applications are

• Electrical generation

• Water heating

• Cooking

• Powering machines and vehicles

• Agriculture and horticulture

• Heating, cooling and ventilation

• Solar lighting

• Water treatment



9

• Industrial processes

• Desalinization plants

World insolation

Our planet doesn’t receive the irradiation of the sun equal, during the day among the year. The

amount of electricity produced by a solar panel depends on several factors, such as typical

weather patterns, sun’s angle relative to the panel and amount of the earth's atmosphere the

light is passing through.

The most important factor in reflective loss depends on latitude or location of the site. This

means, that during winter is produced the least sunlight because of shorter days and increased

cloud cover, as well as the sun's lower position in the sky. Usually, averages are meassured in

two periods June - July and December - January.

For countries which are located closer to the tropics or between them, solar insolation is high

almost all the year. This is an awesome property considering the potential of building solar

centrals on-grid and off-grid. Too many countries can take advantage of their location.

The image below roughly represents the zones where instalation of solar energy systems is

profitable. 4

Cortesy of ICP Solar Maps

Insolation, or sunlight intensity is measured in peak sun hours. One hour of maximum, or

100% sunshine received by a solar panel equals one equivalent full or peak sun hour, at sea

level. It is expressed as kilowatt-hours per square meter per day (kWh/M2/day).

The most productive hours of sunlight are from 9:00 a.m. to 3:00 p.m., around solar noon.

When the sun is directly overhead, the distance from the sun to the solar panel is the shortest.

Thus, the light is passing through the least amount of atmosphere with the least amount of

reflection, and the panel produces the most energy. In the morning and evening, the sun is

lower in the sky, and sunlight passes through more atmosphere, and has a greater angle of

reflection. During these periods the panel receives less sunlight to make power.



10

Disadvantages of the solar energy

- The main disadvantage of the solar energy lies in its incapacity of having a continual and constant current flow. By night the solar panels get useless and in

winter or during a very cloudy day, the current can severely decrease.

- The initial cost of the solar systems is also said to be a serious disadvantage. As the

price of the solar equipment decreases, we are likely to see an increase in the use of

the technology.

- A more powerful solar installation requires a larger area to be placed. This may be a

disadvantage in areas where space is limited, or expensive, due to possible

obstructions from the surrounding buildings or landscape. In rural communities or

where settlements are widely located, this is not often a problem.

- Stability of solar cells, dirtiness on the surface and other physic factors can be

influenced by natural effects in the region and can decrease the efficiency of the

systems. In case of breakdowns, recovery of the systems is most of the times

delimited by infrastructure of the local community and surroundings.

- Off-grid systems are not connected to the utility grid, as a result of which they need

batteries to store electricity and continue supplying during off-peak demand periods.

Production of batteries in-mass can yield to an excessively production of waste.



11

Photovoltaic systems (PV)

Photovoltaic systems use sunlight to power ordinary electrical equipment. A PV cell consists

of two or more thin layers of semi-conducting material, most commonly silicon. When the

silicon is exposed to light, electrical charges are generated and this can be conducted away by

wires as direct current (DC). The electrical output from a single cell is small, so multiple cells

are connected together and encapsulated (usually behind glass) to form a module or panel.5

ERROR: undefined

OFFENDING COMMAND: f‘~

STACK:

svoc 2009 - chavez fuentes. renewable energy resources and technologies – a perspective and...

Documents

project solar energy

renewable energy resources

use of renewable energy

energy demand

grid solar systems

worlds energy development

rural community

grid systems