Plan

1. Introduction to the concept of renewable energy

2. Sources and kinds of renewable energy

a) Solar energy

b) Hydro energy

c) Wind energy

d) Geothermal energy

e) Biomass

3. Implication for sustainable development and management

4. Conclusion

Renewable energy - is energy derived from resources that are regenerative or for all practical purposes cannot be

depleted • Renewable (flow) resources:

– Continuous sources (will never run out; not affected by human action)

» solar radiation, tidal energy, wind, waves, geothermal, running water

– Flow sources (are sustainable providing that they are carefully managed and maintained; affected by humans)

» Biomass, soils, forests etc.

Sources of renewable energy and energy flows

• From sun solar radiation - sensible heating heating devices and ocean thermal energy

- latent heat, potential energy hydropower - kinetic energy wind and wave conversion

- photosynthesis biofuels

Sensible heat is heat energy that is transported by a body that has a temperature higher than its surroundings via conduction, convection, or both. (heat that you can feel)

Latent heat is the amount of energy in the form of heat released or absorbed by a substance during evaporation. (heat that is ‘hidden’ inside the particles)

Kinetic energy is the energy of motion

• From planetary motion gravitation, orbital motion tides tidal power

• From earth geothermal heat geothermal installations

Solar Energy• The Sun is the primary

source of the Earth’s energy (with the exception of nuclear, geothermal and tidal energy, all forms of energy used

on earth originate from the sun’s energy)

• The amount of solar energy intercepted by the Earth every minute is greater than the amount of energy the world uses in fossil fuels each year

Classification of solar power

• Direct

- involves a single transformation of sunlight which results in a usable form of energy

• Indirect

- involves multiple transformations of sunlight which result in a usable form of energy

- e.g. biomass, wind energy

(powered by the sun) etc.

Direct Solar Power

• Example Sunlight hits a solar (photovoltaic) cell creating electricity.

Solar energy use

1) Generate electricity using photovoltaic solar cells.

Earth-orbiting satellites

Consumer systems (e.g. calculators, wrist watches, radiotelephones etc.)

Water pumping applications

2) Generate electricity by heating trapped air which rotates turbines in a Solar updraft tower (a type of renewable-energy power plant )

• A research prototype operated in Spain in 1982-1989.

3) Heat buildings, directly, through solar design (e.g. slanting windows in a house and facing them to the south).

convert sunlight into usable heat

cause air-movement for ventilation or cooling

store heat for future use, without the assistance of other

energy sources

4) Heat foodstuffs, through solar ovens

Solar box cooker

5) Produce vehicles that run on solar power

Case study The Dominican republic

• Approximately 400,000 rural households in the Dominican Republic lack access to grid electricity.

• Increasing demand for electricity throughout the country, particularly in poor rural areas, has meant finding alternative sources of power.

• A new approach to solar electrification

• 2000 homes have been solarised in the last 9 years due to the efforts of Enersola

• Enersola is a US non-profit group

Advantages of solar power• Pollution free during use; • Facilities can operate with little maintenance or

intervention after initial setup;• Solar electric generation is economically

competitive where grid connection or fuel transport is difficult, costly or impossible (e.g. island communities);

• Once the initial capital cost of building a solar power plant has been spent, operating costs are low when compared to existing power technologie;

• It is a continuous resource, meaning it doesn't run out

Disadvantages of solar power

• Solar electricity is expensive compared to grid electricity;

• To get enough energy for larger applications, a large number of photovoltaic cells is needed. This increases the cost of the technology and requires a large plot of land;

• Dependence on weather patterns.

Hydro energy

• The water is primary source of the hydro energy.

• Hydro energy is the energy created when the water passes through turbines.

• It has continuous sources

Revelance of hydro energy

• Hydro energy has great potential of being an extremely important source

• In 1991. water energy contributed with 1/5 of world’s electricity

• Last 20 years water power using increased double in spite of it representing only 6 % of all world’s energy

Two ways of producing hydro energy

• Micro-hydro scheme -smaller human creations from: natural river flow from mountain, waterfalls or natural lakes

• Large-scale scheme -processes involving multi-companies on national or international level e.g. building water reservoars and dams for energy supplies

Physical factors

• Using of nature to produce hydro energy

-natural lakes

-waterfalls

Human factors

• Flooded valley turned into the reservoar

• Using techonolgy for building dams and extracting the water energy

e.g. Cambora-Bassa in Mozambique

hydroelectric power plant

Case Study

• Micro-hydro in Nepal

-use of micro-hydro schemes for agriculture

-for producing electricity since only 10% has the access to it

-very cheap to run and sustain ~ practical

Positive sides

• Renewable source• Clean source• High efficinecy• Environmentaly

friendly• Physicaly determined • Profitable and

practical

Negative sides

• Possibilty of reduced amount of water due to builing of reservoars

• Great danger of destruction

• Possibility of flooding entire areas

Wind energy

• Wind energy is renewable source of the energy produced by generators powered on wind in a windmill

windmill

Spatial use

• Wind energy is mostly used in rural areas

and is widely spread around the world

e.g. Australia, Brasil, India, Canada, South Africa

• It is used in wind farm type

e.g. California (Palm Spring),

Denmark, Japan, New Zeland, UK

Wind farm

• Wind farm is a smaller collection of wind turbines in the same location that is used for producing the wind power electricity.

e.g. Australia

(the larges one)

Case study

• California, US

-wind farm

-90% of the USA’s capacity comes from

-one of the larges wind-farms in the world

-due to widely spreading of wind-farm, land is using for cattle grazing as well

Advantages of wind energy

• Clean source• Continuous source• Cheap to operate• Does not contribute to

global warming or acid rain

• Can be used as transportational mean

Disadvanages of wind energy• Wind is not constant and does not have same strength all the

time

• Using storage bateries would improve but is very expensive

• Wind turbines are expensive

• Windmills are making huge noise and interfereing with signals (TV, satelite, mobile phones)

• It could be but still is inefficient way of getting energy

• Expensive to maintaine

Geothermal energy derives from the radioactive decay in the core of the Earth, which heats the Earth from the inside out.

Distribution : areas of volcanic activity, especially countries along the circum-Pacific "Ring of Fire“, spreading centers and hot spots.

Geothermal energy is produced by drilling a well into the ground where thermal activity is occuring.

• Once a well has been identified and a well head attached, the steam is separated from the water, the water is diverted through a turbine engine which turns a generator.

• Usually the water is injected back into the ground to resupply the geothermal source

Power plants generate electricity from geothermal energy. They can

be:• Dry steam pp steam is taken out of fractures in the ground

and used to directly drive a turbine that spins a generator

• Flash pp hot water is taken out of the ground it boils while rising to the surface the steam is separated in steam/water

separators the steam through a turbine

• Binary pp hot water flows through heat exchangers it boils an organic fluid that spins the turbine.

Some facts…• The largest dry steam field in the

world is The Geysers, about 145 km north of San Francisco.

• It began in 1960. There are 21 power plants now.

• The United States is the country with the greatest geothermal energy production.

• Geothermal power is generated in over 21 countries around the world including Iceland (producing over 50% of its electricity from geothermal sources in 2006), the United States, Italy, New Zealand, Mexico, Nicaragua, Costa Rica, Russia, the Philippines (2nd to US, 27% of electricity), Indonesia, the People's Republic of China, Japan etc.

• Because of high capital costs and the technological problems involved, world interest in it was negligible until the 1950s.

• Since the first geothermally-generated electricity in the world was produced at Larderello, Italy, in 1904 the use of geothermal energy for electricity has grown worldwide to about 7,000 megawatts in twenty-one countries around the world.

• The United States alone produces 2700 megawatts of electricity from geothermal energy, electricity comparable to burning sixty million barrels of oil each

year.

How can we use geothermal power?

• Generate electricity (indirect use)• Geothermal heat pumps (Space heating or cooling of

individual buildings and of entire districts)

• Direct uses– Hot spring bathing and health spas (balneology)– Agriculture: to help grow crops in greenhouses while

snow-drifts pile up outside– Industry: to pasteurise milk, to dry onions and lumber, to

wash wool

Advantages:• Operating costs are low resulting in low energy

costs for suitable sites;• It creates less disposal and has a long life

span;• The Earth's heat is so vast that it is possible to

take only a small fraction of it, and still sustain the world;

• Benefits remote areas;• Reliable (a geothermal power plant sits right on top of its fuel

source it is resistant to interruptions of power generation due to weather or political rifts)

Disadvantages:

• Power plants might be damaged because of ground movement;

• Specific locations may cool down;

• Expensive to set up power plants.

http://www.ren21.net/globalstatusreport/download/RE_GSR_2006_Update.pdf

• http://www.ren21.net/globalstatusreport/download/RE_GSR_2006_Update.pdf

Renewable energy is sustainable

Other energy resources (e.g. coal, oil) cannot be replenished by nature as fast as they are used.

Energy is the driving force behind most human activities, so it is fundamental to development.

Therefore, sustainable energy leads towards sustainable development.

Use of Renewable Energy:

• Reduces demand for fossil-fuelled electricity generation, thereby reducing greenhouse gas emissions. Let us say NO to global warming!

respects and cares for the community of life

conserves the Earth’s vitality and diversity

minimises the depletion of non-renewable resources

• Has the potential to provide affordable and clean sources of electricity to remote populations

enables communities to care about their own environment

improves the quality of human life

• Helps to reconcile economic development with environmental protection.

• Makes us ‘intergenerationally’ responsible (think about future generations)

• The rapidly increasing industrialisation in developing countries puts a strain on already limited resources and adds to the continuing deterioration of the global environment.

Finding alternative sources of energy is crucial!

-higher efficiency;

-increasing quality;

-the high cost will drop once the benefits of RE, including its sustainable nature and the minimal pollution it creates, are recognized by a larger percentage of the population.

Critisisms

• Unreliability

• People dislike the aesthetics of large solar-electric installations

• Noise pollution

• The large amount of land required

• Longevity issues (RE infrastructure does not last

forever; changing weather patterns etc)

• the materials, industrial processes, and construction equipment used to create them may generate waste and pollution.

• Some renewable energy systems actually create environmental problems. For instance, older wind turbines can be hazardous to flying birds.

• Not enough to satisfy growing demands

Conclusion• Although most of today’s electricity comes from large, central-station

power plants, new technologies offer a range of options for generating electricity nearer to where it is needed, saving on the cost of transmitting and distributing power and improving the overall efficiency and reliability of the system.

• Improving energy efficiency represents the most immediate and often the most cost-effectiveway to reduce oil dependence, improve energy security, and reduce the health and environmental impact of the energy system.

• By reducing the total energy requirements of the economies, improved energy efficiency will make increased reliance on renewable energy sources more practical and affordable