SOLAR ENERGYCOURSE CODE:SES 864E

COURSE TITLE:ENEGY AND ENVIRONMENTPRESENTED BY:GEOFREY YATOR

COURSE INSTRCTOR: Dr. E. UCAKUWUNDATE: 17TH FEBRUARY 2014

INTRODUCTION Solar energy is an inexhaustible/renewable resource. The sun produces vast amounts of renewable solar energy that

can be collected by use of various technologies and converted to heat and electricity.

Solar energy is clean, releases almost no greenhouse gases, and produces no waste.

Every year the earth receives 8380 times the amount of energy spent annually by humankind – 11 billion tons of oil equivalent.

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History of Solar Energy

The History dates back to 5th century B.C. in the Greeks era. They used solar passively by designing their homes to capture the sun’s heat during the winter.

Later, the Romans improved on solar architecture by covering south-facing windows with clear materials such as mica or glass, preventing the escape of solar heat captured during the day.

Horace de Saussure In the 1760’s built an insulated rectangular box with a glass cover that became the prototype for solar collectors used to heat water.

In 1954, three scientists at Bell Labs developed the first commercial photovoltaic (PV) cells, panels of which were capable of converting sunlight into enough energy

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History of Kenya In Kenya solar energy took center stage in the mid 1990’s and by

2013 Kenya had invested more than $500M (Kshs 4.3 bn) on solar power.

By 2016 the Kenyan government is planning to invest $1.2bn (Kshs 103billion) on solar energy.

Kenya ranks 22nd in Africa for the amount of electricity it generates, and 46th in the world in the generation of solar energy.

But it could rank third worldwide for solar in the next four years, according to figures from the Energy Regulatory Commission (ERC).

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Uses of Solar Energy Solar energy has many uses. It can be used to provide heat, light

or to generate electricity. Passive solar energy refers to the collection of heat and light;

passive solar design, for instance, uses the sun’s energy to make homes and buildings more energy-efficient by eliminating the need for daytime lighting and reducing the amount of energy needed for heating and cooling.

Active solar energy refers to storing and converting this energy for other uses, either as photovoltaic (PV) electricity or thermal energy.

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Uses of Solar EnergySolar Heating Solar systems that heat water for homes and businesses, and passive solar

design for buildings of all sizes, both have the same effect on the electric grid as conservation. They do not generate electricity but reduce the demand for electricity and natural gas.

From 1998 to 2005, the solar water heating market produced about the thermal equivalent of 124,000 megawatt-hours (MWh) annually.

Uses and Illustration of Solar works

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Uses of Solar Energy The most powerful large-scale solar thermal technology,

however, is concentrating solar power (CSP). CSP can be PV-based, it generally refers to three solar thermal

systems–parabolic troughs, solar dish/engines and power towers–each of which is in use or under development today.

A solar dish/engine system consists of a solar concentrator – glass mirrors in the shape of a dish that reflect sunlight onto a small area

Generation of electricity through CSP

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Uses of Solar EnergySolar Electricity A unique advantage of small-scale solar energy systems is that, if they

include storage devices-batteries (dry cell and lithium ion batteries) they may eliminate the need to connect to the electric grid.

Solar energy through Photovoltaic cells Photovoltaic cells (PV) are used worldwide to convert sunlight into electricity. The PV cell contains two layers of semiconducting material, one with a positive charge

and the other with a negative charge. Several PV technologies are in use or in development. The silicon-based PV cell,

made with the same silicon used in the semiconductor industry, has dominated the market and continues to do so.

Utility-scale concentrating solar power (CSP) systems, for instance, typically offer capacities of from 50 to 200 megawatts (MW)

How solar electricity is generated

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Impact on the environment

Solar energy technologies generate electricity without producing air or water pollution.

Most PV systems are installed on existing structures such as homes and commercial buildings and require no additional land.

CSP plants do not damage the land they are installed in. Solar electricity can reduce carbon emissions by offsetting the need for

carbon-producing fuels. Example a plant n Austin that will generate about 33.7 Mwh annually can eliminate about 24.5 metric tons of carbon emissions each year.

PV and CSP systems do not generate solid waste in creating electricity.

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Impact on the environmentNegative Impacts Their manufacture generates small amounts of hazardous materials such as

arsenic and cadmium, which must be disposed of properly to avoid harm to the environment and humans.

CSP plants can merely take land out of use for other applications such as agriculture. Wildlife habitat may be displaced from land used for such systems.

CSP plants can cause change in the local grounds reflective power (albedo) causing change in temperatures

CSP plants needs massive land for installation, it is estimated that a typically CSP plant needs about five to 10 acres of land to produce 1 megawatt of installed capacity

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The Future of Solar Energy The future of solar Energy is bright, wider and with great and massive

opportunities backed up by developing technologies. Currently Solar panels encircling the Moon's equator that would transmit

energy to Earth via microwaves and lasers are being developed it will provide up to 13,000 terawatts of electricity per year

Japan flipped the switch on its largest solar power plant to date which is built offshore on reclaimed land jutting into the cerulean waters of Kagoshima Bay. The mega solar plant generates enough electricity to power roughly 22,000 homes.

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The Future of Solar Energy

Another technology currently being studied is the solar chimney, whose operation is based on the principle of circulating air. A flat- plate collector with a greenhouse-like structure heats the air that rises naturally inside the central tower. The airflow drives turbines that are connected to generators.

P.V silicon cells are not 100% effective they are 33% effective and this is because of the wavelengths that its photons absorb sun rays. Technology is being tested by the Massachusetts Institute of Technology on installing infrared on the layer before the silicon layer for maximum conversion of wavelengths when this is done P.V cells will be 77-80% effective.

Planes, motor vehicles (sports, buses and golf course vans) boats are being installed with P.V panels but they are too expensive to manufacture and can hardly do 33.4miiles on a single charge without recharge.

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Conclusion Though the installation and construction of solar power stations is

relatively expensive its renewable nature and the durability of P.V cells makes solar energy the most reliable source of energy and the future source to power the planet.

THE FUTUREIS BRIGHTER,SUSTAINABLE

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