Energy & Power

Renewable

In Search of Renewables

Saleque Sufi

(Continue)

Sometimes between 6000 to 2000 years BCE (Before the Common Era), the first discovery of natural gas seeps were made in Iran. Many early writers described the natural gas seeps in the Middle East, specially in Baku region of what is now Azerbaijan. The gas seeps probably first ignited by lightning, provided the fuel for the “eternal firs” of the first worshiping religion of the ancient Persians.

Fossil fuels take millions of years to make. We are using up the fuels that were made more than 300 million years ago before the time of dinosaurs. Once they are gone, they are gone forever.

Bangladesh does have a finite reserve of natural gas and good quality coal. These can ensure energy security for at least 30-40 years if these are judiciously utilized. But for longer term energy security possible renewable options must be exploited. We have already discussed hydroelectricity prospect. This time let us discuss solar energy. Before discussing Bangladesh prospect let us have an insight into solar energy.

Mankind has always used the energy of the sun as a human has existed on this planet. As far back as 5000 years ago, people “Worshipped” the sun, Ra the sun god who was considered the king of Egypt. Ten Mesopotamia, the sun god Shamash was a major deity and was equated with justice In Greece there were two sun deities, Apollo and Helios. The influence of the son also appears in other religions -- Zoroastrianism, Mithraism, and Roman religion. Hinduism, Buddhism, the Druids of England, the Aztecs in Mexico, the Incas of Peru and many Native American tribes.

We know today, the sun is simply our nearest star. Without it life would not exist on our planet. We use the sun’s energy in many different ways. When we hang laundry outside to dry in the sun, we are using the sun’s heats to do work drying our clothes.

Plants use the sunlight to make food Animals eat plants for food. Decaying plants for hundreds of millions of years ago produced the coal, oil and natural gas that we use today. So, fossil fuels is actually sunlight stored millions and millions of years ago.

Indirectly, the sun or other stars are responsible for all our energy. Even nuclear energy comes from a star; because uranium atoms used in nuclear energy created in the fury of a nova a star exploding.

Solar Hot Water
In the 1890s solar water heaters were being used all over the United States. They proved to be a big improvement over wood and coal burning stoves. Artificial gas made from coal was available too to heat water but it cost 10 times the price that is paid for natural gas. Electricity is even more expensive.

Today, solar water heaters are making a comeback, Solar heaters are extensively used to heat homes and businesses. They also heat swimming pools. Panels on the roof of a building contain water pipes. When the sun hits the panels and the pipes, the sunlight warms them. The warmed water can be used in the swimming pool.

Solar Thermal Electricity
Solar energy can also be used to make electricity. Some solar power plants use a highly curved mirror calls parabolic trough to focus the sunlight on a pipe running down a central point above the curve of the mirror. The mirror focuses the sunlight to strike the pipe, at it gets so hot that it can boil water into steam. The steam can then be used to turn a turbine to make electricity. The problem with solar energy is that it works only when the sun is shining so on cloudy day and night, the power plant can’t create energy. Some solar plants are a “hybrid technology. During the daytime they use the sun.

At night and cloudy days they burn natural gas to boil the water so they can continue to make electricity. Another form of solar power plants to make electricity is called central Tower Power Plant, like the one to the right the solar Tower Project. Sunlight is reflected off 1800 mirrors circling the tall tower. The mirrors are called heliostats and move and turn to face the sun all day long. Center of the circle where a fluid is turned very hot by the sun’s rays. That fluid can be used to boil water to make steam to turn a turbine and a generator.

Solar Cells or Photovoltaic Energy
Sunlight can also be directly changed to electricity using solar cells. Solar cells are also called photovoltaic cells or PV cells for short and can be found on many small appliances, like calculators on even on spacecraft. They were first developed in the 1950s for use on U.S. space satellites. They are made of silicon, a special type of melted sand.

When sunlight strikes the solar cell, electrons (red circles) are knocked loose. They move toward the treated front surface/dark blue color). An electron imbalance is created between the front and back when the two surfaces are joined by a connector, like a wire, a current of electricity occurs between the negative and positive sides.

The individual solar cells are arranged together in a PV module and the modules are grouped together in an array. Some the arrays are set on special tracking devices to follow sunlight all day long.

The electrical energy from solar cells can then be used directly. It can be used in a home for lights and appliances. It can be used in a business. Solar energy can be storied in batteries to light a roadside billboard at night. Or the energy can be stored in a battery for an emergency roadside cellular telephone when no telephone wires are around. Some experimental cars also use PV cells. They convert sunlight directly into energy to power electric motors on the car.

Solar Energy Development in Bangladesh
Bangladesh is at very early stage of utilization of non conventional and renewable energy resources. Availability of advanced technologies has broadened the scope of application of the renewable energy today. Several renewable energy options are being considered for implementation under the sustainable Rural Energy (SRE) project, with a focus on demonstration of sustainability of technologies. Investigation of their long-term suitability in rural Bangladesh will be followed by technology transfer.

Introduction of solar photovoltaic systems and its increasing use of worldwide is a major stop towards an ecological and sustainable energy system. It is more environmental friendly technology than any other means of generating electricity, making power available anywhere thus leapfrogging the present prohibitively expensive process of extending electrical grid everywhere. The modular nature low maintenance and availability make this new and immerging power sources an attractive alternative by planners to use in large scale in rural locations.

Through Japan International Cooperation Agency (JICA) assisted cyclone shelters project LGED has established more than 15kw of solar photovoltaic system in several cyclone shelters, the solar installations have been designed to operate 18 lamps and one TV. The solar installations have tremendously reinforced the importance of cyclone shelters and the effective utilization during the period of natural disaster. Now solar installations at the shelters have increased its wide and diversified use by the local community. It enables the local community to continue adult education and similar program at night. Moreover, solar lighting at night transforms the shelters to act as guide house for ocean vases and fishermen trawlers to safely reach to the shore.
List of Solar Installations Under LGED
Solar System Capacity (Watt) Location
Solar House Hold systems at coastal cyclone shelters 12635 Kuakata in Patuakhali Cox’s Bazar, Madaripur Khustia, Kishoreganj Kutubdia, Chittagong, Khagrachhari District
Solar Street Lighting at coastal cyclone shelters 2640 Kutubdia & Chokoria of Cox’s Bazar and Banskhali & Anwara of Chittagong District
Solar Battery Charging Station 150 Kazikanda, Patuakhali District
Solar Pumping Station 300 Prantik lake, Banderban District

Solar Water Pumping System at Prantik Lake Tourist Resort
Pranki Lake is a unique example of Solar energy application within the framework of integrated mountain development practices under LGED. A dam was constructed by LGED to conserve water from small streams of sounding hills in Bandarban district. Eventually a beautiful lake (Prantik Lake) has been created which serves as a potential source of water fro drinking and household purposes for the local people. Eventually this remote lake area has become an attraction for the tourists and LGED constructed access roads and necessary tourist structure to develop the area as an attractive tourist spot. Since national power grid was not available in the vicinity, solar energy based technologies have been applied for electrification and water pumping purposes.

Solar energy cannot be a standalone source of power generation in Bangladesh. It can serve small isolated off grid areas to supplement and complement power supply through national grid. However, given the finite source of our nonrenewable energy source solar energy exploitation must be aggressively taken up for our energy security. (concluded)