Tracing the journey of alternative energy sources
The quest for newer or alternative energy sources has been going on for a long time beginning with employing animals as alternative energy sources to human labour. As the thirst for energy has increased with growing human populations and the multiplication of devices used in daily life, new sources of energy have been sort to meet this demand. Society has therefore strived to find more efficient energy sources with the least impact to the environment. For now,it seems electric energy is emerging as the preferred source of energy.
Basic source of energy for human beings
Living things need energy, which mainly comes from the sun as solar energy, to grow and do work. Plants transform the sun’s energy into chemical energy (carbohydrates, fat, and protein) through a process called photosynthesis, animals feed on the plants and transform the plant energy into animal chemical energy (carbohydrates, fat, and protein). Human beings feed on plants and animals and transform this chemical energy into carbohydrates, fat, and protein for growth, body heat and doing work.
Source of energy
Human basic needs
Human beings need air, water, food and shelter for survival. Air contains oxygen which the body uses to convert food into energy. Water regulates body temperature, carries waste products out of the body, and is used in digestion of food. Food provides energy for the body, and shelter creates a safe environment for human survival.
Energy sources in the beginning
In the history of human development - through the stages as hunter gatherers, agriculturalists, and industrialists, energy sources for doing work have evolved as the stages have changed. As hunter gatherers, food was the main source of energy required to live. As humans moved away from hunting and gathering into agriculture, a human tilling the land was the main source of energy. Increasing populations led to increased demand for agricultural products and larger areas of land to be tilled. More humans were needed to produce sufficient food. The need for increased labour led to the introduction of animals (oxen and horses) to be used as energy sources in the production of agricultural products.
Oxen as an energy source
As human beings moved away from being hunter gatherers, the shelters used for protection improved from caves to constructed structures. Wood and dung were initially used as the main sources of energy to provide heat in the households.
Improvement in level of comfort
Growth in human population and improvement in living conditions increased the demand for agricultural produce, transport, and need for better shelters. To satisfy these needs, more tools and equipment were required leading to the introduction and growth of industries. Industry needed energy for smelting and other industrial tasks. Industries used wood as the main source of energy for heating and employed animals for the other tasks. The need for more energy and increased efficiencies drove innovation and with time watermills and windmills were introduced.
Further improvement in the levels of comfort introduced additional uses for wood for example furniture and construction of shelters. Consequently, the competition for wood led to scarcity and higher prices. Coal was then introduced as an alternative source of energy for households to meet their heating needs.
Watermill and Windmill
The dawn of engines
The discovery of the steam engine expanded the use of coal from households to industry. Gradually the steam engine replaced windmills, watermills and animals (horses and oxen) both in industry and transport. Although oil as a source of energy was first introduced for lighting and heating, the discovery of the internal combustion engine was the catalyst for oil becoming a major source of energy for human development.
Classification of energy sources
Energy is not created but rather transformed from one form into another. This characteristic provides a basis for classifying energy sources. When energy is extracted or captured directly from natural resources and converted into heat or work, the source is referred to as a primary source. Crude oil, coal, and wind are examples of primary sources of energy. Energy resulting from the transformation of a primary source into another type of energy is referred to as secondary source. Examples of secondary sources are petroleum, electricity, heat, biofuels, and gas.
Energy sources in industry
The invention of electromagnetic induction and subsequent development of the electric generator and electric motor accelerated industrial development and growth. Prior to the electric motor, power in industries was distributed using overhead belts and shafts. The energy to run the belts and shafts came from steam engines, waterfalls or windmills. Therefore, industries were generally located near waterfalls or coal sources. However, with the advent of electricity, energy could be delivered to a wide range of places without the constraint of locating near the energy source. Further advancements in the transmission of electricity, which capitalised on the characteristics of electricity being weightless and easily controllable, meant electric energy could be delivered in any size required to a wide geographical area unlike steam engines which came in particular sizes.
Overhead belts and shafts
Electricity as a source of energy
Electric energy can easily be converted to other forms of energy with minimal loses (heating, lighting, and kinetic energy). At the same time, many sources of energy can be converted to electric energy (hydro, coal, oil, and nuclear). This versatility has made electric energy, the energy source of choice.
Increases in consumer wealth has led to improvements in the level of human comfort and consequently a surge in the need for consumer durables. More and more households now have televisions, radios, refrigerators, dishwashers, laundry machines, dryers, vacuum cleaners, air conditioners, home security, computer networks, telephones, cookers, kettles, and microwave ovens as regular devices in the household. Commercial establishments and other institutions like government offices, hospitals, and industries need, among others, lighting, air conditioning, computers, computer networks, communication systems, refrigeration, automation systems, and data centres. Most of these devices and machines use electricity as a source of energy.
The role of electric energy and search for alternative sources
Electric energy now plays an important role in sustaining human life and development to the point where electricity can be placed in the same category as water to drink and air to breathe. Businesses and the general public, especially in the developed world, do not realise that they rely so heavily on electric energy for almost every task performed.
Population growth, the proliferation of computerisation into every aspect of human life, and the multiplication of devices that use electricity, all enhance the importance of electricity in everyday life. Whereas these changes contribute to improvements in human welfare there is an associated negative impact on the environment. The deterioration of the environment (air, land and water) because of some energy sources has led to regulations on emissions and a search for alternative sources of energy. Electricity as a source of energy is environmentally clean however; the challenge continues to find sources that are transformed into electricity without affecting the environment.