Fossil fuels (coal, oil, and natural gas), which are non-renewable sources of energy are currently the major sources of energy in many countries (both developing and developed). These energy sources take years to form; for instance, coal, a solid fossil fuel formed over millions of years by decay of land vegetation. Oil is a liquid fossil fuel that is formed from the remains of marine microorganisms deposited on the sea floor. After millions of years, the deposits end up in rocks and sediments where oil is trapped in small spaces. Just like oil, natural gas is formed from the remains of microorganisms. Natural gas happens to be versatile, abundant and relatively clean compared to coal and oil. Overall, fossil fuels are used to a large extent simply because they are cheaper than any alternative available presently.
However, the burning of fossil fuels has been singled out as the cause of many environmental problems that are high on the political agenda in recent times. The burning of fossil fuels releases green house gases into the atmosphere; these gases form a blanket in the atmosphere, trapping the long wave radiations leaving the earth’s surface causing an increase in global temperatures. Consequently, other undesirable events including; sea level rise, floods, and droughts begin to occur more frequently. Other pollutants are released into the air, soil and water when fossil fuels are burnt. This contributes to air and water pollution, acidification, damage to land, surface and ground-level ozone. It has been estimated that oil burning is responsible for about 30% of the total carbon dioxide emissions into the atmosphere.
According to the United Nations, the world’s population is expected to reach 8.7 billion by 2035. This coupled with increasing standards of living for many people in developing countries will cause an increase in energy demand. Thus, developing countries will account for over 70% of the increase in energy demand. The spike in energy demand mounts pressure on fossil fuel as the rate at which they are being extracted far exceeds the rate at which they are being formed.
Many reports have shown that oil reserves are declining. According to IHS Energy, 90% of all known oil reserves are now being tapped; this implies that few oil reserve sites remain to be discovered. Furthermore, some experts state that conventional oil reserves are now declining at a rate of about 4-6% annually worldwide. If this reports are true, oil production could come to an end sooner rather than later.
The decline in fossil fuel reserves combined with the need to mitigate environmental issues has shifted attention to sustainable and environmentally friendly sources of energy; namely Renewable Energy.
Renewable Energy is sometimes referred to as “green” or “clean” energy, because it produces few if any pollutants and uses energy sources that are continually replenished by nature – the sun, wind, water, and the earth’s heat. These fuels are converted into usable forms of energy by renewable energy technologies. Often, they are turned into electrical energy, and sometimes heat energy. Renewable energy abounds and the technologies to harvest these energy sources has improved over the years. These include:
The Akosombo dam, constructed between 1961 and 1965, supplies electricity to Ghana and its neighboring countries including Togo and Benin.
Hydropower is the world’s largest source of non-fossil-fuel power. This form of renewable energy is produced in 150 countries with China being the largest hydroelectricity producer (721 TWh) in 2010. British Petroleum’s 2014 statistical Review of World Energy showed that hydroelectricity (the energy generated from hydropower) has been increasing over the last decade. This is not surprising as the cost of hydroelectricity is fairly low, and hydropower plants emit very little CO2 into the atmosphere. In addition, hydroelectricity is an easily scaled resource – the amount of energy produced can quickly be increased to meet a rise in energy demand. However, hydropower plants can affect water quality and wildlife habitats. Another problem associated with hydropower is drought. Hydroelectricity production depends on the amount of water available; thus if the quantity of water falls below the required amount, energy production will be greatly affected.
The sun releases an enormous amount of energy each day, and this amount could meet the world’s energy needs with a huge amount to spare. But how can we convert the energy stored in sunlight into usable forms? First, an understanding of the nature and properties of light, the sun’s light in this case, is required. It has been found that when light hits the surface of some objects, the energy it contains turns to heat, like the warmth you feel when sitting in the sun. It is not always the case that light turns into heat when it comes into contact with some objects; certain materials are able to convert light into electricity. The earliest solar energy technologies made use of large silicon crystals capable of producing electric currents when struck by light. However, Scientists faced challenges growing larger crystals, so new materials had to be developed. Presently, solar technologies use smaller, cheaper crystals, such as copper-indium-gallium-selenide, that can be shaped into flexible films.
Solar energy technology can be applied to several sectors including architecture and urban planning, agriculture, transportation, and electricity. The technology is continually being recognized as a replacement for fossil fuels, and growth in solar power capacity over the years is evidence that solar energy will one day be the major source of energy. In 2013, the European Photovoltaic Association reported that solar power capacity increased by 35%, and it projected that the rate of adoption will be faster in the coming years.
Solar energy seems to have no disadvantages except for the cost involved. At present, solar energy is much more expensive, about five times the cost of cheap but polluting coal and oil. To make the technology available to all, cheaper materials that can convert sufficient sunlight into energy must be produced. This may not happen now, but looking at the rate at which technology is advancing, solar energy could be made accessible to most people in a few years.