Energy is provided in many forms by nature (Luo and Hong, 2016). We need the energy to perform work and operate other tools. Energy helps us to maintain life in the cities. The sources of energy we rely upon are fossil fuels (coal, oil, natural gas) and solar, wind, tidal, and hydroelectric energy (Einspruch, 2013). Energy consumption grows because of the economic and financial development of countries that lead to overconsumption of resources (Shahbaz et al., 2013). Increasing capital, trade, international relationships require countries to seek for additional energy (Shahbaz et al., 2013).
Conventional sources of energy include oil, natural gas, coal, nuclear energy, and hydroelectric energy (Einspruch, 2013). Oil and gas are formed from the remains of plants and animals that are drilled from their reservoirs (Einspruch, 2013). Drilling is expensive and risky; however, the sources are valuable and traded for a high price (Einspruch, 2013). Coal is dug up from the Earth and burned to create energy; like oil and gas, coal is highly pollutant and one of the leading causes of the greenhouse effect. Coal is a low-cost energy source (Ali et al., 2012). Nuclear energy is created from radioactive decay of uranium atoms (Einspruch, 2013). Lower maintenance cost is its advantage, but any adverse situations at nuclear plants can lead to radiation exposure and nuclear crisis (Ali et al., 2012). Hydroelectric energy is created from water; its flow powers the turbines and machinery, which generate electricity (Einspruch, 2013). It is a renewable source of energy. However, many areas have to be altered to build a dam, which hurts the environment. All of the mentioned sources are used to produce electricity, heat dwelling units, or as gasoline in cars.
Renewable fuels are not as pollutive as fossil fuels; they can be reproduced quickly and are produced from domestic resources (Ramadhas, 2016). They became so popular because of the decreasing amount of fossil fuels and their impact on the environment and human health. Renewable fuels include vegetable oils, biodiesel, methanol, ethanol, and dimethyl ether (Ramadhas, 2016). Vegetable oils are created from edible oils (e.g. sunflower) and non-edible oils (e.g. karanji). Vegetable oils are cheap and energy-efficient, but they can lead to damages in vehicles (Ramadhas, 2016). Biodiesel is produced from animal fat and other components (soybean oil); it is not as pollutive as fossil fuels, but can lead to water shortage if produced massively (Spellman and Bieber, 2016). Methanol is produced from natural gas and biomass; it is less pollutive and not as flammable as gasoline, but quite expensive (Ramadhas, 2016). Ethanol is made from plants (e.g. corn, sugarcane); it can be domestically produced, it is not very pollutive, but only works in a particular type of vehicles (Ramadhas, 2016). Dimethyl ether is converted from natural gas or organic waste; it can be produced locally but is highly flammable (Ramadhas, 2016). All of these fuels are used as alternatives to gasoline and diesel.
It appears that energy consumption will grow; since the human race cannot renew some of the resources it used, it has to find new energy resources that are not as toxic and pollutive as the ones we use now. I believe the human race will gradually shift to renewable sources since they are more efficient and inexpensive (sometimes).
Nuclear energy is not safe, but it is still used in many countries because it is cheap and relatively low-cost to maintain. However, the events in Japan, as well as past catastrophes, showed that nuclear energy is not compatible with natural disasters and can increase the damage to those. The human race has to find other sources of energy.
Renewable sources are more reliable, less pollutive, and are present in larger amounts than fossil fuels (Ramadhas, 2016). If we want to avoid further pollution and spread of death and diseases linked to it, we have to choose other sources of energy. Our race is responsible not only for our future but also for the future of the Earth.
References
Ali, R.; Daut, I.; Taib, S. A Review on Existing and Future Energy Sources for Electrical Power Generation in Malaysia. Renewable and Sustainable Energy Reviews 2012, 16, 4047-4055.
Einspruch, A. What Is Energy?; The Rosen Publishing Group: New York, 2013; pp 6-22.
Luo, F.; Hong, Y. Renewable Energy Systems: Advanced Conversion Technologies And Applications; CRC Press: New York, 2016; pp 23-49.
Ramadhas, A. Alternative Fuels for Transportation; CRC Press: New York, 2016; pp 21-171.
Shahbaz, M.; Khan, S.; Tahir, M. I. The Dynamic Links Between Energy Consumption, Economic Growth, Financial Development and Trade in China: Fresh Evidence from Multivariate Framework Analysis. Energy Economics 2013, 40, 8-21.
Spellman, F.; Bieber, R. The Science of Renewable Energy; CRC Press: New York, 2016; pp 13-100.