With the world facing an energy crisis, due to the increasing population and diminishing conventional sources of energy, and an environmental crisis, we are witnessing vigorous growth in the use of renewable energy, which a lot more than what was anticipated. This ongoing shift towards a brighter future is the result of the contrast between renewable and non-renewable energy. Among all the other differences, that make both the energies poles apart, the most intriguing one is the dissimilarity in the sources of these energies. While non-renewable energy sources are formed by different processes going in nature, mostly decomposition, the renewable energy source, on the other hand, is nature itself. The processes for making non-renewable resources take millions of years which renders them almost non-replenishable. Contrarily, since renewable resources are elements of nature themselves, they can never get exhausted.
Panchtatva is a Sanskrit term, formed from two words- ‘panch’ means five, and ‘tatva’ indicates elements. When put together, the word formed means the five fundamental elements of life- fire, water, air, earth, and sky. These five elements are the building blocks of everything in nature and carry a surplus amount of energy. All renewable energies are directly related to these five elements of nature and can be divided based on their relation to them. The different types of renewable energies are- solar energy, wind energy, hydro energy, tidal energy, geothermal energy, and biomass energy. To better understand each renewable energy and its source, categorizing them under the five elements is the most straightforward way.
The first one, out of the five elements, is ‘earth’. In this context, earth refers to the land surface of our planet, on which we live and move about. The energy related to earth is geothermal energy, which is derived from geothermal sources located inside earth, mostly near the boundaries of earth’s tectonic plates. Basically, geothermal energy is the thermal energy generated and stored inside earth in form of vapor or water. It is generated from constant heat loss from earth’s formation and from radioactive decay of the materials. Hot springs are the oldest use of geothermal energy, dating back palaeolithic times, where it was used for bathing, and was later used by Romans for space heating. But, in today’s era it is mostly used for electricity generation. According to US Energy Information Administration, in 2019, there were geothermal power plants in seven states, which produced about 16 billion kilowatt hours (kWh) of electricity. It is considered possible to produce up to 8.3% of the total world electricity with geothermal resources, supplying 17% of the world population. Geothermal power is cost-effective, reliable, sustainable, and environmentally friendly.
The second element is ‘water’ which serves in formation of two renewable energies hydropower and tidal energy. Hydropower or hydro energy is the power generated from the energy of fast-running or falling water, using turbines. In ancient time, hydro energy was used in irrigation and mills using waterwheels. The concept of these waterwheels became the basic idea behind the invention of turbines. In the late 19th century, people started using these turbines to generate electricity. Even today hydropower stands as the most used renewable resource for electricity generation. In 2015, hydropower generated 16.6% of the world’s total electricity and 70% of all renewable electricity.
Tidal energy is another type of energy that uses water for generating power. It is harnessed by converting energy from tides using various methods. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth. In ancient times, dating back to middle ages, tides mills were used in Europe and the Atlantic Coast of North America, where incoming tidal water was stored in large storage ponds, which used to rotate the waterwheel with the seaward flow. The process of using falling water and spinning turbines to create electricity was introduced in the U.S. and Europe in the 19th century. Since then, with the advancement of time, many methods were formed for power generation from tides, like tidal stream generator, that uses kinetic energy of the moving water to rotate turbines and generate electricity, and tidal barrage, that uses potential energy of in the difference in height between high and low tides. Sadly, the amount of energy produced worldwide using tides is low, but with technological advancement it is estimated that it will supply at least 10% of the world’s energy consumption in near future.
The third element of nature is ‘air’ and power generated using it is called wind energy. Wind energy is produced by using fast movement of the wind, which rotates windmills or wind turbines, generating energy. Although the use of wind as source of energy dates back to 5000 BC when it was used to propel boats along the Nile river, but the first electricity generating turbine was invented in 1888 in Cleveland, Ohio by Charles F. Brush which generated about 12 kilowatts of power. The world’s first wind farm, a group of wind turbines in the same location used for the production of electric power, was installed on the shoulder of Crotched Mountain in southern New Hampshire in December 1980. It consisted of 20 wind turbines, each rated at 30 kilowatts, generating 0.6 kilowatts of power. Today there are over 3,41,000 wind turbines on the planet generating great amount of energy. In 2019, wind supplied 1430 TWh of electricity, which was 5.3% of worldwide electrical generation, with the global installed wind power capacity reaching more than 651 GW.
The fourth element is ‘fire’ and the energy related to it is biomass. Although biomass itself is not related to fire, but it serves as fuel to ignite it. Biomass is any organic matter- woods, crops, seaweed, animal waste- that can be used as energy source. Biomass is probably our oldest source of energy after the sun, as people have been using wood to produce heat energy, by burning it, since stone age. Even today the largest source of biomass energy is wood and its residues. Throughout the world, biomass is the largest renewable energy source. It generated 71.4 billion kilowatt hours of electricity in 2016, constituting 70% of the share among all renewable energy sources.
The fifth and the last element is ‘sky’ or ‘space’. This element holds the most important energy source, not only for humans but to support life throughout the planet, and this energy source is the sun. The sun is the only renewable energy source that is present everywhere and radiates abundance of energy across the globe. Solar energy can be harnessed using a range of ever evolving technologies. The earth receives 174 petawatts of incoming solar radiation out of which only 30% is reflected back while the rest is absorbed by clouds, land masses and oceans. With the invention of the first solar cell in 1883, New York, by Charles Fritz, the solar energy never ceased to exist and is thriving with modern technologies. In 2019, solar power provided 2.7% of total worldwide electricity production. Although, it is the smallest energy source in the world, but it has the fastest growth rate with most emerging technologies.
This relation of renewable energy with the nature is the main reason behind its abundance in the world. Renewable energy is clean energy deriving its powers from the five basic elements, and with fossil fuels and other non-renewable energies being on the edge of extinction, humans need to adopt these renewable energies as soon as possible to carve out a better future.