TOP 5 SOURCES OF RENEWABLE ENERGY

Renewable energy sources are energy sources that can be constantly replenished through various natural processes. Unlike non-renewable fossil fuels, they form cleaner and more environmentally friendly alternatives. In the past, renewables were not so widely used as the technology was quite basic and prices to set them up were quite high. 

However, this has changed drastically over the last decade or so, with the threat of global warming and increased greenhouse gas (GHG) emissions. People have turned to renewable energy sources as a solution towards sustainable energy usage. With more nations and people welcoming renewables as a viable source of energy, they are now more cost-effective and some can even be smart financial decisions for homeowners, businesses, and governments. Solar energy, which has seen immense developments since its discovery, has become so economic that homeowners can now save money and reduce their environmental impact just by using it. This makes solar energy one of the top five renewable energy sources used in the world today.

1. Solar Energy

As mentioned above, solar energy is the most popular and form of renewable energy. Major technological breakthroughs in solar cell manufacturing and storage have allowed it to be more powerful and cheaper than before. Research suggests that if this trend continues, electricity generated through solar energy in India will cost a lot less than that generated by coal by 2020. The global installed capacity of solar is now greater than 450 GW at the end of 2018, making it the third biggest renewable power source in the world; with PV being the most dominant form of solar energy and Concentrated Solar Power (CSP) on the rise as well.

Advantages:

Very low maintenance is needed for the upkeep of a solar plant. This is mainly because solar panels do not consist of any mechanical or moving parts that might break-down or malfunction at times. The panels will need a good cleaning from time to time, but otherwise, they are fairly reliable sources of energy. Another advantage is that there is no noise produced and hence, no disturbance caused. They also have economic benefits like in the long run, your energy will be almost free and you will have zero maintenance costs.

Disadvantages:

The main and most obvious disadvantage is the dependency of solar energy on sunlight, as panels should always be placed at an optimal angle towards the sun. They might need a mechanical tower at times to correct their angle continuously. At night there will be no generation and during cloudy days, the generation will drop as well, but scientists are constantly working on solar energy storage techniques that will make a constant supply of energy available. For example, CSP technology can use thermal heat batteries to produce electricity in the absence of sunlight.

Cost of Installation of a Solar Plant:

India has bagged the tag of the ‘lowest-cost producer of solar power globally’. The total installed cost of utility-scale solar PV in 2018 was less than Rs. 4.5 crores (45 million USD) per MW. When the cost of the different components of a simple PV system is broken-down, the PV modules themselves constitute 52% of the total cost, followed by the inverters at 23%, and the balance of systems at 17%. Installation of a typical rooftop PV plant costs around 8%. A normal 1 kWp plant costs INR 1 lakh without a storage facility which constantly decreasing as well.

1. Wind Power

Wind energy is the second most widely used renewable energy source. Wind Turbines in wind farms generate electricity that can then be purchased at a wholesale price on the power market, either contractually or through a competitive bidding process. This form of energy is essentially pollution-free and that is why, in 2018, wind power accounted for more than 5% of India’s total installed power generation capacity.

Advantages:

Wind turbines, once installed, use more vertical space than horizontal space; this means that they utilize lesser space on the ground as compared to a solar power plant. The efficiency of wind turbines is also greater than that of solar at 35-40% efficiency as compared to solar’s 15-20%.

Disadvantages:

Wind turbines can be quite noisy and more so when they are functioning at their maximum output phase. This can affect local ecosystems and can sometimes hinder the path of migratory birds that might be harmed by the turbines themselves. Their dependence on the wind can also make them unpredictable, even in predominantly windy areas. Wind farms are also not feasible for individual homeowners to install due to their size.

Cost of Installation of a Wind Power Plant:

While the wind is not always a practical source of renewable energy for an individual homeowner, it is becoming increasingly popular for utility-scale applications, with an average cost of Rs. 6.5 crores (65 million USD) per MW in 2018.

1. Hydropower

This is the oldest renewable energy source to be utilized by us. Almost 16% of the world’s net electricity production comes from hydropower. The most common method of generation involves the construction of dams on rivers and the releasing of water from reservoirs to drive turbines. Hydro plants can also have pumped storage.

Advantages:

The water once used by the system is returned to its original place. This makes it an unlimited renewable energy source. A hydroelectric plant does not produce any waste by-products, therefore making it a perfectly clean energy source. 

Disadvantages:

Hydro projects have high initial costs due to the need for a dam to be built around a river. This expense can sometimes limit the project to industrial and government use only. The installation of a hydropower plant can cause environmental problems like water-logging, that can lead to the loss of the biodiversity of fish populations and other aquatic animals. It can also affect human settlements. 

Cost of Installation of a Hydropower Plant:

Hydropower is still a resource that even small towns can harness using the energy from local waterways by building moderately sized systems. The cost of a utility-scale hydro plant will be between Rs. 7-9 crores (70-90 million USD) per MW in 2018.

1. Bioenergy

This is a form of energy that has gained popularity in the last few years due to breakthrough developments that have occurred in the field. Bioenergy can be divided into two main categories—biofuel and biodiesel.

Common biofuel sources are corn or sugar-based ethanol. Common biodiesels are made of vegetable oils, recycled greases, or animal fats. These biofuels could help replace fossil fuels used for transportation in the future. At the moment, bioenergy is the fourth-largest renewable energy source after hydro, wind, and solar energy. Modern biomass fuels are used for heat and power generation, alongside traditional biomass sources. They account for almost 15% of the world’s total energy supply and as much as 35% in developing countries, mostly for cooking food and heating homes.

Advantages:

The use of biofuels to power vehicles will not only serve to create environmentally-friendly vehicles but will also be a smoother transition for fossil fuel-powered vehicles. This is due to that fact that vehicles that run on fossil fuels will not need significant modifications to utilize biofuels.

Disadvantages:

The main and probably most striking disadvantage is that biofuels are not 100% carbon-free since the machinery utilized to produce biofuels and biodiesels is powered by fossil fuels. Biofuels also produce carbon emissions when they are combusted.

Cost of Installation of a Biomass Power Plant:

The average cost of a utility-scale biomass plant is between Rs. 4.5-5 crores (45-50 million USD) per MW in 2018. We also can tap the methane gas that is created by the anaerobic digestion of organic waste and use it as a fuel for energy generation.

1. Geothermal Energy

This form of technology can produce electricity and power by utilizing the heat generated by the earth’s core. At the moment, electricity generation accounts for about one-third of the renewable energy provided by geothermal sources, while the remaining two-thirds are used for direct heat generation. On a much smaller scale, a geothermal heat pump system can leverage a constant temperature of the ground to help supply heat to a nearby building in the winter or help cool it in the summer.

Advantages:

Although the initial installation is quite expensive and complex, it is a reliable, sustainable source of energy that can function 24/7. The pump can easily last for 20 years and is very efficient for electrical usage. Geothermal pumps utilize 25-50% less electricity than conventional heating and cooling systems. These pumps are also silent and produce no waste by-products. 

Disadvantages:

As mentioned above, the initial investment is quite high and complex. Geothermal pumps also require a large amount of land for installation.

Cost of Installation of a Geothermal Power Plant:

The cost of a plant varies between Rs. 30-35 crores (300-350 million USD) per MW in 2018 and that is why geothermal forms only a small part of our renewable energy mix, yet it is still a promising renewable energy source with massive potential for energy supply in the future.