6 Types Of Renewable Energy Sources: Which Sustainable Resources Could Be Used By Mumbai?

About 40% of global CO2 emissions are emitted from electricity generation through the combustion of fossil fuels

It is difficult to imagine life without electricity for most of us. Electricity improves people’s lives and is also a measure of progress. Electricity not only provides social amenities but also, more importantly, stimulates economic development and growth.

But where does this energy come from?


Electric energy could be generated from fossil fuels like coal, oil, and natural gas. It could also be generated from various renewable sources like solar, wind, tidal energy and more.

Fossil fuels do substantially more harm than renewable energy sources by most measures, including air and water pollution, damage to public health, wildlife and habitat loss, and global warming emissions.

Costa Rica’s 97% of the energy requirements come from renewable sources. The country’s target is to become carbon neutral by 2021.

In India, 71% of the installed power capacity is thermal, about 12% is hydro power, 15% is other renewable sources and about 2% is Nuclear power.

Although renewable sources of electrical energy have been growing rapidly, (between 20 to 24%) as compared to Thermal which has grown by about 3 to 4%, renewable energy still constitutes a small percentage of the total energy.

India is the world’s 3rd largest producer and consumer of electricity.


There are various types of renewable sources of energy available which can be used based on the geographic location and suitability.

Solar Power

  • Sunlight is one of our planet’s most abundant and freely available energy resources.
  • The amount of solar energy that reaches the earth’s surface in one hour is more than the planet’s total energy requirements for a whole year.
  • The amount of solar energy that we can use varies according to the time of day and the season of the year as well as geographical location.
  • There are 2 possible operation modes are capturing sun rays and converting them into energy: through photovoltaic solar panels or, capturing, collecting and turning the sunlight into heat to warm up water or air.

Wind  Energy

  • Wind is a free, and readily available renewable energy source. 
  • Each day, around the world, wind turbines are capturing the wind’s power and converting it to electricity. 
  • Wind power generation plays an increasingly important role in the way we power our world – in a clean, sustainable manner.
  • Wind turbines convert the kinetic energy in the wind into mechanical power. A generator can convert mechanical power into electricity.

Hydropower Energy

  • Hydro-electric power involves the transformation of the kinetic energy of the water (from rivers, dams, marine currents or tides)  into mechanical energy by turbines.
  • Hydro power is one of the most commercially developed renewable energy sources
  • This energy source can often be more reliable than solar or wind power (especially if it’s tidal rather than river) and also allows electricity to be stored for use when demand reaches a peak.

Tidal Energy

  • Another form of hydro energy that is produced by the surge of ocean waters during the rise and fall of tides.
  • Although tidal flow unlike some other hydro energy sources isn’t constant, it is highly predictable and can therefore compensate for the periods when the tide current is low.
  • Tidal energy production is still in its infancy. The amount of power produced so far has been small and there are very few commercial-sized tidal power plants operating in the world.
  • There are currently three different ways to get tidal energy: tidal streams, barrages, and tidal lagoons.


  • Biomass is made up of organic materials from plants or animals that contain stored energy which could be used by combustion.
  • Although fundamentally, biomass involves burning organic materials to produce electricity, it is a much cleaner, more energy-efficient process.
  • By converting agricultural, industrial and domestic waste into solid, liquid and gaseous fuel, biomass generates power at a much lower economical and environmental cost as compared to thermal from combusting fossil fuel.


  • Geothermal energy is heat that is generated from within the Earth.
  • The heat can be captured and used directly for heat, or the steam can be used to generate electricity.
  • Geothermal energy can be used to heat structures such as buildings, parking lots, and sidewalks. 
  • Many countries have developed methods of tapping into geothermal energy.
  • Different types of geothermal energy are available in different parts of the world. In Iceland, abundant sources of hot and  easily accessible underground water make it possible for most people to rely on geothermal sources as a safe, dependable, and inexpensive source of energy. Other countries, such as the U.S., must drill for geothermal energy at greater cost.
  • This is an evolving technology.


In India, 71% of the installed power capacity is Thermal, About 12% is Hydro power, 15% is other renewable sources and about 2% is Nuclear power.

Mumbai is a financial hub and people come here from all parts of India in search of employment opportunities. It has a population of approximately 20 million and growing. The electricity consumption in Mumbai City was about 12,952 GWh in 2011 and has been increasing every year. Bulk of the power consumed is from thermal power plants.

“Replacing traditional sources of energy completely with renewable energy is going to be a challenging task. However, by adding renewable energy to the grid and gradually increasing its contribution, we can realistically expect a future that is powered completely by green energy.” – Tulsi Tanti

The following renewable energy options can help Mumbai become sustainable, and cleaner by reducing pollution.

Solar power

Mumbai receives sufficient light throughout the year except during Monsoons. A large scale Solar Power plant requires large space and space constraints makes it a difficult proposition. However, small scale projects of solar panels on roofs of residential buildings and parking areas to generate electricity can be put into the Grid.

The government can mandate every housing society to implement the same in Capex (Capital Expenditures) or OPEX (Operating Expenditure) model which can sum up to a large amount of power and also provide subsidies in the property tax or electricity bills which will encourage societies to implement.

Housing society in Mumbai suburbs are shifting to solar to reduce electricity bill by 60% (Hindustan Times)

Wind Energy

Wind mills can be set up along the sea coast where sufficient wind energy could be harvested. This is one of the cleanest and sustainable forms of energy.


Mumbai produces about 7500 metric tonnes of solid waste per day,  of which about 6000 tons is organic waste. These can be converted through nano reactors using microbes to produce electricity and also compost which can be used for agriculture, gardening, horticulture etc. This apart it can also produce cooking gas.

6000 metric tonnes of organic waste can generate about 15 to 20 MW of electricity, about 2000 tons of compost and about 20,000 cylinders of cooking gas.

The procedure is smoke, ash and noise free , requires very less space and investment is not large. It can significantly reduce landfill and release the space used by landfill.

The Biomass plant can be installed in every housing societies, industries, slums and the power generated can be put into the grid. It is an effective way of treating the waste at source. The government can provide subsidies in power bills or in some other form to encourage people to implement such projects.

The Earth5R team has installed composting units in residential buildings in Powai, Mumbai to promote segregation and use of organic waste (Earth5R)

Tidal and Geothermal energies can be a source in future once the technology becomes more mature.


According to United Nations reports about 789 million people are yet to have access to electricity. SDG 7 (Affordable and Clean energy) focuses on sustainable energy and Universal access to affordable energy and energy services.

“I believe access to electricity and light can radically improve people, lives” – Olafur Eliasson

Renewable energy satisfies all the three pillars of sustainability i.e. Social, Environmental and Economic as outlined by UN SDGs.

Social – It can provide employment opportunities for many and ensure availability of affordable energy.

Environmental – Although it has some impact on the environment it is significantly lower than thermal power plants.

Economic – It can reduce energy costs for business and stimulate growth in the economy in a sustainable way.

Renewable energy projects can be small with  low investments and less impact. However a large number of such projects undertaken by various groups such as residential houses, industries, and in the government sectors can add up to a significant amount of generation of energy and lead to larger impact.

“A transition to clean energy is about making an investment in our future.” – Gloria Reuben


  1. Energy Statistics 2018 , Central Statistics Office, Ministry of Statistics and Programme Implementation, Government of India
  2., Environmental Impacts of Renewable Energy Technology


Earth5R is an environmental organization from India with its head office at Mumbai. It works with the NGO sector, Companies and helps them conduct environmental corporate social responsibility (CSR) programs across India. Earth5R specializes in circular economy-based projects. Earth5R also offers short term and long-term environmental courses. 

Earth5R’s Global Sustainability Hub is a cross-sector and cross-country collaboration in pursuit of UN Sustainable Development Goals. It is an excellent opportunity for governments and the private sector to engage with communities, use Sustainability-based models to drive economic changes and create social and environmental impact.

– Reported by Sukumar Krishnamurthy, Edited by Riya Dani