Glossary of terms and definitions

Sometimes, over the course of my work and often in this blog, I come across and refer to various technologies, policies, international mechanisms that might sound gibberish to a layman. And usually these words mean a lot to an energy professional and cannot be adequately explained over the course of a blog post. So, I thought of writing this short piece to try and explain their meanings and their importance to the energy sector.

What do we mean by Primary and Secondary Energy and what are their sources?

A Primary Energy source is energy at its rawest form. This means that it is either available in the form of stored chemical energy, heat, potential or kinetic energy (energy from falling or flowing bodies). Anything that stores such kind of energy and from which it can be directly extracted are called a Primary Energy Sources.

Coal, oil, natural gas all store prehistoric hydrocarbons as chemical energy which can be extracted as thermal energy through the chemical procedure of combustion. Solar energy is basically a combination of heat and light energies formed though nuclear fusion at the Sun’s core. Nuclear energy is also stored energy within the atoms of an element that can be harvested as thermal energy. Wind and water can either be harvested as a kinetic energy (blowing wind harvested through windmills or flowing water harvested through watermills) or as potential energy (dams store water at a height that can be released and harvested).

A Secondary Energy is an energy that has itself been created through another secondary energy or a primary energy source. Electricity is a form of secondary energy that can be created by harvesting solar heat (Solar Thermal) or solar energy (Photovoltaics), water as Hydroelectricity generated from dams, wind from Wind Turbines and from coal, oil and gas by burning them and utilizing the released thermal energy to produce steam that can then drive a turbine to produce electricity.

What do we mean by Sustainability and what is the Energy Trilemma?

Sustainability in its essence means anything that can be maintained at a certain level for ages without much effort. In case of the energy scenario it means something similar as well. It is pretty much certain at this point of time that human behavior can in fact affect or even change the environment around us. (Read: Anthropogenic effects of human development) Thus, our energy systems needs to be as mindful of the environment as possible with concerned efforts to avoid long-reaching effects that might severely affect our future generations.


This effectively brings us to an Energy Trilemma. Because sadly energy though a most necessary commodity is not equally enjoyed by all. A significant section of people globally lack even the basic access to modern energy. Further lack access to a clean source of fuel for cooking and even more lack the financial power to access it on a regular basis. Largely concentrated in India and sub-Saharan Africa, energy poverty is an issue in almost all nations across the planet. Thus, it is necessary to have an energy system that is not only environmentally sustainable but also is affordable for the entire populace. But then again, it is necessary to maintain an independent energy position for a nation to maintain its security. That is a nation should not position itself thus that any external factors can severely disrupt its domestic economy. Thus, a good energy policy essentially calls for the creation of an Energy Trilemma or a three-way energy balance that promotes environmental sustainability through the usage of non-conventional energy systems, energy equity by ensuring that the energy is affordable for all while maintaining energy security for the nation.

What are Millennium Development and Sustainable Development Goals?

In September 2000, world leaders gathered at the UN to adopt the UN Millennium Declaration to eradicate extreme poverty and set time-bound targets to solve other essential issues like improvement and access to healthcare, promotion of education, etc. The reason this often is referred to while speaking about an energy policy is that it is largely accepted that to reach the MDG-specified target will require facilitating universal access to cheap, clean and secure energy. The MDGs were initially adopted with a target date of 2015 upon which they would expire or be replaced depending upon the amount of success seen.


Varying levels of development in achieving the goals have been seen. Average global incomes have risen by over 21% between 1990 and 2002 and population in extreme poverty has declined by 130 million. Child mortality rates have fallen from 103 to 88 deaths per 1000 births a year. Life expectancies have risen from 63 to 65 and an additional 8% and 15% acquired access to water and sanitation respectively. (Figures taken from Millennium Project website here).

However, the development has not been uniform over the world. Millions across sub-Saharan Africa and Asia (particularly India) remain in extreme poverty without access to proper shelters, clean water, sanitation, education and healthcare. Thus, the Sustainable Development Goals were adopted by the UN on the 25th of September, 2015 in a bid to transform the world by ending hunger, poverty and mitigating climate change with a new target date of 2030. (Website here).


What is Kyoto Protocol?

The official document of the Kyoto Protocol can be found here.

The Kyoto Protocol is a legally binding (but controversial) agreement that was signed by attending parties on 11th December, 1997 at Kyoto, Japan. The document is controversial because it recognizes the impact of over 150 years of industrialization in developed nations on the environment and in the increase of greenhouse gases in the Earth’s atmosphere. It made the signatory parties commit to efforts in reducing domestic greenhouse gas emissions. The effort would be proportional to the historic emissions by the nations, thus shifting a heavier responsibility towards developed countries.

The United States of America have objected to the shifting of blame towards the developed nations and have refused to sign the Kyoto Protocol. India and China have maintained that it is a fundamental right for under-developed or developing economies to increase their energy intensity (thus increasing their emissions) to develop their economy and cuts backs should mainly be aimed at developed economies. This impasse was solved to some extent at the Paris Climate Talks held in December, 2015.

What is Paris Agreement?

The Paris Agreement or the Paris Climate Talks or the 21st Conference of Parties (COP21) is a historic talk at par to the Kyoto Protocol. However, it is more successful as it is the first time where all parties could come to a common conclusion to tackle climate change. The conference took place in Paris on 15th December, 2015. Here, all parties came to the common conclusion regarding the anthropogenic effects of human behavior and pledged to take necessary steps to restrict global temperature rise to 2 degrees Celsius with an aim to restrict at 1.5 degrees if possible.

The countries aimed at putting together a new funding and technology framework with knowledge sharing between developed and developing countries to reach the pre-determined target. Instead of a global target, each country could come up with their own competitive targets (Nationally Determined Contributions) for mitigating climate change which they would try to attain within the necessary period (2035). The countries would meet every 5 years to take stock of the progress made and make recommendations to the intensity of work to be put in the future. The first meeting would be taking place in 2018. However, no country could be legally challenged for failing to attain their targets. The Agreement has since been signed by 193 attending parties and was set to go into effect once the total GHG contribution by the subsequently ratifying parties have reached at least 55% of the global contribution.

This milestone was reached on the 5th of October, 2016 following which after a gap of 30 days (i.e. on the 4th of November, 2016), the Paris Agreement has come into effect.

What do we mean by the Plant Load Factor or Capacity Factor of a power plant?

The PLF or the CF of a power station is a ratio between the actual output generated by the station and the rated total capacity of the power station. Both capacities being within the same period. It is different from the efficiency of a power plant.

A higher PLF means that a plant has better run-time and thus a better option in recouping its costs in a competitive energy system.

As we move forward, I will aim towards completely updating this post as a volume by volume basis. If there are any specific terms that I have missed or are needed to be explained please feel free to inform me by commenting below.

Please like, comment and share if you like it. Your feedback is greatly appreciated.

Written by Sagnik Ghoshal

2 thoughts on “Glossary of terms and definitions

  1. What an interesting way to share knowledge and indeed remind and teach self.
    You may add LCOE. Also consider a 3-point approach – Use technology and markets terms to explain the issues, and then policy terms to explain how the issues can be managed.
    Good luck!

    Liked by 1 person

    1. Thanks for your comment buddy. I will keep your points in mind. I am basically going through the terms that I have already mentioned earlier. I will explain those that you’ve mentioned soon. It is good to know that you’re going through my posts. And thanks for your feedback.


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