Keywords and definitions

Energy: Energy is the capacity to do work or produce change. It exists in various forms, including kinetic, potential, thermal, chemical, and electrical. Energy powers natural processes and human activities, following the law of conservation, which states it cannot be created or destroyed, only transformed from one form to another. (United Nations Educational, Scientific and Cultural Organization, n.d.).

Affordable Energy: Affordable energy means that people can pay for the energy they need without placing an excessive financial burden on their household. Affordability depends on energy prices, the amount of energy consumed, and the consumer’s income and ability to pay. It is essential to ensure that access to energy translates into real and usable energy services for everyone (United Nations Department of Economic and Social Affairs [UNDESA], 2018, p. 158).

Accessible/Available Energy: Energy is accessible or available when people can obtain and use modern energy services, particularly electricity and clean cooking technologies. Universal energy access requires these services to reach all people, including those living in rural, remote, and vulnerable communities (UNDESA, n.d.). 

Reliable Energy: Reliable energy means that energy services are consistently available when needed, without frequent or unexpected interruptions. A reliable energy system requires adequate infrastructure, generation capacity, and resilient networks to provide households and businesses with a stable supply of energy (UNDESA, 2018).

Energy Infrastructure: Energy infrastructure refers to the physical systems and facilities required to produce, transmit, distribute, and deliver energy, including power plants, electricity grids, transmission lines, and distribution networks. Modern and resilient infrastructure is essential for expanding access to reliable and sustainable energy services and supporting the transition towards cleaner energy sources (UNDESA, n.d.).

Renewable Energy: Renewable energy is energy derived from natural sources that are replenished at a higher rate than they are consumed. Sunlight and wind, for example, are such sources that are constantly being replenished. Renewable energy sources are plentiful and all around us (United Nations, n.d.a).

Fossil Fuels: Fossil fuels are non-renewable energy sources formed from the remains of ancient plants and animals over millions of years. They include coal, oil, and natural gas, and their combustion releases greenhouse gases, particularly carbon dioxide, which are a major contributor to climate change (United Nations, n.d.a).

Alternative/ Clean Energy: Alternative or clean energy refers to energy sources and technologies that produce little to no greenhouse gas emissions compared with conventional fossil fuels. It includes renewable sources such as solar, wind, hydropower, geothermal and bioenergy, and can also include other low-carbon technologies that contribute to reducing emissions from the energy sector (United Nations, n.d.b).

Wind Energy: Wind energy harnesses the kinetic energy of moving air by using large wind turbines located on land (onshore) or in sea- or freshwater (offshore). Wind energy has been used for millennia, but onshore and offshore wind energy technologies have evolved over the last few years to maximize the electricity produced - with taller turbines and larger rotor diameters (United Nations, n.d.a).

Solar Energy: Solar energy is the most abundant of all energy resources and can even be harnessed in cloudy weather. The rate at which solar energy is intercepted by the Earth is about 10,000 times greater than the rate at which humankind consumes energy (United Nations, n.d.a). 

Geothermal Energy: Geothermal energy utilizes the accessible thermal energy from the Earth’s interior. Heat is extracted from geothermal reservoirs using wells or other means (United Nations, n.d.a).

Hydroelectric Energy: Hydropower harnesses the energy of water moving from higher to lower elevations. It can be generated from reservoirs and rivers. Reservoir hydropower plants rely on stored water in a reservoir, while run-of-river hydropower plants harness energy from the available flow of the river (United Nations, n.d.a).

Energy Efficiency: Using less energy to perform the same task (e.g., using LED lightbulbs instead of old incandescent ones) (International Energy Agency, n.d.). 

Carbon Footprint: A carbon footprint is the total amount of greenhouse gas emissions generated directly or indirectly by an individual, activity, product, organization, or other entity. It is generally expressed in carbon dioxide equivalent (CO₂e), allowing different greenhouse gases to be measured according to their contribution to climate change (United Nations Development Programme, 2023, p. 13).

Carbon Capture: Carbon capture, use, and storage (CCUS) is the process of capturing carbon dioxide (CO2) emissions from fossil power generation and industrial processes for storage deep underground or re-use (United Nations Economic Commission for Europe, n.d.).

Emission: Emissions are the release of substances, usually gases such as carbon dioxide, into the atmosphere. In the context of sustainable development, reducing emissions is essential to limit climate change and promote cleaner energy systems (UNDESA, n.d.).

Greenhouse: Greenhouse gases are gases in the atmosphere that trap heat and contribute to global warming and climate change. Reducing greenhouse gas emissions is an important part of achieving sustainable energy and environmental protection (United Nations Framework Convention on Climate Change, n.d.).

Biofuel: Biofuel is a fuel produced from biomass such as plants, crops, or organic waste. It is considered a renewable source of energy and can help reduce dependence on fossil fuels and lower greenhouse gas emissions (United Nations, n.d.a).

Energy Sovereignty: Energy sovereignty refers to a country’s ability to control and manage its own energy resources and policies independently. It focuses on ensuring secure, reliable, and sustainable access to energy while reducing dependence on external sources (UNDESA, n.d.).

Energy Security: Energy security means having reliable and uninterrupted access to affordable energy sources. It is essential for economic stability, sustainable development, and ensuring that people and industries can meet their energy needs safely (UNDESA, n.d.).

Energy Education: Energy education refers to teaching and raising awareness about energy use, energy efficiency, and sustainable energy sources. It helps people make informed decisions that support sustainable development and environmental protection (UNDESA, n.d.).

List of references

International Energy Agency. (n.d.). Glossary. International Energy Agency. Retrieved September 7, 2026, from https://www.iea.org/glossary  

United Nations. (n.d.a). What is Renewable Energy? Retrieved September 7, 2026, from https://www.un.org/en/climatechange/what-is-renewable-energy

United Nations. (n.d.b). Renewable energy - powering a safer and prosperous future. Retrieved September 7, 2026. from https://www.un.org/en/climatechange/raising-ambition/renewable-energy

United Nations. (n.d.). Causes and Effects of Climate Change. United Nations. from https://www.un.org/en/climatechange/science/causes-effects-climate-change

United Nations Economic Commission for Europe. (n.d.). Carbon Capture, Use and Storage (CCUS). Retrieved September 7, 2026, from https://unece.org/sustainable-energy/cleaner-electricity-systems/carbon-capture-use-and-storage-ccus

United Nations Department of Economic and Social Affairs. (2018). Accelerating SDG 7 Achievement: Policy Briefs in Support of the First SDG 7 Review at the UN High-Level Political Forum 2018 [Policy Brief]. https://sdgs.un.org/sites/default/files/2021-05/Report%20-%20SDG7%20Policy%20Briefs%2C%202018.pdf

United Nations Department of Economic and Social Affairs. (n.d.). Ensure access to affordable, reliable, sustainable and modern energy for all. Retrieved September 7, 2026, from https://sdgs.un.org/goals/goal7

United Nations Development Programme. (2023). The Climate Dictionary: Speak climate fluently. Retrieved September 7, 2026 from https://www.undp.org/publications/climate-dictionary

United Nations Educational, Scientific and Cultural Organization. (n.d.). Energy. Retrieved September 7, 2026, from https://www.unesco.org/en/query-list/e/energy

United Nations Framework Convention on Climate Change. (n.d.). The Paris Agreement. Retrieved September 7, 2026, from https://unfccc.int/process-and-meetings/the-paris-agreement