Energy and Environment Encyclopedias Articles

Electricity storage is a major challenge for our energy systems. Today, only hydroelectric dams allow the storage of decarbonated energy in sufficiently large quantities and on sufficiently long time scales. However, the needs are always growing and economic interests depend largely on the regulation of the electricity sector. This article reviews the context in which hydroelectric storage is situated, its role and its capacities according to the different types of installations.

In countries committed to decarbonisation and security of supply, the public authorities are once again the main players in decision-making on investments in the electricity sector. Indeed, a hybrid regime has been developed in these countries, mixing public authorities and market mechanisms. What are the reasons for the emergence of this regime? Which impacts will it have on the efficiency of electricity markets and the decarbonisation targets of governments?

The 2021 Nobel Prize in Physics was awarded to three laureates, including Syukuro Manabe and Klaus Hasselmann, for "laying the foundation of our knowledge of the Earth’s climate and how humanity influences it" as described by the Swedish Academy of Sciences. Why is their work on the role of human activities in global warming and the sensitivity of climate to the CO2 content of the atmosphere, fundamental to physical climatology?

Hydropower remains the most widely used renewable energy source to date. It combines environmental advantages with decisive operational qualities often reserved for fossil fuels, such as controllability and storage. Thanks to its long experience, the hydropower sector has been able to meet the technological challenges to take advantage of a wide variety of terrains. Unique and sustainable infrastructures have thus been created to adapt to each environment, benefiting from exemplary energy efficiency.

The Earth has always been subject to different climatic eras, which produce ice ages and warmer periods, longer or shorter. However, for almost 200 years, our planet has been facing unprecedented climate changes on much shorter time scales than in the past. Extreme weather events are becoming more frequent and intense: storms, fires, floods, droughts, etc. What is the causal link between climate change and these weather shocks?

Electricity systems based on a variable renewable energy sources (or VRE – sources based on natural, uncontrollable flows such as wind and solar) require the development of electricity storage facilities to guarantee the balance and stability of the system. But what economic conditions allow the implementation of various electrical storage solutions? To answer this question, we examine a variety of storage systems, the state of their development, and the services they can provide both to the various actors involved and to the electricity system as a whole.

In a context of more and more fake news, fraud and opacity of many systems, the blockchain is reversing the trend. This technology makes it possible to ensure the authenticity of information, thanks in particular to a history of operations stored in a decentralised manner. Bitcoin, the first product based on this technology, has thus developed very quickly: this cryptocurrency is by definition impossible to counterfeit and the transactions are transparent and validated by the network of users. Replace money with energy and let's see how to use the blockchain for energy management.

Natural gas is widely promoted in energy transition projects as the "least polluting fossil fuel". This article looks at the various technical and economic elements of this sector, from production to end use, but also at its environmental impacts.

The evolution of climate change and its consequences is often summarised as the average temperature of the Earth with future scenarios ranging from +1.5°C, the objective of the Paris Agreement, up to +7°C. However, as climate sceptics often point out, this is not always what is observed on one's personal thermometer. So what exactly does this global temperature represent? How is it calculated and how can its variations be interpreted? This article proposes to clarify these points about this often misused indicator.

It is now difficult not to admit that we are living in a phase of global climate change. We regularly hear about various scenarios for the future, with temperature increases ranging from 1.5°C to more than 6°C by the end of the century. The Paris Agreement, which came out of COP21, aims specifically to limit this rise to 1.5 to 2°C. But where do these trajectories and objectives come from? In practice, these climate projections have been established by climate models. How are they designed? Are they reliable and robust? Under what conditions are they used to imagine the climate of the future? Find out through this article written by two researchers from the National Meteorological Research Centre.

Among the renewable energy sources that have been put on stage by the energy transition, biomass is the least known. Derived mainly from agriculture, livestock, forests and the seas, biomass is the source of very diverse end products, ranging from food and other materials to energy sources used for lighting and cooking, and especially fuels for heating. To fully understand the role played by biomass now – and the role it will increasingly play in the future energy balance – it is important to review what biomass is, its energy properties, its recovery cycle, and the various ways in which it contributes to meeting energy needs.

Some kinds of energy consumption are familiar: Litres of petrol or diesel purchased to fill your gas tank, or kilowatt-hours displayed on your electricity meter at home. But what are these measurements really for? To answer this question, we must first understand energy needs, which are not to be confused with energy consumption (because the same need can be met by different forms of consumption). Several concepts explained in this article help us understand this distinction, including technical systems and the energy paradigm, which explains the origin and evolution of real energy needs.