Evolution of EROIs of Electricity Until 2050:Estimation Using the Input-Output Model THEMIS - Adrien FABRE - 13th February 2019

The EROI –for Energy Returned On Invested– of an energy technology measures its ability to provide energy efficiently. Previous studies draw a link between the affluence of a society and the EROI of its energy system, and show that EROIs of renewables are lower than those of conventional fossil fuels. Logically, concerns have been expressed that system-wide EROI may decrease during a renewable energy transition. First, I explain theoretically that the EROIs of renewables themselves could then decrease as energy-efficient fossil fuels would be replaced by less energy-efficient renewables in the chain of production. Then, using the multiregional input-output model THEMIS, I estimate the evolution of EROIs and prices of electric technologies from 2010 to 2050 for the baseline and the Blue Map scenarios of the International Energy Agency, and for the 100% renewable Greenpeace’s electricity [r]evolution scenario. Global EROI of electricity is predicted to remain quite stable, going from 8 in 2010 to 6 or 7 in 2050, depending on the scenario. Finally, I study the economic implication of a declining EROI through its relation with price. I show that in theory both quantities can decrease at the same time. This suggests that the inverse relation found empirically represents an average tendency which should not overshadow the high unexplained variability and the theoretical finding that “anything can happen”.

Towards 100% renewable electricity in France: dealing with uncertainties - Behrang SHIRIZADEH - 16/01/2019

COP21 resulted in a global agreement on net zero CO₂ emissions in the second half of the 21^st century which led to a global interest in studying high renewable share energy systems. While several studies have been done to introduce renewable energies in energy systems’ modelling, 100% renewable energy systems have been studied less. This study aims to analyze how France can reach to a 100% renewable electricity mix by 2050, taking into account the cost of the key energy sources, carriers and storage, intermittence of variable renewable energy resources, reliability factors, and the related uncertainties.

This study shows that (1) modelling one single year can be misleading, very different energetic mixes are possible with respect to different meteorological years and demand profiles; the choice of representative year should be made by an optimization over longer period, (2) optimal energetic mix is highly sensitive to economic uncertainties, (3) extending the optimization period, increases the difficult meteorological conditions to handle; therefore, the needed storage and total cost of the system increase respectively but only a small amount and finally, (4) taking into account the uncertainties decreases the expected cost, if the system can be optimized using the new information.

How to decarbonize the transport sector in France by 2050? - Aurélien BIGO - 19/12/2018

In order to keep global warming below 2°C, France set itself the target of reaching carbon neutrality by 2050, which implies near zero direct emissions for the transport sector. This study aims at identifying the possible paths to meet this objective, on the basis of a comparison of 13 papers including 27 prospective scenarios related to energy transition on transport to 2050. This comparison illustrates the difficulty to meet the targets, and the need for significant changes on the following drivers of CO2 emissions: (i) moderate the transport demand; (ii) shift to efficient transport modes; (iii) increase the occupancy rate of vehicles; (iv) improve the energy efficiency of vehicles; and (v) shift to less carbon intensive fuels. These factors are used in a decomposition analysis of the transport CO2 emissions (in the same form as the Kaya identity) to better understand historical CO2 emission trends and emission reduction potential of these factors.

Historical trends were mainly driven by increasing transport demand over the 1960-2015 period. Although changes in carbon intensity of energy used to be historically marginal, most energy transition scenarios heavily rely on this factor to achieve the emission reduction targets. Besides, ambitious scenarios assume a significant reduction in transport energy consumption (up to a factor 3), a moderation of transport demand, a reduction of the modal share of road and air transport, and improvements both in occupancy rate and energy efficiency of vehicles. These last measures appear to be essential to meet the short and long-term targets, due to their co-benefits on other externalities and the high level of uncertainty on the impact of and costs associated to decarbonization technologies (e.g. resources availability for biomass and metals, risk of rebound effects, stronger impact in life-cycle analyses, etc.).

The comparison of energy scenarios (in French) is available at: http://www.chair-energy-prosperity.org/publications/atteindre-facteur-4-transports/.

Fair Sharing of Natural Resources among Countries and Generations: a Dynamic Cooperative Game - Fatma ROSTOM - 26/09/2018

We propose an innovative approach to investigate the coalition possibilities between countries with heterogenous endowments in resources, capital infrastructures, technologies and population. We build on the cooperative market games framework proposed by Shapley and Shubik in 1969, who showed that the core of such games is nonempty, meaning that free-trade appears as a profitable option for everyone. In the game we develop, we consider natural resources flows as limited inputs resulting from endoenous extraction decisions. We show that the core of such a game is nonempty in a static setup. We then solve the game dynamically using Bellman's dynamic programming approach, state variables following country specific dynamics across generations. This enables us to compare short-term and long-term decisions, checking whether optimal payments resulting from the long-term optimization decisions also belong to the core of the sequence of instantaneous market games whenever the latter respect the optimal long-term extraction paths' constraints. In other words, we assess whether the compliance with intergenerational social justice criteria is compatible with free-trade.

Crowdfunding for Renewable Energy: Case Study of a French Platform - Clémence BOURCET - 05/07/2018

The crowdfunding for renewable energy (REC) sector has experienced a substantial growth and particularly in France where public authorities have implemented support measures (premium on tenders of the Energy Regulation Commission, Crowdfunding for Green Growth Label...). This paper is a case study of a French REC platform. It aims at presenting the business model and the risks faced by this platform in order to discuss the strategies implemented to deal with them.