Désinvestissement des énergies fossiles

vignette|Début 2021, institutions ont désinvesti milliards de dollars de l'industrie des énergies fossiles. vignette|Manifestation pour le climat et le désinvestissement des énergies fossiles (Berlin, 2015). vignette|Étudiants réclamant que leur université désinvestisse des énergies fossiles (États-Unis, 2013). Le désinvestissement des énergies fossiles est l'élimination des placements (actions, obligations et fonds d'investissement) des entreprises impliquées dans l'extraction de combustibles fossiles (charbon, pétrole et gaz), dans le but de réduire le réchauffement climatique en s'attaquant à ses causes. L'organisation non gouvernementale environnementale 350.org a annoncé, en décembre 2015, que 500 institutions dans le monde, représentant milliards d’euros d’actifs, ont décidé de désinvestir des énergies fossiles (principalement des fondations philanthropiques, collectivités publiques, fonds de pension et universités). En 2020, institutions ont désinve

Reclamation of low fertility soils using by-products and fast-growing trees

Marc Adami

The world population being increasing, a good energy production management is therefore necessary. Biomass production through short forest rotation by using fast-growing trees appears as a sensible way to limit fossil fuel uses. In Mediterranean regions of south-east Spain, soils present weakened ecosystem with low organic matter and nutrients content which are prone to irremediable degradation processes. The very low fertility of those soils usually makes them unfit to food production and so tree plantation with amendment addition seems to be a possible solution in order to use those soil and improve their qualities. In this study, a low fertility soil was exposed to the addition of two types of amendment (a compost of “Alperujo” and one of biosolid) and to the plantation of two different fast-growing trees (poplars and eucalyptus) during a time period of four months. The soil quality was determined by measuring different selected biochemical (β-glucosidase, phosphatase, dehydrogenase and urease activities), chemical (pH, electrical conductivity, organic matter, phosphate, potassium, water-soluble carbon, N-Kjeldahl, permanganate oxidizable carbon and metal extractible with CaCl2) and plants (nutrients, and trace elements) parameters. No significant differences between the different conditions were found. This was due to the very short time period, the too small doses of compost additions and the very high spatial variability due to the field conditions. It seems however that the composts had a positive effect on the chemical and biochemical parameters in the plots planted with poplars as the results presented systematically higher values for the amended plots than for the control plots (without amendment addition). This was attributed to the fact that all poplars were dead at the time of the study and so the soil was not confronted to any interference by the rhizosphere. Most of the parameters (chemical as well as biochemical) of the soil were improved in the eucalyptus plots compared to the poplar ones. This suggests the stimulation of the nutrient cycles by the tree roots, which improved the conditions for the microorganisms, increasing therefore their metabolic activities. The effect of composts in the eucalyptus plots were therefore clearly less obvious, probably due to the fact that the rhizosphere have had more time (tree planted in July 2011) to influence the soil properties than the compost (added in November 2011). Although both composts contained a non negligible quantity of micronutrients and trace elements, the extractible by CaCl2 0.01M quantities in soil (representing the available quantity for plants) did not present values too high to be toxic for plants and were all in normal ranges. The biomass development of the trees seems to have been improved by the compost of “Alperujo”, but presented a very high spatial variability. The compost of biosolids for its part did not show any difference as compared to the control. Next studies should reveal more significant differences between the plots, the soil having more time to react to the new conditions. It is however recommended to increase the addition doses of composts (double or more) in order to show better their effects

2012

Optimal Integration of Renewable Energy in Buildings Using Predictive Control

Tomasz Kaminski

Today’s world faces a large problem which is global warming. Glaciers melting see, and oceans water level rising, and droughts in Africa. According to [1] there are seven main sources of CO2 emissions from fossil fuels combustion: 1. Solid fuels (e.g. coal) – 35% of CO2 emission 2. Liquid fuels (e.g. gasoline, fuel oil) – 36% of CO2 emission 3. Gaseous fuels (e.g. natural gas) – 20% of CO2 emission 4. Flaring gas industrially and at wells:

2009

District energy network potentials in a city territory

Raphaël Briguet

Following the Covid crisis and the war in Ukraine, the rise of fossil fuels prices demonstrates the insecurity of the supply in addition to the adverse impact it has on the environment. These crises could lead to a global shift in the strategy of building heating. Renewable systems are promising alternatives to fossil fuel heating system. One of them is the District Heating Network that has the advantages of recovering the waste heat from the industry. In the context of a neutral carbon objective set by the aluminium factory Novelis, the city of Sierre is interested in investigating the possibility of develop- ing a District Heating Network (DHN). This study develops a method to design a network between a heat source and a city, based only on open data building’s inventory. The method, applied to the case study of Sierre, shows that, coupled with heat pumps, the DHN could reduce the heating emissions of the connected buildings, between 88% and 96 % and that 50% of the Novelis’ heat is recovered when half of the city is connected to the network. In addition to that, using new generation of DHN, like CO2 based network makes possible to supply cold with the same infrastructure.

2022

Reclamation of low fertility soils using by-products and fast-growing trees

Marc Adami

2012