C. Mansilla

On the possibilities of producing hydrogen by high temperature electrolysis of water steam supplied from biomass or waste incineration units.

The incineration of biomass and waste is considered to produce water steam, which then would feed the High Temperature Electrolysis (HTE) process in order to produce hydrogen. For these energy sources, in a French context, results show that water steam production cost could be in a range of 0.02 to 0.06 euros per steam kilogram. Potentially 78 million vehicles could be fed with hydrogen coming from the steam produced by the incineration of the currently nonvalorised biomass and domestic waste. Furthermore, for each energy source the optimized hydrogen production cost estimation has been performed, including investment and operation costs.

HycycleS: a project on nuclear and solar hydrogen production by sulphur-based thermochemical cycles

The European FP7 project HycycleS focuses on providing detailed solutions for the design of specific key components for sulphur-based thermochemical cycles for hydrogen production. The key components necessary for the high temperature part of those processes, the thermal decomposition of H2SO4, are a compact heat exchanger for SO3 decomposition for operation by solar and nuclear heat, a receiver-reactor for solar H2SO4 decomposition, and membranes as product separator and as promoter of the SO3 decomposition. Silicon carbide has been identified as the preferred construction material. Its stability is tested at high temperature and in a highly corrosive atmosphere. Another focus is catalyst materials for the reduction of SO3. Requirement specifications were set up as basis for design and sizing of the intended prototypes. Rigs for corrosion tests, catalyst tests and selectivity of separation membranes have been designed, built and completed. Prototypes of the mentioned components have been designed and tested.

Hydrogen production by high temperature electrolysis coupled with an EPR, SFR or HTR: techno-economic study and coupling possibilities

Hydrogen production by high temperature electrolysis coupled with three nuclear reactors (the European pressurised reactor, the sodium-cooled fast reactor and the very high temperature reactor) was studied in terms of perspectives and hydrogen production costs. Firstly, we present the features of producing water steam by using the three nuclear reactors. Secondly, we present the hydrogen production cost for the HTE process coupled with each type of nuclear reactor. These costs are optimal values of the hydrogen production cost for the mentioned couplings and they were estimated by using a genetic algorithm procedure. High potentiality for these HTE couplings was assessed and contrary to steam source temperatures, the electricity price appeared to be a key parameter for low hydrogen production costs.

Taking into Account Environmental Criteria in the Design of a Process: Application to Steam Methane Reforming by Performing a Multi-Objective Techno-Economic Optimisation of the System

In the current context of sustainable development, industrial process development should no longer only take economic goals into account. Environmental criteria should be considered as well. Therefore, multi-objective optimisations should be carried out. A techno-economic model of steam methane reforming was implemented through the use of genetic algorithms. Different criteria can be then simultaneously considered. The optimisation result represents one objective versus the other: the hydrogen production cost and the carbon dioxide emissions of the process. This allows making compromises between the objectives. These compromises can be led either by regulations or by an overcost linked to taxes, for example.

A Key Player Towards a Sustainable Energy Mix

The energetic issues are on the top of the political agenda in many countries, for environmental reasons, for its driving role in all the economic sectors, as well as for the energetic independency concerns. This problematic is stressed by the increasing weight of renewable intermittent power sources in the global mix. In particular, due to its high potential and the strong national policy support it beneficiated, solar photovoltaic energy is now a key player in the world energy mutation and the way it is integrated into the global mix should be carefully performed. To deeply understand the way the solar energy can penetrate and transform the forthcoming energy framework, we adopted a three-level strategy to provide some answers to the following questions: i/ how can we situate the photovoltaic power role in future energy mixes?; ii/due to its main drawback, intermittency, could we provide an optimal design of a system combining storage devices?; iii/ what is the efficiency of the incentive policies that are or have been implemented to accelerate its deployment? That is why, in a first part, the peculiar position of the solar photovoltaic energy in the energy mix is analyzed. After recalling the general issue of future global energetic mixes, we propose a brief description of the different photovoltaic technologies and their promising evolutions in terms of technical improvements and cost reductions. Then, we describe the fast growing photovoltaic market and its consequences both on the electricity mix and the industry sector. In the second part we investigate the problematic of integrating such intermittent energy in the electricity mix, by developing a multi-criteria optimization methodology which simulates a system composed of photovoltaic panels and storage devices. Applications on a real case in the Cirque de Mafate (L’ile de la Reunion, France) are provided to illustrate the interest of our method. Finally, we question the efficiency of different public supports to the photovoltaic technologies in the most relevant countries. We focus on correlating the installed power capacity with the spent public money and the electricity prices. In these works, we put into relief the necessity to consider energy issues through the prism of technical basis. Indeed, solutions that cannot be efficient should not be implemented in the system. However, a solely technical treatment of energy challenges is obviously insufficient, since energy is core point for the economy, for the citizen and so for the politician. Such a combined approach needs to remain anchored on concrete data close to the reality of the technical devices and keeping in mind the financial feasibility of the proposed solutions, when designing a new energy landscape and thus a new societal model.

Nuclear power: What optimal contribution to the French electric power mix?

In the French context of increasing renewable penetration and significant nuclear power, the optimal contribution of this energy source is discussed from two viewpoints. On the one hand, from the social planner viewpoint, the nuclear optimum contribution is the one that minimizes the overall electric price, whatever the resulting load factor. The use of screening curves, often implemented to design the optimal power mix is questioned, being highly sensitive to the assumptions. On the other hand, from the plant operator viewpoint, the nuclear power plants need to amortize the capital expenses, hence achieve the longest operating time. With a view to make the two viewpoints meet, we propose to operate nuclear power plants as baseloads and consider modulation through the power use, i.e. supply electricity to the electric system when requested and use the remaining power to produce other valuable products, such as heat or hydrogen.