Life cycle assessment integration into energy system models: An application for Power-to-Methane in the EU

As the EU energy system transitions to low carbon, the technology choices should consider a broader set of criteria. The use of Life Cycle Assessment (LCA) prevents burden shift across life cycle stages or impact categories, while the use of Energy System Models (ESM) allows evaluating alternative policies, capacity evolution and covering all the sectors. This study does an ex-post LCA analysis of results from JRC-EU-TIMES and estimates the environmental impact indicators across 18 categories in scenarios that achieve 80-95% CO2 emission reduction by 2050. Results indicate that indirect CO2 emissions can be as large as direct ones for an 80% CO2 reduction target and up to three times as large for 95% CO2 reduction. Impact across most categories decreases by 20-40% as the CO2 emission target becomes stricter. However, toxicity related impacts can become 35-100% higher. The integrated framework was also used to evaluate the Power-to-Methane (PtM) system to relate the electricity mix and various CO2 sources to the PtM environmental impact. To be more attractive than natural gas, the climate change impact of the electricity used for PtM should be 123-181 gCO(2eq)/kWh when the CO2 comes from air or biogenic sources and 4-62 gCO(2eq)/kWh if the CO2 is from fossil fuels. PtM can have an impact up to 10 times larger for impact categories other than climate change. A system without PtM results in similar to 4% higher climate change impact and 9% higher fossil depletion, while having 5-15% lower impact for most of the other categories. This is based on a scenario where 9 parameters favor PtM deployment and establishes the upper bound of the environmental impact PtM can have. Further studies should work towards integrating LCA feedback into ESM and standardizing the methodology.

Alternative Methods for Assessing Air Quality and Energy Strategies for Developing Countries: A Case Study on Cuba

Jessie Madrazo Bacallao

The worldwide increasing energy consumption is mainly based on fossil fuel which leads to a large number of environmental problems. Indeed, the combustion of fossil fuels releases into the atmosphere different greenhouse gases and harmful pollutants which are responsible for climate change and cause air quality degradation. Moreover, fossil fuel resources are limited and their depletion will happen sooner or later. Governments of the whole world are urged to take relevant measures and policies for energy transition. To support their choices, different decision support approaches have been developed, mainly in industrialized countries. However, these approaches usually lack coherent integration and rely on expensive and often unavailable detailed data, especially in developing countries. This PhD aims at developing alternative methods for the assessment of air quality and energy strategies in the framework of developing countries. The developed methods are implemented in Cuba which seems an excellent test case to design and apply energy strategies for developing countries. The first part of this work deals with methods intended to reliable assess air quality. For this purpose, an air pollution measurement campaign was carried out in Havana. It provided data to implement and improve a pre-existing methodology capable of estimating Cuban vehicle emission factors. Statistical analysis indicated that traffic accounted for around 50% of particular matter concentration levels. Furthermore, vehicles pre-1980s were identified as the most polluting technologies at the street level. This work also demonstrates the usability of an emission inventory designed for air quality simulations. Benchmarking tools developed in the framework of the Forum for Air Quality Modelling in Europe helped to pinpoint differences between global and regional inventories, and identify where efforts should concentrate for improving emission data. This research also sets up simplified algebraic relationships (i.e. so-called Source-Receptor Relationship) capable of predicting the impacts on concentration levels resulting from regional emission abatement strategies, while being more time-efficient than traditional methods. The second part is dedicated to exploring scenarios for a reliable Cuban energy transition. To this end, the energy fluxes between resources, technologies and final demand were computed for the year 2015. A set of scenarios were then designed on the basis of different mixes of energy resources. These scenarios have been compared according to three criteria that seemed the most relevant for the country geopolitical and economic situation: energy security (degree of dependence from energy imports), sustainability of the energy resources and population exposure to harmful pollutants. Overall, the results indicated that energy security and sustainability increase with wind and solar penetration at different rates. A penetration rate of 20% of the demand significantly decreases fossil fuel requirements and imports. Once raised to 50%, Cuba can achieve complete energy independence. The scenario which fulfils 100% of the electricity demands from solar and wind resources shows the maximum of sustainability. Not surprisingly, the penetration of renewables had positive effects on air quality.

EPFL2018

Life Cycle Analysis and Thermo-Environomic Optimization of Concentrated Solar Thermal Power Plants

Aurélie Kuenlin

Confronted to resources depletion and the global warming, the humanity has to reduce its fossil fuels dependence. The renewable energy is an interesting option to reach this aim. The most powerful one is the solar energy since in few hours, the Earth receives more energy than the humanity consumes in one year. In order to convert this energy to electricity, the concentrated solar power plants (CSP) are more advantageous than photovoltaics (PV) because of the possibility to store the energy. Indeed, they concentrate with numerous mirrors the sunlight to heat up a ﬂuid which can be stored in a big insulated tank. Then, the heat energy is transferred to a steam which drives a turbine and a generator to produce electricity. Nowadays, this type of power plants has a real potential. The aim of this work is to test and conﬁrm that the CSP engender less environmental impacts than other types of power plants over their entire life cycle including production, operation and end of life. Furthermore, four different technologies of CSP (tower, parabolic trough, Fresnel and dish) are compared in order to ﬁnd the most efﬁcient one for the environment and identify their strong and weak points. Finally, multi-objectives optimizations, which consider economic and thermodynamic aspects, are performed to ﬁnd the optimal conﬁguration for each power plant. In this work, the environmental impacts are calculated by carrying out a life cycle analysis (LCA) with the Impact 2002+ method. It takes into account the damages on resources, climate change, human health and ecosystem quality. According to this study, the results indicate that CSP produce lightly less impacts than PV but much less impacts than fossil fuels energy. The comparisons between the different CSP reveal that the dish technology engenders less damages than other due to its high efﬁciency and less facilities. However, its investment costs are too important to be competitive. From the other hand, Fresnel and parabolic technologies produce too much environmental impacts for lower costs. The weak point of Fresnel is its very low efﬁciency and the disadvantage of parabolic is the use of a speciﬁc synthetic oil which is very harmful for the environment, without speaking of the possible spills. Moreover, the hybridation with natural gas of both technologies reduces their costs but increases considerably the impacts on climate change and resources categories. Finally, the tower technology is the most advantageous CSP regarding the impacts, the electricity production and costs. It does not need hybridation to have low costs and have an important storage capacity to produce electricity during nights and cloudy days. However, the investment is still too important to be more attractive than fossil fuel power plants. Therefore, there are two possibilities: to implement a CO2 tax of around 60$/MWh or to improve CSP technology. For the last option, the steel of the mirrors structure, which is the most harmful material according to LCA results, can be reduced and thus, the impacts and the costs will be lower. It can also be possible to use recycled steel or another material. Another hint is to build CSP in a very sunny regions with a DNI of at least 1750 kWh/m2 /yr with short transmission lines. Finally, it is important to increase as much as possible the efﬁciency of CSP to produce more energy and decrease the environmental impacts too.

2011

Reducing Greenhouse Gas emissions is not the only solution

Justine Brun

With the increasing strength and frequency of climate change events, the urgency to mitigate climate change impact is ever so important. Canada reported his Nationally Determined Contribution (NDC) and submitted its ambition to reduce his Greenhouse Gas (GHG) emissions by 40-45% by 2030 compared to 2005 and reach net-zero emissions by 2050. Interest for energy system modelling has been increasing for planning future energy systems, as a result of growing concern for sustainable development and transition towards renewable energies. Nevertheless, planning a decarbonization of energy system can potentially lead to environmental burden shifting, and can increase impacts on other environmental impacts such as ecosystem quality or human health. Thus, this project aims towards integrating Life Cycle Analysis (LCA) and more specifically Life Cycle Impact Assessment (LCIA) within Energy Systems Modelling, in order to minimize not only climate change impacts, but human health and ecosystem quality. In addition, a dual spatial resolution was integrated in the model in order to increase data precision and computational efficiency. The results show that a low-carbon energy system, based on the optimization of GHG emissions allows to greatly reduce all the environmental impacts under analysis, compared to an all economic- based energy system, but a multi-objective optimization allows to simultaneously reduce impacts on ecosystem quality and human health, while reducing GHG emissions and keeping good economical and technical performances. The results also show that it is theoretically possible for Canada to keep on track with their emission reduction ambition by 2030, by deploying more renewable energies. This project does not allow assessing Canada’s potential to reach net-zero emissions, as environmental impacts from carbon capture technologies are still to be characterized and integrated in the model.