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Modeling the European power sector evolution: low-carbon generation technologies (renewables, CCS, nuclear), the electric infrastructure and their role in the EU leadership in climate policy

Periodic Reporting for period 1 - MERCURY (Modeling the European power sector evolution: low-carbon generation technologies (renewables, CCS, nuclear), the electric infrastructure and their role in the EU leadership in climate policy)

Reporting period: 2017-01-16 to 2018-01-15

Climate change is one of the biggest challenges that mankind has to face in the 21st century. There is undisputable scientific evidence that world climate is experiencing global warming, which might have detrimental effects on socio-economic systems if not sufficiently mitigated. The greenhouse gas emissions related to human activities, fostered by economic and population growth, have been identified as being “extremely likely” the cause of such an increase. The reduction of such emissions is thus a vital target for the coming decades.

From a technology perspective, power generation is the largest responsible for CO2 emissions, therefore great mitigation efforts will be required in this area. From a policy perspective, it is common opinion that the European Union is and will remain leader in implementing clean policies. Basing on these considerations, the power sector and the EU are the two key actors of the MERCURY project.

The main objective of the project is to explore the future prospects of the main low-carbon power generation technologies – renewables, Carbon Capture & Storage (CCS), and nuclear – adopting the Integrated Assessment Model (IAM) WITCH. This assessment is carried out in two phases. Firstly, the prospects in Europe of renewables, CCS and nuclear are analyzed. In particular, attention is focused not so much on the pure technology aspects, but rather on policy issues such as i) the role of incentives and, more in general, of the cost evolution in renewable diffusion, ii) the slow CCS deployment, or iii) the effects of the nuclear reactors ageing, or of their phase-out. Secondly, the focus moves on assessing the role of these technologies (and the consequent evolution of the electric infrastructure) according to different mitigation scenarios, and in particular considering different levels of global participation in EU-led climate mitigation.

Indeed, this macro-activity is planned for the second year of the project, i.e. the return phase. The first year at the outgoing host (the Renewable & Appropriate Energy Laboratory, RAEL, at the University of California, Berkeley) was instead dedicated to a deep modeling work on the WITCH model. In fact an improvement of the WITCH model was necessary, in order to have a high-quality modeling tool suitable to produce credible mitigation scenarios. More in detail, at the beginning of the project the description of the power generation sector in WITCH was already quite detailed, but needed to be integrated, especially concerning the electric infrastructure downstream the power generation system. The modeling of the electric sector was thus completed and refined, focusing in particular on three main aspects: i) system integration (i.e. the issues related to the non-negligible penetration of variable renewables in the grid), ii) electricity storage, iii) electrical grid.

The modeling work has been successful and now the WITCH model is ready to be used in the scenario exercises described above.
The main scientific objective of the first year was to improve the power sector modeling in the WITCH model, concerning system integration, storage, and grid.

Concerning system integration modeling, after a deep literature review, it appeared clear that the best modeling solution was to further develop the modeling scheme already present in the WITCH model, updating the so called capacity and flexibility constraints.
The main improvements regarding storage were i) fully integrate the storage technology in the electricity production system, and ii) introduce technology detail, distinguishing between short-term and seasonal storage technologies. Concerning grid, the work mainly consisted in i) differentiating between transmission and distribution, ii) introducing grid losses, and iii) introducing the pooling effects (i.e. the load balancing over large areas), thus allowing for the integration of grid into the flexibility constraint.

A parallel and complementary activity was the development of joint applications between WITCH and SWITCH, the detailed model of the electricity sector developed at the outgoing host. After a deep study of this model, in fact, SWITCH proved not to be perfectly suitable to provide modeling solutions directly implementable in WITCH, while it was found that linking WITCH and SWITCH in an integrated modelling tool would be much more fruitful. However, this work would have gone beyond the scope and the objectives of the MERCURY project. Therefore, simpler but interesting joint applications of the two models in common research activities were carried out. In particular, firstly the results of the new modeling solutions for storage and grid in WITCH were compared to the SWITCH results, obtaining a positive outcome. Additionally, an activity about the exploration of the dynamics of decarbonization of the electricity sector in China in different mitigation pathways was conducted, which highlighted a non-linear (or non-smooth) behavior resulting from a set of “tipping points” in decarbonization pathways: this suggests that a carbon tax calibrated on the specific conditions of the electricity system should be implemented in order to achieve decarbonization in an effective and efficient way.
The main goal of the outgoing phase of the project was the development of the modeling of system integration of Variable Renewable Energies, storage, and grid in the WITCH model. Concerning system integration, the work allowed re-aligning WITCH to the state-of-the-art of the IAM community, as the implemented modeling scheme was mostly based on published literature. The new storage and grid modeling, instead, now feature beyond state-of-the-art solutions, which make WITCH the trailblazer among IAMs with this respect.

The research outcomes of the MERCURY project are supposed to have a huge impact on society: the objective is to develop mitigation scenarios in the 21st century, analyzing in particular the prospects of low-carbon technologies with a particular focus on the European Union. This is meant to provide policy makers with credible scenarios and information, which would let them pass directives or laws based on a solid scientific basis. Climate change mitigation is one of the top priorities for governments, and in particular for the European Union. Producing thought scenarios in this context can absolutely have a great positive impact towards the European policy objectives.

As said, these scenarios exercises are being carried out in the second part of the project. The first part was mostly dedicated to developing the WITCH model, which will be adopted in those scenarios. Therefore it can be said that the work of the first year did not have an exceptional impact on society per se, but it was a necessary preliminary step to produce policy-impacting results in the second part of the project. In any case, the advancements in the modeling solutions implemented in WITCH are expected to have impacts on the relevant scientific literature.

The project also shows a very strong attention towards the outreach activities, especially conducted in the return phase. The Fellow is committed to giving talks to the general public, visiting schools, etc. in order to raise the public awareness of the fundamental topic of climate change.