Sector Coupling in an Emerging European Renewable Energy Network

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

  • Kun Zhu
To take measures against climate change, the European Commission adopted a long-term strategy towards a climate neutral economy by 2050. While acknowledging the challenges, renewable generation technologies have substantially improved over the last two decades, which makes the highly renewable energy systems feasible and economically viable. This dissertation focuses on the design of future energy systems in Europe and attempts to answer two fundamental questions:

WHAT do the highly renewable energy systems possibly look like?
HOW to achieve such systems?

To further integrate renewable generation into the energy system, I consider both transmission reinforcement and sector coupling in the paper 'Impact of CO2 prices on the design of a highly decarbonised coupled electricity and heating system in Europe'. I deploy the state-of-the-art techno-economic optimisation model with high spatiotemporal resolution, for electricity and heating coupled Europe under 80 to 95% CO2 reductions relative to 1990. It is found that installing large renewable energy capacities itself is not enough to achieve such low emissions. A sufficiently high CO2 tax is required to incentivise an efficient and cost-optimal highly renewable energy system, which is in particular an interesting result for stakeholders and policy makers. The compositions of system cost and primary energy have been examined in detail to answer the first question.

This approach relies on a number of climatic, technical and economic assumptions, and their uncertainties and implications are investigated in the paper 'Impact of climatic, technical and economic uncertainties on the optimal design of a coupled fossil-free electricity, heating and cooling system in Europe'. Net-zero emission energy systems are indeed economically viable, thanks to the synergy among renewable generators, power-to-heat converters, storage units, synthetic gas and transmission. The levelised costs of energy decrease as a result of heat savings, but the synergy drops with increased ambient temperature. These findings offer a broad perspective of how plausible uncertainties impact the highly renewable energy systems and complement the results obtained in the first paper.

The question of how to transit from todays fossil-based energy system towards a fossil-free one by 2050 is addressed in an ongoing research project, 'Early decarbonisation of the European energy system pays off'. Alternative transition pathways with equivalent carbon budget are modelled for the sector-coupled networked European energy system. We find that ambitious CO2 reduction targets in the short-term will end up with lower total transition costs, as well as more stable CO2 prices and investment rates, which could be beneficial from the perspective of social acceptance and local economies. This study contributes to the ongoing discussion about more ambitious renewable targets for 2030 in Europe.

In this PhD project, I demonstrate that low even net-zero emission systems are both feasible and economically viable. To ensure an economical and smooth transition, I would recommend a path with more ambitious short-term emission reduction targets.
ForlagAarhus Universitet
Antal sider196
StatusUdgivet - 30 apr. 2020

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