Renewable energy and the climate sciences - Jan Wohland (Forschungszentrum Jülich)

According to the Paris Agreement, the international community aims for a "balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of the century". Reaching this ambitious goal requires the decarbonization of the electricity system in the next decades since other sectors, such as aviation, are harder to decarbonize. While the economic competitiveness of wind and solar power has dramatically increased in the recent past, the integration of high shares of volatile renewables remains a challenge. This challenge calls for intensified cooperation between energy and climate modelers (and others) as will be exemplified by two recent studies (see below).

Jan Wohland is a PhD student at Forschungszentrum Jülich in Germany and currently visits GFI to work on low-frequency wind variability.

Natural wind variability triggered drop in German redispatch volume and costs from 2015 to 2016

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0190707

Abstract:

Avoiding dangerous climate change necessitates the decarbonization of electricity systems within the next few decades. In Germany, this decarbonization is based on an increased exploitation of variable renewable electricity sources such as wind and solar power. While system security has remained constantly high, the integration of renewables causes additional costs. In 2015, the costs of grid management saw an all time high of about € 1 billion. Despite the addition of renewable capacity, these costs dropped substantially in 2016. We thus investigate the effect of natural climate variability on grid management costs in this study. We show that the decline is triggered by natural wind variability focusing on redispatch as a main cost driver. In particular, we find that 2016 was a weak year in terms of wind generation averages and the occurrence of westerly circulation weather types. Moreover, we show that a simple model based on the wind generation time series is skillful in detecting redispatch events on timescales of weeks and beyond. As a consequence, alterations in annual redispatch costs in the order of hundreds of millions of euros need to be understood and communicated as a normal feature of the current system due to natural wind variability.

More homogeneous wind conditions under strong climate change decrease the potential for inter-state balancing of electricity in Europe

https://www.earth-syst-dynam.net/8/1047/2017/

Abstract:

Limiting anthropogenic climate change requires the fast decarbonization of the electricity system. Renewable electricity generation is determined by the weather and is hence subject to climate change. We simulate the operation of a coarse-scale fully renewable European electricity system based on downscaled high-resolution climate data from EURO-CORDEX. Following a high-emission pathway (RCP8.5), we find a robust but modest increase (up to 7 %) of backup energy in Europe through the end of the 21st century. The absolute increase in the backup energy is almost independent of potential grid expansion, leading to the paradoxical effect that relative impacts of climate change increase in a highly interconnected European system. The increase is rooted in more homogeneous wind conditions over Europe resulting in intensified simultaneous generation shortfalls. Individual country contributions to European generation shortfall increase by up to 9 TWh yr⁻¹, reflecting an increase of up to 4 %. Our results are strengthened by comparison with a large CMIP5 ensemble using an approach based on circulation weather types.