Great find by a follower of this blog who send me a link to this report in German available on the website of the German EPA (‘Umweltbundesamt’). The title translates as ‘Climate protection and regeneratively generated chemical energy carriers – infrastructure and system adaptation for the supply of regenerative chemical fuels from domestic and foreign regenerative energies’.

The report contains Sankey diagrams on 40 pages (!) like the two shown below. All of them are structured the same way with a vertical layout: a certain amount of energy available at production site, losses branching out to the right, and useful energy available on site shown as the remaining arrow at the bottom (colored in green).

From the management summary in English we learn that “this project aims at gaining first insights into the potential of renewable chemical fuels from renewable energy sources both domestic and abroad as well as the associated transport requirements. (…) [P]otentials and transport infrastructure for using renewable energy to provide storable energy carriers were analysed, being followed by a systematic comparison of the import routes of renewable gases, namely hydrogen (eH2) and methane (eCH4)”.

The assumption is that there are countries (e.g. Norway) that may have wind energy in excess, and regions (e.g. Turkey, Spain) where there is abundant potential for solar energy (PV). This electricity could be used for methanisation (power-to-gas, P2G). Gas from renewable energy could be stored in the German gas grid. The Sankey diagrams then show power-to-gas transformation on site and transporting the gas through pipelines to Germany, compared to the scenario of transporting electricity on the grid (with the associated losses) and to produce methane in Germany.

‘Klimaschutz und regenerativ erzeugte chemische Energieträger – Infrastruktur und Systemanpassung zur Versorgung mit regenerativen chemischen Energieträgern aus in- und ausländischen regenerativen Energien’ by Stefan Schütz of DBI Gas- und Umwelttechnik, Leipzig and Philipp Härtel of Fraunhofer-Institut für Windenergie und Energiesystemtechnik, Kassel. Report published Aug 2016 by German EPA (Umweltbundesamt, UBA). Download full report PDF here.

Thanks Axel from Germany for pointing me to this.

The European R&D project RenewIT studied energy concepts for renewable energy supply of data centres. The project partners from Spain, Italy, UK, Germany and The Netherlands looked at 18 different energy models.

In the final project report each of the concepts are described, accompanied by a Sankey diagram.

The above is figure 3.53 from p. 177 of the report showing the “Sankey chart for the distribution of average energy flows per year within different subsystems of concept 7 for scenario 3”.

Many more equally beautifully crafted Sankey diagrams can be found in the report, check chapter 3.5 Simulation Results of the publication Deliverable D4.5 Catalogue of advanced technical concepts for Net Zero Energy Data Centres. Authors: Nirendra Lal Shrestha, Noah Pflugradt, Thorsten Urbaneck (TUC); Angel Carrera (Aiguasol); Eduard Oró, Albert Garcia (IREC); Hans Trapman, Gilbert de Nijis, Joris van Dorp (DEERNS); Mario Macías (BSC) (get it here)

Didn’t know what wind gas was until I saw this presentation on “Towards 100% renewables and beyond power: The possibility of wind to generate renewable fuels and materials” by Michael Sterner of Fraunhofer IWES institute. Page 16 has this diagram:

The process described is actually a way of storing energy. Electricity from wind power is used to produced hydrogen and converted to methane. As such it can be stored (e.g. in gas pipelines) and is available to generate electric energy during peak hours. Efficiency is only 36%, but alternatively wind turbines would have to be cut-off if they can’t feed their power into the grid. Other storage alternatives (such as pumped storage power) are capacity limited.

An overall interesting presentation, access the PDF here.