Centralized or decentralized? Scientific academies show ways forward to a sustainable energy supply

16. January 2020

Astutely combining centralized and decentralized technologies is the only way of ensuring Germany's energy supply will be climate-friendly, reliable and competitive by 2050. This is the conclusion of a position paper published today by the Academies' Project “Energy Systems of the Future”. Every possible opportunity to expand wind and solar power must be grasped, from rooftop solar panels to offshore wind farms. To ensure a successful energy transition, the German academies of sciences are also calling for grid expansion to go ahead as quickly as possible and for secure digital control of the energy system to be put in place. The expansion of power grids, and of wind power and solar systems must be environmentally and socially responsible to alleviate conflict.

Increasing numbers of private individuals, energy cooperatives and municipalities are deciding to make their important, albeit small contribution to the energy transition by generating power with their own solar or wind power systems. However, these “prosumers” will not be enough to meet power demand, especially since, as levels of energy sector integration rise, renewable electricity will also be the basis for climate-friendly mobility and heating. Instead, centralized and decentralized technologies will have to be astutely combined. Scientists from the “Energy Systems of the Future” (ESYS) project initiated by acatech – National Academy of Science and Engineering, the German National Academy of Sciences Leopoldina and the Union of the German Academies of Sciences and Humanities have been investigating how this approach can lead to a stable and sustainable system.

Exploit all potential for expanding renewable energies

The experts emphasize that the expansion of wind and solar systems will have to be environmentally and socially responsible in order to alleviate conflict with the environment and the population. Most citizens are willing to accept decentralized photovoltaic systems in built-up areas such as on roofs or in car parking or commercial areas. At the same time, there is a need for centralized solar and wind farms both onshore and offshore to generate electricity at low cost. However, the usable potential in Germany will probably not be sufficient to meet the energy needs of the future climate-neutrally. ESYS experts accordingly recommend importing renewable energy from regions with good solar and wind resources. Within Europe, green electricity can be transported via the integrated grid.


Grid expansion - a prerequisite for a successful energy transition

Another finding is that transmission and distribution grids will have to be expanded and this is the case even for an energy system which depends more heavily on decentralized technologies. “In the absence of grid expansion, the energy transition will undoubtedly fail”, explains Jutta Hanson (Technische Universität Darmstadt), who jointly headed the relevant ESYS working group with Peter Dabrock (Friedrich-Alexander-Universität Nürnberg-Erlangen) and Christoph Weber (University of Duisburg-Essen). “However, if expansion continues to be delayed, a combination of decentralized solar systems with storage systems and power-to-gas technologies could help to ensure that short-term climate targets are still met.”

The more decentralized generating plants, storage systems and consumers there are, the more fragmented will the energy system be. Digital applications including artificial intelligence and autonomous systems can be of assistance in controlling an increasingly complex system. In order to mitigate risks such as cyberattacks, the ESYS working group advises a foresighted approach to designing resilient digital technologies. Plant technology should thus permit rapid adaptation to new requirements by software updates, since it would otherwise be a very complex, costly and protracted task to retrofit numerous small installations with new hardware.

In addition to suitable hardware and software, a well thought out regulatory framework is also essential to ensure smooth interplay between all systems. "The market must enable various prosumption models but without creating ever more special arrangements. Prosumers and other investors must also receive consistent incentives to select the mode of operation and location of their installations in such a way that excessive grid expansion is not necessary", explains Christoph Weber, joint head of the working group.

If citizens are to be supportive of an expansion in wind turbines, solar farms and power grids, they must be able to play an active part in shaping the energy transition. Peter Dabrock, joint head of the ESYS working group, is familiar with the various options: “Households and municipalities can benefit financially from the wealth creation arising from renewable energy sources, for instance by a national Investment Participation Act or special levies payable by operators to local authorities. The population must also have the opportunity to be involved politically. This already works well at the regional level but we need more participation at the federal and federal state levels.” Round tables, citizens' assemblies and discussion platforms might be helpful here.

Further Information