Complete photovoltaic-based power supply for Germany – II. Configuration of power generation

There are numerous ways to configure PV power generation, and selection can be implemented using reasonable and widely feasible solutions. What prerequisites are necessary? As the sun shines everywhere, a fully decentralised solution is possible. This has the advantage of each person being responsible for their own power supply, resulting in a great level of freedom and high supply security, even during crises or times of war. Other variants with high output potential for large-area power generation are suitable, particularly in the industrial sector. In this case too, there would be a high level of supply security, particularly against terrorist attacks, due to the decentralised technical methods. The overall supply would be stabilised by mixing and networking both variants.

CONFIGURATION TYPES

The area required (AR), as calculated in Article I. Power generation, for optimal, complete PV – currently 1,900 km2 – can be logically split into three types of availability:

  1. Existing premises – all roofs of almost all buildings in Germany.
    These are only partially suitable for high-yield power generation and are also used in parallel for solar heating [1]. Total PV power generation would require an area of 5,500 km(not 1,880 km2, see  Complete photovoltaic-based power supply for Germany. I. Power generation ), where settlement and traffic areas cover 47,000 km2 (13.8 %). The settlement areas are primarily privately owned, scarcely used for PV in large cities and also pose difficulties for global planning – in contrast to the countryside. Tangible efforts to sustainably change this in cities have been around for some time and do show promise for long-term success. In particular, the strong heating due to climate change that occurs in cities during the summer would be reduced by the actual efficiency of the PV areas, i.e., by 23%, which would be a significant additional benefit. This part of the radiation energy would of course be converted into electricity.
  2. Wasteland – 11,000 km2 (3%) [2] of polluted land, comprising former munitions-polluted military grounds, brown coal mine pits, etc. This land would be suitable for large-area PV after decontamination, if no other obstacles are present. These areas are usually state-owned and could, in principle, be rapidly made available for PV at relatively low costs.
  3. Traffic areas – these have the advantage that they are owned by the state, counties and communities, so they would be rapidly available and offer numerous synergistic effects. Traffic routes in detail [3, 4]:
MotorwaysLength: 35,000 km, width: 35 m Area: 450 km2
Main roadsLength: 38,000 km, width: > 10 mArea: > 380 km2
Rural roadsLength: 87,000 km, width: 10 mArea: 870 km2
RailwayLength: 35,000 km, width: 10 mArea: 250 km2
  Total area: 
= 1,950 km2

Just the overall area calculated in Point 3 could be sufficient for total PC power supply with state-of-the-art solar cells. The PV units would be set up 6-10 meters above the traffic areas and would thus have no effect on traffic.

POINT 3 ADVANTAGES

The structures indicated in Point 3.1 to 3.4 includes multiple synergistic effects. 

  • Railways can produce the power they need directly above the tracks. 
  • Trucks could also drive with electrical overhead lines.
  • The shade produced by the PV units could prevent roads from being damaged by bubbles and cracks during hot summers, resulting in enormous cost savings.
  • Winter road clearing services can be greatly minimised due to the roofing effect of the PV units, and, depending on the structural configuration, it may even be possible to reduce ice and snow on the roads. 
  • Roads can be illuminated at night → greatly increasing safety when travelling at night.
  • The new structures would also make it possible to lay any number of additional supply lines, e.g., for the IT sector, or future purposes, in easily accessible at a secure height.

The road and railway network structures could be used as carriers for the entire German power network.

The investments required for Point 3 are very high, but would save enormous costs over the long term, and would create a strong self-sufficient energy backbone for numerous applications. 

→ A good investment for the future.

Unfortunately, PV energy distribution per year fluctuates greatly, due to the PV system itself and the day-night cycle, which means that this must be compensated for where necessary by means of energy storage. More about this in the next article.

REFERENCES

  1. https://de.wikipedia.org/Photovoltaik_in_Deutschland
  2. https://www.umweltbundesamt.de/daten/flaeche-boden-land-oekosysteme/flaeche/struktur-der-flaechennutzung#textpart-1
  3. https://de.statista.com/themen/1199/strassen-in-deutschland/
  4. https://de.statista.com/statistik/daten/studie/13349/umfrage/laenge-vom-schienennetz-der-db-ag/

It must be noted that the secondary data used here is taken from literature published before 2010 and is therefore no longer up-to-date, particularly with regards to the performance capacity of solar cells. Some cells had an efficiency of 10-15% at that time, while modern solar cells now achieve an efficiency of 23%.

This article can also be downloaded here as a PDF.