1. Short introduction of the target region

The county Straubing-Bogen includes the administratively separated parts of the city Straubing with an area of 68 km2 and 44.500 inhabitants as well as the “Landkreis” Straubing-Bogen with an area of 1.200 km2 and 97.500 inhabitants. The Landkreis comprises of 37 municipalities, five of them being small cities.

There are 2.723 farms with an agricultural area of 73.354 ha, with the number of farms decreasing while the size of the residual farms is increasing. More than half of the number (61 %) of farmers are working sideline and are therefore dependent on other sources of income. This relation switched since 1971, when only 40 % of the farms were operated by sideline-farmers.

The district Straubing-Bogen has a total of about 31,000 hectares of forest. This is distributed quite unequally on the existing natural areas. While in the Bavarian Forest north of the Danube, with about 35% forest coverage wood is of importance for land owners, the Danube Plain is almost forest-free and only the tertiary hill country has again some forest areas, which result in a forest coverage of about 15% there. Altogether the region has a forest coverage of 26%.

The yearly growth of wood in the region is about 300.000 solid cubic metres and between 1980 and 2006 60 ha of forest have been cleared while 568 ha of forest have been afforested. There are about 8.200 forest owners in the region, some of them organised in three forest owners associations, most of them having very small areas with a size of less than five hectare.

2. Characteristic of energy demand

The characteristics of energy demand in Bavaria show a favourable development for the share of renewables.

3. Availability of energy sources

Beside the efficiency of the agricultural production of plants the changes in availability of land is mainly influenced by the increase of sealed area for buildings and infrastructure in general. On an international level the land use is also influenced by the increase of meat consumption while in Germany the decrease of meat consumption could have a positive effect on land availability on the long run.

As a part of Bavaria the region Straubing-Bogen has a traditional well established use of wood as an energy source. This results in estimated 30.000 small combustion units for the heating of single rooms and approximately 2.000 log-wood boilers as central heating systems. Most of the log-wood boilers as well as the roughly 500 wood-chip boilers have already been converted to modern systems.
Apart from these more or less smaller facilities there exist 33 larger installations, 22 of them biogas plants, 3 biomass-CHPs and 8 biomass heat-plant.

For an attempt to estimate the local bioenergy potential other facilities could also be taken into account. This includes installations, which produce energy carriers out of renewable resources. In the region Straubing-Bogen two such facilities are installed.

The first one is a biomethane production site in Aiterhofen, with an input of 10.000 kW biomass fuel equivalent, mostly maize. The produced biomethane is fed into the grid and can therefore not be directly linked to bioenergy production in the region, but nevertheless has a strong impact on the local production and use of biomass, especially from agricultural areas (the consumption of the installation equals about 2.000 ha maize).

The second site is a pellet production plant in the main industrial location of Straubing, with a production capacity of 120.000 tons of wood pellets per year. Although the plant has not been working with full load since production start in 2006 and the operating company is bankrupt since the end of 2010, the possible wood demand is having effect well beyond the county limits. On the other hand the produced wood pellets have not only been distributed within the region during the last years.

Apart from these installations, which are directly linked to bioenergy use, there are of course a lot of other facilities, which process agricultural products. One example should demonstrate that it could be quite problematic, to measure the bioenergy potential only by local circumstances and consumption patterns.

Next to the Danube-river-harbour, which is also a part of the main industrial location, in 2007 an oil mill started to operate, which has the capacity to process 600.000 tons of rapeseed. If the oil mill would be working with full load, it would need the yield from about 200.000 ha agricultural land.

Taking into account the total agricultural area in the region of a little more than 73.000 ha, this shows the weakness of a calculation for a small region as a closed system.

4. Proposed actions/programs/projects

Taking into account the above described situation in Germany, Bavaria and the region the future energy system has been modelled and compared to the primary energy demand. Basis for these rough calculations is the aim to replace as much fossil energy by renewable energy as possible. This is an accepted goal in politics but a lot of the implications have up to now not been transferred into practically relevant actions and rules. Therefore it is expected that, apart from imminent environmental catastrophes, the future situation is mainly influenced by economical necessities, caused by the prices for fossil fuels and uranium.

The situation in the region is characterised by an already high usage of biomass, both for solid biomass for combustion or diverse substrates for biogas production. Considering the above described agricultural situation in the region and the higher than average solar radiation the future possibilities of more biomass production for energy purposes are not very huge. The scenarios include an increase of bioenergy production up to about the double of the actual Bavarian average which can be gained partly by a slight increase in biomass use, partly be an increase in efficiency especially with regard to log wood use in small firing units. In the Best Case Scenario the energetic use of biomass is reduced significantly after renewable energies meet the primary energy demand.

The scenarios include a low contribution of hydroelectric power (the Danube river hydro-electric power plant next to Straubing can not be fully implicated to be regional), which is increasing only slightly, most likely by efficiency gains.

With regard to geothermal energy a tripling should be possible, resulting especially from the already fast growing usage in the residential sector.

Although wind energy is not existent in the region, in the scenario a mentionable part of the electricity production originates from wind mills. For the before mentioned economic reasons, most of the 37 municipalities in the region are to be expected to have at least one wind power plant in a future energy system.

The highest and therefore decisive part of energy production in the future is accomplished by solar energy. Already now the region has a strong solar infrastructure, compared to other parts of Germany or even Bavaria. Altogether in the county 5.200 PV power plants have been installed until the end of 2009, which represent a total output of 180 MWpeak. In the Best Case Scenario the increase of solar energy production is on a comparatively high level, while in the Average Case Scenario and the Worst Case Scenario the climb is quite slowly.

Apart from the differences in energy production the Scenarios differ mainly in the development of the primary energy demand. While in the Best Case Scenario the reduction of energy demand starts with 3 percent and weakens to 1,3 percent in 2050, in the Average Case Scenario the starting point is 2 percent with an end at 0,6 percent and in the Worst Case Scenario the savings slow from 1 percent down to 0,2 percent.

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