Biogas - facts rather than prejudices

Like any other innovative technical development, the production of electricity, heat and fuel from biomass also raises critical considerations.

By answering the most frequently asked questions below, we would like to give you the opportunity to distinguish between the prejudices and the facts about biogas. This will allow you to evaluate problems and risks and, more importantly, help you understand the advantages of biogas as an energy source. Our answers are based on a statement issued by the Fachverband Biogas e.V. [Professional Association for Biogas] of which ÖKOBIT is an active member. Should this section not provide you satisfactory answers to your burning questions, we would be pleased to clarify your concern in a personal discussion.


Is it true that biogas plants push up leasing prices?

Since biogas plant operators have to set up reserves in the years in which the market price for biomass is relatively low, they are not able to pay high land rents. Despite this, the price per hectare may rise disproportionately in regions with scarce land. However, the development of biogas plants is not the only reason for this; rising prices for agricultural products, particularly market crops, and land-based premium payments from EU funds do also have an impact on land rents. ÖKOBIT therefore recommends that biogas plants should be planned and constructed according to site conditions. The size of the plant should be adapted to the quantity of substrate available; if additional energy crops are required, additional substrate should be purchased rather than renting land. The construction of communal plants usually gives fourtler synergy effects.

Is it true that biogas plants compete with food production and push up food prices? (“Fuel or food debate”)

Even when the area currently cultivated for energy crops was doubled, covering food requirements in Germany would still be possible. Converting land for the cultivation of energy crops relieves conventional agriculture of surpluses in favor of more efficient land use and therefore has a positive impact on the market. By entering into the biogas production, farmers can create an additional income and thus better safeguard themselves economically. Jobs and value creation are retained in the rural area; biogas and food production complement each other.

The price for cereal crops and malting barley is determined by the world market and not by the cultivation of energy crops for biogas plants in Germany which represents less than four percent of the useable agricultural land. Considering several decades, prices for food have fallen since the beginning of the seventies, as shown by a study of the Food and Agriculture Organization (of the UN) in 2009. Today prices are on the level of the mid-eighties or mid-nineties. The use of biogas in Germany cannot be linked to the development of food prices.

Famine catastrophes in the world are a result of decades of misguided agricultural policy, poor harvests and speculation but not of the cultivation of energy crops for biogas plants. The hunger in the world is a distribution problem generated by politics.

Is it true that biogas plants are responsible for land being turned over entirely to maize growing?

In 2010, approx. 650,000 hectares of land was used to grow energy crops for the production of energy in biogas plants; 530,000 hectares of this was used to grow maize, which is less than four percent of the useable agricultural land. The growth rate is little compared to the late eighties.

Maize is currently the most popular energy plant for biogas plants due to its ability to form large masses with a relatively low water requirements and an excellent gas yield. Usually the entire plant is used. Its cultivation offers ecological advantages: The use of crop protection products and herbicides is limited and can be reduced further during the digestion process, as weed is also digested in the biogas plant.

Together with hunters, bee-keepers and nature conservation associations, the biogas industry is constantly working on optimizing the landscape and is looking for site-compliant alternatives that deliver equally good gas revenues. These include sugar beet, millet, Jerusalem artichoke, silphium perfoliatum, hollyhocks, wild flowers or rumex (a cross of various types of sorrel).

Is it true that biogas plants smell and that fermentation products cause problems?

Actually the odor intensity of semi-liquid manure is reduced significantly when spread after it has passed through the digestion process in the digester. At the same time, the proportion of nutrients available for plants increases during the digestion process. Odor emissions from biogas plants can only arise if the biomass is not stored properly before or after the process or badly digested material is spread on agricultural land.

Even earthworms are not harmed if fermentation products are spread properly. In the long-term, fermentation products have a positive effect on the occurrence of earthworms compared to unfertilized or inorganically fertilized land.

Increasing priority is being given to precise plant planning and controlled operation of the plant as well as to the correct storage of the biomass and digestate. The question of proper storage in particular affects the prevention of water pollution. Regular information events of the Professional Association for Biogas lead to constant improvement in this area.

The assumption that biogas plants increase botulism pathogens (clostridia) have been disproved. The amount of clostridia could even be reduced through stable digestion of cattle slurry in biogas plants.

Is it true that biogas plants use more energy than they produce?

Both the energy balance and greenhouse gas balance of biogas plants is positive.

One hectare of energy crops replaces four to six times as much fossil energy as used during the cultivation and gas production process. The balance improves even further when using waste materials and residuals.

Compared to fossil energy sources, the emission of greenhouse gases due to the digestion of biomass is up to 50 percent lower. Moreover, the use of nutrient cycles in biogas production entails significant savings potentials in the producution of inorganic fertilizers.

Is it true that the feral pig population is increasing rapidly due to biogas production?

The feral pig population in Germany has already increased heavily prior to the expansion of the biogas industry. There is no connection between an increased cultivation of maize and the occurrence of feral pig, unless in a negative way, as more feral pigs occur in areas with less corn cultivation.

There are many reasons for the feral pig population’s increase. Strong growth of oak and beech trees and mild winters are excellent fattening conditions for wild boar - particularly if they are also fed too much and only few sows are culled.

Is it true that electricity from renewable energy sources leads to higher electricity prices?

The monthly electricity price in Germany has been rising continuously since years. It is estimated that renewable energies account for a one sixth share. According to the German Institute for Economic Research (DIW), renewable energies (RE) are more likely to keep the electricity price stable.

The hidden costs of fossil energy sources are still not taken into account in any calculations: Climate change and damage to human health, removal/renaturation and waste disposal (around eight billion euros in 2010). The additional costs for renewable energies are therefore an investment in a sustainable, affordable and climate-compatible future energy supply.

Moreover, approximately 2.2 billion euros for import costs come on top of this. In the case of renewables, the value creation takes place at home: in 2010, this accounted for some 9.2 billion euros, mainly to the benefit of towns and municipalities.

Is it true that the operation of a biogas plant contributes to an increased volume of traffic?

Traffic does in fact increase in some areas due to the operation of a biogas plant. With regard to neighbors, the Fachverband Biogas [Professional Association for Biogas] expressly asks its members to be respectful: preferably no journeys at night and on weekends, moderate speed, particularly in the area of schools and nurseries, etc. The Bavarian Biogas Forum has summarized these recommendations on two pages in its “Driver’s Etiquette Manual - Rules of Conduct and Manners for Biomass Transports”.



Source: Fachverband Biogas e.V.: "Fakten statt Vorurteile" (Feb. 2011)