Energy plant
An energy plant is a plant that is specially grown for energetic use. The bioenergy is usually thermally, that is, by combustion , of solid, liquid or gaseous plant products ( biogenic fuel won).
Definition and demarcation
Agricultural crops are designated as energy crops , which are cultivated with the main aim of generating energy, in contrast to crops for food production , forage crops and industrial crops . Wild plants that z. B. are used energetically as firewood , are not counted as energy crops. Forest plants that are grown on agricultural land for energy use (for example in short rotation plantations ) are usually also recorded. In some cases, energy plants are only used when the whole plant is used for energy.
So the use of the plant is crucial. So z. B. corn both as sweet corn for human consumption as well as feed maize ( corn silage ) for animal feed or as energy maize are cultivated for biogas production. Depending on the direction of use, the varieties and cultivation methods used for energy crops sometimes differ from those used for food and feed.
Plant groups and use
Numerous plant species are suitable for energetic use. These include both traditional crops of agriculture, are bred for the partially optimized for energy use varieties (eg. As canola , corn ), as well as crops that were previously not or hardly used for agricultural purposes, but are interesting in terms of energy use can (e.g. Chinese reed , streaky Silphie , Sida hermaphrodita ). So far, cultivation has been concentrated on arable crops that are already widespread. The breeding of new varieties and the use of new crops are only just beginning. The table below lists some of the plant species and groups cultivated as energy crops in Central Europe. Energy crops with significant arable land or great potential in other regions may be. a. Soy , oil palm , physic nut and sugar cane .
Fast-growing woody plants such as willows, poplars or robinia are also increasingly being grown on agricultural sites in Central Europe in order to meet the increasing demand for woody biomass. This shows that moist field locations are particularly suitable for growing willows and poplars, as their growth is strongly linked to the availability of water. Estimates of the potential for Germany show particularly favorable locations in the north-west (procedures and results, with data and maps in the sources). When cultivating, however, it should be noted that the heavy water consumption of plants can also have negative effects on vulnerable aquatic ecosystems. Nevertheless, cultivation offers an alternative form of use for crowded arable sites.
| raw material | Procedure | product | Plant (fruit) |
|---|---|---|---|
| plant parts containing sugar and starch | Fermentation ( ethanol fermentation ) | biogenic liquid fuel ( bioethanol , fuel additives ) |
Sugar beet , potato , grain , corn |
| oily parts of plants | Pressing / extracting, (transesterification) |
biogenic liquid fuel ( vegetable oil fuel , biodiesel ) |
Rapeseed , sunflower seeds |
| biogenic solid fuels (whole or partial plants, logs , wood chips , pellets ) |
combustion | Heat and electricity from biogenic solid fuel |
Trees , grasses , cereals, miscanthus |
| fermentable biomass ( substrate : whole or partial plant, organic waste) |
Fermentation (anaerobic degradation with methane formation ) | Heat and electricity from biomass, biogenic fuel gas ( biomethane ) |
Corn (grain), grasses, cereals (grain), sugar beet |
Energy crops are used to generate heat and electrical energy and as biofuels . A variety of usage paths are used, especially fermentation or biogas generation in biogas plants (use as fermentation substrate ), combustion (use as biofuel ) and various other forms of complete or partial conversion of biomass ( e.g. pyrolysis , production of synthetic biofuels ( BtL )). Energy carriers are either the plant substrate itself after shredding (e.g. biogenic solid fuels such as firewood , pellets ), pressing / extraction or further processing (e.g. biogenic liquid fuels such as vegetable oil fuel , bioethanol , biodiesel , BTL ) or through gasification of the biomass Energy-rich gases obtained (e.g. biogenic fuel gases such as biogas, syngas , hydrogen ).
Cultivation scope and development
In Germany, energy crops are grown on 2.28 million hectares (as of 2011). This corresponds to 19% of the total arable area in Germany. Of this, over a million hectares are used for the cultivation of rapeseed for biodiesel and vegetable oil fuel, over 500,000 hectares grow plants for biogas production, and over 250,000 hectares are used for the cultivation of sugar and starch plants for bioethanol. The cultivation of energy crops has increased sharply in recent years - in 1998 the total cultivation area for renewable raw materials (including cultivation for material use) was still less than 500,000 ha. According to current estimates, the Agency for Renewable Raw Materials (FNR) quantifies the cultivation area for renewable raw materials in Germany in 2012 on around 2.5 million hectares. The majority of this, with 2.1 million hectares, is cultivated with energy crops. The most important energy crops are still rapeseed for biofuels as well as maize, other cereals and grasses for biogas plants. The smaller part of the cultivation area is used for renewable raw materials that are used for chemical-technical purposes in industry.
advancement
The cultivation of energy crops has so far been financially supported within the framework of the common agricultural policy of the European Union with direct payments (so-called energy crop premium ). This subsidy of a maximum of 45 € / ha was abolished in 2010. As part of the set-aside , which was mandatory until 2007 , farmers were not allowed to grow food or feed on part of their arable land and received a set-aside premium for this. However, the cultivation of energy crops on these areas was permitted. Farmers only receive an energy crop premium for cultivation on land that has not been set aside. With the abolition of the compulsory set-aside and the energy crop premium, the direct promotion of energy crop cultivation is becoming less important.
Environmental impact
- (see article bioenergy )
By using energy crops, energy sources can be provided in an environmentally friendly manner. The reduction of carbon dioxide (CO 2 ) emissions is an important factor in reducing the greenhouse effect . The climate impact of the cultivation and use of energy crops is controversial. In addition to the CO 2 savings through the use of renewable raw materials, the climate footprints of arable farming and the climate-relevant emissions of nitrous oxide N 2 O must be taken into account, which is mainly produced by nitrogen-fertilized arable crops. Cultivation methods and land use can also have a major impact on the climate impact of energy crops: clearing rainforests , cultivating moors or plowing up grassland for the cultivation of energy crops release large amounts of greenhouse gases.
The European Union has issued the Renewable Energy Sources Directive (EC) , which will apply from June 2009 . Among other things, it introduces sustainability criteria for the promotion of biofuels and their inclusion in the EU biofuel targets. These sustainability criteria were implemented in German law with the Biomass Electricity Sustainability Ordinance (Biost-NachV, valid from August 2009) and the Biofuel Sustainability Ordinance (Biokraft-NachV, valid from September 2009).
One goal of research on energy crop use is to improve the energy yield per cultivated area through the use of all plants and process optimization. In addition, methods for expanding the usable area are being investigated, e.g. B. Breeding of saltwater algae in desert areas or cultivation of the frugal oil plant Jatropha .
The areas that are necessary for the cultivation of energy crops could also be used for other economically and ecologically sensible purposes (e.g. renewable raw materials for material use, extensification of agriculture). In addition, they are no longer available for food production ( competition for land ). In view of the population growth , ethical problems are discussed in this context , especially the use of food such as grain (e.g. grain burning ) is criticized ( competition in use ).
The cultivation of energy crops is often operated as a high-intensity crop , u. a. with regard to the use of fertilizers and pesticides, which can lead to ecological damage. The cultivation of plants from foreign regions of origin as energy crops involves risks, e.g. B. by spreading neophytes .
literature
- Rolf Meyer, Armin Grunwald, Christine Rösch, Arnold Sauter: Chances and challenges of new energy crops - basic analyzes. (PDF) Work report No. 121 of the Office for Technology Assessment at the German Bundestag, 2007.
- Energy crops - data for planning energy crops. Board of Trustees for Technology and Construction in Agriculture, Darmstadt 2006, ISBN 978-3-939371-21-2 .
Web links
- “Biomass” portal at the Renewable Energy Agency.
- Energy crops . Fachagentur Nachwachsende Rohstoffe e. V.
- Short rotation crops at the Bavarian State Institute for Forests and Forestry.
- Special energy crop cultivation
- Cultivation methods of energy crops
- Ulla Burchardt, Thomas Feist, René Röspel, Martin Neumann, Petra Sitte, Hans-Josef Fell: Technology assessment: opportunities and challenges of new energy crops . (PDF; 1.3 MB) November 23, 2010; German Bundestag
Individual evidence
- ↑ Rolf Meyer, Armin Grunwald, Christine Rösch, Arnold Sauter: Chances and Challenges of New Energy Crops - Basic Analyzes (PDF) Working Report No. 121 of the Office for Technology Assessment at the German Bundestag, 2007, p. 31.
- ^ Jens Hartwich: Assessment of the regional suitability of short rotation coppice in Germany . Dissertation. Freie Universität Berlin - Institute for Geographical Sciences, Berlin January 20, 2017, doi : 10.13140 / rg.2.2.17825.20326 ( rgdoi.net [accessed January 22, 2017]).
- ↑ Jens Hartwich, Markus Schmidt, Jens Bölscher, Christian Reinhardt-Imjela, Dieter Murach: Hydrological modeling of changes in the water balance due to the impact of woody biomass production in the North German Plain . In: Environmental Earth Sciences . tape 75 , no. 14 , July 11, 2016, ISSN 1866-6280 , p. 1–17 , doi : 10.1007 / s12665-016-5870-4 ( link.springer.com [accessed July 18, 2016]).
- ↑ Jens Hartwich, Jens Bölscher, Achim Schulte: Impact of short-rotation coppice on water and land resources . In: Water International . tape 39 , no. 6 , September 19, 2014, ISSN 0250-8060 , p. 813-825 , doi : 10.1080 / 02508060.2014.959870 .
- ↑ The availability of transpiration water as a controlling factor for the production of energy from pastures in short rotation plantations - assessment of the bioenergy potential for Germany - HyWa. October 12, 2015, accessed August 4, 2016 .
- ↑ CARMEN e. V .: Background on renewable raw materials: 1.4 Product lines ( Memento from June 15, 2012 in the Internet Archive ) (modified)
- ↑ Richard E. Schneider: Renewable raw materials complement natural resources: Great hopes for energy and industrial plants. In: LABO. October 2011, pp. 8-11.
- ↑ Cultivation of renewable raw materials in Germany. Fachagentur Nachwachsende Rohstoffe e. V. (FNR), 2008.
- ↑ Rape and maize dominate as energy crops. Gastipp.de, August 16, 2012.
- ↑ Biomass Sustainability Ordinance, 2009. (PDF) Federal Ministry for the Environment, Nature Conservation and Nuclear Safety.