• Wir optimieren auch Ihre Biogasanlage

    Wir optimieren auch Ihre Biogasanlage

  • Unsere Ziele sind Ihr Vorteil

    Unsere Ziele sind Ihr Vorteil

A new methanation and membrane based power-to-gas process for the direct integration of raw biogas – Feasability and comparison

Florian Kirchbacher, Philipp Biegger, Martin Miltner, Markus Lehner, Michael Harasek


Storage options for increasing amounts of volatile energy supplied by renewable sources are of growing interest. One promising concept is power-to-gas, where electrical energy is transformed to gas that can be stored more easily. H2 produced by electrolysis powered by excess energy is combined with CO2 in a methanation to produce CH4. Possible CO2 sources are numerous, but biogas is special, as it is a renewable source itself and already contains CH4 concentrations of up to 60% v/v. Normally the CH4 needs to be removed prior to methanation, requiring two gas upgrading steps.

The newly developed process described in this paper circumvents this by directly feeding biogas to the methanation. For evaluation of this concept two process chains were realized. The classic setup consisted of a catalytic methanation and membrane based gas upgrading being fed with H2 and CO2 from bottles. The alternative process was coupled with a two-stage fermentation to study effects of changing biogas compositions. Both process chains have been demonstrated on a scale of about 0.5 m3 (STP)/h. Results for both will be presented in this work and the positive implications regarding the future implementation of biogas into power-to-gas systems will be discussed.

Link: http://dx.doi.org/10.1016/j.energy.2017.05.026

Biogas – Part of Austria’s future energy supply or political experiment?

Bernhard Stürmer


Biogas production expanded significantly across Europe after turn of the millennium. The development was particularly advanced by national laws and regulations. Before millennium, the main aspects of biogas production were the energy independence, the reduction of odor emissions from manure and the improved fertilization effect of biogas slurry. After the year 2000, the main focus was on installation of green electricity capacities to replace fossil power plants with the motive of lowering CO2 emission. As shown in this article, in Central Europe concrete political objectives have resulted in a remarkable expansion of biogas plants. Changes at the legal framework had direct impacts on the development. This article focuses on Austria's biogas sector. Its history, the legal framework and the today's turning point.

In Austria, feed-in tariffs were granted for 13 years. Because of such a flat rate, adjustments to market changes are difficult. Thirteen years are gone, feed-in tariffs expire and production costs are still above exchange price. Balancing electricity production is a promising market for biogas. As well as biomethane as fuel could make a major contribution by lowering CO2 emissions at the transport sector. However, the biogas sector needs political support yet to be able to utilize the advantages in a modern energy sector of the future.

Link: https://doi.org/10.1016/j.rser.2017.05.106

Biogas desulfurization and biogas upgrading using a hybrid membrane system - Modeling study

Aleksander Makaruk, Martin Miltner, Michael Harasek


Membrane gas permeation using glassy membranes proved to be a suitable method for biogas upgrading and natural gas substitute production on account of low energy consumption and high compactness. Glassy membranes are very effective in the separation of bulk carbon dioxide and water from a methane-containing stream. However, the content of hydrogen sulfide can be lowered only partially. This work employs process modeling based upon the finite difference method to evaluate a hybrid membrane system built of a combination of rubbery and glassy membranes. The former are responsible for the separation of hydrogen sulfide and the latter separate carbon dioxide to produce standard-conform natural gas substitute. The evaluation focuses on the most critical upgrading parameters like achievable gas purity, methane recovery and specific energy consumption. The obtained results indicate that the evaluated hybrid membrane configuration is a potentially efficient system for the biogas processing tasks that do not require high methane recoveries, and allows effective desulfurization for medium and high hydrogen sulfide concentrations without additional process steps.

Link: http://dx.doi.org/10.2166/wst.2012.566

Biomethan aus biogenen Abfällen und agrarischen Reststoffen

Bernhard Stürmer


Biogas kann aus fast allen organischen Substanzen produziert werden. In diesem Beitrag liegt der Fokus auf biogene Abfälle und landwirtschaftliche Reststoffe. Vor allem energiereiche, flüssige bis breiige Abfälle mit geringen Störstoffanteilen lassen sich kostengünstig in Biogasanlagen zu Biogas und organischen Dünger verarbeiten. Das Biomethanpotential von über 300 Mio. m³ entspricht dabei rund dem doppelten Energieoutput der derzeitigen Biogasproduktion. Über eine Aufreinigung des Biogases zu Biomethan stellt diese Energieform eine Möglichkeit dar, den erneuerbaren Energie-Anteil im urbanen Raum zu erhöhen.

Frei verfügbar unter: http://oega.boku.ac.at/fileadmin/user_upload/Tagung/2016/Short_Papers_2016/OEGA_TAGUNGSBAND_2016.pdf

Cost efficiency and economies of diversification of biogas-fuelled cogeneration plants in Austria: a nonparametric approach

Andreas Eder


This paper investigates the existence and the degree of economies of diversification for small-scaled, renewable-fuelled cogeneration systems using 2014 cross-sectional data from 67 Austrian biogas plants. In addition, cost efficiency of those biogas plants is estimated with a non-parametric linear programming technique, known as Data Envelopment Analysis. This is the first study applying the methodology proposed by Chavas and Kim (2010). Economies of diversification are decomposed into three additive parts: a part measuring complementarity among outputs; a part reflecting economies of scale; a part reflecting convexity. Furthermore, this paper extends the decomposition introduced by Chavas and Kim (2010) in such a way that the contribution of each input to economies of diversification and its components can be investigated. The results indicate substantial cost savings from diversification. For very-small scaled plants (<100 kWel) most of the cost savings come from scale economies. For larger plants (>250 kWel) positive complementarity and convexity effects are the main source of economies of diversification and outweigh the negative effect from scale diseconomies. In addition to substantial fuel/feedstock cost reductions, significant costs saving effects from the jointness in labour and other inputs positively contribute to the complementarity effect. While on average capital and labour costs positively contribute to economies of scale, feedstock costs work in the direction of diseconomies of scale.

Frei verfügbar unter: https://mpra.ub.uni-muenchen.de/80369/

Demonstration of a biogas methanation combined with membrane based gas upgrading in a promising power-to-gas concept

Florian Kirchbacher, Martin Miltner, Markus Lehner, Horst Steinmüller, Michael Harasek


The further development of photovoltaic and wind power as renewable energies with their production  rate fluctuations both on short and medium timescale result in the necessity of smarter grids and higher energy storage capacities. One very prominent and promising technology for meeting this future electric energy storage demand is the concept of power to gas. Here, the excess electric energy is converted to hydrogen using alkaline or PEM electrolysis. Most concepts incorporate an immediate subsequent conversion to methane using a local carbon dioxide source and a process of thermocatalytic or biological methanation. After a final gas upgrading mainly comprising the separation of H2, CO2 and H2O the produced SNG can be fed to the natural gas grid owning a huge potential for energy storage and distribution.

The current work presents the joint research efforts undertaken by the authors in the field of power to gas processes. A process chain consisting of a coupled hydrogen dark fermentation and a biogas fermentation, a thermocatalytic methanation step and product gas upgrading applying membrane-based gas permeation is developed and demonstrated on laboratory scale. The described process chain has been demonstrated on a scale of roughly 0.5 m³(STP)/h and experimental results will be presented. Special emphasize is laid on the analysis of the methanation performance considering the changing content of the mixed raw biogas. It is shown that the combination of methanation with membrane-based gas separation technology provides significant advantages for process integration.

Link: http://dx.doi.org/10.3303/CET1652206

BFiT - Endbericht, Berechnung der wirtschaftlich günstigsten Variante zur Nutzung von Biogasanlagen nach Auslaufen der Ökostromförderung

Philipp Novakovits, Richard Zweiler, Bernhard Mahlberg, Bernhard Stürmer, Michael Harasek, Martin Miltner, Karl Puchas, Alexander Luidolt


Als richtungsweisend kann dieser Auftrag der steiermärkischen Landesregierung, der Energienetze Steiermark AG und der steirischen Landwirtschaftskammer an das BiGa-Net bezeichnet werden. Erstmals wurden systematisch auf Basis der letzten wissenschaftlichen Erkenntnisse im Bereich Biogas und Biogasnutzung alle steirischen Biogasanlagen berechnet und im Rahmen einer breit angelegten Parametervariation Cluster gebildet, um eine Möglichkeit für den Betrieb nach Auslaufen der Ökostromförderung zu berechnen. Dies ist einzigartig in Österreich und stellt eine solide Basis für weiterführende Diskussionen dar.

Berechnet wurden zahlreiche Varianten, wie Strom- und Wärmeerzeugung, direkte Biogasnutzung, Aufbereitung zu Biomethan, Nutzung in einer betriebseigenen Tankstelle, Einspeisung ins Erdgasnetz, mobiler Transport des Biogases, bzw. des Biomethans, Abdeckung von Lastspitzen durch Bereitstellung von Regelenergie, usw.

Es zeigte sich, dass Biomethan in der Produktion mehr als Erdgas kostet. Systemtechnisch kann die Produktion von Biomethan allerdings sinnvoller sein, als die derzeitige Variante der Strom-Wärmeproduktion, daher ist es ratsam einen Einspeisetarif für Biomethan einzuführen, wie dies in zahlreichen Ländern bereits der Fall ist. Besonders interessant ist das Ergebnis, dass Anlagenverbünde die Wirtschaftlichkeit verbessern. Unter der Annahme einer akzeptablen wirtschaftlichen Grenze von 100 EUR/MWhho für Biomethan könnten die steirischen Biogasanlagen 11 Mio. m3 Biomethan pro Jahr erzeugen. Schließt man einzelne Anlagen zu Verbünden zusammen, dann können zum gleichen Preis 18 Mio. m3 Biomethan pro Jahr erzeugt werden.

Link: Endbericht BFiT

Feedstock change at biogas plants - Impact on production costs

Bernhard Stürmer


At the beginning of the millennium, regulatory changes relating to energy production from biogas triggered a significant increase in the installation of biogas plants in Europe. During the past few years, the regulatory framework has been adapted to accommodate biogenic waste and agricultural residues as a primary source of raw materials.

Based on individual data of Austrian biogas plants, this article performs a detailed costs assessment in case of feedstock changes. Various scenarios of possible agricultural raw material changes are examined assuming a base scenario of a 500 kW biogas plant feed with a mix of maize silage and slurry. The presented technical and economic analysis focuses on the scenarios “mix”, “manure”, “stover/catch crops”, and “second crops”. The results show that the use of alternative feedstocks has only limited effects on the cost of feedstock procurement as the advantage of lower specific costs is counter-balanced by the need for higher quantity. The substantial technical efforts and additional investments negatively impact the cost of biogas production, resulting in an average cost increase of 30%.

Link: https://doi.org/10.1016/j.biombioe.2017.01.032

Gesamtwirtschaftliche Effekte durch die Biogaserzeugung in Österreich

Wolfgang Koller


Die etwa 300 österreichischen Biogasanlagen produzieren Energie und Dienstleistungen im Wert von 125 Mio. Euro und bieten etwa 580 Arbeitsplätze (Vollzeitäquivalente). Sie speisten im Jahr 2013 Ökostrom im Umfang von 544 TWh ins Netz ein. Von der Biogasbranche gehen sowohl durch ihre Produktion als auch durch ihre Investitionstätigkeit Impulse auf die gesamte Volkswirtschaft aus. Im Rahmen der vorliegenden Untersuchung werden die gesamtwirt­schaftlichen Effekte der Branche für die österreichische Wirtschaft ermittelt, wobei die Daten der offiziellen Statistiken (Energiebilanzen und Energiestatistik, Ökostromstatistik) mit detaillierten Daten, die die ARGE Kompost & Biogas Österreich bereitstellte, verknüpft wurden. Mit Hilfe des Instruments der Input-Output-Analyse (IO), werden die direkten, indirekten und induzierten Effekte auf Produktion, Wertschöpfung und Beschäftigung in der österreichischen Wirtschaft ermittelt. Es kommt ein für die Branche maßgeschneidertes IO-Modell zum Einsatz, das die detaillierten vorliegenden Informationen zu den unmittelbaren Produktionszahlen (Erzeugung von elektrischem Strom, Biogas und sonstigen Energiedienstleistungen) und den unmittelbaren Inputs (Vorleistungen, Wertschöpfung) in konsistenter Weise mit den Informationen der Input-Output-Tabelle kombiniert. Insgesamt, unter Berücksichtigung auch der im Wege der Vorleistungsverflechtung (= indirekte Effekte) und des Einkommen—Konsum—Produktion—Kreislaufes (= induzierte Effekte) generierten Effekte, führt die Biogaserzeugung zu einer gesamtwirtschaftlichen Produktion von 357 Mio. Euro, Wertschöpfung von 109 Mio. Euro und bewirkt 3.330 Vollzeitarbeitsplätze. Die von der Investitionstätigkeit ausgehenden Effekte können nur schwer auf jährlicher Basis ermittelt werden. Für den Zeitraum 2002-2014 betrugen die von den Investitionen in der österreichischen Wirtschaft ausgelöste Produktion und Wertschöpfung 684 Mio. Euro bzw. 298 Mio. Euro. Jährlich wurden dadurch durchschnittlich etwa 280 Vollzeitarbeitsplätze generiert. Bei diesen Effekten handelt es sich um die Bruttoeffekte der Biogaserzeugung, die nicht berücksichtigen, was bei einer Stilllegung der Branche mit den freigewordenen Ressourcen alternativ produziert werden könnte bzw. von welchen inländischen oder ausländischen Produzenten die dann fehlende Energieproduktion bereitgestellt werden würde.

Frei verfügbar unter: https://issuu.com/fachverband.biogas/docs/bgj_english_autumn_2016_gesamtansic

Measuring and explaining productivity growth of renewable energy producers: An empirical study of Austrian biogas plants

Andreas Eder, Bernhard Mahlberg, Bernhard Stürmer


This study explores productivity growth for a group of 65 Austrian biogas plants from 2006 to 2014 using Data Envelopment Analysis. The sample covers about 25 % of the installed electric capacity of Austrian biogas plants. Productivity growth is measured by calculating the Malmquist productiv­ity index, and the contributions of technical change, efficiency change and scale change to productiv­ity growth are isolated. Average annual productivity growth between 2006 and 2014 is 1.1 %. The decomposition of the Malmquist index shows that the annual scale change, technical change, and efficiency change for the average plant is 0.6 %, 0.3 % and 0.3 %, respectively. Those results indicate that the exploitation of returns to scale is a major driver of productivity growth in the Austrian biogas sector. However, there is a large variation in productivity growth across bio­gas plants. A second-stage regression analysis identifies important determinants of productivity growth. The results show that i) the exploitation of returns to scale as well as changes in ii) output diversifica­tion iii) capital intensity, iv) capacity utilization and v) feedstock prices are positively associated with productivity growth.

Frei verfügbar unter: https://mpra.ub.uni-muenchen.de/79826/

Membrane biogas upgrading processes for the production of natural gas substitute

Aleksander Makaruk, Martin Miltner, Michael Harasek


The biogas processing and production of natural gas substitute have gained importance in recent years. It is often considered to be superior to the production of electricity with internal combustion engines mainly because of the better energy utilisation. The processed biogas in the form of natural gas substitute can be supplied to the already developed natural gas grids and delivered to households and industry. Alternatively, it can be used as a fuel for CNG-vehicles.

The present work reviews the literature information that is available on the biogas upgrading processes, the biogas compositions and the permeation of biogas components through typical polymeric membranes. Subsequently, the membrane configurations for biogas upgrading are discussed and thoroughly simulated using numerical modelling. The work proposes basic concepts for the integration of membrane biogas upgrading plants into biogas plants while taking into account the permeate utilisation and the heating requirements of biogas plants.

The membrane gas permeation systems provide enough flexibility for heat integration within biogas plants. The expected energy requirement for a single produced cubic meter of natural gas substitute is equal to around 0.3 kWh.

Link: http://dx.doi.org/10.1016/j.seppur.2010.05.010

Review on available biogas upgrading technologies and innovations towards advanced solutions

Martin Miltner, Alexander Makaruk, Michael Harasek


Biogas from anaerobic digestion of organic wastes or energy crops has proven to be a valuable alternative energy source both climate-neutral and sustainable on a global scale. The alternate valorization path of cleaning the biogas for the production of biomethane to be injected into the natural gas grid or to be used as a local vehicle fuel has gained significant importance in the last years. Considerable efforts in contemporary research are undertaken in order to improve efficiency and flexibility of biogas upgrading to enhance economic viability of biogas plants in times of expiring green-electricity feed-in tariffs, rising or strongly fluctuating costs for substrates and the currently low global energy prices. Current work tries to contribute to these questions suggesting and introducing innovative and highly effective technologies along the whole chain of biomethane production. A novel technique to separate high and fluctuating amounts of hydrogen sulphide from raw biogas is presented that relies on a highly intensified method of chemical-oxidative scrubbing. Single-stage separation efficiencies of 92% have been identified with this technology. A recently commissioned three-staged demonstration plant with an expected separation efficiency >99% is presented briefly. Furthermore, membrane-based gaspermeation is presented as a capable and economic method of CO2 removal and drying of raw biogas. While this technique is not new, authors try to demonstrate the huge potential for further development and exploitation peculiar to this method. Specific power demand for upgrading of 0.26 kWh/m3 biogas and specific upgrading costs of less than 0.15 €/m3 biomethane can be achieved. Today and in the future similar concepts and systems will be able to increase economic and ecologic performance of biogas plants thus contributing to strengthen biogas industry within the renewable energy sector.

Link: http://dx.doi.org/10.1016/j.jclepro.2017.06.045

Selected methods of advanced biogas upgrading

Martin Miltner, Aleksander Makaruk, Michael Harasek


The upgrading of biogas for the production of biomethane to be injected to the natural gas grid has gained significant importance in recent years. It is often considered to be superior to the production of electricity and district heat with internal combustion engines mainly because of better energy utilisation, higher flexibility and beneficial economic prospects. Biogas upgrading is commonly accepted as state-of-the-art and a considerable number of small and industrial scale plants have been commissioned to date representing the portfolio of currently available upgrading technologies. Nevertheless, academic research clearly demonstrates that still a huge potential for optimisation and development is existing in this field.

The current work contributes to the field of biogas upgrading by suggesting innovative and powerful approaches along the whole process chain. The importance of trace component separation is exemplary depicted by introducing a novel desulphurization technology based on chemical-oxidative scrubbing applying an innovative short-contact-time apparatus. Thus, separation efficiency for hydrogen sulphide is maximized while the simultaneous separation of carbon dioxide is minimized to assure minimum chemicals consumption.

As an example for the major biogas upgrading step of carbon dioxide removal, the process of membrane-based gas permeation is suggested. This technique stands out for its excellent adaptability regarding biomethane quality and methane recovery already during the design phase, simple and robust plant operation, low specific energy demand as well as reasonable upgrading costs. Finally, a combination of biogas upgrading with the Power-to-Gas approach is presented. This process provides the possibility of storing renewable electrical excess energy in form of biomethane in the high-capacity natural gas grid, an overall increase of biomethane output of a given biogas plant by maximizing carbon utilization and a reduction of the specific carbon footprint of a biomethane site.

Frei verfügbar unter: http://dx.doi.org/10.3303/CET1652078

Simulation of Membrane Gas Separation Process Using Aspen Plus® V8.6

Seyedmehdi Sharifian, Michael Harasek, Bahram Haddadi


Implementing membrane gas separation systems have led to remarkable profits in both processes and products. This study presents the modeling and simulation of membrane gas separation systems using Aspen Plus®V8.6. A FORTRAN user model and a numerical solution procedure have been developed to characterize asymmetric hollow fiber membrane modules. The main benefit of this model is that it can be easily incorporated into a commercial simulator and used as a unit operation model in complex systems. A comparison between the model and the experimental cases at different operation conditions shows that calculated values are in good agreement with measured values. This model is suitable for future developments as well as design and performance analysis of multicomponent gas permeation systems prior to experimental realization.

The valence of flexible green electricity generation units

Bernhard Stürmer


In dieser Präsentation auf der 5. Europäischen Biomassekonferenz im Jänner 2017 in Graz wurde auf die zukünftigen Rahmenbedingungen des Strommarktes eingegangen. Dabei wurde die zukünftige Versorgungssicherheit auf Basis unterschiedlicher Ausbauszenarien von Erneuerbaren Energieformen mit volatilen Produktionseigenschaften (Wind, Solar) diskutiert. Herausgestrichen wurde die Bedeutung des Zusammenspiels unterschiedlicher Erneuerbarer Energieformen, die Speicherung von Energie und die Möglichkeiten der Regelenergieproduktion von Kraftwerken auf Biomasse-Basis.

Frei verfügbar unter: http://www.energiepark.at/fileadmin/user_upload/Dokumente/BioFlexNet/Pr_nsentation_CEBC2017.pdf

Untersuchungen des Substrates: Analysen, Auswertung und Ergebnisinterpretation

Ludek Kamarad, Wolfgang Gabauer

In dieser Präsentation auf dem Biogas16-Kongress in Graz im Dezember 2016 wurden die für Fermenterbiologie prozessrelevanten Parameter und deren Bedeutung präsentiert. Weiters wurden wichtige Parameter für die Substrat- und Prozessanalytik und deren Einfluss auf eine stabile Prozessführung erklärt. Bei konkreten Praxisbeispielen wurden die Zusammenhänge beschrieben und erklärt. Dies sollte den Biogasanlagenbereibern helfen, die Analysenberichte richtig zu verstehen und zu interpretieren.

Präsentation zu Untersuchungen des Substrates (Frei verfügbar unter Download PDF - 2MB)


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Kuhfutter: Das Comeback der Futterrübe



Die Futterrübe führte in den letzten Jahren eher ein Stiefkindleben bei der Fütterung von Milchkühen. Nicht zuletzt wohl auch deshalb, weil Studien einen Rückgang in der Milchleistung feststellten. Doch wie bei vielen Dingen gilt auch für die Futterrübe das richtige Maß zu finden. Maissilage galt bisher in der modernen Fütterung als die beste Variante. Doch abgesehen von hohen Lagerkapazitäten lässt das energiereiche Futter Milchkühe auch leichter verfetten. Landwirte, die vor allem mit Letzterem ein Problem hatten, konnten nach der Umstellung auf die alte Futterrübe positive Erfolge verzeichnen. Besteht der Hauptanteil des Futters aus der proteinarmen Futterrübe ist tatsächlich ein deutlicher Rückgang der Milchleistung zu erkennen. Allerdings steigt der Fettgehalt der Milch ebenso ersichtlich. Hier hat der Milchbauer nun die Wahl, welche Prioritäten er setzen möchte - mehr Milch, oder weniger Milch mit höheren Fettgehalt. Letzteres dürfte in erster Linie für Bauern mit direkter Weiterverarbeitung der Milch z.B. zu Käse interessant sein. Geht es allerdings in erster Linie um die Milchleistung, wird empfohlen, den Rübenanteil nicht über 15 % im Gesamtfutter steigen zu lassen. Landwirte, die sich zumindest teilweise von der konventionellen Silagefütterung trennen möchten, finden in der traditionellen Futterrübe eine echte Alternative. Die Website www.agrarnetz.com hat Futtersorten genauer unter die Lupe genommen und bietet hilfreiche Informationen zu den Klassikern und Alternativen

Frei verfügbar unter: http://www.agrarnetz.com/files/ebooks/milchkuehe.pdf (400 KB)