Sida: Intelligent Densified Energy Carriers for Austria (acronym: SIDecA).

Sida hermaphrodita (L.) Rusby is a relatively new, very promising energy crop in Austria, whose potential has been little explored so far.

Stand establishment by seed

Philipp von Gehren, Markus Gansberger, Josef Mayr Austrian Agency for Health and Food Safety GmbH (AGES), Institute for Seeds and Seedlings, Plant Protection Service and Bees, Spargelfeldstraße 191, A-1220 Vienna www.ages.at

In crop production, a uniform and closed stand is a basic requirement for a successful and high-yielding harvest. Currently, stand establishment of S. hermaphrodita is usually done by a cost- and labor-intensive outplanting of seedlings pre-grown in the greenhouse. In rare cases, cultivation using root cuttings is also reported. Stand establishment by seeding could significantly reduce cost, labor, and material requirements, thus increasing the competitiveness of S. hermaphrodita relative to established energy crops. This requires the provision of a purified seed that is highly germinable and applicable with conventional seeding technology. The Institute for Seeds and Seedlings, Plant Protection Service and Bees of the AGES GmbH dealt with the realization of these tendered project goals in the project SIDecA. First, the germination behavior of S. hermaphrodita seeds was investigated in detail in multi-stage laboratory trials. A pronounced dormancy was observed in freshly harvested seeds, which prevented a uniform and rapid field emergence. By testing a wide variety of pretreatment measures, a pronounced hard-shelledness of the seeds was identified as the main cause of low germination. A tailored pretreatment of the seeds achieved a multiple increase in germination. Building on the findings on germination behavior obtained in the laboratory trials, a randomized sowing trial in a split-plot design was set up in 2016. This replicated the results obtained in the laboratory, so that pretreatment of the seed is highly recommended for stand establishment by sowing. The field trial also provided valuable insights into the sowing technology to be used and the optimum sowing time. At the end of the sowing trial, depending on the trial parameters applied, there was a satisfactory stand with tall plants, some of which were already flowering. It remains to be seen to what extent the yield figures will behave in the coming cultivation years.

Optimization of raw material production

Harald Bock, Johannes Hösch Austrian Agency for Health and Food Safety GmbH (AGES), Institute for Sustainable Plant Production, Spargelfeldstraße 191, A-1220 Vienna www.ages.at,www.gaertnerei-am-berg.at

S. hermaphrodita as a perennial plant provides consistently usable yields of green or woody biomass over 10-15 crop years if well managed. In this context, various parameters such as stand density, planting date, harvest date, fertilization, and crop protection have a considerable influence on the yield to be harvested. The provision of a competitive raw material for downstream energetic utilization, adapted to the type of utilization, was the core task of work package 2, which was carried out by the Institute for Sustainable Plant Production of AGES GmbH in cooperation with the Department of Crop Sciences, BOKU and the horticulturalist Michael Höller. The influence of the crop density as well as the harvesting strategies adapted to the respective utilization scenario on the yield to be obtained was determined by means of a specially designed partially randomized field trial in a split-plot design. The experimental field is located at the AGES GmbH experimental station Grabenegg (Lower Austria) in the semi-humid climate zone. In 2014, three plots of 150 m2 each were established with three different planting associations (1.33, 1.77 and 2.66 plants/m2). In addition, established stands at the Großweikersdorf site (Lower Austria) are sampled to test the influence of age and location. Due to the dense growth of S. hermaphrodita, chemical plant protection measures could be completely omitted, only in the year of stand establishment it is recommended to give the freshly planted seedlings an advantage by manual weed control. In order to compensate for the nutrient withdrawal, 70 kg/ha of nitrogen were fertilized in spring. Depending on the energy recovery, the harvest strategy was adjusted. Woody biomass with low water content for thermal utilization was harvested in late January/early February. Green, fresh biomass for biogas and bioethanol production was cut twice a year: first in June, and another time in October. The primary goal of the work package was to achieve maximum energy yield through optimized feedstock production. In this context, harvesting in the year of cultivation proves to be economically unviable, as only low yields per hectare can be harvested. At this time, plant protection measures in particular must be carried out conscientiously in order to create a robust stand for the following 10-15 years of cultivation. Once established, the stands produced stable yields of between eight and ten tons of dry matter per hectare in the crop years. However, the planting density of 1.33 plants/m2 lagged significantly behind the other two planting densities. Whether the yields are symptomatic of the present climatic region, and how they behave in subsequent crop years, remains to be seen.

Fuel characterization and pelleting

Wilfried Pichler, Valerie Minihold Holzforschung Austria (HFA) , Franz Grill-Straße 7, A-1030 Vienna www.holzforschung.at

In work package 3, the potential of Virginia mallow - Sida hermaphrodita (L.) Rusby is investigated and evaluated with respect to mechanical processing and thermal utilization. Raw materials from 3 different locations will be chemically characterized, partially pelletized and tested for their combustion properties. In order to generate a practical process sequence for this new energy crop, the different process steps in the pelleting process were designed variably, such as different drying regimes, comminution techniques, different pressing technologies (ring die press and flat die press), .... Reference trials with other feedstocks (e.g. willow, miscanthus) serve a qualitative classification in comparison to already researched alternative fuels. The results of the tests in the biomass pilot plant of Holzforschung Austria show that pelleting of Sida is possible under similar conditions as for coniferous wood, although the process course is subject to greater variability. A small amount of drying of the feedstock is usually required, but may not be necessary at all if harvesting conditions are favorable. The roller mill has proven to be a favorable size reduction technology, since pre-compaction of the material takes place here at the same time. For pelletizing, it was found that the best process flow can be achieved on the flat die plant with a die size below 30 mm. The finished pellets have very good mechanical strength when properly processed, and an ash content of about 3%, the ash melting behavior and the content of nitrogen and chlorine are in a favorable range, the dependence of the nitrogen content on fertilizer intensity has not yet been investigated. A final evaluation of Sida as a fuel will be made in the last year of the project, taking into account all analytical results. The data so far suggest that Sida is a very promising raw material for fuel production. The full potential of the energy plant Sida is still in the development stage, and cannot yet be fully determined.

Potential for use as fuel

Elisabeth Wopienka, Sabine Feldmeier, Manuel Schwabl BIOENERGY2020+ GmbH, Gewerbepark Haag 3, A-3250 Wieselburg http://www.bioenergy2020.eu,www.gilles.at

The fuel composition of pellets not produced from bark-free softwood can be a problem for many combustion plants. The key challenges are therefore dealing with the formation of slag and deposits, increased risk of corrosion, and higher emission levels - which can be fuel-related (SO2, NOx, HCl), but also as a result of non-optimized combustion control of the plant (CO).

Within the SIDecA project, the potential of Sida as a fuel was addressed. Specifically, the applicability of Sida pellets in small combustion plants was investigated and initial practical operating experience gained. The raw material Sida proved to be plant-friendly, as no significant slagging tendency could be detected despite the relatively high ash content of the fuel. The results of these trials serve as a basis for evaluating the general suitability as a fuel for small combustion plants. From the test results, basic technological requirements can be derived - especially in the area of ash management and emissions. Reference tests with other raw materials (e.g. willow, miscanthus) serve as a first qualitative classification of Sida in comparison to already researched alternative fuels.

The measured NOx emissions when operating with Sida would meet the current legal requirements. The dust emissions are comparable to the dust emissions when operating with pellets from short rotation (pasture). The data so far suggest that Sida is a very promising feedstock for fuel production.

Biogas and Biomethane

Lucy Montgomery, Ludek Kamarad, Lorenz Miller, Günther Bochmann University of Natural Resources and Life Sciences Vienna, Institute of Environmental Biotechnology, Konrad-Lorenz-Straße 20, A-3430 Tulln an der Donau http://www.boku.ac.at,http://www.ing-aigner.at

Biogas is currently produced in Austria mainly by the fermentation of corn silage and liquid manure. Other energy crops such as grass or rye are also used. Like corn, the fresh biomass of the Sida plant can also be ensiled and fermented into biogas. The environmental benefits of a flowering perennial plant, like Sida, make it a good substitute biogas substrate instead of corn.

The Institute of Environmental Biotechnology (BOKU) investigated how much methane can be extracted from the sida crop that was harvested twice a year (once in June, and another time in October). For this purpose, biomethane potential tests were conducted with a duration of 35 days.

The results show that the Sida biomass harvested in June produces the same amount of methane as corn silage. October harvested biomass produces 12% less methane. On average, the biomethane potential is 312 Nl/kg oTS. Difficulties have been noted with agitation in the biogas reactor. Long, strong fibers could not be decomposed and interfered with the agitation process.

Trials are currently ongoing to measure the bioethanol potential of the Sida plant and the influence of stand density on methane yield.