De rol van de Bio-energiesector in de Biobased Economy : achtergronddocument voor het opstellen van een

Met name de niet energie gerelateerde onderdelen van de Biobased Economy nemen in de komende jaren naar verwachting een grote vlucht. Dit legt een druk op het gebruik van biomassastromen voor bio-energie.Een te radicale transitie waarbij de aandacht voor bio-energie zou verslappen, heeft potentieel negatieve gevolgen voor de introductiesnelheid van nieuwe Biobased Economy toepassingen. In deze analyse wordt geargumenteerd dat de bio-energie sector juist een belangrijke rol kan spelen in de transitie naar de bredere Biobased Economy, o.a. bij het in stand houden, ontwikkelen en uitbouwen van biomassaketens en bij het verwerken van biomassareststromen

Nieuwe grondstoffen voor biobrandstoffen : alternatieve 1e generatie energiegewassen

Bioenergie en dan vooral biobrandstoffen (voor transport) staan in de belangstelling. Hierbij gaat het vooral om de huidige zogenaamde 1e generatie biobrandstoffen. Deze zijn gebaseerd op suikers en zetmeel voor de productie van bioethanol als benzinevervanging of oliën en vetten voor de productie van biodiesel als dieselvervanging. De meeste biobrandstoffen zijn gebaseerd op gangbare grondstoffen zoals bijvoorbeeld suikerriet, koolzaad, maïs of palmolie. Er is ook een aanzienlijk aantal “nieuwe” of minder bekende biobrandstof grondstoffen. Regelmatig wordt er in de media aandacht besteed aan dergelijke nieuwe gewassen en worden deze gepresenteerd als veelbelovend en duurzaam. Echter, van deze “nieuwe” biobrandstof grondstoffen is veelal onduidelijk wat het potentieel is. Er zijn hierover veel vragen bij publiek, industrie en de overheid. Daarom wordt er in dit rapport een kort overzicht gegeven van een aantal alternatieve gewassen die grondstoffen voor 1e generatie biobrandstoffen kunnen leveren en wordt er een korte analyse gegeven van de mogelijkheid voor duurzame biobrandstofproductie. De volgende perspectiefvolle bioethanol- en biodieselgewassen zijn beschreven: Suikerpalm, Tropische suikerbiet, Cassave,Suiker sorghum, Nipa palm, Jatropha, Castor en Kokospal

Controlled Doping Methods for Radial p/n Junctions in Silicon

P/n and n/p junctions with depths of 200 nm to several micrometers have been created in flat silicon substrates as well as on 3D microstructures by means of a variety of methods, including solid source dotation (SSD), low-pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition, and plasma-enhanced chemical vapor deposition. Radial junctions in Si micropillars are inspected by optical and scanning electron micro­scopies, using a CrO3-based staining solution, which enables visualization of the junction depth. When applying identical-doping parameters to flat substrates, ball grooving, followed by staining and optical microscopy, yields similar junction depth values as high-resolution scanning electron microscopy imaging on stained cross-sections and secondary ion mass spectrometry depth profilometry. For the investigated 3D microstructures, doping based on SSD and LPCVD give uniform and conformal junctions. Junctions made with SSD-boron doping and CVD-phosphorus doping could be accurately predicted with a model based on Fick's diffusion law. 3D-microstructured silicon pillar arrays show an increased efficiency for sunlight capturing. The functionality of micropillar arrays with radial junctions is evidenced by improved short-circuit current densities and photovoltaic efficiencies compared with flat surfaces, for both n- and p-type wafers (average pillar arrays efficiencies of 9.4% and 11%, respectively, compared with 8.3% and 6.4% for the flat samples)

Agricultural biomass as provisioning ecosystem service: quantification of energy flows

Agro-ecosystems supply provisioning, regulating and cultural services to human society. This study focuses on the agro-ecosystem provisioning services regarding the production of agricultural biomass. These services strongly respond to the socio-economic demands of human beings, and are characterised by an injection of energy in the ecosystems production cycle which is often exceeding the ecological capacity of the ecosystem, i.e. the overall ability of the ecosystem to produce goods and services linked to its bio-physical structure and processes that take place during the agricultural production. Agricultural production is identified as ecosystem service in widely recognised ecosystem service frameworks, but currently there is no clear agreement within the scientific and policy communities on how the ecological-socio-economic flow linked to this provisioning service should be assessed, beyond a mere accounting of yields. This study attempts to provide a new insight to this issue by proposing an approach based on the energy budget, which takes into consideration the energy needed by the ecosystem to supply the service. The approach is based on the concepts of Energy Return on Investment (EROI) and Net Energy Balance (NEB), and considers different bio-physical structures and processes of agroecosystems. The work is structured in three parts: the first aims at estimating inputs (machinery, seeds, fertilizers, irrigation, labour) in energy terms; the second at estimating biomass output in energy terms; the third to compare actual agricultural production with three reference scenarios encompassing a range of human input (no input – low input –high input scenarios). Results show that in general terms cereal and grassland systems have the largest energy gains (both in terms of EROI and NEB). Such systems are characterised by a lower economic value of their output compared to other producing systems such as fruits, which have lower energy gains but a higher embodied energy, which is recognized in the market as valuable. Comparison of actual production systems with the high input scenario confirms that current production in Europe is already highly intensive, and that increasing the energy input would not improve the efficiency of the conversion of such additional energy into biomass. Overall, the proposed approach seems a useful tool to identify which are the factors in the agricultural production process that could be modified to improve the energy efficiency in agricultural systems and the sustainability of their production. This study can be considered as a first step in the assessment of the total energy balance of the agro-ecosystem. In fact it deals with the quantification of energy regarding human inputs and the corresponding output and further analysis should address crucial issues such as the quality of the energy and the embodied energy in the plant production, which will help to better understand the complexity of the agro-ecosystems

The financial and GHG cost of avoiding ILUC in biomass sourcing - a comparison between switchgrass produced with and without ILUC in Ukraine

Avoiding ILUC is becoming important. An important option is the use of land that would otherwise not be used for food or feed production. This generally means that lower quality or marginal land will be used. Switchgrass is one of the main perennial biomass crops that can produce high biomass yields under low input conditions and which can be established at low cost by seeds. In Ukraine this crop has in recent years been tested, yielding information that can be used to assess the cost and GHG balance of growing the crop, pelletizing, transport to the Netherlands and conversion into electricity. Results show that GHG emissions on low quality soil without ILUC are higher than for good quality soil grown switchgrass with ILUC. Analysis of the costs of growing switchgrass on low productive soils are 22% higher compared to high quality soils. It is concluded that ILUC avoidance needs to be quantified and rewarded