• Energy Research
• Embargo close
• natural sciences close
• 7. Clean energy close
• 2. Zero hunger close

AbstractTransition to a bio‐based economy will create new demand for biomass, e.g. the increasing use of bioenergy, but the impacts on existing markets are unclear. Furthermore, there is a growing public concern on the sustainability of biomass. This study proposes a methodological framework for mapping national biomass flows based on domestic production‐consumption and cross‐border trade, and respective share of sustainably‐certified biomass. A case study was performed on the Netherlands for 2010‐2011, focusing on three categories: (i) woody biomass, (ii) oils and fats, and (iii) carbohydrates. Between 2010‐2011 few major shifts were found, besides the increasing biofuel production. The share of sustainably‐certified feedstock is growing in many categories. Woody biomass used for energy amounted to 3.45 MT, including 1.3 MT imported wood pellets ( >85% certified). About 0.6 MT of oils and fats and 1.2 MT (estimation) of carbohydrates were used for biofuel production. It is assumed that only certified materials were used for biofuel production. For non‐energy purpose, more than 50% of woody biomass used was either certified or derived from recycled streams. Certified oils has entered the Dutch food sector since 2011, accounted for 7% of total vegetable oils consumption. It is expected that carbohydrates will also be certified in the near future. Methodological challenges encountered are: inconsistency in data definitions, lack of coherent cross‐sectorial reporting systems, low reliability of bilateral trade statistics, lack of transparency in biomass supply chains, and disparity in sustainability requirements. The methodology may be expanded for future projection in different scenarios. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd

Organic solar cells utilize an energy-level offset to generate free charge carriers. Although a very small energy-level offset increases the open-circuit voltage, it remains unclear how exactly charge generation is affected. Here we investigate organic solar cell blends with highest occupied molecular orbital energy-level offsets (∆EHOMO) between the donor and acceptor that range from 0 to 300 meV. We demonstrate that exciton quenching at a negligible ∆EHOMO takes place on timescales that approach the exciton lifetime of the pristine materials, which drastically limits the external quantum efficiency. We quantitatively describe this finding via the Boltzmann stationary-state equilibrium between charge-transfer states and excitons and further reveal a long exciton lifetime to be decisive in maintaining an efficient charge generation at a negligible ∆EHOMO. Moreover, the Boltzmann equilibrium quantitatively describes the major reduction in non-radiative voltage losses at a very small ∆EHOMO. Ultimately, highly luminescent near-infrared emitters with very long exciton lifetimes are suggested to enable highly efficient organic solar cells. Donor–acceptor systems with low energy-level offset enable high power efficiency in organic solar cells yet it is unclear what drives charge generation. Classen et al. show that long exciton lifetimes enable efficient exciton splitting and thus generation of free charges while also suppressing voltage losses.

Seaweed fibre is usually discarded as biomass waste after extraction of useful ingredients from seaweed. However this seaweed fibre, a natural abundant cellulose material with uniform dimensions 10 times smaller than other plant-based fibre can be utilized as electrode material for energy storage. In this work, we converted seaweed fibre into conductive carbon electrodes by a thermal carbonisation method. The morphology, chemical composition and conductivity are highly influenced by the carbonisation temperature. In comparison to other biomass sources such as cotton pulp, seaweed fibre is finer, smoother and more conductive at low carbonisation temperature. These carbonized seaweeds were then used as a supercapacitor, giving a high supercapacitance (226.3 Fg−1) at the carbonisation temperature of 900°C, and good stability within 2400 cycles. This specific capacitance is significantly higher than values obtained from filter paper or cotton pulp.

This paper analyzes the ability of water utilities to contribute to sustainability transition processes. More specifically, we compare the capacity of utilities, embedded in purely public, mixed and largely private governance modes, to innovate. We employ dynamic capabilities as core indicators for innovativeness and therefore as major enabling factors for sustainable sector transitions. We assess the relationship between governance modes and innovation by conducting an in-depth comparative analysis of three water utilities, each within a differing governance mode along the public-to-private continuum: Zurich, Berlin and Leeds. While we find that the private and mixed governance modes have an increased degree of innovativeness, they perform lower in terms of static sustainability criteria than the public mode. We therefore conclude that the impact of privatization on sustainability transitions in the water sector involves multi-dimensional trade-offs between static and dynamic sustainability criteria.

Revolutionary catalyst protection by single layer graphene capping, tremendous catalyst lifetime longevity and activity enhancement towards oxygen reduction reaction.

A one-pot fuel cell for specific, enzyme-catalysed organic synthesis, with continuous monitoring of rate and reaction progress, combines an electrode catalysing rapid, reversible and diffusion-controlled interconversion of NADP+ and NADPH with a Pt electrode catalysing 2H+/H2 interconversion.

Boron removal from water environment is a critical issue for scientific spotlight because its removal from wastewater is difficult and costly with conventional treatment method. Herein, an innovative, cost effective and attractive method which depends on duckweed-based wastewater treatment systems coupled with microbial fuel cell reactor (DWWT-MFC) was investigated for B-polluted domestic wastewater treatment and simultaneous electricity generation for the first time in an eco-technological study. Lemna gibba L. was selected as a model duckweed species, and different reactors were also designed to identify which mechanisms are dominant for B removal in a DWWT-MFC reactor matrix. DWWT-MFC reactor achieved 71% B removal in experiment period, and the plant effect on B removal mechanisms in the reactor matrix was recorded as 37.7 ± 4.92% (F = 2.543, p < 0.05). However, supplementary aeration and microbial effects on B removal were determined as negligible. Average maximum voltage output was found as 1.47 V, and maximum power density was 34.8 mW/m2 at a current density of 43.9 mA/m2 with supplementary aeration. Moreover, DWWT-MFC reactor achieved 84%, 81% and 76% of COD, NH4+ and PO43- removal efficiencies, respectively. Moreover, L. gibba grew well in the anode chamber of DWWT-MFC with an average biomass yield of 218 ± 43 g/m2 and a total chlorophyll (a+b) concentration of 30.2 mg g-1, which indicates that anolyte environment was not toxic for L. gibba growth. Consequently, it can be suggested that environmental experts may use DWWT-MFC as an efficient removal method to treat B from domestic wastewater and to produce bioelectricity.

Some Parties (Countries) to the UNFCCC decided to include the carbon uptake by harvested wood products (HWP) in a new general accounting framework after 2012 (post Kyoto). The analysis aims to make a comparison between the cascaded use of HWP and the use of wood for energy. We combine the new HWP framework with an assumed increased 50 million m3harvest level in Canada and evaluate the impact of the GHG emissions over a 100-year period. Our reference case assumes all harvested wood is an immediate CO2emission (IPCC default) and no substitution effects, i.e. annual GHG emissions of 41 million tonnes CO2eq. In our wood utilization scenario's, harvested trees are allocated (in varying shares) to three end-products: construction wood, paper products and pellets for power production. In comparison with our base case, a combination of fossil fuel substitution, material substitution and temporary carbon uptake by HWP leads to significant decreases in GHG emissions. All scenario's show annual GHG emission between 18 and 21 million tonnes CO2eqexcept for triple use without recycling (at least 24 million tonnes CO2eq). We conclude that GHG emissions of our scenarios are substantially lower than IPCC default. However, it is difficult to incorporate one single method to account for GHG uptake and emissions by HWP, due to end use efficiency and recycling options. Further GHG allocation over individual countries is not straightforward and needs further research. © 2013 Elsevier Ltd.