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With about 22%, the transport sector is one of the largest global emitters of the greenhouse gas CO₂. Long-distance road freight transport accounts for a large and rising share within this sector. For this reason, in February 2019, the European Union agreed to introduce CO₂ emission standards following Canada, China, Japan and the United States. One way to reduce CO₂ emissions from long-distance road freight transport is to use alternative powertrains in trucks — especially heavy-duty vehicles (HDV) because of their high mileage, weight and fuel consumption. Multiple alternative fuels and powertrains (AFPs) have been proposed as potential options to lower CO₂ emissions. However, the current research does not paint a clear picture of the path towards decarbonizing transport that uses AFPs in HDVs. The aim of this literature review is to understand the current state of research on the market diffusion of HDVs with alternative powertrains. We present a summary of market diffusion studies of AFPs in HDVs, including their methods, main findings and policy recommendations. We compare and synthesize the results of these studies to identify strengths and weaknesses in the field, and to propose further options to improve AFP HDV market diffusion modelling. All the studies expect AFPs on a small scale in their reference scenarios under current regulations. In climate protection scenarios, however, AFPs dominate the market, indicating their positive effect on CO₂ reduction. There is a high degree of uncertainty regarding the emergence of a superior AFP technology for HDVs. The authors of this review recommend more research into policy measures, and that infrastructure development and energy supply should be included in order to obtain a holistic understanding of modelling AFP market diffusion for HDVs.

In this work, we investigate practical approaches of available degradation models and their usage in photovoltaic (PV) modules and systems. On the one hand, degradation prediction of models is described for the calculation of degradation at system level where the degradation mode is unknown and hence the physics cannot be included by the use of analytical models. Several statistical models are thus described and applied for the calculation of the performance loss using as case study two PV systems, installed in Bolzano/Italy. Namely, simple linear regression (SLR), classical seasonal-decomposition, seasonal- and trend-decomposition using Loess (STL), Holt–Winters exponential smoothing and autoregressive integrated moving average (ARIMA) are discussed. The performance loss results show that SLR produces results with highest uncertainties. In comparison, STL and ARIMA perform with the highest accuracy, whereby STL is favored because of its easier implementation. On the other hand, if monitoring data at PV module level are available in controlled conditions, analytical models can be applied. Several analytical models depending on different degradations modes are thus discussed. A comparison study is carried out for models proposed for corrosion. Although the results of the models in question agree in explanation of experimental observations, a big difference in degradation prediction was observed. Finally, a model proposed for potential induced degradation was applied to simulate the degradation of PV systems maximum power in three climatic zones: alpine (Zugspitze, Germany), maritime (Gran Canaria, Spain), and arid (Negev, Israel). As expected, a more severe degradation is predicted for arid climates.

The contribution that no-lose target schemes for non-Annex I (NAI) countries could make to achieve the 2°C target is explored by accounting for the incentives of 18 NAI countries’ participation in no-lose target schemes. Using various scenarios, it is shown that implementing uniform no-lose targets as part of the burden-sharing will not lead to global emissions levels compatible with the 2°C target, because uniform no-lose targets will only be beneficial to a few NAI countries. Employing more lenient uniform no-lose targets or individual no-lose targets for large emitters could increase participation by NAI countries and decrease global emissions, global compliance costs, rents by NAI countries, and compliance costs for Annex I (AI) countries. However, the resulting global emissions levels will not be compatible with attaining the 2°C target. Achieving this target will require more stringent emissions targets for AI countries and more lenient no-lose targets for NAI countries. As such, no-lose targets sho...

Climate change and limited availability of fossil fuel reserves stress both the importance of deploying renewable energy sources (RES) for electricity generation and the need for a stronger integration of regional electricity markets. This analysis focuses on North African (NA) countries, which possess vast resources of renewable energy but whose electricity supply is still largely dependent on fossil fuels. An analysis of cost-optimized deployment scenarios for RES is conducted in five NA countries in 2030 and 2050. Three electricity models are combined to derive results covering trans-regional to sub-national level, including a detailed analysis of grid capacities and future transmission challenges. Further, opportunities for integration of European and NA electricity markets are evaluated. Results confirm that, by 2050, high RES shares – close to 100% – are possible in NA. Wind energy is the dominant technology. Concentrated Solar Power (CSP) plants also play an important role with rising RES shares due to the possibility to store thermal energy. Electricity exports to Europe gain particular importance in the period after 2030. Substantial transmission grid reinforcements on AC-level and the construction of a high voltage DC overlay grid are prerequisites for the forecasted scenarios.

AbstractIn 2008 the German Ministry of Economic Affairs and Energy launched an initiative for new or retrofitted energy-efficient school buildings as focus area within their research programme “EnOB” (Energy Optimised Buildings). The initiative (www.eneff-schule.de) comprises three different energy levels:•Best practice schools with energy-efficient renovations above the requirements in the energy-saving ordinance•Three-liter-house schools with energy needs for heating, hot water and auxiliary below 34 kWh/m2year•Plus energy schools that produce more energy than they use in the annual balanceCurrently three different plus energy school buildings have been planned, realized and monitored within the initiative, two of them being renovations (Stuttgart and Rostock), the last one being a new school building (Hohen Neuendorf). The three energy concepts include rather different technologies to generate heat and to reduce the energy consumption of ventilation and lighting systems. This is partly due to the research initiative approach of “EnEff:Schule” that asks for testing innovative technologies. There is however a general tendency to:•Low U-values of the building envelope with about 0.11–0.15W/m2K at the walls and roof, 0.10W/m2K for new base plates and 0.20–0.34W/m2K for renovated ground slabs and basement ceilings and 0.80W/m2K for windows•Large PV areas to compensate for the remaining energy use, sometimes in combination with other technologies or systems that generate electricity•Mechanical ventilation systems with high heat recovery rates but in combination with natural ventilation•User-dependent control strategies for ventilation and heating•Use of daylight at both the window/solar shading side and the electrical lighting controlThe paper compares the different technologies used at the building envelope, the heating, ventilation and lighting systems, the calculated and measured energy consumptions and the building costs.

Increasing energy efficiency is discussed as an effective way to protect the climate, even though this is frequently associated with additional (investment) costs when compared to standard technologies. However, the investment costs of emerging energy-efficient technologies can be reduced by economies of scale and experience curve effects. This also brings about higher market penetration by lowering market barriers. Experience curves have already been analyzed in detail for renewable energy technologies, but are not as well documented for energy-efficient technologies despite their significance for energy and climate policy decisions. This work provides empirical evidence for effects of economies of scale and experience on the costs of energy-efficient electric motors. We apply a new methodology to the estimation of learning effects that is particularly promising for energy-efficient technologies where the very low data availability did not allow calculations of learning rates so far. Energy-efficient electric motors are a highly relevant energy technology that is responsible for about 55% of German electricity consumption. The analysis consists of three main steps. First, the calculation of composite price indices based on gross value added statistics for Germany which show the changes in cost components of electric motors over the period 1995 to 2006; second, an estimation of the corresponding learning rate which is, in a third step, compared with learning rates observed for other energy-efficient technologies in a literature review. Due to restrictions of data availability, it was not possible to calculate a learning rate for the differential costs of energy-efficient motors compared to standard motors. Still, we estimated a learning rate of 9% for “Eff2” motors in a period when they penetrated the market and replaced the less efficient “Eff3” motors. Furthermore, we showed the contribution of different effects to these cost reductions, like a reduction of material use per motor produced by 15% and an improvement of labor productivity of 43%.

The paper reports on the methodology and results of several studies on the long-term efficiency potentials in the two energy transformation steps from primary energy to final and useful energy and, more importantly, from useful energy to energy services. The examination of these potentials considers the lifetimes and periods of refurbishment of manufactured artefacts: Buildings and infrastructure that will save or waste energy in 2050 that are being built or restored today. The paper emphasises the enormous size of energy conservation potentials achievable not only by reducing energy losses but also by decreasing the specific activity levels for several energy services through improved material efficiency and intensified use of products, plants, and vehicles. It also reports on major definitive conclusions on R&D needs and challenges to R&D-policies as well as immediate policy action in OECD-countries in order to realise the vision of reducing primary energy use per capita by two thirds in industrialised countries within the next five decades.

Abstract Fuels produced from microalgae are a promising alternative for fuels from fossil resources. Algae biomass may be transformed by hydrothermal liquefaction (HTL) into biocrudes, which need upgrading by hydrotreatment to meet transportation fuel requirements. In this study, analyses of HTL biocrude catalytically hydrogenated in a batch reactor at temperatures between 360 and 400 °C and residence times between 2.5 and 10.2 h are presented. Selected samples were investigated by comprehensive gas chromatography mass spectrometry (GC×GC) using flame ionization (FID) or mass spectrometry (MS). The main components of the samples before and after the hydrogenation are hydrocarbons of different unsaturation including alkanes, alkenes, monocyclic and bicyclic hydrocarbons and monocyclic aromatic hydrocarbons. Also, small amounts of polyaromatic hydrocarbons are formed. The most frequent class of heteroatomic compounds are nitrogen and oxygen containing compounds. Oxygen containing compounds are primarily of phenolic nature, whilst nitrogen containing compounds show aromatic amine (alkylated aniline and isomers) and pyrrolic structures (alkylated indoles and carbazoles and isomers). Upon proceeding hydrogenation, an increasing content of lower molecular weight hydrocarbons is observed. The analyses allow to track the decrease of heteroatomic compounds and reveal the structure of refractory compounds. Ultimately, the results allow to identify optimum parameters for the hydrogenation of HTL biocrudes from algae, which correspond to a maximum yield of hydrocarbons and acceptable levels of heteroatomic compounds.