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The widely recognised Energiewende, ("energy transition") in Germany has lost its original momentum. We therefore address the question of how the transition process to a new energy system can be reignited. To do so, we developed the "5Ds approach", which lays the groundwork for a process analysis and the identification of important catalysts and barriers. Focusing on the five major fields required for the energy transition, we analyse the effects of: (1) Decarbonisation: How can efficiency and renewable energies be expanded successfully? (2) Digitalisation: Which digital solutions facilitate this conversion and would be suitable as sustainable business models? (3) Decentralisation: How can potential decentralised energy and efficiency opportunities be developed? (4) Democratisation: How can participation be strengthened in order to foster acceptance (and prevent "yellow vest" protests, etc.)? (5) Diversification of service: Which services can make significant contributions in the context of flexible power generation, demand-side management, storage and grids? Our paper comes to the conclusion that German policy efforts in the "5D" fields have been implemented very differently. Particularly with regard to democratisation, the opportunities for genuine participation among the different social actors must be further strengthened to get the Energiewende back on track. New market models are needed to meet the challenges of the energy transition and to increase the performance of "5D" through economic incentives.
Biomass-fueled combined heat and power systems (CHPs) can potentially offer environmental benefits compared to conventional separate production technologies. This study presents the first environmental life cycle assessment (LCA) of a novel high-efficiency bio-based power (HBP) technology, which combines biomass gasification with a 199 kW solid oxide fuel cell (SOFC) to produce heat and electricity. The aim is to identify the main sources of environmental impacts and to assess the potential environmental performance compared to benchmark technologies. The use of various biomass fuels and alternative allocation methods were scrutinized. The LCA results reveal that most of the environmental impacts of the energy supplied with the HBP technology are caused by the production of the biomass fuel. This contribution is higher for pelletized than for chipped biomass. Overall, HBP technology shows better environmental performance than heat from natural gas and electricity from the German/European grid. When comparing the HBP technology with the biomass-fueled ORC technology, the former offers significant benefits in terms of particulate matter (about 22 times lower), photochemical ozone formation (11 times lower), acidification (8 times lower) and terrestrial eutrophication (about 26 times lower). The environmental performance was not affected by the allocation parameter (exergy or economic) used. However, the tested substitution approaches showed to be inadequate to model multiple environmental impacts of CHP plants under the investigated context and goal.
This paper examines the current and prospective greenhouse gas (GHG) emissions of e-fuels produced via electrolysis and Fischer-Tropsch synthesis (FTS) for the years 2021, 2030, and 2050 for use in Germany. The GHG emissions are determined by a scenario approach as a combination of a literature-based top-down and bottom-up approach. Considered process steps are the provision of feedstocks, electrolysis (via solid oxide co-electrolysis; SOEC), synthesis (via Fischer-Tropsch synthesis; FTS), e-crude refining, eventual transport to, and use in Germany. The results indicate that the current GHG emissions for e-fuel production in the exemplary export countries Saudi Arabia and Chile are above those of conventional fuels. Scenarios for the production in Germany lead to current GHG emissions of 2.78-3.47 kgCO2-eq/L e-fuel in 2021 as the reference year and 0.064-0.082 kgCO2-eq/L e-fuel in 2050. With a share of 58-96%, according to the respective scenario, the electrolysis is the main determinant of the GHG emissions in the production process. The use of additional renewable energy during the production process in combination with direct air capture (DAC) are the main leverages to reduce GHG emissions.
The South African government started the development of a basic energy efficiency policy framework in 2005, including a voluntary label for refrigerators. This initial label was the intended precursor to a mandatory standards and labelling (S&L) programme, but the impacts achieved were only very limited. Based on this first experience, the South African Bureau of Standards (SABS) formed in 2008 a working group for the development of the new and more specific South African National Standard SANS 941. This standard identifies energy efficiency requirements, labelling and measurement methods as well as the maximum allowable standby power for a set of appliances as reliable basis for introducing a mandatory regulation. Nevertheless, due to many existing barriers, such as lack of funding and low priority assigned to the initiative, a very long period passed by between the S&L planning and final policy implementation. Finally, in November 2014, the South African government published mandatory performance standards coming into force in 2015/2016 for a first set of appliances consisting of refrigerators, washing machines, dryers, dishwashers, electric water heaters, ovens, A/C and heat pumps. To analyse the effectiveness of the new S&L programme and the potential influence of delays in the implementing process, the authors performed an immediate first-hand evaluation of the new policy.
As analytical reference base for available energy efficiency potentials, results from bottom-up scenario calculations will be presented exemplarily as case study for cold appliances covered by the S&L programme. A retrospective market study will show market trends before policy implementation and compare results with the new mandatory requirements. For the further policy analysis, a programme theory approach will be applied, in order to better understand why, how and under what conditions the policy works. Relationships with other energy efficiency policies and measures as well as positive or negative effects will be described. Furthermore, cause-impact relationships will be analysed to explain the functioning of the policy. Finally, success and failure factors will illustrate what needs to be done to achieve the desired energy efficiency targets. Henceforth, even though this study does not assess the direct transferability of the South African S&L programme to other regions, its findings could be relevant and useful for countries planning the implementation of similar policies.
Washing laundry is one of the most widespread housework tasks in the world. Washing machines, performing this task already in many private households, are now responsible for about 2% of the global electricity consumption. Worldwide, more than 840 million domestic washing machines are in use, with an annual consumption exceeding 92 TWh of electricity and 19 billion m3 of water as well as causing emissions of more than 62 megatons CO2eq. In North America, Western Europe and Pacific OECD countries, most households own a washing machine. In these economies standard and label policy programs already addressed and reduced the specific electricity and water consumption of washing machines per wash cycle. Nevertheless, in other world regions, the level of ownership for washing machines is still well below saturation and high growth rates can be observed in developing and newly industrialising countries. As washing machines use water, electricity, chemical substances and process time as resources, also the absolute worldwide resource consumption and emissions of these appliances are still on the rise. Due to different washing habits and practices as well as types of washing machines in different world regions, the specific consumption of resources for doing the laundry is varying to a large extent. On that score, this paper presents an overview of the current situation worldwide as well as respective saving potentials. Bottom-up scenario calculations, carried out for the 11 world regions according to the Intergovernmental Panel on Climate Change classification, show that large energy, water and greenhouse gas savings are possible with the "Best Available Technologies" today, and even higher savings will be possible with next generation "Best Not yet Available Technologies". According to model results, these savings are usually also very cost-effective. Following these calculations, it is highly advisable for policymakers world-wide to pay even more attention to improvement options in order to implement ambitious and product-specific policy packages, including minimum performance standards and labelling schemes.
Contemporary combined heat and power (CHP) systems are often based on fossil fuels, such as natural gas or heating oil. Thereby, small-scale cogeneration systems are intended to replace or complement traditional heating equipment in residential buildings. In addition to space heating or domestic hot water supply, electricity is generated for the own consumption of the building or to be sold to the electric power grid.
The adaptation of CHP-systems to renewable energy sources, such as solid biomass applications is challenging, because of feedstock composition and heat integration. Nevertheless, in particular smallscale CHP technologies based on biomass gasification and solid oxide fuel cells (SOFCs) offer significant potentials, also regarding important co-benefits, such as security of energy supply as well as emission reductions in terms of greenhouse gases or air pollutants. Besides emission or air quality regulations, the development of CHP technologies for clean on-site small-scale power generation is also strongly incentivised by energy efficiency policies for residential appliances, such as e.g. Ecodesign and Energy Labelling in the European Union (EU). Furthermore, solid residual biomass as renewable local energy source is best suited for decentralised operations such as micro-grids, also to reduce long-haul fuel transports. By this means such distributed energy resource technology can become an essential part of a forward-looking strategy for net zero energy or even smart plus energy buildings.
In this context, this paper presents preliminary impact assessment results and most recent environmental considerations from the EU Horizon 2020 project "FlexiFuel-SOFC" (Grant Agreement no. 641229), which aims at the development of a novel CHP system, consisting of a fuel flexible smallscale fixed-bed updraft gasifier technology, a compact gas cleaning concept and an SOFC for electricity generation. Besides sole system efficiencies, in particular resource and emission aspects of solid fuel combustion and net electricity effects need to be considered. The latter means that vastly less emission intensive gasifier-fuel cell CHP technologies cause significant less fuel related emissions than traditional heating systems, an effect which is further strengthened by avoided emissions from more emission intensive traditional grid electricity generation. As promising result, operation "net" emissions of such on-site generation installations may be virtually zero or even negative. Additionally, this paper scopes central regulatory instruments for small-scale CHP systems in the EU to discuss ways to improve the framework for system deployment.