• Energy Research

AbstractBioenergy policies affect both the environment and biomass availability for food, feed, and fiber on a national and international scale. To support policy makers, knowledge and methods from different scientific disciplines in the form of integrated assessments is necessary. Therefore we developed the MILESTONES framework which models the links between the national bioenergy system and the global land-use system as an integrated modeling approach. It builds on a set of three well-tested models (MAGNET, LandSHIFT and BENSIM). The prototype's functionality was demonstrated by assessing the environmental impacts of future German bioenergy strategies on a global level and along the entire biomass provision chain. The results from the case study show that, on the one hand, German bioenergy strategies have little effect on international market prices, but on the other hand land-use policies on an international level strongly influence the environmental performance of any German bioenergy strategy.

With the Renewable Energy Directive 2018/2001 (RED II), adopted in December 2018, the EU is continuing the political framework for the use of renewable energy sources in the transport sector for the period from 2021 to 2030. At the same time, the German federal government has set a target of reducing greenhouse gas (GHG) emissions in the transport sector by at least 40% to 42% by 2030 compared to the 1990 GHG level. To investigate the possible effects of the European and national requirements on the German GHG quota, cost-optimal fuel mixes were modelled to achieve the GHG targets of 26 fuel options in each of the nine different scenarios. The results show clear differences between the scenarios that implement the RED II targets (including 14% renewables in transport by 2030) and those that implement the climate protection target (40–42% GHG reduction compared to 1990 by 2030). If only the minimum requirements of RED II are met, the German climate protection target is clearly missed without further measures. In order to achieve the climate protection target, a significant reduction in the final energy consumption in transport is required, as well as a very high GHG quota of 34.5%, meaning a high proportion of renewables of ca. 40% and using almost all the fuel options considered.

Renewable transport fuels stem either from renewable electricity or biomass. We perform a model-based systems analysis of the usage of electricity, biomass and carbon for fuel production, focusing on greenhouse gas abatement and cost.

Abstract The competitiveness of conventional and advanced (second generation) biofuels is a critical issue for the implementation of a sustainable transport strategy. We model biofuel competition under different feedstock cost development scenarios, assessing what costs and cost developments can be expected for energy crops in Germany and how these feedstock cost developments affect the competitiveness between biofuels. Perennial poplar was found to be the least-cost energy crop, with non-perennial silage maize being strongly competitive at increasing feedstock price developments. Assuming increasing feedstock costs for the future, neither conventional biodiesel from rape seed nor advanced biodiesel were found to be competitive in the long run. Feedstock costs were found to overshadow all other factors, leading to costs for advanced biodiesel to be between 27.0 and 53.6€ GJ−1 in 2030, which is above most expectations. Of the advanced biofuels, only synthetic natural gas was cost-competitive under some circumstances, but biomethane from silage maize and bioethanol from sugar beet were the strongest options, as they combine high yields with high conversion efficiencies while avoiding the high upfront costs of advanced biofuels and the risk of switching to perennial crops. However, such a transition leads to less mobile feedstocks being used than presently and in the case of gaseous fuels requires stimulation of the demand side in order to function. The high dependence on and increasing relevance of feedstock costs is characteristic for the biobased renewables only and is detrimental and inhibiting for investments and research and development efforts, in contrast to for e.g. wind and solar photovoltaics, and must be considered when designing policy for any sector of the bioeconomy.

Abstract Biomass is a versatile renewable energy source that can be used in all parts of the energy system, but it is a limited resource and usage needs prioritisation. Here we use a sector-coupled European energy system model to explore the range of cost-effective near-optimal solutions for achieving stringent emissions targets. We show that provision of biogenic carbon rather than energy is the main value of biomass, with the energy system cost increasing by 20% if biomass is excluded. It is not crucial in which sector biomass is used if it is combined with carbon capture to enable negative emissions and e-fuel production. A shortage of renewable electricity or hydrogen primarily increases the value of biomass for fuel production, which appears as the marginal abatement option and is most sensitive to uncertainties. Biomass usage is significantly affected if the biomass is associated with upstream emissions.

BioENergy OPTimisation model version 2.1

Wind and solar PV have become the lowest-cost alternatives for power generation in many countries and are expected to dominate the renewable power supply in many regions of the world. The temporal volatility in power production from these sources leads to new challenges for a stable and secure power supply system. Possible technologies to improve the integration of wind and solar PV are electrical energy storage and the flexible power provision by bioenergy. A third option is the system-friendly layout of wind and solar PV systems and the optimized mix of wind and solar PV capacities. To assess these different options at hand, a case study was conducted covering various scenarios for a regional power supply based on a high share of wind and solar PV. State-of-the-art concepts for all the stated technologies are modelled and a numerical optimization approach is applied on temporally-resolved time series data to identify the potential role of each option and their respective interactions. Power storage was found to be most relevant in solar dominated systems, due to the diurnal generation pattern, whereas bioenergy is more suitably combined with high wind power shares due to the less regular generation pattern. System-friendly wind and solar power can reduce the need for generation capacity and flexible options by fitting generation and demand patterns better.