How diet portfolio shifts combined with land-based climate change mitigation strategies could reduce climate burdens in Germany

Many studies have analysed the environmental impact of vegan, vegetarian, or reduced meat diets. To date, literature has not evaluated how diet shifts affect environmental impacts by utilising portfolios which reflect personal nutrition preferences. Further, changing diets could alter the available land for non-food uses. This paper defines novel diet portfolios to outline alternative diet transitions and choices within the population and finds their effect on greenhouse gas (GHG) emissions, primary energy use, and land use in Germany. The aim of this study is to capture how these diet shifts affect land availability and increase the options for land-based climate change mitigation strategies. To do so, a contextualisation is made to compare the use of freed-up land for afforestation or biomethane production (with and without carbon capture and storage). The investigated diet portfolios lead to a reduction of the investigated impacts (GHG emissions: 7–67%; energy use: 5–46%; land use: 6–64%). Additionally, afforestation of freed-up land from each diet portfolio leads to further emission removals of 4–37%. In comparison, using the land to produce energy crops for biomethane production could lead to 2–23% further CO2-eq emission reductions when replacing fossil methane. If biomethane production is paired with carbon capture and storage, emission abatement is increased to 3–34%. This research indicates various short-term pathways to reduce GHG emissions with portfolio diet shifts. Utilising freed-up land for climate change mitigation strategies could prove essential to meet climate targets, but trade-offs with, e.g. biodiversity and ecosystem services exist and should be considered

Electrofuels from excess renewable electricity: costs, emissions, carbon use

Large shares of variable renewable electricity (VRE) generation are pursued in order to achieve emissions targets in the energy sectors. This results in increased excess renewable electricity (ERE) at times when supply exceeds conventional inflexible electricity demand. ERE can be utilized as a low-emission energy source for sector coupling through e.g. hydrogen production via flexible electrolysis, Which can be used directly or combined With a carbon source to produce electrofuels. Such fuels are crucial for the transport sector, where renewable alternatives are scarce. However, while ERE increases With raising VRE shares, carbon emissions decrease and may become a limited resource with several usage options, including carbon storage (CCS). Here We perform a model based analysis for the German case until 2050, with a general analysis for regions with a high VRE reliance. The capital expenditure of electrolysers was found not to be crucial for the cost, despite low capacity factors due to variable ERE patterns. Carbon will likely become a limiting factor when aiming for stringent climate targets and renewable electricity-based hydrocarbon electrofuels replacing fossil fuels achieve up to 70% more greenhouse gas (GHG) abatement than CCS. Given (1) an unsaturated demand for renewable hydrocarbon fuels, (2) a saturated renewable hydrogen demand and (3) unused ERE capacities which would otherwise be curtailed, we find that carbon used for renewable fuel production abates more GHG than if the carbon would be stored. This effect may increase substantially if shale oil or gas is displaced

Abandoning the Residual Load Duration Curve and Overcoming the Computational Challenge

As the importance of variable energy sources in-creased in the power sector, employing the Residual Load Duration Curve (RLDC) method became standard practice in many energy system models. RLDCs allow modelers to integrate temporally high-resolution data sets in the energy system while keeping the underlying model tractable. Although the RLDC approach can assist us in simplifying calculations, this comes at a cost: RLDCs disregard the inter-relations between time slices. In this manuscript, we elaborate on our strategy to overcome the computational burden caused by abandoning the RLDC method in the BioENergy OPTimization model (BENOPT). For that purpose, the available resources are utilized efficiently to reduce the run-time

The Design of Large Real-Time Systems: The Time-Triggered Approach

The time-triggered (TT) architecture approach supports the spatial partitioning of a large, distributed real-time system into a set of autonomous subsystems with small control-free data-sharing interfaces between them. This paper presents such a TT architecture and gives a detailed description of the interface between an autonomous time-triggered communication subsystem based on the TTP protocol and the host computer within a node of this architecture. This interface acts as a temporal firewall that eliminates the possibility of control error propagation from one subsystem to another subsystem. It thus facilitates the independent development and validation of the subsystems and supports the composability of the distributed architecture with respect to timeliness, validation, and certification

ATHENA X ray Optics Development and Accommodation

The Athena mission, under study and preparation by ESA as its second Large-class science mission, requires the largest X-ray optics ever flown, building on a novel optics technology based on mono crystalline silicon. Referred to as Silicon Pore Optics technology (SPO), the optics is highly modular and benefits from technology spin-in from the semiconductor industry. The telescope aperture of about 2.5 meters is populated by around 700 mirror modules, accurately co-aligned to produce a common focus. The development of the SPO technology is a joint effort by European industrial and research entities, working together to address the challenges to demonstrate the imaging performance, robustness and efficient series production of the Athena optics. A technology development plan was established and is being regularly updated to reflect the latest developments, and is fully funded by the ESA technology development programmes. An industrial consortium was formed to ensure coherence of the individual technology development activities. The SPO technology uses precision machined mirror plates produced using the latest generation top quality 12 inch silicon wafers, which are assembled into rugged stacks. The surfaces of the mirror plates and the integral support structure is such, that no glue is required to join the individual mirror plates. Once accurately aligned with respect to each other, the surfaces of the mirror plates merge in a physical bonding process. The resultant SPO mirror modules are therefore very accurate and stable and can sustain the harsh conditions encountered during launch and are able to tolerate the space environment expected during operations. The accommodation of the Athena telescope is also innovative, relying on a hexapod mechanism to align the optics to the selected detector instruments located in the focal plane. System studies are complemented by dedicated technology development activities to demonstrate the capabilities before the adoption of the Athena mission