Energy storage management in electric vehicles
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The closing longevity gap between battery electric vehicles and internal combustion vehicles in Great Britain
Electric vehicles are increasingly being adopted in Great Britain and other parts of the world, driven by the perception that they offer a cost-effective alternative to internal combustion engine vehicles while reducing emissions. However, a key element that underpins this perception is the longevity of electric vehicles, which remains relatively under researched. Here we show that although early battery electric vehicles (BEVs) exhibited lower reliability than internal combustion engine vehicles, rapid technological advancements have allowed newer BEVs to achieve comparable lifespans, even under more intensive use. Longevity is also found to be impacted by engine size, location and make of vehicle. We provide parameter estimates for life mileage that can be used to update life cycle assessment and total cost of ownership studies of different vehicle powertrains. Our results also shed light on BEV diffusion patterns, fleet replacement strategies and end-of-life treatment planning, including the increasingly important debate around BEV battery recycling and second-life options.
Development of accessible and scalable maize pollen storage technology
The inherent short lifespan of Zea mays (maize, corn) pollen hinders crop improvement and challenges the hybrid seed production required to produce food, fuel, and feed. Decades of scientific effort on maize pollen storage technology have been unable to deliver a widely accessible protocol that works for liters of pollen at a hybrid seed production scale. Here we show how suppressing the pollen cellular respiration rate through refrigeration and optimizing gas exchange within the storage environment are the critical combination of factors for maintaining pollen viability in storage. The common practice of preserving maize pollen by mixing the pollen with talcum powder is critically examined using pollen tube germination testing, electron microscopy of pollen-silk (stigma) interaction, and test pollinations in production environments. These techniques lead to mixing maize pollen collected for storage with anti-clumping carrier compounds, including microcrystalline cellulose. These carriers improve stored pollen flowability during pollination and enable increased seed sets to be obtained from stored pollen. Field testing in maize seed production demonstrates that a wide range of pollen volumes can be stored for up to seven days using low-cost, globally available materials and that stored pollen can achieve seed-set equivalency to fresh pollen.
Management practices and manufacturing firm responses to a randomized energy audit
Increasing the efficiency of industrial energy use is widely considered important for mitigating climate change. We randomize assignment of an energy audit intervention aimed at improving energy efficiency and reducing energy expenditures of small- and medium-sized metal processing firms in Shandong Province, China, and examine impacts on energy outcomes and interactions with firms’ management practices. We find that the intervention reduced firms’ unit cost of electricity by 8% on average. Firms with more developed structured management practices showed higher rates of recommendation adoption. However, the post-intervention electricity unit cost reduction is larger in firms with less developed practices, primarily driven by a single recommendation that corrected managers’ inaccurate reporting of transformer usage at baseline, lowering their electricity costs. By closing management-associated gaps in awareness of energy expenditures, energy audit programmes may reduce a firm’s unit cost of energy but have an ambiguous impact on energy use and climate change.
A combination of measures limits demand for critical materials in Sweden’s electric car transition
Electrification of passenger cars will result in an increased demand for critical raw materials. Here we estimate the quantities of nickel, manganese, cobalt, lithium, and graphite that could be required for a transition to electric cars in Sweden and how different measures can limit material demand. We find notable reduction potentials for shorter battery range—enabled by improved charging infrastructure, increased vehicle energy efficiency, and reduced travel demand compared to a reference scenario. The reduction potentials for downsizing and more lightweight cars, and car sharing are more modest. The combined impact of these measures would be 50–75% reduction in cumulative demand and 72–87% reduction in in-use stock in 2050, depending on the material and battery chemistry pathway. Generally, the reduction potentials are larger than the potential contributions from recycling, suggesting that these complementary measures may be more effective in reducing material demand.
Community composition and physiological plasticity control microbial carbon storage across natural and experimental soil fertility gradients
Many microorganisms synthesise carbon (C)-rich compounds under resource deprivation. Such compounds likely serve as intracellular C-storage pools that sustain the activities of microorganisms growing on stoichiometrically imbalanced substrates, making them potentially vital to the function of ecosystems on infertile soils. We examined the dynamics and drivers of three putative C-storage compounds (neutral lipid fatty acids [NLFAs], polyhydroxybutyrate [PHB], and trehalose) across a natural gradient of soil fertility in eastern Australia. Together, NLFAs, PHB, and trehalose corresponded to 8.5–40% of microbial C and 0.06–0.6% of soil organic C. When scaled to “structural” microbial biomass (indexed by polar lipid fatty acids; PLFAs), NLFA and PHB allocation was 2–3-times greater in infertile soils derived from ironstone and sandstone than in comparatively fertile basalt- and shale-derived soils. PHB allocation was positively correlated with belowground biological phosphorus (P)-demand, while NLFA allocation was positively correlated with fungal PLFA : bacterial PLFA ratios. A complementary incubation revealed positive responses of respiration, storage, and fungal PLFAs to glucose, while bacterial PLFAs responded positively to PO43-. By comparing these results to a model of microbial C-allocation, we reason that NLFA primarily served the “reserve” storage mode for C-limited taxa (i.e., fungi), while the variable portion of PHB likely served as “surplus” C-storage for P-limited bacteria. Thus, our findings reveal a convergence of community-level processes (i.e., changes in taxonomic composition that underpin reserve-mode storage dynamics) and intracellular mechanisms (e.g., physiological plasticity of surplus-mode storage) that drives strong, predictable community-level microbial C-storage dynamics across gradients of soil fertility and substrate stoichiometry.
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