New Generation: Building a clean European electricity system by 2035

This study explores the least-cost pathways to a clean power system in Europe, compatible with the Paris Agreement climate goals (1.5C). Detailed, country-by-country, hour-by-hour power system modelling confirms the feasibility of almost completely decarbonising Europe's power sector by 2035, while expanding the electricity supply. Key metrics are quantified in order to benchmark progress, while accounting for a range of uncertainties. Crucially, the costs of competing routes are assessed, including the costs of developing the power system according to current plans. This report summarises the results of three modelled pathways for the European power sector. The Stated Policy pathway is aligned with stated national policies until 2035. The other two pathways -- Technology Driven and System Change -- are computed to minimise cost while remaining within a carbon budget compatible with the Paris Agreement climate goals. The latter two pathways expand clean electrification, but differ in their assumptions about available technologies and the levels of energy savings resulting from societal change

Galaxy Zoo: comparing the demographics of spiral arm number and a new method for correcting redshift bias

The majority of galaxies in the local Universe exhibit spiral structure with a variety of forms. Many galaxies possess two prominent spiral arms, some have more, while others display a many-armed flocculent appearance. Spiral arms are associated with enhanced gas content and star formation in the discs of low-redshift galaxies, so are important in the understanding of star formation in the local universe. As both the visual appearance of spiral structure, and the mechanisms responsible for it vary from galaxy to galaxy, a reliable method for defining spiral samples with different visual morphologies is required. In this paper, we develop a new debiasing method to reliably correct for redshift-dependent bias in Galaxy Zoo 2, and release the new set of debiased classifications. Using these, a luminosity-limited sample of ∼18 000 Sloan Digital Sky Survey spiral galaxies is defined, which are then further sub-categorized by spiral arm number. In order to explore how different spiral galaxies form, the demographics of spiral galaxies with different spiral arm numbers are compared. It is found that whilst all spiral galaxies occupy similar ranges of stellar mass and environment, many-armed galaxies display much bluer colours than their two-armed counterparts. We conclude that two-armed structure is ubiquitous in star-forming discs, whereas many-armed spiral structure appears to be a short-lived phase, associated with more recent, stochastic star-formation activity

Land use and Europe’s renewable energy transition: identifying low-conflict areas for wind and solar development

Continued dependence on imported fossil fuels is rapidly becoming unsustainable in the face of the twin challenges of global climate change and energy security demands in Europe. Here we present scenarios in line with REPowerEU package to identify Renewables Acceleration Areas that support rapid renewable expansion, while ensuring minimal harm to places important for biodiversity and rural communities. We calculated the area needed to meet renewable energy objectives under Business-as-Usual (BAU) and Low-conflict (LCON) development scenarios within each country, providing a broad overview of the potential for renewable energy generation to reduce impacts when development is steered toward lower conflict lands. Our analysis shows that meeting renewable energy objectives would require a network of land-based wind turbines and solar arrays encompassing upwards of 164,789 km2 by 2030 and 445,654 km2 by 2050, the latter roughly equivalent to the land area of Sweden. Our results highlight that BAU development patterns disproportionately target high-conflict land cover types. By 2030, depending on the development pathway, solar and wind development are projected to impact approximately 4,386–20,996 km2 and 65,735–138,454 km2 of natural and agricultural lands, respectively. As renewable energy objectives increase from 2030 to 2050 impacts to natural and agricultural lands also increase, with upwards of 33,911 km2 from future solar development and 399,879 km2 from wind development. Despite this large footprint, low-conflict lands can generate substantial renewable energy: 6.6 million GWh of solar and 3.5 million GWh of wind, 8–31 times 2030 solar objectives and 3–5 times 2030 wind objectives. Given these patterns, we emphasize the need for careful planning in areas with greater impact potential, either due to a larger demand for land area or limited land availability. Top-emitting countries with large renewable energy objectives (Germany, Italy, Poland, France, Spain) and those with limited flexibility in meeting objectives on low-conflict land (Albania, Slovenia, Montenegro, Hungary, Croatia, Serbia, Bosnia Herzegovina, Finland, Greece, Portugal, and Norway) should be priorities for country-level customizations to guide low-conflict siting and avoid disproportionate impacts on high-value areas

DataSheet1_Land use and Europe’s renewable energy transition: identifying low-conflict areas for wind and solar development.xlsx

Continued dependence on imported fossil fuels is rapidly becoming unsustainable in the face of the twin challenges of global climate change and energy security demands in Europe. Here we present scenarios in line with REPowerEU package to identify Renewables Acceleration Areas that support rapid renewable expansion, while ensuring minimal harm to places important for biodiversity and rural communities. We calculated the area needed to meet renewable energy objectives under Business-as-Usual (BAU) and Low-conflict (LCON) development scenarios within each country, providing a broad overview of the potential for renewable energy generation to reduce impacts when development is steered toward lower conflict lands. Our analysis shows that meeting renewable energy objectives would require a network of land-based wind turbines and solar arrays encompassing upwards of 164,789 km2 by 2030 and 445,654 km2 by 2050, the latter roughly equivalent to the land area of Sweden. Our results highlight that BAU development patterns disproportionately target high-conflict land cover types. By 2030, depending on the development pathway, solar and wind development are projected to impact approximately 4,386–20,996 km2 and 65,735–138,454 km2 of natural and agricultural lands, respectively. As renewable energy objectives increase from 2030 to 2050 impacts to natural and agricultural lands also increase, with upwards of 33,911 km2 from future solar development and 399,879 km2 from wind development. Despite this large footprint, low-conflict lands can generate substantial renewable energy: 6.6 million GWh of solar and 3.5 million GWh of wind, 8–31 times 2030 solar objectives and 3–5 times 2030 wind objectives. Given these patterns, we emphasize the need for careful planning in areas with greater impact potential, either due to a larger demand for land area or limited land availability. Top-emitting countries with large renewable energy objectives (Germany, Italy, Poland, France, Spain) and those with limited flexibility in meeting objectives on low-conflict land (Albania, Slovenia, Montenegro, Hungary, Croatia, Serbia, Bosnia Herzegovina, Finland, Greece, Portugal, and Norway) should be priorities for country-level customizations to guide low-conflict siting and avoid disproportionate impacts on high-value areas.</p