Christian Breyer’s research while affiliated with Lappeenranta – Lahti University of Technology LUT and other places

This study evaluates the environmental performance of advanced solar photovoltaic technologies, including floating, bifacial ground-mounted, and building-integrated photovoltaics systems, compared to conventional technologies in Finland, Germany and Spain from 2022 to 2050. A novel aspect of this research is the integration of multiple photovoltaics technologies, time horizons (2022, 2030, and 2050), and climatic zones, providing a more complete understanding of their lifecycle impacts. The study uses a prospective life cycle assessment approach, offering scenario-based projections to assess future environmental impacts under changing energy mixes and climatic conditions. The results highlight the critical role of local solar irradiation, as seen in the higher carbon footprint of floating photovoltaic systems in Murcia (30.2 gCO2/kWh, 2022) than in Lappeenranta (15.7 gCO2/kWh). Over time, environmental impacts decrease significantly; floating photovoltaics in Murcia reduces to 17.5 gCO2/kWh in 2050, and bifacial systems drop from to 14.9 gCO2/kWh. Overall, bifacial systems have the lowest environmental impact, followed by floating photovoltaics, while building-integrated systems show the highest impact. The findings highlight the critical importance of transitioning to renewable energy in electricity grids to reduce environmental impacts, while emphasizing the role of location-specific factors, technological advancements, and evolving energy systems in shaping the environmental performance of photovoltaics technologies.

Energy solutions are rapidly needed to mitigate the problems of climate change and the high dependence on expensive imported petroleum products, which have continued to dampen Caribbean competitiveness and potential growth. This research comprehensively analyses and compares energy pathways with scenarios that contextualise the eventualities and intricacies of carbon-intensive and carbon-neutral pathway options for the Caribbean using a proven techno-economic modelling tool, the LUT Energy System Transition Model. Due to the Caribbean's geographic limitation, offshore renewable technology's role is researched in a fully integrated energy system. The results show a solar energy momentum driven by excellent resource conditions and fast-improving economic attractiveness. The electricity generation mix is led by solar photovoltaics (67-90%) and wind power (6-30%), complemented by hydropower, bioenergy, and geothermal energy. Offshore floating solar photovoltaics could supply reliable and stable energy, thus fostering a sustainable blue economy. The Carib-bean's future energy system is best characterised as a Solar-to-X Economy. Storage, sector coupling, and power-to-heat, carbon dioxide, water, fuels, and mobility solutions provide flexibility in the renewable pathways. Notably, renewable electricity and green e-hydrogen are the main precursors in Power-to-X processes. The adoption of electric vehicles spurs a cost-competitive transition in the road transport segment, and the vehicle-to-grid strategy provides additional flexibility in the system. The renewables pathways are 7-10% lower in costs than alternatives and could create new industry opportunities, jobs, and investments. This research advances the international perspective on sustainable energy transition for land-limited archipelago regions.

The fight against global warming requires novel approaches for the defossilisation of industrial processes, and the limitation of global warming requires options for negative carbon dioxide (CO2) emissions. The production of carbon fibre (CF) is an energy-intensive chain of processes which cause CO2 emissions. Having in mind the high market growth for CF composite materials, CF production might stand against the fight against global warming. CF also offers a huge mitigation opportunity, as CF contain up to 95–98wt% of pure carbon. This study investigates possible ways to link CF production to atmospheric CO2, enabling negative CO2 emissions through CF manufacturing. Production value chains for CF based on poly(acrylonitrile) (PAN) and pitch, the two most important CF precursor materials, are developed and analysed regarding their energy and mass balances. The PAN value chain is further assessed regarding a first economic estimation of CF production cost with atmospheric CO2 as carbon source. The results show that production costs per ton CO2 removed might be unattractive at 2949 €/tCO2 in 2050. However, from a CF perspective, production cost of 10.3 €/kgCF in 2050 might enable a business case for electricity-based CF production from atmospheric CO2 in the future. Each ton of CF produced can store about 3.5 tCO2 due to a very high carbon share in the final product. With an increasing market for CF, a total negative emission potential of at least 0.7 GtCO2 per year can be enabled by 2050. Further research opportunities are discussed.

The supply security of fossil gas has been disrupted by the Russo-Ukrainian War. Decisions to relocate the production and transport of gas have become so urgent that new long-term contracts are imminent that undermine the Paris Climate Agreement. Here, we simulate how quickly the addition of renewable electricity and the installation of heat pumps can substitute enough gas to reduce supply risk, while taking a decisive step towards meeting the Paris Agreement. Our bottom-up modelling, using Germany as an example, shows technical pathways on how installing heat pumps is one of the fastest ways to reduce gas consumption, in addition to reducing the load hours of gas-fired power plants. With targeted efforts, maximally 60% of gas from the Russian Federation can be substituted by 2025 with heat pumps and grid expansions, and enough electricity will remain available that the phase-out of coal and the entry into e-mobility will still be practicable.

Germany currently imports 500 TWh/a of natural gas from the Russian Federation. Most of this gas is used to generate process and space heat. By accelerating the conversion of heat supply to heat pumps powered by renewable electricity, renew-able heat in district heating networks, and the substitution of natural gas in electricity generation with renewable energy, as well as energy conservation, as much natural gas can be saved in a few years as is currently imported from the Russian Federation. This requires greatly accelerating the spread of district heating networks and heat pumps in conjunction with a training offensive in the skilled trades. Changes to the regulatory framework in the form of a ban on oil and gas heating systems, as well as financial incentives and targeted subsidy programs, are also required. With such tar-geted efforts, Germany can at the same time make a significant contribution in the fight against the climate crisis.

This article is a product of a collaboration between ecosystem scientists and energy system modelers. It is currently in review at Nature Geoscience. The main points are: 1. Climate mitigation goals of 1.5-2°C are not adequate given current understanding of ecosystem sensitivity to climate and the high social costs of carbon emissions. 2. More aggressive goals of climate restoration (what we call getting back to the Holocene) have not been fully considered because of political and technological obstacles as well as disciplinary divides between energy system and Earth system researchers. 3. The renewable revolution has fundamentally transformed the climate response space, opening pathways back to the Holocene if we ensure strategic financing and policy prioritization of clean electrification. The paper provides an update for the Earth system research community of changes in global energy—including observations that renewable energy cost and rollout assumptions in current integrated assessment models are off by an order of magnitude and three decades. This results in unrealistically pessimistic projections of clean energy transitions with fundamental implications for climate targets and planning. For the energy research community, the paper summarizes new research on marine and terrestrial ecosystem response to sub-1.5°C levels of warming, including updated estimates of icesheet destabilization thresholds and carbon sink dynamics. More specifically, we propose a new metric for climate risk (gigaton-years) and compare the costs and risks of two "clean electrification" scenarios with standard Shared Socioeconomic Pathways. We finish by outlining specific policy actions and research priorities to accelerate the renewable revolution.

Copper is required for the transformation of global energy systems, and its production is intensive in water and energy. Several studies have investigated the design of renewable energy systems for copper production, aiming at reducing its environmental footprint. Here, we present the first integrated design for desalinated water and energy supply that considers all forms of energy required in the copper production process. For this, we develop an optimization model for planning integrated multi-vector energy and water systems. The model includes -for the first time in an energy system planning model- a concept for integrated pumped-hydro storage using sweater and reverse osmosis desalination. Our results show that water-energy systems for copper production based exclusively on renewables can today achieve costs as low as those of conventional fossil-based systems, when integrating multi-vector planning and seawater pumped-hydro storage. For a case study in Chile and in fully renewable scenarios, the specific cost of supplying energy and desalinated water decreases from 520–670 € per ton of copper at current costs to 330–360 by 2050. By 2030, using seawater pumped-hydro storage makes a fully renewable, multi-energy scenario the least-cost alternative. Such an integrated system is an enabler for reducing the environmental footprint that copper brings into the global energy transition.