• Energy Research

Abstract Solar irradiation and wind speed vary with climatic, as well as seasonal and daily weather conditions. In order to represent these variable renewable energy (VRE) resources in specialized energy system models, high temporal and spatial resolution information on their availability is used. In contrast, integrated assessment models (IAM), typically characterized by long-term time scales and low temporal and spatial resolution, require aggregated information on VRE availability and balancing requirements at various levels of VRE penetration and mix. Parametric studies that provide such information typically regard solar energy synonymously with photovoltaic power generation. However, solar energy can also be harvested with concentrating solar power (CSP) plants, which can be dispatchable if equipped with thermal storage. Accounting for this dispatchable use of the variable solar resource can change the balancing requirements at any solar energy penetration level. In this paper, we present an application of the high-resolution energy system model REMix to a set of European supply scenarios with theoretical VRE shares ranging from 0% to 140%, three solar-to-wind ratios, with CSP included in the solar share. We evaluate balancing measures, curtailments and costs and compare the findings to previous results in which CSP is regarded a backup option among other dispatchable power plants. The results show that CSP potentials in Europe are widely exploited in most scenarios. System costs are found to be lowest for wind-dominated systems or balanced mixes of wind and solar and for an overall VRE share between 40% for a low and 80% for a high scenario of the future CO2 emission certificate price. The comparison with previous results shows that storage capacity is the only system variable that is significantly affected by allocating CSP to the VRE resources category. It is reduced by 24% on average across all VRE shares and proportions and by around 80% at most.

Large emission reductions in buildings and transport are possible by integrating demand-side strategies to electrify energy use, improve technological efficiency, and reduce or shift patterns of activity. With enabling policies and infrastructures, final energy users can make significant contributions to climate goals, particularly through widespread deployment of heat pumps and electric vehicles.

The EU Green Deal calls for climate neutrality by 2050 and emission reductions of 50–55% in 2030 in comparison to 1990. Achieving these reductions requires a substantial tightening of the regulations of the EU emissions trading system (EU ETS). This paper explores how the power sector would have to change in reaction to a tighter EU ETS target, and analyses the technological and economic implications. To cover the major ETS sectors, we combine a detailed power sector model with a marginal-abatement cost curve representation of industry emission abatement. We find that tightening the target would speed up the transformation by 3–17 years for different parts of the electricity system, with renewables contributing 74% of the electricity in 2030, EU-wide coal use almost completely phased-out by 2030 instead of 2045, and zero electricity generation emissions reached by 2040. Carbon prices within the EU ETS would more than triple to 129€/tCO2 in 2030, reducing cumulated power sector emissions from 2017 to 2057 by 54% compared to a scenario with the current target. This transformation would come at limited costs: total discounted power system costs would only increase by 5%. We test our findings against a number of sensitivities: an increased electricity demand, which might arise from sector coupling, increases deployment of wind and solar and prolongs gas usage. Not allowing transmission expansion beyond 2020 levels shifts investments from wind to PV, hydrogen and batteries, and increases total system costs by 3%. Finally, the unavailability of fossil carbon capture and storage (CCS) or further nuclear investments does not impact results. Unavailability of bioenergy-based CCS (BECCS) has a visible impact (18% increase) on cumulated power sector emissions, thus shifting more of the mitigation burden to the industry sector, but does not increase electricity prices or total system costs (<1% increase). © 2021 The Authors

Photovoltaics (PV) and wind are the most important energy-conversion technologies for cost-efficient climate change mitigation. To reach international climate goals, the annual PV module production must be expanded to multi-terawatt (TW) scale. Economic and resource restraints demand the implementation of cost-efficient multi-junction technologies, for which perovskite-based tandem technologies are highly promising. In this work, the resource demand of the emerging perovskite PV technology is investigated, considering two factors of supply criticality, namely, mining capacity for minerals and the production capacity for synthetic materials. Overall, the expansion of perovskite PV to a multi-TW scale may not be limited by material supply if certainmaterials, especially indium, canbereplaced. Moreover, organic charge-transport materials face currently unresolved scalability challenges. This study demonstrates that, besides the improvement of efficiency and stability, perovskite PV research and development also need to be guided by sustainable materials choices and design-for-recycling considerations.

India, mainly powered by coal, has adopted ambitious renewable energy targets and currently considers a climate neutrality target for 2050. The rapid growth of solar PV power faces challenges due to its variable generation resulting in a decline in its economic value. In this paper, we evaluate the potential of battery storage to stabilize the market value of solar PV for three scenarios of further battery costs decrease. We estimate optimal battery storage and power generating capacities and their hourly operation in a 2040 Indian wholesale electricity market using an open-source power sector model. We find that battery storage increases the optimal solar PV shares from ∼40-50 % (without batteries) to ∼65 % (90%) in our central (optimistic) battery cost scenarios, while they hardly increase in our pessimistic battery cost scenario. We conclude that if battery cost drop to below ∼200 USD/kWh (including balance-of-system costs) they could become essential in a transition to a solar PV-dominant Indian energy system.

Abstract Limiting global warming below 1.5 °C requires rapid decarbonization of energy systems. Reductions of energy demand have an important role to play in a sustainable energy transition. Here we explore the extent to which the emergence of low energy consuming practices, encompassing new behaviors and the adoption of more efficient technologies, could contribute to lowering energy demand and thereby to reducing CO2 emissions. To this end, we design three detailed energy consumption profiles which could be adopted by individuals in current and future wealthy regions. To what extent does the setting of air conditioners to higher temperatures or the widespread use of efficient showerheads reduce the aggregate energy demand? We investigate the potential of new practices at the global level for 2050 and 2100. The adoption of new, energy saving practices could reduce global energy demand from buildings by up to 47% in 2050 and 61% in 2100 compared to a scenario following current trends. This strong reduction is primarily accounted for by changes in hot water usage, insulation of buildings and consumer choices in air conditioners and heat pumps. New behaviors and efficient technologies could make a significant long-term contribution to reducing buildings' energy demand, and thus facilitate the achieval of stringent climate change mitigation targets while limiting the adverse sustainability impacts from the energy supply system.

Abstract Photovoltaics (PV) has recently undergone impressive growth and substantial cost decreases, while deployment for concentrating solar power (CSP) has been much slower. As the share of PV rises, the challenge of system integration will increase. This favors CSP, which can be combined with thermal storage and co-firing to reduce variability. It is thus an open question how important solar power will be for achieving climate mitigation targets, and which solar technology will be dominant in the long-term. We address these questions with the state-of-the-art integrated energy-economy-climate model REMIND 1.5, which embodies an advanced representation of the most important drivers of solar deployment. We derive up-to-date values for current and future costs of solar technologies. We calculate a consistent global resource potential dataset for both CSP and PV, aggregated to country-level. We also present a simplified representation of system integration costs of variable renewable energies, suitable for large-scale energy-economy-models. Finally, we calculate a large number of scenarios and perform a sensitivity study to analyze how robust our results are towards future cost reductions of PV and CSP. The results show that solar power becomes the dominant electricity source in a scenario limiting global warming to 2 °C, with PV and CSP together supplying 48% of total 2010–2100 electricity. Solar technologies have a stabilizing effect on electricity price: if both solar technologies are excluded in a climate policy scenario, electricity prices rise much higher than in the case with full technology availability. We also analyze the competition between PV and CSP: PV is cheaper on a direct technology basis and is thus deployed earlier, but at high supply shares the PV integration costs become so high that CSP gains a competitive advantage and is rapidly developed, eventually overtaking PV. Even in the most pessimistic scenario of our sensitivity study with no further cost reductions, CSP and PV still supply 19% of 2010–2100 electricity. We conclude that if a stringent climate target of 2 °C is to be met cost-efficiently, solar power will play a paramount role in the long-term transformation of the electricity system.