Reviews & Analysis

The concept of energy security is multifaceted, and can cover a number of seemingly distinct energy- and climate-related risks. Now, research shows that public opinion about energy security reflects the geographic variation in these risks, such that cross-country differences in public concern are explained by national energy context and indicators.

Passivating contact technologies have enabled new record efficiencies in crystalline silicon photovoltaics, but they are still far from implementation into mainstream manufacturing. Now, a passivation approach has been shown that exploits the quick firing step currently employed in industrial fabrication by rethinking material design.

The German Energiewende is an ambitious project, but the expansion of renewables needed to achieve its goals is expensive. Now, research shows that consumers would accept higher levies to finance renewables if exemption policies were abolished, forcing industries to pay their fair share.

Renewable portfolio standards in the United States are widely recognized as a significant state-level instrument to catalyse growth in renewables. Comprehensive analysis now shows that the effectiveness of these standards depends on their stringency, with more demanding standards leading to higher renewable penetration.

Harsh operating conditions, such as high temperatures, hinder the grid-scale application of liquid metal batteries (LMBs). Now, their operating temperature is shown to be substantially lowered thanks to a lithium-ion-conducting solid-state electrolyte.

Voltage fade has been a major barrier to the commercialization of a series of high-energy-density battery electrodes for more than a decade. It is now re-examined with advanced characterization techniques, which find its origin is correlated to oxygen activities.

High-quality liquid transportation fuels can be produced from renewable biomass by using microbial fermentation. This Review explores advances in microbial engineering as well as the barriers and opportunities for such bio-based production of hydrocarbons.

Perovskite solar cells are noted for their high performance and ease of synthesis, but are still plagued by concerns over their stability. Researchers are now demonstrating why higher performance and increased stability go hand-in-hand — and how to continue improving both.

Perovskites, with their wide bandgap range, are good partners for both commercial and novel photovoltaic technologies in multijunction solar cells. Here, McGehee and co-workers review recent material and device developments and highlight future challenges and opportunities for perovskite-based tandems.

Non-fullerene acceptors offer a promising development direction to increase the conversion efficiency and stability of organic photovoltaics. Here, Jianquan Zhang and co-workers highlight recent insight to guide molecular material design and discuss future challenges regarding device design and scalability.

The efficiency of perovskite solar modules is limited by the difficulty in fabricating uniform and high-quality perovskite films. Now, a modified doctor blade method with a surfactant-controlled drying process has been shown to enable high-speed deposition of large-area and uniform perovskite films.

The effectiveness of fuel taxation towards reducing gasoline usage in vehicles has been a subject of debate. Using data from Sweden, which has one of the highest gasoline taxes in the world, research now demonstrates a potential consumer preference for gasoline even at price parity with ethanol.

Cu(In,Ga)(S,Se)₂ photovoltaics exhibit high solar cell efficiencies but the module efficiencies lag far behind. Here, Bermudez and Perez-Rodriguez review the origins of the cell-to-module gap and the solutions proposed to enable the scale-up of this photovoltaic technology.

The photovoltaic reliability community is well-established and links researchers from academia and the industry. Here, Snaith and Hacke draw lessons from the development of international reliability standards for commercial technologies to inform future work on perovskite solar cells and modules.

The energy density of aqueous organic flow batteries is generally low primarily because of the low solubility or instability of charge-storing organic molecules. Now, a phenazine-derived molecule is shown to have both high solubility and long-term stability, leading to an exceptionally high capacity in an aqueous flow battery.

The performance of enzymatic biofuel cells is greatly hindered by the poor electron transfer between enzyme catalysts and electrode surfaces. Now, an efficient electrical connection is made by coupling conventional direct and mediated electron transfer mechanisms, leading to much improved power density and stability.

The energy transition has been alternatively characterized as a gradual transformation, a technological disruption or a systemic change. This Perspective argues that the transition is entering a new phase where it has unique characteristics, and research and policy can no longer treat it as a gradual transformation or mere disruption.

Many consumers encounter electric vehicles for the first time at car dealerships when they are looking to buy a new vehicle. Now, research shows that interactions with sales personnel have an important and often detrimental influence on the purchase of electric vehicles, presenting a critical barrier to their wide-spread adoption.

Wind facilities have generally deployed turbines of the same power and height in regular uniform arrays. Now, the modern generation of turbines, with customer-selectable tower heights and larger rotors, can significantly increase wind energy’s economic potential using less land to generate cheaper electricity.

Capturing CO₂ directly from the air could lead to negative emissions, but more efficient technologies are still required. Now, researchers use a multi-stage cycle based on amino acids and organic salts to capture CO₂ from air, which can be released with concentrated solar power.