As Middle Eastern governments procure utility-scale solar power from developers at record low prices, speculation persists about the role of hidden subsidies in attracting these bids. Apostoleris et al. analyse contracts from 2010 onwards to highlight the role of latent subsidies such as easy financing terms and cheap or free land. However, they also show that the low costs can be replicated outside the Middle East as hardware continues to get cheaper.

See Apostoleris et al.

Cellulose-based biofuels could reduce CO2 emissions while not relying on edible feedstocks, but production of transportation fuel from cellulose with high biofuel content is technically challenging. Deneyer et al. now demonstrate a method that integrates cellulose-based biofuels synthesis with existing petrochemical refinery processes to produce gasoline with 10% bio-derived carbon content.

See Deneyer et al. and News and Views by Barta

In-stream turbines could be an important source of clean energy, but they must be designed so as not to disrupt the sediment bed or alter the river flow. Musa et al. build a scaled test model of 12 turbines in a simulated riverbed (shown here) and monitor the bed’s response and sediment transport under flood conditions, seeking to predict the impact of such turbines in real-world applications.

See Musa et al.

Cooling in thermal power production has always been a water-intensive process, leading to a coupling between electricity production growth and water withdrawal. Research now shows that, through active policy measures including deployment of more efficient plants, China may have managed to grow thermal electricity production while decreasing freshwater withdrawal for cooling overall.

See Zhang et al.

Lithium-rich layered oxides are promising candidate materials for future batteries, but their voltages decay during electrochemical cycling and thus their energies drop. Singer et al. discover links between the voltage decay and lattice dislocations in these oxides (visualized here), allowing them to design an annealing method to re-order the lattice structure and to recover the decayed voltage.

See Singer et al.

Consumer choice for particular fuels is hard to discern because prices are rarely, if ever, equal and fuels are not substitutable. Using data from Sweden, where policies have mandated the availability of ethanol at all filling stations, Cristian Huse shows that given the choice consumers may prefer gasoline over greener ethanol, potentially even when the fuels are at price parity.

See Huse

Large-scale deployment of photovoltaics has overcome expectations in recent decades, calling for further technological innovations and opening new opportunities for integration, such as solar roof tiles (pictured here). In this Focus, we explore two trends in photovoltaic deployment and delve into current challenges in bringing new technologies from the laboratory to the real world.

See Ballif et al.

Great Britain’s carbon emissions fell by 6% between 2015 and 2016, thanks to the displacement of coal power generation by natural gas. Wilson and Staffell analyse the policy and market conditions that allowed Great Britain to undertake a rapid switch between fuels, and consider whether other nations might be able to follow suit.

See Wilson and Staffell

The lithium-ion battery is currently the mainstream energy solution for electrified vehicles, but it faces huge challenges to meet ever-increasing industrial requirements and customer expectations. In this Insight, we highlight developments in the state-of-the-art of automotive batteries and explore challenges and realistic solutions in moving the technologies forward.

More effective climate policy could be developed if we can understand the difference in well-to-refinery emissions and net energy between different types of crude oil. Masnadi et al. compile the well-to-refinery emissions and net energy profile of China’s varied crude supply and find high heterogeneity in carbon emissions, stressing the utility of replacing high-emission, low net-energy supplies towards achieving climate targets.

See Masnadi et al. and Höök.

The operating frequencies of electric power grids fluctuate in response to demand and supply in the system. Effective control of the grid requires in-depth understanding of such fluctuations. To that end, Schäfer et al. examine data from real power grids in North America, Japan and Europe and characterise their fluctuations, finding deviations from Gaussianity and contributions due to energy trading.

See Schäfer et al.

Lithium-ion batteries have become ubiquitous in many applications but still exhibit safety issues. A salient example is potential overheating, which can lead to fires, especially for organic electrolytes (as pictured). To counter this, Wang et al. develop an organic electrolyte with flame-retardant properties that still exhibits comparable performance to flammable alternatives.

See Wang et al.