United States

Energy system optimization models offer insights into energy and emissions futures through least-cost optimization. However real-world energy systems often deviate from deterministic scenarios necessitating rigorous uncertainty exploration in macro-energy system modeling. This study uses modeling techniques to generate diverse near cost-optimal net-zero CO2 pathways for the United States’ energy system. Our findings reveal consistent trends across these pathways including rapid expansion of solar and wind power generation substantial petroleum use reductions near elimination of coal combustion and increased end-use electrification. We also observe varying deployment levels for natural gas hydrogen direct air capture of CO2 and synthetic fuels. Notably carbon-captured coal and synthetic fuels exhibit high adoption rates but only in select decarbonization pathways. By analyzing technology adoption correlations we uncover interconnected technologies. These results demonstrate that diverse pathways for decarbonization exist at comparable system-level costs and provide insights into technology portfolios that enable near cost-optimal net-zero CO2 futures.

The integration of wind and solar energy with green hydrogen technologies represents an innovative approach toward achieving sustainable energy solutions. This review examines state-ofthe-art strategies for synthesizing renewable energy sources aimed at improving the efficiency of hydrogen (H2 ) generation storage and utilization. The complementary characteristics of solar and wind energy where solar power typically peaks during daylight hours while wind energy becomes more accessible at night or during overcast conditions facilitate more reliable and stable hydrogen production. Quantitatively hybrid systems can realize a reduction in the levelized cost of hydrogen (LCOH) ranging from EUR 3.5 to EUR 8.9 per kilogram thereby maximizing the use of renewable resources but also minimizing the overall H2 production and infrastructure costs. Furthermore advancements such as enhanced electrolysis technologies with overall efficiencies rising from 6% in 2008 to over 20% in the near future illustrate significant progress in this domain. The review also addresses operational challenges including intermittency and scalability and introduces system topologies that enhance both efficiency and performance. However it is essential to consider these challenges carefully because they can significantly impact the overall effectiveness of hydrogen production systems. By providing a comprehensive assessment of these hybrid systems (which are gaining traction) this study highlights their potential to address the increasing global energy demands. However it also aims to support the transition toward a carbon-neutral future. This potential is significant because it aligns with both environmental goals and energy requirements. Although challenges remain the promise of these systems is evident.

Renewable hydrogen production from biomass thermochemical conversion is an emerging technology to reduce fossil fuel consumptions and carbon emissions. Biomass-derived hydrogen can be produced by pyrolysis gasification alkaline thermal treatment etc. However the removal of impurities from biomass thermochemical conversion products to improve hydrogen purity is currently technical bottleneck. It is important to assess and investigate the types and properties of impurities the difficulty of separation and the impact on downstream utilization of hydrogen in the biomass-derived hydrogen production process. The key objectives of this comprehensive review are: (1) to reveal the current status and necessity of developing biomass-derived hydrogen production; (2) to evaluate the types devices and impurities distribution of biomass thermochemical conversion; (3) to explore the formation pathways and removal technologies of typical impurities of tar CO2 sulfides and nitrides in hydrogen production process; and (4) to propose future insights on the separation technologies of typical impurities to promote the gradual substitution of biomass-derived hydrogen for fossil-derived energy.

As climate change intensifies determining a developing region’s role in achieving net-zero emissions worldwide is crucial. However regional efforts considering historical emissions remain underexplored. Here we assess energy system changes technology adoption and investments needed for developing regions including five major- and minor-emitting nations. Our analysis using an integrated assessment model shows a large gap in regional efforts toward global net-zero emissions stemming from the necessary shift of energy systems to low-carbon resources. The use of new technologies like electric vehicles hydrogen and carbon capture varies by region with the highest adoption required between 2020 and 2030. Financing this shift needs an average gross domestic product (GDP) investment rise of 0.464% in minor-emitting regions and up to 2.1% in major-emitting regions by 2085. Our results could guide policies and support setting quantifiable targets for developing nations. The findings are key to facilitating strategic technology use and finance mobilization to achieve a carbon-neutral future.

Water electrolysis is a promising technology for sustainable energy conversion and storage of intermittent and fluctuating renewable energy sources and production of high-purity hydrogen for fuel cells and various industrial applications. Low-temperature electrochemical water splitting technologies include alkaline proton exchange membrane and anion exchange membrane water electrolyses which normally consist of two coupled half reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Despite the advances over decades formidable challenges still exist and hinder the practical application of large-scale energy-efficient and economically viable water electrolysis including large energy penalty sluggish kinetics high cost of precious metal based electrocatalysts possible H2/O2 gas crossover difficulty in storage and distribution of H2. Herein we first briefly introduce the fundamentals of water electrolysis summarize the recommended standardized electrochemical characterization protocols and demonstrate the metrics and key performance indicators that are used to evaluate the performances of HER and OER electrocatalysts and electrolyser cells. Then we present six new strategies to mitigate the technical challenges in conventional water electrolysis. These emerging strategies for disruptive innovation of water electrolysis technology include overall water electrolysis based on bifunctional nonprecious electrocatalysts (or pre-catalysts) magnetic field-assisted water electrolysis decoupled water electrolysis hybrid water electrolysis acid/alkaline asymmetric electrolyte electrolysis and tandem water electrolysis. Finally the remaining challenges perspectives and future directions are discussed. This review will provide guidance and inspire more endeavours to deepen the mechanistic understanding and advance the development of water electrolysis.

The depletion of fossil fuels in the current world has been a major concern due to their role as a primary source of energy for many countries. As non-renewable sources continue to deplete there is a need for more research and initiatives to reduce reliance on these sources and explore better alternatives such as renewable energy. Hydrogen is one of the most intriguing energy sources for producing power from fuel cells and heat engines without releasing carbon dioxide or other pollutants. The production of hydrogen via the electrolysis of water using renewable energy sources such as solar energy is one of the possible uses for solid oxide electrolysis cells (SOECs). SOECs can be classified as either oxygen-ion conducting or proton-conducting depending on the electrolyte materials used. This article aims to highlight broad and important aspects of the hybrid SOEC-based solar hydrogen-generating technology which utilizes a mixed-ion conductor capable of transporting both oxygen ions and protons simultaneously. In addition to providing useful information on the technological efficiency of hydrogen production in SOEC this review aims to make hydrogen production more efficient than any other water electrolysis system.

On this episode we speak with Scott Weiss Senior Vice President for Corporate Strategy and Ashleigh Cotting Senior Manager for Green Fuels Marketing with Apex Clean Energy. Apex has a history of developing utility scale renewables with more than 2GW under management and with nearly 8GW of renewables financed. Apex also partnered with Plug Power in April 2021 to develop a 345MW wind facility to support a 30 tonne per day green hydrogen production facility.

We are excited to discuss the emerging opportunities in the US hydrogen market and learn more about the challenges and learnings that the first project is providing and how that helps the team build the next generation of production facilities particularly in the Gulf Coast.

The podcast can be found on their website.

For the second episode in this new season the team interviews Oghosa Erhahon to discuss hydrogen opportunities in Africa including the African Climate Summit in September and what to look forward to at COP28.

The podcast can be found on their website.

A multi-objective optimization is performed to obtain fueling conditions in hydrogen stations leading to improved filling times and thermodynamic efficiency (entropy production) of the de facto standard of operation which is defined by the protocol SAE J2601. After finding the Pareto frontier between filling time and total entropy production it was found that SAE J2601 is suboptimal in terms of these process variables. Specifically reductions of filling time from 47 to 77% are possible in the analyzed range of ambient temperatures (from 10 to 40 °C) with higher saving potential the hotter the weather conditions. Maximum entropy production savings with respect to SAE J2601 (7% for 10 °C 1% for 40 °C) demand a longer filling time that increases with ambient temperature (264% for 10 °C 350% for 40 °C). Considering average electricity prices in California USA the operating cost of the filling process can be reduced between 8 and 28% without increasing the expected filling time.

Green hydrogen is increasingly recognized as a pivotal energy carrier in the global transition toward low-carbon energy systems. Beyond its established applications in industry and transportation the development of green hydrogen could accelerate its integration into the power generation sector thus enabling a more sustainable deployment of renewable energy sources. Vietnam endowed with abundant renewable energy potential—particularly solar and wind—has a strong foundation for green hydrogen. This emerging energy source holds significant potential to support the strategic objectives in recent national energy policies aligning with the country’s socio-economic development. However despite this promise the integration of green hydrogen into Vietnam’s energy system remains limited. This paper provides a critical review of the current landscape of green hydrogen in Vietnam examining both the opportunities and challenges associated with its production and deployment. Special attention is given to regulatory frameworks infrastructure readiness and economic viability. Additionally the study also explores the potential of green hydrogen in enhancing energy security within the context of the national energy transition.