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Energy System Changes in 1.5 °C, Well Below 2 °C and 2 °C Scenarios
Dec 2018
Publication
Meeting the Paris Agreement's goal to limit global warming to well below 2 °C and pursuing efforts towards 1.5 °C is likely to require more rapid and fundamental energy system changes than the previously-agreed 2 °C target. Here we assess over 200 integrated assessment model scenarios which achieve 2 °C and well-below 2 °C targets drawn from the IPCC's fifth assessment report database combined with a set of 1.5 °C scenarios produced in recent years. We specifically assess differences in a range of near-term indicators describing CO2 emissions reductions pathways changes in primary energy and final energy across the economy's major sectors in addition to more detailed metrics around the use of carbon capture and storage (CCS) negative emissions low-carbon electricity and hydrogen.
Techno-Economic Evaluation of Hydrogen-Based Cooking Solutions in Remote African Communities—The Case of Kenya
Apr 2023
Publication
Hydrogen has recently been proposed as a versatile energy carrier to contribute to archiving universal access to clean cooking. In hard-to-reach rural settings decentralized produced hydrogen may be utilized (i) as a clean fuel via direct combustion in pure gaseous form or blended with Liquid Petroleum Gas (LPG) or (ii) via power-to-hydrogen-to-power (P2H2P) to serve electric cooking (e-cooking) appliances. Here we present the first techno-economic evaluation of hydrogen-based cooking solutions. We apply mathematical optimization via energy system modeling to assess the minimal cost configuration of each respective energy system on technical and economic measures under present and future parameters. We further compare the potential costs of cooking for the end user with the costs of cooking with traditional fuels. Today P2H2P-based e-cooking and production of hydrogen for utilization via combustion integrated into the electricity supply system have almost equal energy system costs to simultaneously satisfy the cooking and electricity needs of the isolated rural Kenyan village studied. P2H2P-based e-cooking might become advantageous in the near future when improving the energy efficiency of e-cooking appliances. The economic efficiency of producing hydrogen for utilization by end users via combustion benefits from integrating the water electrolysis into the electricity supply system. More efficient and cheaper hydrogen technologies expected by 2050 may improve the economic performance of integrated hydrogen production and utilization via combustion to be competitive with P2H2P-based e-cooking. The monthly costs of cooking per household may be lower than the traditional use of firewood and charcoal even today when applying the current life-line tariff for the electricity consumed or utilizing hydrogen via combustion. Driven by likely future technological improvements and the expected increase in traditional and fossil fuel prices any hydrogen-based cooking pathway may be cheaper for end users than using charcoal and firewood by 2030 and LPG by 2040. The results suggest that providing clean cooking in rural villages could economically and environmentally benefit from utilizing hydrogen. However facing the complexity of clean cooking projects we emphasize the importance of embedding the results of our techno-economic analysis in holistic energy delivery models. We propose useful starting points for future aspects to be investigated in the discussion section including business and financing models.
Electrofuels from Excess Renewable Electricity at High Variable Renewable Shares: Cost, Greenhouse Gas Abatement, Carbon Use and Competition
Nov 2020
Publication
Increasing shares of variable renewable electricity (VRE) generation are necessary for achieving high renewable shares in all energy sectors. This results in increased excess renewable electricity (ERE) at times when supply exceeds demand. ERE can be utilized as a low-emission energy source for sector coupling through hydrogen production via electrolysis which can be used directly or combined with a carbon source to produce electrofuels. Such fuels are crucial for the transport sector where renewable alternatives are scarce. However while ERE increases with raising VRE shares carbon emissions decrease and may become a limited resource with several usage options including carbon storage (CCS). Here we perform a model based analysis for the German case until 2050 with a general analysis for regions with a high VRE reliance. Results indicate that ERE-based electrofuels could achieve a greenhouse gas (GHG) abatement of 74 MtCO2eq yearly (46% of current German transport emissions) by displacing fossil fuels at high fuel-cell electric vehicle (FCEV) shares at a cost of 250–320 V per tCO2eq. The capital expenditure of electrolysers was found not to be crucial for the cost despite low capacity factors due to variable ERE patterns. Carbon will likely become a limiting factor when aiming for stringent climate targets and renewable electricity-based hydrocarbon electrofuels replacing fossil fuels achieve up to 70% more GHG abatement than CCS. Given (1) an unsaturated demand for renewable hydrocarbon fuels (2) a saturated renewable hydrogen demand and (3) unused ERE capacities which would otherwise be curtailed we find that carbon is better used for renewable fuel production than being stored in terms of overall GHG abatement.
Everything About Hydrogen Podcast: Producing Hydrogen with Wind Energy
Sep 2022
Publication
On this episode of Everything About Hydrogen we are speaking with David Wellard Regulatory Affairs Manager at Orsted. Orsted is a global leader in renewable energy generation projects particularly when it comes to the rapidly expanding wind energy sector. Headquartered in Denmark the company has a global reach across multiple continents and technologies. David helps lead Orsted’s policy and regulatory engagement in the United Kingdom and beyond. We are excited to have him with us to discuss how Orsted is looking at and deploying hydrogen technologies and how they expect to utilized hydrogen in a decarbonized energy future.
The podcast can be found on their website.
The podcast can be found on their website.
Power Balance Control and Dimensioning of a Hybrid Off-grid Energy system for a Nordic Climate Townhouse
Mar 2023
Publication
This paper investigates conversion of a Nordic oil-heated townhouse into carbon-neutral by different energy efficiency (EE) improvements and an off-grid system including solar photovoltaics (PV) wind power and battery and hydrogen energy storage systems (BESS and HESS). A heat-pump-based heating system including waste heat recovery (WHR) from the HESS and an off-grid electrical system are dimensioned for the building by applying models developed in MATLAB and Microsoft Excel to study the life cycle costs (LCC). The work uses a measured electrical load profile and the heat generation of the new heating system and the power generation are simulated by commercial software. It is shown that the EE improvements and WHR from the HESS have a positive effect on the dimensioning of the off-grid system and the LCC can be reduced by up to €2 million. With the EE improvements and WHR the component dimensioning can be reduced by 22%–41% and 13%–51% on average respectively. WHR can cover up to 57% of the building's annual heat demand and full-power dimensioning of the heat pump is not reasonable when WHR is applied. Wind power was found to be very relevant in the Nordic conditions reducing the LCC by 32%.
Configuration Optimization of Hydrogen-Based Multi-Microgrid Systems under Electricity Market Trading and Different Hydrogen Production Strategies
Apr 2023
Publication
Hydrogen-based multi-microgrid systems (HBMMSs) are beneficial for energy saving and emission reductions. However the optimal sizing of HBMMSs lacks a practical configuration optimization model and a reasonable solution method. To address these problems we designed a novel structure of HBMMSs that combines conventional energy renewable energy and a hydrogen energy subsystem. Then we established a bi-level multi-objective capacity optimization model while considering electricity market trading and different hydrogen production strategies. The objective of the inner model which is the minimum annual operation cost and the three objectives of the outer model which are the minimum total annual cost (TAC); the annual carbon emission (ACE); and the maximum self-sufficiency rate (SSR) are researched simultaneously. To solve the above optimization model a two-stage solution method which considers the conflicts between objectives and the objectivity of objective weights is proposed. Finally a case study is performed. The results show that when green hydrogen production strategies are adopted the three objectives of the best configuration optimization scheme are USD 404.987 million 1.106 million tons and 0.486 respectively.
The Potential Role of Flying Vehicles in Progressing the Energy Transition
Oct 2022
Publication
An energy transition is in progress around the globe notably led by an increase in the deployment of renewable energy and a shift toward less emissions-intense options notably in the transportation sector. This research investigates the potential role that new transportation options namely flying vehicles may play toward progressing the energy transition. As flying vehicles are a relatively new technology yet to penetrate the market it is also prudent to consider the ethical legal and social issues (ELSI) associated with their implementation alongside the potential energy and environmental impacts. Through a review of ELSI and energy and environmental literature we identify research gaps and identify how flying vehicles may impact upon the energy transition over time. Our research identifies several critical aspects of both ELSI and energy and environmental academia relevant to the future deployment of flying vehicles and describes a deployment timeline and the resultant societal outcomes. We find that flying vehicles could drive the energy transition and the hydrogen economy and that their widespread adoption could engender shared socio-environmental benefits. Our findings are relevant to transportation and environmental policymakers and identify critical considerations for the planned introduction of new shared transportation options to the market conducive to a sustainable energy transition.
Development and Testing of a 100 kW Fuel-flexible Micro Gas Turbine Running on 100% Hydrogen
Jun 2023
Publication
Hydrogen as a carbon-free energy carrier has emerged as a crucial component in the decarbonization of the energy system serving as both an energy storage option and fuel for dispatchable power generation to mitigate the intermittent nature of renewable energy sources. However the unique physical and combustion characteristics of hydrogen which differ from conventional gaseous fuels such as biogas and natural gas present new challenges that must be addressed. To fully integrate hydrogen as an energy carrier in the energy system the development of low-emission and highly reliable technologies capable of handling hydrogen combustion is imperative. This study presents a ground-breaking achievement - the first successful test of a micro gas turbine running on 100% hydrogen with NOx emissions below the standard limits. Furthermore the combustor of the micro gas turbine demonstrates exceptional fuel flexibility allowing for the use of various blends of hydrogen biogas and natural gas covering a wide range of heating values. In addition to a comprehensive presentation of the test rig and its instrumentation this paper illuminates the challenges of hydrogen combustion and offers real-world operational data from engine operation with 100% hydrogen and its blends with methane.
Hydrogen Combustion, Production, and Applications: A Review
May 2024
Publication
The demand for fossil fuels is rising rapidly leading to increased greenhouse gas emissions. Hydrogen has emerged as a promising clean energy alternative that could help meet future demands way sustainably especially if produced using renewable methods. For hydrogen to meaningfully contribute to energy transitions it needs more integration into sectors like transportation buildings and power that currently have minimal hydrogen usage. This requires developing extensive cross-sector hydrogen infrastructure. This review examines hydrogen combustion as a fuel by exploring and comparing production techniques enriching ammonia with hydrogen as a CO2-free option and hydrogen applications in engines. Additionally a techno-economic environmental risk analysis is discussed. Results showed steam methane reforming is the most established and cost-effective production method at $1.3–1.5/kg H2 and 70–85% efficiency but generates CO2. Biomass gasification costs $1.25–2.20/kg H2 and pyrolysis $1.77–2.05/kg H2 offering renewable options. However bio-photolysis currently has high costs of $1.42–2.13/kg H2 due to low conversion rates requiring large reactors. Blending H2/NH3 could enable carbon-free combustion aiding carbon neutrality pursuits but minimizing resultant NOx is crucial. Hydrogen’s wide uses from transportation to power underline its potential as a transformational energy carrier.
A Review of Hydrogen-based Hybrid Renewable Energy Systems: Simulation and Optimization with Artificial Intelligence
Nov 2021
Publication
With the massive use of traditional fossil fuels greenhouse gas emissions are increasing and environmental pollution is becoming an increasingly serious problem which led to an imminent energy transition. Therefore the development and application of renewable energy are particularly important. This paper reviews a wide range of issues associated with hybrid renewable energy systems (HRESs). The issues concerning system configurations energy storage options simulation and optimization with artificial intelligence are discussed in detail. Storage technology options are introduced for stand-alone (off-grid) and grid-connected (on-grid) HRESs. Different optimization methodologies including classical techniques intelligent techniques hybrid techniques and software tools for sizing system components are presented. Besides the artificial intelligence methods for optimizing the solar/wind HRESs are discussed in detail.
Minimizing Emissions from Grid-based Hydrogen Production in the United States
Jan 2023
Publication
Low-carbon hydrogen could be an important component of a net-zero carbon economy helping to mitigate emissions in a number of hard-to-abate sectors. The United States recently introduced an escalating production tax credit (PTC) to incentivize production of hydrogen meeting increasingly stringent embodied emissions thresholds. Hydrogen produced via electrolysis can qualify for the full subsidy under current federal accounting standards if the input electricity is generated by carbon-free resources but may fail to do so if emitting resources are present in the generation mix. While use of behind-the-meter carbon-free electricity inputs can guarantee compliance with this standard the PTC could also be structured to allow producers using grid-supplied electricity to qualify subject to certain clean energy procurement requirements. Herein we use electricity system capacity expansion modeling to quantitatively assess the impact of grid-connected electrolysis on the evolution of the power sector in the western United States through 2030 under multiple possible implementations of the clean hydrogen PTC. We find that subsidized grid-connected hydrogen production has the potential to induce additional emissions at effective rates worse than those of conventional fossil-based hydrogen production pathways. Emissions can be minimized by requiring grid-based hydrogen producers to match 100% of their electricity consumption on an hourly basis with physically deliverable ‘additional’ clean generation which ensures effective emissions rates equivalent to electrolysis exclusively supplied by behind-the-meter carbon-free generation. While these requirements cannot eliminate indirect emissions caused by competition for limited clean resources which we find to be a persistent result of large hydrogen production subsidies they consistently outperform alternative approaches relying on relaxed time matching or marginal emissions accounting. Added hydrogen production costs from enforcing an hourly matching requirement rather than no requirements are less than $1 kg−1 and can be near zero if clean firm electricity resources are available for procurement.
Green Hydrogen Futures: Tensions of Energy and Justice Within Sociotechnical Imaginaries
May 2024
Publication
As a reformist approach to low-carbon transitions green hydrogen is often promoted as an easy replacement for fossil fuels. This substitution narrative makes this technology compelling as it offers to reduce emissions while continuing the contemporary energy system. Using ‘sociotechnical imaginaries’ this paper explores the underlying political processes on what appears to be a mostly technical vision of green hydrogen. Analysis through expert interviews in Aotearoa New Zealand revealed two contrasting energy visions one emphasizing the technical role of green hydrogen in New Zealand's transition—the green hydrogen imaginary and the other which advocated for a future motivated by social change—the alternative energy imaginary. Comparing the tensions through a lens of hydrogen justice exposed the assumptions and exclusions present in the emerging green hydrogen imaginary. This paper argues that the technocratic business as usual approach of green hydrogen depoliticizes the social nature of energy and thus risks perpetuating inequalities and harms present in the current energy system. However these critiques also suggest that there is hope for green hydrogen to be reimagined in more ethical and just ways.
A Study on the Viability of Fuel Cells as an Alternative to Diesel Fuel Generators on Ships
Jul 2023
Publication
This study investigates methods for reducing air pollution in the shipping sector particularly in port areas. The study examines the use of fuel cells as an alternative to diesel generators. Environmental pollution at ports remains a critical issue so using fuel cells as an alternative to conventional energy systems warrants further research. This study compares commercial fuel cell types that can be used on a case study very large crude carrier (VLCC) vessel specifically although the technology is applicable to other vessels and requirements. Seven different fuel cell types were ranked based on five criteria to accomplish this. The proton-exchange membrane cell type was found to be the most suitable fuel cell type for the case study vessel. Based on the input fuel ammonia-based hydrogen storage has been identified as the most promising option along with using an ammonia reforming unit to produce pure hydrogen. Furthermore this study provides an integrated fuel cell module and highlights the economic environmental and maintenance aspects of implementing the proton-exchange membrane fuel cell module for this case study. It also calculates the required space as a crucial constraint of implementing fuel cell technology at sea.
Potential Economic Benefits of Carbon Dioxide (CO2) Reduction Due to Renewable Energy and Electrolytic Hydrogen Fuel Deployment Under Current and Long Term Forecasting of the Social Carbon Cost (SCC)
May 2019
Publication
The 2016 Paris Agreement (UNFCCC Authors 2015) is the latest of initiative to create an international consensus on action to reduce GHG emissions. However the challenge of meeting its targets lies mainly in the intimate relationship between GHG emissions and energy production which in turn links to industry and economic growth. The Middle East and North African region (MENA) particularly those nations rich oil and gas (O&G) resources depend on these as a main income source. Persuading the region to cut down on O&G production or reduce its GHG emissions is hugely challenging as it is so vital to its economic strength. In this paper an alternative option is established by creating an economic link between GHG emissions measured as their CO2 equivalent (CO2e) and the earning of profits through the concept of Social Carbon Cost (SCC). The case study is a small coastal city in Libya where 6% of electricity is assumed to be generated from renewable sources. At times when renewable energy (RE) output exceeds the demand for power the surplus is used for powering the production of hydrogen by electrolysis thus storing the energy and creating an emission-free fuel. Two scenarios are tested based on short and long term SCCs. In the short term scenario the amount of fossil fuel energy saved matches the renewable energy produced which equates to the same amount of curtailed O&G production. The O&G-producing region can earn profits in two ways: (1) by cutting down CO2 emissions as a result of a reduction in O&G production and (2) by replacing an amount of fossil fuel with electrolytically-produced hydrogen which creates no CO2 emissions. In the short term scenario the value of SCC saved is nearly 39% and in the long term scenario this rose to 83%.
Technology Transfer from Fuel Processing for Fuel Cells to Fuel Synthesis from Hydrogen and Carbon Dioxide
Aug 2023
Publication
Improving the energy efficiency of existing technologies such as the on-board power supply of trucks ships and aircraft is an important endeavor for reducing primary energy consumption. The approach consists of using fuel cell technology in conjunction with hydrogen production from liquid fuels. However the energy transition with the goal of complete climate-neutrality requires technological changes in the use of hydrogen produced from renewable energy via electrolysis. Synthetic fuels are an important building block for drive systems that will continue to require liquid energy carriers in the future due to their range. This study addresses the question of whether technical devices that were developed for the generation of hydrogen from liquid fuels for fuel cells to generate electricity are now suitable for the reverse process chain or can play an important role in it. The new process chain produces hydrogen from sustainable electricity combining it with carbon dioxide to create a synthetic liquid fuel.
Renewable Hydrogen: Modular Concepts from Production over Storage to the Consumer
Jan 2021
Publication
A simulation tool called HYDRA to optimize individual hydrogen infrastructure layouts is presented. The different electrolyzer technologies namely proton exchange membrane electrolysis anion exchange membrane electrolysis alkaline electrolysis and solid oxide electrolysis as well as hydrogen storage possibilities are described in more detail and evaluated. To illustrate the application opportunities of HYDRA three project examples are discussed. The examples include central and decentral applications while taking the usage of hydrogen into account.
Necessary and Sufficient Conditions for Deploying Hydrogen Homes: A Consumer-oriented Perspective
May 2024
Publication
As part of its efforts to secure a ‘net-zero society’ the UK government will take a strategic decision on the role of hydrogen in decarbonising homes within the next years. While scholars have recently advanced the social science research agenda on hydrogen technology acceptance studies are yet to engage with the prospective dynamics of adopting ‘hydrogen homes’. In response this study examines the perceived adoption potential of hydrogen heating and cooking technologies as evaluated through the eyes of consumer. Engaging with behavioural and market acceptance this research draws on data from a broadly nationally representative online survey to examine the influence of safety technological economic environmental and emotional factors on the domestic hydrogen transition in the UK context. The analysis follows a multi-stage empirical approach integrating findings from partial least squares structural equation and necessary condition analysis to crystallise insights on this emergent subject. At this juncture perceived adoption potential may hinge primarily on emotional environmental safety and to a lesser extent technological perspectives. However consumers have an expressed preference for hydrogen heating over hydrogen cooking with perceived boiler performance emerging as a necessary condition for enabling adoption potential. At the formative phase of the transition risks associated with energy insecurity and fuel poverty exceed concerns over purchasing and running costs. Nevertheless economic factors remain less critical during the pre-deployment phase of the innovation-decision process. Across the full sample simple slope analysis highlights the moderating effects of gender age and housing tenure. Moreover statistically significant differences from both a sufficiency- and necessity-based perspective are detected between male property owners aged 55+ and female mortgage owners 18–34 years old. By bridging the knowledge gap between social acceptance and adoption intention this contribution reinforces the need for consumer engagement in the hydrogen economy advocating for more fine-grained mixed-methods analyses of technology acceptance dynamics to support decarbonisation strategies.
Evaluating Hydrogen-based Electricity Generation using the Concept of Total Efficiency
Aug 2023
Publication
The popularity of hydrogen has been increasing globally as a promising sustainable energy source. However hydrogen needs to be produced and processed before it can be used in the energy sector. This paper uses total efficiency to evaluate the lifecycle of hydrogen-driven power generation. Total efficiency introduces the energy requirement of fuel preparation in conventional efficiency and is a reliable method to fairly compare different energy sources. Two case studies in Spain and Germany with nine scenarios each are defined to study different hydrogen-preparation routes. The scenarios include the main colors of hydrogen production (grey turquoise yellow and green) and different combinations of processing and transportation choices. In most cases the highest energy penalty in the overall preparation process of the fuel is linked to the production step. A large difference is found between fossil fuel-based hydrogen and green hydrogen derived from excess renewable energy with fossil fuel-based hydrogen resulting in significantly lower total efficiencies compared to green hydrogen. The use of natural gas as the primary source to generate hydrogen is found to be a critical factor affecting total efficiency particularly in cases where the gas must be transported from far away. This shows the value of using excess renewable energy in the production of hydrogen instead of grid power. Even in the most efficient scenario of green hydrogen studied total efficiency was found to be 7 % lower than the respective conventional efficiency that does not account for hydrogen generation. These results emphasize the importance of considering the impact of fuel preparation stages in comparative thermodynamic analyses and evaluations.
LCA of a Proton Exchange Membrane Fuel Cell Electric Vehicle Considering Different Power System Architectures
Sep 2023
Publication
Fuel cell electric vehicles are a promising solution for reducing the environmental impacts of the automotive sector; however there are still some key points to address in finding the most efficient and less impactful implementation of this technology. In this work three electrical architectures of fuel cell electric vehicles were modeled and compared in terms of the environmental impacts of their manufacturing and use phases. The three architectures differ in terms of the number and position of the DC/DC converters connecting the battery and the fuel cell to the electric motor. The life cycle assessment methodology was employed to compute and compare the impacts of the three vehicles. A model of the production of the main components of vehicles and fuel cell stacks as well as of the production of hydrogen fuel was constructed and the impacts were calculated using the program SimaPro. Eleven impact categories were considered when adopting the ReCiPe 2016 midpoint method and the EF (adapted) method was exploited for a final comparison. The results highlighted the importance of the converters and their influence on fuel consumption which was identified as the main factor in the comparison of the environmental impacts of the vehicle.
Integration of Air-cooled Multi-stack Polymer Electrolyte Fuel Cell Systems into Renewable Microgrids
May 2022
Publication
Currently there is a growing interest in increasing the power range of air-cooled fuel cells (ACFCs) as they are cheaper easier to use and maintain than water-cooled fuel cells (WCFCs). However air-cooled stacks are only available up to medium power (<10 kW). Therefore a good solution may be the development of ACFCs consisting of several stacks until the required power output is reached. This is the concept of air-cooled multi-stack fuel cell (AC-MSFC). The objective of this work is to develop a turnkey solution for the integration of AC-MSFCs in renewable microgrids specifically those with high-voltage DC (HVDC) bus. This is challenging because the AC-MSFCs must operate in the microgrid as a single ACFC with adjustable power depending on the number of stacks in operation. To achieve this the necessary power converter (ACFCs operate at low voltages so high conversion rates are required) and control loops must be developed. Unlike most designs in the literature the proposed solution is compact forming a system (AC-MSFCS) with a single input (hydrogen) and a single output (high voltage regulated power or voltage) that can be easily integrated into any microgrid and easily scalable depending on the power required. The developed AC-MSFCS integrates stacks balance of plant data acquisition and instrumentation power converters and local controllers. In addition a virtual instrument (VI)has been developed which connected to the energy management system (EMS) of the microgrid allows monitoring of the entire AC-MSFCS (operating temperature purging cell voltage monitoring for degradation evaluation stacks operating point control and alarm and event management) as well as serving as a user interface. This allows the EMS to know the degradation of each stack and to carry out energy distribution strategies or specific maintenance actions which improves efficiency lifespan and of course saves costs. The experimental results have been excellent in terms of the correct operation of the developed AC-MSFCS. Likewise the accumulated degradation of the stacks was quantified showing cells with a degradation of >80%. The excellent electrical and thermal performance of the developed power converter was also validated which allowed the correct and efficient supply of regulated power (average efficiency above 90%) to the HVDC bus according to the power setpoint defined by the EMS of the microgrid.
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