5 research outputs found
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Experimental Investigation of Hydrogen and Hydrogen/ Methane Mixture Leakage from Low-Pressure Natural Gas Infrastructure
A global interest to increase the use of renewable resources has spurred an interest in hydrogen (H2) gas as an energy carrier. Natural gas (NG) infrastructure has been proposed as a potential storage, transmission and distribution system for renewably produced gaseous H2 fuel. Introducing H2 to the NG system has raised concerns about H2 leakage from the system. In this thesis, the leakage of H2, NG and H2/NG blends is theoretically and experimentally examined. Experimental evidence that suggests 100% H2 gas leaks at the same rate as H2/ NG mixtures and 100% NG in typical existing low-pressure NG infrastructure on the customer-side of the meter is provided. Additionally, a review of the classical leak analysis literature resulted in the discovery of similar results, though not mentioned in the literature. The efficacy of a commercial mitigation measure to reduce gaseous fuel leakage from piping system known to leak is assessed. Finally, a two-step leakage mechanism theory that involves molecular dynamics and a tortuous leakage path with significant wall interactions is proposed to explain the results that suggest H2 leaks at the same rate as NG in typical low-pressure gas infrastructure
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Envisioning and Designing a Renewable Future with Offshore Wind and Hydrogen in California
Accelerating toward a future that is sustained by green energy is essential to avoid a climate catastrophe. While solar, onshore wind and batteries have become ubiquitous due to massive public funding and investments which have led to reduced costs and significant improvements in the technologies, achieving an energy system that is truly decarbonized across all sectors and net zero emissions requires a myriad of solutions to address the challenges associated with intermittent renewable energy.Offshore wind has a tremendous potential to contribute to decarbonization due to its high capacity factors and recent developments in platform foundation technologies. In the last decade, offshore wind has become a flourishing source of energy with many countries investing and deploying this technology. Hydrogen may be used as a transmission and storage medium for offshore wind. Solid oxide electrolysis (SOE) may also play a vital role in hydrogen production and decarbonization due to its advantageous thermodynamic and kinetic operating conditions. While any source of electricity can be used to power SOE systems, green hydrogen made from a renewable power source represents the most substantial and sustainable pathway forward to achieve net zero emissions. The goal of this work is to explore and assess how offshore wind and hydrogen can support a 100% renewable future in California. To achieve this, this work is divided into three main sections:First, the benefits and challenges of offshore wind are analyzed in California using generation duration curves, correlation analyses, demand-based metrics, and the discrete Fourier transform to assess the feasibility of integrating this energy with the electrical grid. Second, an SOE system coupled with offshore wind is designed and proposed, with an emphasis on modelling the thermodynamics of such a system. This work assesses the heat transfer, electrochemical efficiencies, and dynamics of an offshore platform. The results of this platform are compared with alternative electrolysis technologies including low temperature and high temperature proton exchange membrane systems. Finally, this work experimentally assesses the potential impacts of using seawater as the water source for a high temperature SOE cell. Using a variety of electrochemical analysis methods and tools, including polarization curves, electrochemical impedance spectroscopy, distribution of relaxation times, and Scanning Electron Microscopy, this study finds strong evidence of salt precipitation on the cell which did not appear to negatively impact the performance of the cell in the duration of the experiment
Envisioning and Designing a Renewable Future with Offshore Wind and Hydrogen in California
Recommended from our members
Experimental Investigation of Hydrogen and Hydrogen/ Methane Mixture Leakage from Low-Pressure Natural Gas Infrastructure
A global interest to increase the use of renewable resources has spurred an interest in hydrogen (H2) gas as an energy carrier. Natural gas (NG) infrastructure has been proposed as a potential storage, transmission and distribution system for renewably produced gaseous H2 fuel. Introducing H2 to the NG system has raised concerns about H2 leakage from the system. In this thesis, the leakage of H2, NG and H2/NG blends is theoretically and experimentally examined. Experimental evidence that suggests 100% H2 gas leaks at the same rate as H2/ NG mixtures and 100% NG in typical existing low-pressure NG infrastructure on the customer-side of the meter is provided. Additionally, a review of the classical leak analysis literature resulted in the discovery of similar results, though not mentioned in the literature. The efficacy of a commercial mitigation measure to reduce gaseous fuel leakage from piping system known to leak is assessed. Finally, a two-step leakage mechanism theory that involves molecular dynamics and a tortuous leakage path with significant wall interactions is proposed to explain the results that suggest H2 leaks at the same rate as NG in typical low-pressure gas infrastructure
Wide range in estimates of hydrogen emissions from infrastructure
Hydrogen holds tremendous potential to decarbonize many economic sectors, from chemical and material industries to energy storage and generation. However, hydrogen is a tiny, leak-prone molecule that can indirectly warm the climate. Thus, hydrogen emissions from its value chain (production, conversion, transportation/distribution, storage, and end-use) could considerably undermine the anticipated climate benefits of a hydrogen economy. Several studies have identified value chain components that may intentionally and/or unintentionally emit hydrogen. However, the amount of hydrogen emitted from infrastructure is unknown as emissions have not yet been empirically quantified. Without the capacity to make accurate direct measurements, over the past two decades, some studies have attempted to estimate total value chain and component-level hydrogen emissions using various approaches, e.g., assumptions, calculations via proxies, laboratory experiments, and theory-based models (simulations). Here, we synthesize these studies to provide an overview of the available knowledge on hydrogen emissions across value chains. Briefly, the largest ranges in estimated emissions rates are associated with liquefaction (0.15% to 10%), liquid hydrogen transporting and handling (2% to 20%), and liquid hydrogen refueling (2% to 15%). Moreover, present and future value chain emission rate estimates vary widely (0.2% to 20%). Field measurements of hydrogen emissions throughout the value chain are critically needed to sharpen our understanding of hydrogen emissions and, with them, accurately assess the climate impact of hydrogen deployment