The UK government is undergoing an extensive evidence gathering process and aims to decide the future of the gas grid by 2025. This is a study which aims to determine the technical and economic feasibility of converting the existing natural gas network in Leeds to 100% hydrogen. The theoretical as well as practical issues are currently being actively explored through the pilot H21 Leeds City Gate project. There are considerable safety testing issues for every step in the new hydrogen supply chain. īoth SMR and CCS technology are currently underdeveloped. It does however face many practical hurdles including: -Īll natural gas using appliances would require replacements (most of which currently do not exist). Due to the inherent similarities with gas, it is argued that this would represent a less intrusive transition for end users than a switch to heat pumps or heat networks. Hydrogen could then replace natural gas in the existing distribution pipe work. SMR requires large-scale plant to convert natural gas into hydrogen and capture the carbon dioxide at source for sequestration. This leads to a high capital investment with an unfavorable abatement curve depending on small operating windows. Įlectrolysis requires considerable electricity use and would likely need to be paired with a power source that would otherwise be curtailed (e.g., excess wind at off-peak times). Industrial scale hydrogen production typically comes from either electrolysis, steam methane reforming (SMR), or in small amounts as a by-product of other processes. Hydrogen is the carbon-free gas with higher potential for scalability. Biomethane production can realistically only meet a small fraction of UK heat demand. This typically means a green gas such as biomethane, or hydrogen. The main alternative to electrification is carbon-free gas. If heat pumps were to make up between 60% and 80% of UK heat, then the increase in grid peak loads could be anywhere from 20% to 100% depending on the use of the thermal storage and smart controls. This is the subject of much study, but also much uncertainty given the range of unknowns. Aside from these implementation issues, the core infrastructure challenge to heat pumps is the increase in peak loads that it imposes on the grid. Heat pumps face a range of barriers in the United Kingdom from high upfront costs to low consumer confidence in the technology. Heat pumps currently represent a minute fraction of heating in the United Kingdom (∼2%) but there are calls to increase uptake by over 30 TWh (or 2 million units) (r) by 2030. There are potential efficiency gains through enabling technologies such as heat networks that will be discussed below. Consider first the electrification of heat.Įlectrification of heat primarily refers to heat pumps. However, in terms of core fuels there are really only two options: electricity from a green grid and carbon-free gas. There are a number of enabling technologies such as heat pumps and energy networks that can improve the efficiency of heat delivery. Pegah Mirzania, in Future Energy (Third Edition), 2020 28.13 Electrification versus hydrogen In addition, an overview on the mathematical models used for simulating the MSR reaction in a membrane reactor is also presented and discussed.Īndy Ford. Therefore, in this chapter, the relevant progress achieved so far, the most relevant topics of MSR via membrane reactor technology, and the effects of the most important parameters affecting MSR in membrane reactors are described and critically reviewed. As a result, high-purity hydrogen, methane conversion, and hydrogen production enhancement are obtained as well as the possibility to perform the MSR reaction at milder operating conditions than CRs. In particular, the use of a hydrogen perm-selective membrane inside of a reactor allows the combination of the chemical reaction and hydrogen separation in only one tool. Therefore, in order to intensify the whole process, a membrane reactor can be used as alternative solution to conventional systems. Industrially, the MSR reaction is carried out in conventional reactors (CRs) and, in order to obtain a highly pure hydrogen stream, several steps are necessary, such as the reduction of carbon monoxide content in the reformate stream by water gas shift reactors, pressure swing adsorption, and further hydrogen separation/purification devices. Although MSR is a mature technology, it suffers from significant disadvantages such as mass and heat transfer issues and coke deposition during the reaction. Methane steam reforming (MSR) is the most common and cost-effective method for hydrogen production, and it contributes about 50% of the world's hydrogen production. Iulianelli, in Membrane Reactors for Energy Applications and Basic Chemical Production, 2015 Abstract
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