Production & Supply Chain

This study investigates the decomposition of methane using solar thermal energy as a heat source. Instead of the direct thermal decomposition of the methane at a temperature of 1200 ◦C or higher a catalyst coated with carbon black on a metal foam was used to lower the temperature and activation energy required for the reaction and to increase the yield. To supply solar heat during the reaction a reactor suitable for a solar concentrating system was developed. In this process a direct heating type reactor with quartz was initially applied and a number of problems were identified. An indirect heating type reactor with an insulated cavity and a rotating part was subsequently developed followed by a thermal barrier coating application. Methane decomposition experiments were conducted in a 40 kW solar furnace at the Korea Institute of Energy Research. Conversion rates of 96.7% and 82.6% were achieved when the methane flow rate was 20 L/min and 40 L/min respectively.

Power-to-gas technology plays a key role in the success of the energy transformation. This paper addresses issues related to the legal and technical regulations specifying the rules for adding hydrogen to the natural gas network. The main issue reviewed is the effects of the addition of hydrogen to natural gas on the durability of diaphragm gas meters. The possibility of adding hydrogen to the gas network requires confirmation of whether within the expected hydrogen concentrations long-term operation of gas meters will be ensured without compromising their metrological properties and operational safety. Methods for testing the durability of gas meters applied at test benches and sample results of durability tests of gas meters are presented. Based on these results a metrological and statistical analysis was carried out to establish whether the addition of hydrogen affects the durability of gas meters over time. The most important conclusion resulting from the conducted study indicates that for the tested gas meter specimens there was no significant metrological difference between the obtained changes of errors of indications after testing the durability of gas meters with varying hydrogen content (from 0% to 15%).

Hydrogen production is the key in utilizing an excess renewable energy. Many studies and projects looked at the energy management systems (EMSs) that allow to couple hydrogen production with renewable generation. In the majority of these studies however hydrogen demand is either produced for powering fuel cells or sold to the external hydrogen market. Hydrogen demand from actual industrial plants is rarely considered. In this paper we propose an EMS based on the industrial cluster of GreenLab Skive (GLS) that can minimize the system’s operational cost or maximize its green hydrogen production. EMS utilizes a conventional and P2X demand response (DR) flexibility from electrolysis plant hydrogen storage tank electric battery and hydrogen-consuming plants to design the optimal schedule with maximized benefits. A potential addition to the existing components at GLS - an ammonia plant is modelled to identify its P2X potential and assess the economic viability of its construction. The results show a potential reduction of 51.5–61.6% for the total operational cost of the system and an increase of the share of green hydrogen by 10.4–37.6% due to EMS operation.

This study documents the results of economic assessment concerning four variants of coal gasification to hydrogen in a shell reactor. That assessment has been made using discounting methods (NPV: net present value IRR: internal rate of return) as well as indicators based on a free cash flow to firm (FCFF) approach. Additionally sensitivity analysis has been carried out along with scenario analysis in current market conditions concerning prices of hard coal lignite hydrogen and CO2 allowances as well as capital expenditures and costs related to carbon capture and storage (CCS) systems. Based on NPV results a negative economic assessment has been obtained for all the analyzed variants varying within the range of EUR −903 to −142 million although the variants based on hard coal achieved a positive IRR (5.1–5.7%) but lower than the assumed discount rates. In Polish conditions the gasification of lignite seems to be unprofitable in the assumed scale of total investment outlays and the current price of coal feedstock. The sensitivity analyses indicate that at least a 20% increase of hydrogen price would be required or a similar reduction of capital expenditures (CAPEX) and costs of operation for the best variant to make NPV positive. Analyses have also indicated that on the economic basis only the prices of CO2 allowances exceeding EUR 40/Mg (EUR 52/Mg for lignite) would generate savings due to the availability of CCS systems.

The study is focused on the technology and manipulation of production strategies for the cultivation of biomass from four strains of microalgae. Species of microalgae studied are: Chlorella vulgaris Dunaliella Scenedesmus quadricauda and Synechococcus spp. The effects of the rate and amount of CO₂ removal from the atmosphere and sequestration with dissolved oxygen on lipid production from accumulated biomass were studied. Also the rate of sequestration of both total and dissolved carbon was  investigated. Daily measurements of total organic and inorganic carbon sequestrated optical densities proximate analysis and kinetic parameters of the growing and cultivated microalga were monitored and carried out during the two phases of cultivation: dark and light phases. The values of maximum rate of carbon (IV) oxide removed rmax varied from 11.73 mg L ^-1 min ^-1 to 18.84 mg L ^-1 min ^-1 from Chlorella vulgaris to Synechoccocus spp. Important parameters such as biomass productivity maximum pH values obtained at cultivation lipid content of the produced biomass and the hydraulic detection time for all four strains of microalgae were considered and presented in comparison and with their individual and collective effects. The ratios of the rate of CO₂ absorption constant and the constant for the CO₂ desorption rate (k1/k2) occurred highest in Dunaliella suggesting that with a high uptake of CO₂ the algal strain is more effective in CO₂ CO2 sequestration. The best biomass producer in this study was the C. vulgaris (Xmax = 5400 mg L^-1 and Px = 35.1 mg L h ^-1) where biomass productivity is Px and the maximum cellular concentration is Xmax. C. vulgaris has the highest lipids productivity of 27% while Synechoccocus has the least (11.72%). In general biomass productivity may be inversely related; this fact may be explained by greater metabolic involvement of lipid biosynthesis. This pioneer study may be advanced further to developing models for strategic manipulation and optimisation approach in micro algal biomass cultivation.

Time is rapidly running out to make the crucial planning decisions and secure investment to keep the UK on track to deliver a reliable affordable and decarbonised energy system to meet future emissions regulation enshrined in the 2008 Climate Change Act according to a report published today by the Royal Academy of Engineering.

Prepared for the Prime Minister's Council for Science and Technology A critical time for UK energy policy details the actions needed now to create a secure and affordable low carbon energy system for 2030 and beyond.

The study looks at the future evolution of the UK’s energy system in the short to medium term. It considers how the system is expected to develop across a range of possible trajectories identified through modelling and scenarios.

The following actions for government are identified as a matter of urgency:

• enable local or regional whole-system large scale pilot projects to establish real-world examples of how the future system will work. These must move beyond  current single technology demonstrators and include all aspects of the energy systems along with consumer behaviour and financial mechanisms
• drive forward new capacity in the three main low carbon electricity generating technologies: nuclear carbon capture and storage (CCS) and offshore wind
• develop policies to accelerate demand reduction especially in domestic heating and introduce smarter demand management
• clarify and stabilise market mechanisms and incentives in order to give industry the confidence to invest.

New technologies could become unexpectedly significant – such as solar PV which has recently become much cheaper. But large scale deployment of novel technologies would take decades and the system cannot be planned on promises and aspirations alone. The Academy calls instead for a combination of known technologies to be scaled up to unprecedented levels and integrated in smarter ways.

The report notes that the addition of shale gas or tight oil is unlikely to have a major impact on the evolution of the UK's energy system as we already have secure and diverse supplies of hydrocarbons from multiple sources.

Dr David Clarke FREng who led the group that produced the report says: “Updating the UK energy system to meet the ‘trilemma’ of decarbonisation security and affordability is a massive undertaking. Meeting national targets affordably requires substantial decarbonisation of the electricity system by 2030 through a mix of nuclear power CCS and renewables with gas generation for balancing. Beyond 2030 we must then largely decarbonise heat and transport potentially through electrification but also using other options such as hydrogen and biofuels. We also need to adapt our transmission and distribution networks to become ‘smarter’”.

"Failure to plan the development of the whole energy system carefully will result at best in huge increases in the cost of delivery or at worst a failure to deliver. Substantial investment is needed and current investment capacity is fragile. For example in the last month projects like Carlton’s new Trafford CCGT plant have announced further financing delays and the hoped-for investment by Drax in the White Rose CCS demonstrator has been withdrawn. The UK has also dropped four places to 11th in EY’s renewable energy country attractiveness index.”

Link to document download on Royal Society Website

This paper presents a beneficial combination of biomass gasification and pyrolysis oil hydrodeoxygenation for advanced biofuel production. Hydrogen for hydrodeoxygenation (HDO) of liquid phase pyrolysis oil (LPP oil) was generated by gasification of softwood. The process merges dual fluidized bed (DFB) steam gasification which produces a hydrogen rich product gas and the HDO of LPP oil. Synthesis gas was used directly without further cleaning and upgrading by making use of the water gas-shift (WGS) reaction. The water needed for the water gas-shift reaction was provided by LPP oil. HDO was successfully performed in a lab scale over 36 h time on stream (TOS). Competing reactions like the Boudouard reaction and Sabatier reaction were not observed. Product quality was close to Diesel fuel specification according to EN 590 with a carbon content of 85.4 w% and a residual water content of 0.28 w%. The water-gas shift reaction was confirmed by CO/CO₂-balance high water consumption and 28% less hydrogen consumption during HDO.

LCAs of electric cars and electrolytic hydrogen production are governed by the consumption of electricity. Therefore LCA benchmarking is prone to choices on electricity data. There are four issues: (1) leading Life Cycle Impact (LCI) databases suffer from inconvenient uncertainties and inaccuracies (2) electricity mix in countries is rapidly changing year after year (3) the electricity mix is strongly fluctuating on an hourly and daily basis which requires time-based allocation approaches and (4) how to deal with nuclear power in benchmarking. This analysis shows that: (a) the differences of the GHG emissions of the country production mix in leading databases are rather high (30%) (b) in LCA a distinction must be made between bundled and unbundled registered electricity certificates (RECs) and guarantees of origin (GOs); the residual mix should not be applied in LCA because of its huge inaccuracy (c) time-based allocation rules for renewables are required to cope with periods of overproduction (d) benchmarking of electricity is highly affected by the choice of midpoints and/or endpoint systems and (e) there is an urgent need for a new LCI database based on measured emission data continuously kept up-to-date transparent and open access.

Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side forming an explosive gas. In this study a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement permeation cell pressure current density and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V while above the cell polarization is decisive. In addition a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness. This approach indicates that thin membranes do not provide increased safety issues compared to thick membranes. However operating an N212-based system instead of an N117-based one can generate twice the amount of hydrogen at the same system efficiency while only one compressor stage must be added.

End-of-Life (EoL) technologies and strategies are needed to support the deployment of fuel cells and hydrogen (FCH) products. This article explores current and novel EoL technologies to recover valuable materials from the stacks of proton exchange membrane fuel cells and water electrolysers alkaline water electrolysers and solid oxide fuel cells. Current EoL technologies are mainly based on hydrometallurgical and pyro-hydrometallurgical methods for the recovery of noble metals while novel methods attempt to recover additional materials through efficient safe and cost-competitive pathways. Strengths weaknesses opportunities and threats of the reviewed EoL technologies are identified under techno-economic environmental and regulatory aspects. Beyond technologies strategies for the EoL of FCH stacks are defined mainly based on the role of manufacturers and recovery centres in the short- mid- and long-term. In this regard a dual role manufacturer/recovery centre would characterise long-term scenarios within a potential context of a well-established hydrogen economy.