Avoidance of partial load operation at coal-fired power plants by storing nuclear power through power to gas

The need of fast regulation of electricity production leads to a number of inconveniences occurred to the electric generation system and the electric market, especially to the nuclear power. A new concept to control nuclear power production is posed in order to allow the regulation of the electricity sent to the grid. This concept proposes the joint operation of a nuclear power plant, a coal power plant with postcombustion capture and a methanation plant. The cost effectiveness of this technology and its capability to reduce the CO₂ emissions -consumed in the methanation process- are assessed through the design and economic and environmental analysis of a hybrid facility. Mainly due to the increase of the operating hours of the coal-fired power plant, the environmental feasibility of the initial proposal seems to be limited. However, given that benefits are expected in the medium and long-term (2020–2030) for the Power to Gas facility, a future alternative use is proposed. The target of this new alternative configuration will be the storage of CO₂ together with the storage of renewable energy.     

Incentives and legal barriers for power-to-hydrogen pathways: An international snapshot

Rendering the energy system more sustainable can only be achieved through a combination of low-carbon energy production, energy efficiency, and coupling of energy sectors. In this context, Power-to-Hydrogen concepts for managing supply and demand, providing seasonal storage, and being the linking element between different sectors (electricity generation, gas grids, transport and industry), has attracted significant interest during the last decade. However, the deployment of technology is subject to legal barriers, which may differ from one region to another. On the contrary, there may be incentives to facilitate market introduction of a new technology.In this paper, an international network of experts under the umbrella of Task 38 of the International Energy Agency's Hydrogen Technology Collaboration Programme assesses the legal framework in ten countries regarding power-to-hydrogen applications. The most frequently considered pathway, from a legal standpoint, is using hydrogen for mobility applications. Only a few countries are implementing legal frameworks for diverse hydrogen applications.     

Power-to-gas: Amphibious yacht and fueling station

Renewable energy sources are being increasingly adopted, however their efficiency is limited by their intermittent nature leading to a mismatch with peak energy grid loading hours and dumping of excess produced energy. To date, much of the focus in renewable vehicles has been on automobiles. This largely overlooks the contribution from recreational boating to greenhouse gas emissions. We demonstrate that a power-to-gas model utilizing excess renewable energy can support boating activities in Ontario, Canada. As a proof-of-concept, we designed the refueling infrastructure, the fHuel+™ refueling station, and the onboard hydrogen utilization system for a high-speed luxury boat, the Hydronautic+™. The concept is built around a localized hydrogen economy. The present report focuses on the design and implementation of a technology specific to the demonstration site, but the overarching goal is to use this project as a proof of concept applicable to other sites across Canada and the United States.     

Coking behavior of nickel and a rhodium based catalyst used in steam reforming for power-to-gas applications

This paper proposes partial steam reforming of natural gas as a chemical storage option for excess electricity. Thermodynamic simulations with Aspen Plus^® show that highest process efficiencies are reached at low steam-to-carbon (S/C) ratios in the feed. However, coke deposition due to unwanted side or follow-up reactions and thus catalyst deactivation is likely in this operation range. In an experimental evaluation three catalysts were selected to test their resistance towards coking: two nickel based and one rhodium based noble metal catalyst. They were tested regarding their long-term stability at S/C ratios as low as 0 to 0.1 and reaction temperatures between 450 and 500 °C. A different reaction and deactivation behavior was observed for nickel and the noble metal catalysts. The measured life times of the noble metal catalyst were by a factor of at least 100 higher than for the two selected nickel catalysts at the applied reforming conditions. Furthermore, after each reforming experiment, a temperature-programmed oxidation (TPO) analysis was performed for the spent catalysts. Based on literature data, the measured CO₂ peaks at corresponding temperatures were related to the different forms of solid carbon depositions. Main carbonaceous species found on the nickel catalysts were of filamentous nature, whereas one or two more reactive C species with monoatomic or polymeric structure at much lower amount were detected on the noble metal catalyst. Further SEM analysis confirmed these findings.     

电转气地质储能技术的经济性分析

电转气(power-to-gas)是一项将电能转化为高能量密度可燃气体的化学储能技术,该技术与地质储能相结合,有望满足未来大容量储能需求,并成为未来有效储能技术选择之一.电转气地质储能技术中涉及电离制氢、甲烷化、二氧化碳(CO2)地质储存、人工合成甲烷(CH4)地质储存4个阶段.由于电转气地质储能技术发展处于初步阶段,...     

Investment screening model for spatial deployment of power-to-gas plants on a national scale – A Danish case

When transitioning to a 100% renewable energy system storing electricity becomes a focal point, as the resource flexibility is lost and the design of the energy system needs to provide flexibility and balancing options to integrate intermittent renewable resources. Using technologies such as power-to-gas offers an opportunity to store electricity in chemical form, which can be used as a long-term storage option. This paper develops a spatial modelling method by using a GIS tool to investigate potential generation sites for power-to-gas plants. The method determines the location of the plants by carbon source potential, proximity of the grid, costs of grid transmission and investment costs of the technology itself. By combining these types of data, it is possible to identify the investment costs of the power-to-gas plants. The method focuses on two paths: biogas upgrade and CO₂ methanation. The method is applied to a specific case by investigating the power-to-gas potential in Denmark. The potential and spatial deployment is found by examining the investment costs of plants with an annual gas production of 60 GWh. The findings of the analysis indicate that the biogas upgrade path is the cheapest one of the two, at the present cost level, but due to the relatively small number of biogas plants in Denmark, the chosen plant size is limited to around 55 plants. CO₂ methanation is a more costly path, but it has a larger potential of around 800 plants. As the analysis is based on the current sources for biogas and CO₂, it is important to emphasise that the potential for CO₂ methanation plants can be expected to diminish in the future as more renewable energy is introduced, lowering the need for thermal energy producers, while biogas production could see an increase. Nevertheless, the analysis of a specific case shows that the method gives a good indication of the extent of the power-to-gas resources by using a novel approach to the matter. The method can be applied in other countries as well, giving it a wide appeal.     

Flexible sector coupling with hydrogen: A climate-friendly fuel supply for road transport

The substantial expansion of renewable energy sources is creating the foundation to successfully transform the German energy sector (the so-called ‘Energiewende’). A by-product of this development is the corresponding capacity demand for the transportation, distribution and storage of energy. Hydrogen produced by electrolysis offers a promising solution to these challenges, although the willingness to invest in hydrogen technologies requires the identification of competitive and climate-friendly pathways in the long run. Therefore, this paper employs a pathway analysis to investigate the use of renewable hydrogen in the German passenger car transportation sector in terms of varying market penetration scenarios for fuel cell-electric vehicles (FCEVs). The investigation focuses on how an H₂ infrastructure can be designed on a national scale with various supply chain networks to establish robust pathways and important technologies, which has not yet been done. Therefore, the study includes all related aspects, from hydrogen production to fueling stations, for a given FCEV market penetration scenario, as well as the CO₂ reduction potential that can be achieved for the transport sector. A total of four scenarios are considered, estimating an FCEV market share of 1–75% by the year 2050. This corresponds to an annual production of 0.02–2.88 million tons of hydrogen. The findings show that the most cost-efficient H₂ supply (well-to-tank: 6.7–7.5 €/kg_H2) can be achieved in high demand scenarios (FCEV market shares of 30% and 75%) through a combination of cavern storage and pipeline transport. For low-demand scenarios, however, technology pathways involving LH₂ and LOHC truck transport represent the most cost-efficient options (well-to-tank: 8.2–11.4 €/kg_H2).     

Hybridization strategies of power-to-gas systems and battery storage using renewable energy

In this paper, the hybrid concept to use renewable electricity to produce hydrogen with an electrolyser in combination with a battery is introduced and analysed. This hybrid system opens the possibility to optimise operation and to increase operation times of the system and thus to improve the techno-economic performance. To analyse the performance, a model has been developed, which designs and operates a single or hybrid power-to-gas system in a cost optimal manner. The underlying method is a mixed integer linear programming (MILP) approach, which minimises total system costs. The cost optimisation modelling is performed by a case study for a hybrid electrolyser/battery system directly coupled with a large PV power plant without grid connection. The results show, that batteries can support electrolyser operation in a reasonable way. This is however associated with higher hydrogen production costs and not competitive compared to the installation of additional electrolyser capacity or curtailment of electricity.     

Fossil fuel reduction potential in Germany's transport sector by wind-to-hydrogen

Wind-to-hydrogen (WH) is a promising option for reducing greenhouse gas emissions in the transport sector. Therefore, the reduction potential of fossil fuels by WH was estimated taking meteorological, geographical, and technical constraints into account. The wind resource estimation is based on the application of the high-resolution (200 m × 200 m) wind speed-wind shear model (WSWS). Together with the power curves of the six most frequently installed wind turbines in 2017, WSWS was used to assess Germany's technical wind energy potential. The WH and fossil fuel reduction potentials were calculated based on proton exchange membrane electrolysis. Results from the wind resource assessment demonstrate that in addition to the currently realized wind energy (89 TWh/yr in 2017), which is directly used for electricity generation, Germany's technical onshore potential for WH is 780 TWh/yr. This amount of renewable energy available for WH could replace 80.1% of the fossil fuels currently used in the transport sector.     

Hydrogen for heat: Using underground hydrogen storage for seasonal energy shifting in northern climates

To determine if a power-to-gas pilot-scale plant would be possible in Oregon, a feasibility study was conducted that assessed the technical, political, economic, environmental, safety, and policy aspects of a potential project in the region. The results of this study were submitted as part of Oregon State University – Cascades' entry to the Hydrogen Education Foundation's 2018 student design competition. The Pacific Northwest has a need for long term energy storage (seasonal energy shifting) due to seasonally available low-priced, low-carbon electricity. There appears to be the political motivation and the technical feasibility to install a demonstration-scale power-to-gas plant in the region to assess the technical and economic performance of the system when exposed to real-world boundary conditions. However, preliminary economic analyses show the system will be challenged by low capacity factor operation resulting in a levelized cost of hydrogen of $121.81/kg_H2 when only using otherwise curtailed electricity, or $8.84/kg_H2 when running continuously for 6 months per annum. To fund a pilot scale plant a renewable gas development surcharge of $0.18/therm is proposed as a way for willing customers to support the decarbonization mission. There is precedent within the utility for such an incentive, indicating that it would be approved by the utility commission and could be a viable path forward for a pilot-scale plant.