National Grid (United Kingdom)

Abstract The assessment of transmission H2 pipelines requires consideration of H2 degradation on fracture toughness, ductility and fatigue life. Gas inhibition is a technology that could assist the integrity management of future pipelines. Oxygen has shown strong mitigating effects against H2 embrittlement in laboratory experiments. However, its effectiveness and transferability to real pipeline conditions must be understood before implementing this technology. National Gas Transmission in collaboration with ROSEN investigated the viability of oxygen inhibition. Our results showed that oxygen is effective inhibiting H2 embrittlement, increasing the fracture resistance JQ to in-air levels and reducing fatigue crack growth rates by up to an order of magnitude depending on grade, frequency and loading conditions. These findings were consistent with the observed transition from quasi-cleavage to ductile fracture surfaces. OLGA simulations identified the flow conditions necessary to maintain a safe and uniform oxygen concentration within the H2 gas stream in terms of flow velocity, mixing configurations, injection locations and intervals. A high-level model of oxygen consumption at the pipe wall was developed. If these results could be proven transferable to representative pipeline scales, the use of gas inhibitors could enable optimised network efficiency, reduce H2 adoption cost and facilitate the energy transition.

Our study shows that site-specific estimates of dermal exposure to selected polycyclic aromatic hydrocarbons contained in contaminated gasworks soil result in lower average daily exposure and risk to human health when compared to the generic assumptions used in risk assessment software. We use site specific in vitro dermal bioavailability flux (μg/cm2/h) for benzo[a]pyrene measured by earlier research published by the authors, where dermal flux provides an analogue of diffusion through the skin and into systemic circulation. We used measured in vitro dermal flux for gasworks contaminated soil containing 150mg/kg of benzo[a]pyrene to estimate average daily exposure and risk using the Contaminated Land Exposure Assessment (CLEA) framework. Site-specific flux (0.00237ng/cm2/hour) was used to calculate an uptake of 23.7ng benzo[a]pyrene/m2 skin/hour, resulting in an average daily exposure (ADE) ranging from 20.7 to 37.3ng benzo[a]pyrene/kg bw/day for the first six years of a female child's life. The average ratio of average daily exposure to the Health Criteria Value (Index Dose) was 0.54, where a soil concentration of 278.4mg/kg is equivalent to a ratio of ADE to Index Dose of one. The results show that for the dermal pathway only, the risk to human health calculated using site-specific dermal flux is lower than using default values used in CLEA. In our discussion we highlight that dermal bioavailability varies between sites and PAH and that differences are likely to be influenced by the source of contamination and the physico-chemical properties of soil. Our findings support an evidence-based shift toward sample-specific parameters in regulatory risk assessment frameworks, but the scalability, inter-laboratory reproducibility, range and contaminants tested and the cost-effectiveness of in vitro flux testing need to be researched further before broader regulatory adoption.

As climate change accelerates and the energy crisis deepens, electric vehicle adoption is growing rapidly with strong governmental support. However, this growth is straining electricity networks, prompting expensive infrastructure upgrades and a need for smart charging solutions, including Grid-to-Vehicle and Vehicle-to-Grid. This research synthesizes residential vehicle travel patterns from statistical data to model the electrical demand profile from uncoordinated charging, capturing the diversity in driving behaviour. It then develops scalable models for unidirectional and bidirectional smart charging to assess their impact on system reliability and their capacity credit within a probabilistic Monte Carlo framework. The case studies additionally present sensitivities on smart charging participation, electric vehicle uptake, and installed wind capacity. Results show that both smart charging concepts enhance reliability and that their capacity contributions grow with increased user engagement and wind generation, though the benefits plateau beyond certain thresholds.

Abstract Environmental DNA (eDNA) monitoring has been used for great crested newt ( Triturus cristatus ) survey in the UK since the publication of a Defra‐funded trial in 2014. If eDNA results are to be used in support of a great crested newt licence, surveys must be performed during a 76‐day survey window (15 April–30 June) to coincide with peak great crested newt activity, and must follow the approved ethanol precipitation protocol. However, eDNA detection is possible in other months and filtration may be a more effective method of eDNA capture. We investigated whether the great crested newt eDNA survey season could be extended and filtration could be used for great crested newt eDNA capture by reviewing the available evidence and conducting a field study from April to October 2022. Paired water samples for ethanol precipitation and filtration were collected from 25 ponds once a month, resulting in 124 samples of each type. All samples ( N = 248) were analysed with the approved great crested newt quantitative PCR assay. Our results indicate that great crested newts can be reliably detected using both eDNA capture methods from April to August, with detection rates decreasing in September and October. Great crested newt eDNA detection was comparable or higher with filtration than ethanol precipitation. Practical implication. Acceptance of filtration for great crested newt eDNA surveys could allow more water to be processed for robust and reliable estimates of great crested newt presence. Extending the great crested newt eDNA survey season to August could allow more waterbodies to be surveyed for great crested newt presence (but not absence), and identification of sites that provide important habitat for great crested newts outside of the breeding season. This would also remove logistical challenges and costs associated with completing sampling within 11 weeks and laboratory analysis within 10 working days from sample receipt. Furthermore, great crested newt eDNA surveys could be more frequently carried out alongside monitoring for other species, which are typically surveyed from April to September/October or year‐round with conventional methods or eDNA surveys using filtration. This could enable infrastructure projects to develop more effective mitigation measures as well as reduce time required from surveyors and survey costs.

Composite insulators are widely adopted in power systems as they are vital transmission network assets, thanks to their beneficial properties such as lightweight, simple maintenance and deployment, and hydrophobicity. Unlike traditional inspection methods, such as visual inspection, monitoring the changes in the electric field profile could be a non-invasive aging indicator to assess the insulation integrity of composite insulators. In this paper, the changes in the electric field profile of a 66 kV composite insulator due to artificial defects were investigated using electro-optic (EO) probes. By implementing two probes, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$E_{z}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$E_{y}$</tex> components were taken into consideration. The results show that adopting such EO probes to measure the electric field profile changes is very promising for the early detection of composite insulator degradation and the avoidance of unplanned outages due to insulation failure.

The compatibility between insulating gases and solid materials is an important aspect of the assessment of newly developed eco-friendly replacement candidates of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SF}_{6}$</tex>. During the long-term operation of gas insulated switchgear (GIS) and lines (GIL), the insulation system is subjected to combined thermal and electrical stress. In this study, the compatibility of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{5} \boldsymbol{/} \text{1 3} / \text{82} \% \mathrm{C}_{4} ~\mathrm{F}_{7} ~\mathrm{N} / \mathrm{O}_{2} / \text{CO}_{2}$</tex> gas mixture with epoxy resin is investigated using long-duration thermal and electro-thermal tests. Two different experimental set-ups were implemented for the two different types of tests. The solid dielectric samples were extracted from an actual cone-type GIL spacer. The gas samples were analysed by means of gas chromatography mass spectroscopy (GC-MS) and the resulting decomposition products were identified. The solid insulation samples were examined by surface observation. The more noticeable impact on the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{5} / \text{1 3} / \text{8 2} \% \mathrm{C}_{4} ~\mathrm{F}_{7} ~\mathrm{N} / \mathrm{O}_{2} / \text{CO}_{2}$</tex> gas mixture was observed at test temperatures close to the glass transition temperature of epoxy resin. Decomposition products such as CO and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{C}_{3} ~\mathrm{F}_{6}$</tex> were found to be indicators of interaction between the gas and the solid dielectric.

In this investigation we have carried out a comparative electrical aging study of a natural ester, a synthetic ester, a biosourced hydrocarbon fluid and a conventional mineral oil. Repeated electrical discharges were applied to the oils and the resulting physical, chemical, and dielectric changes were characterized. General effects of aging include yellowing, increased water content, reduced viscosity and increased dielectric loss. Whilst the aged oils continue to meet the requirements of the applicable IEC standards for service aged oils after the maximum period of aging, the synthetic ester is less resistant to electrical aging than the natural ester, whilst the biofluid and mineral oil offer comparably good performance.

This paper examines the induced electromagnetic effects on T-pylon transmission line caused by circuit coupling in a newly implemented 400 kV double-circuit power network in the United Kingdom. This system comprises interconnected segments of T-pylons, lattice towers, and underground cables. The study further evaluates the effectiveness of Drain Earth Shorting Scheme (DrESS) conductors in mitigating these effects by analyzing induced currents on earth wires, phase-to-ground induced voltages, and tower footing currents. The induced effects in the hybrid power network are investigated using ATP-EMTP assuming the pi-transmission line model, considering a soil resistivity of 100 Ω.m, and tower footing resistance of 3 Ω. The results indicate that induced currents on the ground wires of the energized side are consistently higher due to strong magnetic coupling. However, after the installation of DrESS conductors, a significant reduction is observed in the ground wire current on the non-energized side. Regarding induced voltages, a V-shaped distribution is identified along the T-pylon line, with peak magnitudes occurring at the endpoints. The application of DrESS significantly reduces the peak induced voltages while altering the overall voltage profile. Additionally, tower footing currents exhibit a U-shaped distribution, with peak values near transition points between T-pylons and lattice towers, as well as at underground cable junctions. The highest current is recorded at the final T-pylon, while the lowest values appear at segment midpoints. The installation of DrESS conductors effectively reduces tower footing currents at the initial T-pylons. These findings demonstrate that DrESS installation significantly mitigates induced voltages and currents on the non-energized circuit, enhancing safety for maintenance personnel working on T-pylons.

Modern-day progress in industrial, agricultural, and commercial sectors as well as desired human comfort, entirely depend on the availability of the energy. Over the years, the importance of energy in daily routine activities has dominantly increased. Customers mainly use multiple energy streams/carriers, such as electricity, natural gas, coal, liquid fossil fuels, biogas, renewables and steam, etc., in a building to fulfill their energy needs. To successfully operate a multi-energy community, planning, development and operations of the energy system may be conducted in a manner to attain energy justice and equity among different stakeholders. Primary elements in a just and fair energy community are that all the stakeholders (customers and utilities) get identical, unbiased, and sustainable energy access to attain their objectives. Energy market participants focus on the objectives that affect human safety, environmental cleanliness as well as quality, affordability, and reliability of different types of energy streams, available to every stakeholder in an unbiased way. However, a question as to how this equity and justice may be promoted among the participants of the energy community remains an important area to be studied yet. This chapter discusses the structure, characteristics, and schemes of an equal and just multi-energy system that serves all the key players on a fair basis to promote justice among them. Further, solution for various energy injustices have been proposed.

Retrofitting existing buildings for sustainability has become a critical endeavor in the quest for more energy-efficient and environmentally friendly built environments. This abstract explores the techniques and case studies associated with sustainable retrofitting, highlighting the challenges, benefits, and best practices in this field. The sustainable retrofitting of existing buildings involves the application of innovative technologies and strategies to improve energy efficiency, reduce environmental impact, and enhance occupant comfort. Techniques such as improved insulation, energy-efficient lighting, and HVAC system upgrades are commonly employed to achieve these goals. Additionally, the integration of renewable energy sources, such as solar panels and wind turbines, can further enhance the sustainability of retrofitted buildings. Several case studies illustrate the successful implementation of sustainable retrofitting techniques. For example, the Empire State Building in New York City underwent a comprehensive retrofitting project that resulted in a 38% reduction in energy consumption and a 105,000 metric ton reduction in greenhouse gas emissions annually. Similarly, the Bullitt Center in Seattle, Washington, is a net-zero energy building that was retrofitted to achieve high levels of energy efficiency and environmental sustainability. Challenges associated with sustainable retrofitting include high initial costs, technical complexities, and the need for skilled labor. However, the long-term benefits, such as reduced energy bills, increased property value, and a smaller environmental footprint, outweigh these challenges. Best practices for sustainable retrofitting include conducting a thorough energy audit, engaging with stakeholders, and selecting cost-effective and environmentally friendly technologies. In conclusion, sustainable retrofitting of existing buildings is a key strategy for achieving energy efficiency and environmental sustainability in the built environment. By employing innovative techniques and drawing on successful case studies, stakeholders can overcome challenges and reap the benefits of sustainable retrofitting.