## 4 Discussion
### Use of Geospatial Techniques in HVC
Incorporating social-acceptance factors (visibility, land use, population density) into spatial LCOH models can further guide infrastructure sitting with minimal public resistance. Safety is one of the key barriers to holding back the development of hydrogen technologies. Remote sensing has also been recently applied to detecting leaks in pipelines. One of the characteristics of hydrogen is that the flame is invisible, which makes it difficult to detect visually, especially in large installations or in remote applications such as the hydrogen pipeline network. For this reason, provided that multispectral and infrared satellite imagery can identify thermal variations on the Earth's surface, they can be applied in this context to detect thermal losses or temperature changes caused by leaks in surface pipelines and identify abnormal heating zones that could indicate uncontrolled evaporation. They can also be used to monitor remote areas to improve maintenance efficiency. On the other hand, hydrogen pipelines are often underground making leak detection by traditional methods (such as anomalous pressure differentials) challenging. In this sense, the use of machine learning-based models trained with GIS layer variables can estimate the probability of failure or leakage in different segments of the network considering variables such as material age, pressure, geological environment and slopes, among others. Maintenance and failure history can also be used to train supervised models that detect risk patterns and help implement predictive maintenance systems when an increased likelihood of structural deterioration is indicated. The integration of Satellite Based Augmentation System (SBAS) with GIS can generate dynamic ground deformation maps in areas where critical infrastructure is located, allowing georeferenced alerts to be generated in areas with shifting and deformed soils. Pressure, temperature, and vibration sensors can be added to create an integrated geospatial monitoring system. Finally, the end-use stage within HVC is considered to have a significant impact on the social acceptance of the technology. It is the stage closest to the end-user, and it is vital that those first renewable hydrogen applications are successful for the perception and penetration of the technology to improve. In this sense, a GIS-IoT application with a web interface or mobile app can help improve the transparency of a facility's operation. For example, in an energy community that proposes hydrogen as a seasonal storage system, users' real-time availability of the energy flows of the facility and the hydrogen system increases the transparency of the energy system and significantly improves the end-user's perception. Along the same lines, the use of a geolocalized blockchain could improve the traceability of renewable hydrogen, guaranteeing that it was originally produced by renewable energies. The use of geospatial techniques in the hydrogen field is not only limited to applications with absolute coordinates, but it has also been detected in the review that they can have small scale applications using relative reference systems. This is the case of manufacturing defect detection using geo-visualization or IRT and AI. The quality of the manufacturing process of the components is key to ensure a high service life and efficiency. Advances in AR make it possible to generate didactic material with which to train new professionals in a simulated and safe environment, before undertaking an action in the installation that could become dangerous.