Catenaries

Renewables and Power Electronics for grid stabilisation and improvement

The potential of Spain’s Catenary Network for Energy Transition and its Integration into Electric Mobility

The transition to a sustainable and decarbonised energy system in Spain requires a major transformation of the current energy infrastructures and the integration of innovative solutions. In this context, the railway catenary network, a key infrastructure for public transport, emerges as a strategic option to optimise energy use and contribute to the sustainability of the electricity system.

Railway infrastructure, in particular catenaries, can offer solutions both to improve the flexibility of the power grid and to enhance electric mobility. This article explores the possibilities of using this network to facilitate the energy transition in Spain, optimising the use of renewable energy sources, and assessing its impact on electric mobility. It also discusses the challenges and opportunities of integrating the catenary network into the electricity transmission and distribution grid.

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1. Use of the Catenary Network for Electricity Distribution

The Spanish railway network is known for its extensive catenary infrastructure that supplies power to electric trains. According to Adif, the electric railway network in Spain has an extension of more than 15,000 kilometres, of which 50% is electrified. This infrastructure offers a unique opportunity to be reused as part of the national electricity system.

In addition, their presence in areas of high urban density and strategic industrial zones facilitates the integration of the railway network with the electricity distribution network.

How can this infrastructure be used?

1. Energy Generation and Storage: The energy currently flowing through the catenaries can be used in multiple ways to inject it into the electrical distribution network. By installing conversion and storage systems (batteries, supercapacitors, etc.), it is possible to recover the energy generated during train braking, a process known as energy regeneration. This recovered energy can be stored and used at times of high demand or to balance the electrical system.
2. Renewable Energy Injection: Following the energy transition to cleaner sources, catenaries can also be used to transfer electricity from renewable sources (mainly solar and wind). Spain has experienced a boom in renewable energy generation, with an increase in installed solar photovoltaic capacity of 13.8% by 2022, which enables an efficient integration of clean energy into the rail network.
3. Electricity System Flexibility: The interconnection between the railway grid and the electricity distribution grid can operate as an energy storage mechanism during periods of low demand. This flexibility can allow for better integration of variable renewable energies, such as solar and wind, which require storage mechanisms to ensure a stable supply.

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2. Integration of the Catenary Network with Electric Mobility

As electric mobility gains ground in Spain, the integration of rail infrastructure with electric vehicles (EVs) is positioned as a key solution to facilitate the transition to a clean and sustainable transport system.

How the catenary network contributes to electric mobility?

1. Electric Vehicle Charging: The use of train stations, mainly in urban areas, to provide charging points for electric vehicles is one of the most immediate strategies. The use of energy from train catenaries can power electric vehicle charging stations, improving the existing charging infrastructure in the country. In fact, in 2022, Spain reached more than 15,000 public EV charging points, an increase of 15% over the previous year, reflecting the need to expand this infrastructure.
2. Intelligent recharging: Implementing smart charging systems in railway stations, where the energy supplied by the catenary can be used to charge electric vehicles according to the demand and availability of energy, optimizing resources thus.
3. Decarbonization of Transport: The electric train in Spain is already a low-emission mode of transport, and the integration of this infrastructure with electric vehicles can extend decarbonisation to other modes of transport. The electrification of the whole train fleet and the expansion of the charging infrastructure for electric vehicles will contribute to the country’s decarbonisation goals.

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3. Environmental and Economic Benefits

The integration of the catenary network into the infrastructure and electric mobility not only has technological benefits, but also environmental and economic benefits.

1. Reducing emissions: The use of the catenary network for the distribution of clean energy and for the recharging of electric vehicles contributes significantly to the reduction of greenhouse gas emissions. According to the Ministry of Ecological Transition and the Demographic Challenge (MITECO), the transport sector is responsible for around 27% of CO2 emissions in Spain, so the integration of clean energy in this area is key to achieving emission reduction targets.
2. Energy Efficiency: Taking advantage of existing infrastructure to optimise power distribution and electric vehicle charging improves the overall energy efficiency of the system. The ability of the rail network to provide power to the electricity grid and electric vehicles without major additional investment in new infrastructure reduces the overall cost of the energy transition.
3. Promoting Employment and Innovation: The integration of the rail infrastructure into the electricity grid and the expansion of electric mobility favour the creation of jobs in the engineering, electric vehicle manufacturing and renewable energy sectors. According to the Fundación Biodiversidad report (2021), the energy transition could generate up to 500,000 new jobs in Spain by 2030.

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4. Challenges and Considerations

While the opportunities for integrating the catenary network with the power grid and electric mobility are obvious, there are also several challenges that need to be addressed.

1. Technical Adaptation of the Infrastructure: The catenary infrastructure will need to be adapted to allow the electricity injection into the grid and the recharging of electric vehicles. This will require the installation of appropriate energy conversion and storage systems, which will require investment in new technologies.
2. Rules & Regulations: A clear regulatory framework is needed to enable interoperability between rail infrastructure and the electricity grid. Coordination between Adif, energy operators and local authorities will be essential to ensure efficient system integration.
3. Initial Investment: Despite the fact that the proposed solutions offer important long-term benefits, the initial investment required to adapt the rail infrastructure to these new uses will be significant.

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Conclusions

The catenary network in Spain has great potential to contribute to the country’s energy transition and the promotion of electric mobility. By using this infrastructure, it is possible to improve the efficiency of electricity distribution, integrate renewable sources more effectively, and promote the use of electric vehicles. However, it will be necessary to overcome technical and regulatory challenges and make adequate investments to ensure the success of these initiatives. Collaboration between public authorities, rail operators and energy companies will be key to maximising the potential of this infrastructure in the transition to a sustainable energy system.

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References

1. Ministry for Ecological Transition and Demographic Challenge. (2021). National Integrated Energy and Climate Plan 2021-2030. Retrieved from: https://www.miteco.gob.es/en.html
2. Fundación Biodiversidad (2021). Employment opportunities and green economy in Spain. Retrieved from: https://fundacion-biodiversidad.es/en/
3. Adif (2023). Fast charging of electric vehicles at train stations. Retrieved from: https://www.adif.es/inicio
4. Red Eléctrica de España (2023). Report about the integration of renewable energies in the Spanish electricity system. Retrieved from: https://www.ree.es/en

Photo of Rhodonite, from which Manganese is extracted, by Evgeny.