(735a) Whole-System Optimisation of Integrated Wind-Electricity-Hydrogen Networks for Decarbonising the Domestic Transport Sector in Great Britain

The advantages of hydrogen as an environmentally clean fuel can be fully realised when hydrogen is produced from renewable energy sources. Hydrogen, like electricity, can complement renewable sources particularly well. Both are energy carriers that can transmit energy from primary energy sources to end-users and must be produced, transported and stored for later use. If hydrogen were to play an important role as an energy carrier, then new network infrastructures for producing, transporting, storing and delivering hydrogen to end-users are required. Storage, which will be the key-enabling component of these networks, ensures that energy produced from variable renewable sources is available when and where it is needed. Hydrogen is a flexible energy storage medium that can be used for both short- and long-term storage applications, in addition to being a versatile intermediate that can be converted to electricity, heat and transport fuel.

It is widely accepted that hydrogen has a role to play in decarbonising the transport sector, which still relies almost exclusively on oil. In Great Britain (GB), for example, the transport sector is a major oil user and consequently, responsible for the majority of greenhouse gas emissions. The domestic transport sector alone makes up approximately 20% of total GB carbon emissions [1]. Indeed, decarbonising this sector is a main driver behind the development of fuel cell and electric vehicles. On a more positive note, GB has a very strong potential for wind power; in fact, it is considered as one of the best locations in the world and the best in Europe [2]. Converting wind energy to either electricity or hydrogen that can be used in electric or fuel cell cars results in zero emissions (or low emissions if the emissions in manufacturing and installing the network components are considered).

In this conference, we will present a mixed integer linear programming (MILP) model of integrated wind-electricity-hydrogen networks. The model accounts for the spatial distribution and temporal variability of energy demands and wind availability. The network comprises technologies for production (e.g. wind turbines), conversion (e.g. electrolysers and fuel cells), hydrogen storage (e.g. pressurised vessels and underground storage), transmission (e.g. hydrogen pipelines and electricity overhead/underground lines) and distribution (e.g. fuelling stations and distribution pipelines).  We also recognise that one of the main concerns of wind energy projects is the siting of wind turbines. Therefore, the suitable sites for wind turbines were identified using GIS by applying a total of 10 technical and environmental constraints (e.g. buffer distances from urban areas, rivers, roads, airports, woodland and so on). The overlay of the 10 constraint layers was used in the model as the land footprint constraint that determines the maximum number and locations of new wind turbines that can be installed. With an objective of minimising the total cost of the system, the model simultaneously determines:

• the optimal number, size and location of wind turbines, electrolysers and fuel cells,
• the optimal number, size and location of hydrogen storage,
• whether to transmit the energy as electricity or hydrogen,
• the transmission infrastructure needed,
• the number of fuelling stations and the length of the distribution pipeline, and
• the hourly operation of each network component.

In this presentation, we will discuss the challenges involved in developing such a large-scale optimisation model. We will also present different optimal network configurations considering different scenarios.

References:

[1] Energy consumption in the UK (2014). < https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/337454/ecuk_chapter_2_transport_factsheet.pdf> [accessed 30.03.2015]

[2] UK Renewable Energy Roadmap, July 2011. < https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/48128/2167-uk-renewable-energy-roadmap.pdf> [accessed 30.03.2015]