As the United Kingdom continues to discuss a transition towards a more energy efficient and renewable energy system, decentralised energy is becoming an increasingly mentioned concept. However, decentralised energy remains ill-defined and loosely applied, making it difficult to understand its potential and consequences from a system point of view. This research aims to understand what the implications are of a decentralised energy system for the UK, looking to 2050. First, the notion of decentralised energy is discussed both in social and technical terms, then placed within a Smart Energy Systems context in order to conceptualise a decentralised energy system. This is modelled alongside a centralised energy system scenario and a business as usual scenario, to compare the impacts in terms of structure and performance. This is then used to discuss the further impacts of a decentralised energy system with regards to how the energy system is viewed and organised, what contribution smart energy could bring, and what kind of planning processes would be necessary in a decentralised energy system.
The modelling shows that a decentralised energy system presents a highly cost-effective strategy to decarbonise the energy system. In addition to reducing CO2 emissions by 11% more than the centralised scenario, the decentralised energy system integrates a fundamentally higher level of intermittent renewables and costs 15 billion euro less per year than the centralised energy system. This is due to the increased connectivity and flexiblity in the decentralised energy system. A trust and coordination game is used as an analogy to show the technical interconnectivity and interdependance of a decentralised energy system has concequences for the way energy is viewed, and the levels of trust, coordination, and regulation necessary in order to sustain such a system. The focus moves from towards investing in infrastructure, redistributing the benefits of a decentralised energy system and planning practices that enable the interconnected nature of the decentralised energy system. The conclusion is a decentralised energy system could provide great benefits in terms of carbon emmisions reduction and cost, but would imply a shift in the way energy is invested in, planned, and regulated. This provides an impetus for further research to discuss in which ways a decentralised energy system could be impemented, and how an energy transition could be achieved.