Capabilities of fuel cell micro-CHPs in a smart grid perspective

Abstract

Fuel cell (FC) micro combined heat and power (micro-CHP) is a distributed generation technology which can help stabilise the electricity grid. The FC micro-CHP technology promises to support the grid by compensating production fluctuations of intermittent electricity production. FC micro-CHPs have the potential of being an attractive technology in a market where flexibility is of increased importance. As the European electricity mix moves towards a higher share of intermittently generated electricity, the generated energy will to a lessening extend correspond to patterns of consumption. Pressure on balancing supply and demand may also be enlarged by increasing peak demand, as electric vehicles and electric heating become more prevalent. This creates a necessity for technologies which can help compensate for the induced electricity fluctuations. At the EU level, policymakers recognise that our current energy system will need to adapt to this new context. As part of the Energy Union framework strategy1, the European Commission has launched a process to rethink the present assumptions governing our energy markets and allow for the transition from highly centralised to more decentralised generation. It is expected that this will give new market players the opportunity to play a greater role in the energy system in areas such as flexible generation, demand response, renewables and as energy service providers2. The findings presented in this paper contribute to this discussion by highlighting the potential of FC-based micro-CHP in addressing some of the challenges of the future energy systems, through enabling technologies like smart grids and energy storage. A systems approach must be taken when evaluating FC micro-CHP technologies, looking at the potential of this technology in the framework of the smart grid development. Grid stabilisation and distributed generation require a smart grid to be as effective as possible. A smart grid is a grid where information and communication technology is used to coordinate generation and distribution and ensure high degrees of interactions between generation technologies, utilities, consumers and additional stakeholders. From a technical point of view, FC-based micro-CHP is well equipped for smart grid integration. Systems are typically equipped with the possibility of being remotely operated and controlled. Further FC-based micro-CHP systems can adjust to external heat and power demands at seconds notice when at operation temperature. Other advantages of the technology include that the generation is inherently distributed eschewing transmission losses, that generated power can be sold back to the grid and low to zero emission of CO2 and NOx. Finally, fast response time and aggregation capabilities make FC-based micro-CHPs well suited for smart grid controlled distributed generation which can limit transmission losses in the grid. For FC-micro-CHP to positively contribute to grid stability in the context of the emerging smart grid model, the viability of aggregation of multiple units into a virtual power plant needs to be considered. At a capacity of 1 kW per system, an estimated minimum of 1000 units in a virtual power plant is required (1 MW). The rewards for the aggregator and installation owners will need to outweigh the administrative and coordination costs required for such a complex operation in order for the virtual power plant model to gain ground. FC micro-CHP is a dispatchable technology, which can provide services to the grid in a flexible way, especially when coupled with heat or electricity storage and controls. Yet in certain situations, when the technology is installed in regions where heat is not needed for long period of time as well as in non-residential use where the unit is not in operation over the weekend, the potential of the technology to support the grid is reduced. It is suggested that utility companies should be able to control the systems. Here, the utility companies would act as operators and aggregators of the micro-CHP systems. Baseline operation of the systems should be a continuous production of a fixed amount of electricity. This should be supplemented with generation profile adjustments based on household and external needs. A generation profile based on the household’s average needs could be the basis of such operation.