Tom Houghton

Modeling the Benefits of Vehicle-to-Grid Technology to a Power System

Electric vehicle (EV) numbers are expected to significantly increase in the coming years reflecting their potential to reduce air pollutants and greenhouse gas emissions. Charging such vehicles will impose additional demands on the electricity network but given the pattern of vehicle usage, the possibility exists to discharge the stored energy back to the grid when required, for example when lower than expected wind generation is available. Such vehicle-to-grid operation could see vehicle owners supplying the grid if they are rewarded for providing such services. This paper describes a model of an electric vehicle storage system integrated with a standardized power system (the IEEE 30-node power system model). A decision-making strategy is established for the deployment of the battery energy stored, taking account of the state of charge, time of day, electricity prices and vehicle charging requirements. Applying empirical data, the benefits to the network in terms of load balancing and the energy and cost savings available to the vehicle owner are analyzed. The results show that for the case under study, the EVs have only a minor impact on the network in terms of distribution system losses and voltage regulation but more importantly the vehicle owners costs are roughly halved.

Systemic risk elicitation : using causal maps to engage stakeholders and build a comprehensive view of risks

As evidenced through both a historical and contemporary number of reported over-runs, managing projects can be a risky business. Managers are faced with the need to effectively work with a multitude of parties and deal with a wealth of interlocking uncertainties. This paper describes a modelling process developed to assist managers facing such situations. The process helps managers to develop a comprehensive appreciation of risks and gain an understanding of the impact of the interactions between these risks through explicitly engaging a wide stakeholder base using a group support system and causal mapping process. Using a real case the paper describes the modelling process and outcomes along with its implications, before reflecting on the insights, limitations and future research.

Fuel cells as distributed generation

This paper presents an overview of fuel cells as a form of distributed generation within the context of a highly distributed power system, by discussing some example demonstration systems categorized by the type of primary fuel used, namely fossil fuels, hydrogen gas, or biofuels. It discusses the background to fuel cells as a stationary, grid connected, power source, briefly compared with conventional thermal electrical generation, while describing the main characteristics of their performance and an electric equivalent circuit model. Additionally, it presents a view of the current state of commercialization of fuel cell technology for stationary power applications.