In the financial world, portfolio selection is used to give a balanced collection of assets that provides investors with an appropriate balance of security and opportunity. Similarly, in the energy and environmental sectors there is often a need to select an optimum set of activities that together satisfy a range of requirements, rather than trying to achieve them with a single option.
Portfolio selection is useful at all levels of decision making. At a national or organisational level, it can be used to help select the most appropriate mix of policy options to meet strategic goals. At a programme level, it can help to decide the optimum mix of projects that meet agreed policies in the most efficient manner in the face of uncertain externalities. At a project level, it can be a useful automated tool for picking a set of tasks that are consistent with a range of complex constraints. For example, Quintessa has applied portfolio analysis:
- to provide a powerful method for optimising an environmental monitoring programme;
- to identify a suite of measurements in soil, water and environmental materials at a variety of locations that best characterise a nuclear site’s discharges;
- to identify a preferred restoration strategy for an entire nuclear site which also considers the 'portfolio' of individual facilities that are present, and their individual characteristics and constraints; and
- to provide support to Sellafield’s Plutonium Contaminated Material (PCM) BPEO programme.
Quintessa supports clients in developing a balanced portfolio of options using structured approaches ranging from qualitative decision analysis (underpinned by quantitative evidence) to highly quantitative decision-support techniques embedded in custom software packages.
An example of a qualitative approach is the facilitation of decision meetings to select an optimal set of radioactive waste treatment options meeting a variety of technical, environmental and financial constraints. For example, legacy wastes may involve a wide range of forms, inventories and uncertainties that might not be resolvable at the start of a decommissioning and/or waste treatment programme. A selection of techniques will need to be available to deal with the uncertainties involved. We have supported a range of portfolio selection options studies that are based upon maximising confidence in the ability of a portfolio of techniques to deal with uncertainty in waste forms and treatment.
At the quantitative end of the spectrum, Quintessa has developed a custom software package, CHANSELA (Channel Selection Assistant), which takes account of a wide range of factors to support decisions on which selection of channels of a nuclear reactor should be inspected to support continued safe operation. This software employs some novel concepts including a genetic algorithm for optimising channel selections and flexible methods for providing queries to the software.
We have included some of these ideas in the freely downloadable software Portfolio Picker. The software is designed to provide a straightforward introduction to portfolio selection and the Portfolio Picker Case Studies document describes a diverse range of illustrative applications including planning financial investment portfolios, university choices, what to wear and what to eat.