Investing in natural gas: drilling down into the risks
A BG Group case study

Page 5: Investment appraisal

Discounted cash flow is an important technique for investment appraisal. The discounted cash flow approach is a way of valuing the future returns on investment by assessing the values of these returns in terms of their value today. It places emphasis on the cost of funds tied up in a project by considering the timing of cash flows.

For example, we all instinctively know that £1 in the hand today is worth more than a promise of £1 in the future. This is because:

  • Inflation may lower the real value of money.
  • The money cannot be put to constructive use in the meantime (i.e. earning interest in the bank or applied to another project).
  • There is always the risk that unforeseen circumstances will prevent you receiving the amount you have been promised.

Appraising investments using the discounted cashflow method allows the company to undertake a capital allocation process, which involves ranking projects and selecting those that add the most value to the company. It therefore incurs the opportunity cost of those projects that add value but cannot be financed as sufficient funds are not available to undertake them.

Ultimately, the value of any investment is the present value of the future free cash flows - Net Present Value (NPV) - that the investment is expected to generate. Therefore, it is necessary to forecast the economic cashflows and discount them appropriately to allow for the fact that they will not be received until some time in the future. BG Group uses a discount rate that reflects the return its investors (shareholders and banks) expect for investing in a non risk free activity (compared to depositing money in a bank account).

The NPV calculation always assumes the project is a success. However, there is a chance that no oil or gas is present (geological risk), this must therefore be reflected in the valuation. This is achieved by assigning probabilities to the values of successful and unsuccessful outcomes. The sum of these risked values is the Expected Monetary Value (EMV).

The EMV calculation can be illustrated by a decision tree. Decision trees are a simple way of choosing from alternative courses of action when faced with uncertainty. The basic procedure for constructing a decision tree is to set out a series of alternative branches of the tree and then to calculate the probability of the event occurring and the likely money value of the return.

In a decision tree, it is possible to distinguish between points of decision and points where chance and probability (uncertainty) may come into play. For example, this process can be used to illustrate possible returns from drilling a well and then exploiting a gas field. The diagram shows how inputs from geologists, engineers and others underpin the economic analysis and ultimately the calculation of value.

These inputs relate to both internal and external data:

  • Internal (technical data) relating to the costs involved in developing the block, e.g. the costs of building and developing the gas platforms, likely volume and quality of hydrocarbons.
  • External (commercial data) about the future demand for, and the price of, gas as well as likely tax changes, and information about local markets and other data.

BG Group | Investing in natural gas: drilling down into the risks


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