Hi mari, Yes, the ungeared cost of equity is used, because the projects are fully funded out of debt.
If the projects are 100% debt financed, the tax saved from the use of debt would be significant. Therefore, we’re expected to estimate the impact of such a benefit on the project.
Before doing that, we need to separate the impact of debt financing and calculate the NPV of the project as if it is all-equity financed(so called base-case NPV). Therefore, asset beta is used to drive ungeared cost of equity, and this is used as discount rate.