The loan life cover ratio (LLCR) is often used by banks, both for corporate loans and for project finance. It is a measure of ability to pay over the life of a loan, whereas the debt service cover ratio provides a snapshot of ability to pay in the short term. It is the ratio of the NPV of cash flows available to repay debt to the amount of debt outstanding.
As well as its use in assessing prospective borrowers, the loan life cover ratio is also used in debt covenants.
The discount rate used to calculate the NPV is the weighted average interest rate of all debt; similar to a WACC but only for debt finance. In the case of project finance all numbers, would be those relating to the project, but in most other cases they would be calculated for the borrower.
Cash balances are sometimes added to the NPV, as they are available to repay debt. However, cash balances held by a borrower are likely to be needed (otherwise they would immediately be applied to reduce borrowing) and are therefore not available to repay debt.