Usually, the discount rate reflects the interest cost of borrowing capital to finance an investment.
As the discount rate can be varied according to different contexts, the economic instability of the country could have been considered by UE's management as conducive to potentially high interest rates and high uncertainty. So, they chose a relatively high discount rate of 8\%.
Another consideration could be for U E to have an established cut-off or criterion rate for their projects. This rate would be used to discount the returns on an investment, and if the net present value turns out to be positive, then the project would be feasible. Even if we do not know UEs cut-off rate it is likely to be high due to the contextual uncertainty and economic instability in the country, pushing UE to choose a high discount rate of 8 %. This point needs to refer to the economic uncertainty otherwise there is no application.
Another possible factor is the opportunity cost of capital i.e. what UE could earn on other projects.