The most important responsibility of power system operators is to ensure the reliability of the system. Protecting the load-generator balance is an important part of reliability. There are some uncertainties in the power systems in this regard. In Turkey, the fact that renewable (both solar and wind) penetration, changing peak loads and production results can change unexpectedly must be taken into consideration. The country has more difficulty in operating the energy system, so there is a greater need for system reserves to be created. The demand side needs to be well examined to ensure that the amount of reserves to be kept is at optimum cost. The socioeconomic parameters affecting this cost are added to the account and the minimum cost is created. For this reason, this study shows that the support reserves must maintain the required amount, depending on the demand side conditions.