This paper represents an approach for renewable energy sources integration with the existing grid. Unique types of loads can be exploited to allow for a sustainable solution to energy integration. A case study of Saudi Arabia is investigated where desalination plants coupled with a water storage tank is utilized to mitigate the variability of renewable sources. A hybrid photovoltaic-wind turbine generator system (PV-WTG) is proposed. The results indicate two critical points. First, even in a fossil fuel-rich country, sustainable renewable sources are economically feasible. The second point is that the typical storage element (i.e., batteries), is not always the best candidate for energy storage as in the case of desalination plants. Instead, storing the excess energy as water in a storage tank is economical and less prone to failures as compared to large-scale batteries. The problem is formulated as an optimization problem and solved using heuristic techniques.