Large-scale hydraulic projects and water infrastructures have direct impacts on the social and ecological landscape in which they are located and vice versa. In accordance to the sustainable development concept, multipurpose hydroelectric plants apart from power generation and thus profitability, should cover socioeconomic and environmental services. In the proposed method-ology, the aforementioned services are attributed in monetary terms in order to trigger a custom economic tool that is based on the Net Present Value rule so as to assess the economic viability of a new hydropower plant. Moreover, the impact of climate change on the natural resources feeding the plant is considered as an externality that should be evaluated and introduced in the feasibility study of a new renewable energy project. The results from the coupling of mathematical models such as hydrological, hydropower plants' operation, climate change and capital investment models, revealed that the projected meso and macro timescale decrease of water discharges will have direct negative effect on the investment profitability and thus the planned payback period. Moreover, the coupling of climate change with electricity wholesale prices fluc-tuations could completely jeopardize the project and consequently have a deterrent effect rather than attracting investors.