Tidal energy has significant potential yet to be developed. Sizeable investments, operating costs and environmental impact are barriers that have to date restricted its development. However, microturbine arrays which are viable in coastal locations can help minimize the initial investment as well as operating costs and environmental impact. This paper puts forward a complete smart grid design based on tidal microturbine arrays following a methodology that includes a selection of optimal locations, the design of smart grid tidal generation and consumption components. The methodology has been applied to the estuary of the Nalón River. For the evaluation of the tidal resource and determination of the optimum locations free license software is used to simulate a one-dimensional flow. In order to achieve this, a geometrical model of the river mouth using open source geographic data and nautical information has been built. The results demonstrate high water velocities throughout the year as well as high tidal energy potential in zones that make the installation of a smart grid feasible. This smart grid includes a microturbine tidal array to generate energy and an intelligent Lighting Smart Grid system to light a promenade along the river mouth depicted as an application of the energy produced.