Climate and energy targets, as well as decreasing costs have been leading to a growing utilization of solar photovoltaic generation in residential buildings. However, even in buildings with the same level of yearly generation and consumption the mismatch between the demand and photovoltaic generation profiles leads to large power flows between the household and the grid. Such situation creates problems to the electrical grid management and can be a source of economic losses to the end-user. This paper presents an energy storage system designed in the context of residential buildings with photovoltaic generation. The objective of such system is to increase the matching between the local generation and consumption, as well as to decease the energy bill, using lithium-ion batteries as a storage device. Such system was modelled and simulated using real data of solar radiation and energy consumption from a typical residential household in Coimbra (Portugal). The results show that the designed system was able to reduce the energy sent to and consumed from the grid in 76% and in 78.3%, respectively, as well as the energy bill in 87.2%. (C) 2016 Elsevier Ltd. All rights reserved.