The polluting effect has always been one of the great concerns when generating energy. Before the advent of lithium batteries, you were concerned about how to store electricity and have that power available when needed. And it is that the photovoltaic batteries where it was stored were very polluting and carried many risks. What is "green building"? The main objective is to introduce building automation and control systems to accelerate the cost-effective renovation of existing buildings, such as the integration of home automation systems. Thus, it introduces an intelligence indicator to evaluate the technological readiness of the building. How to achieve this ambitious goal? Improving the constructive conditions of the houses, to require much less energy than the current constructions. And also getting the necessary energy with a lower ecological impact and in a more efficient way. What role do batteries play in a photovoltaic installation? The batteries help to n