These structures, GEODESIC domes calls, constitute the most efficient way to close a space.
In other words, There is another building that use a reduced amount of material to be built. In this case, ecological means that the structure of the dome does not waste building materials. As an example, to build a wall and ceiling of a house you need a few tons of building materials while on a dome are only required 160s kg of metal and coverage. Think of the cost and energy involved in the transportation of materials needed for a traditional construction. In the case of the dome is a commercial van!