Material and energy cycles

It is difficult to pinpoint the demand for material resources (food, raw materials and other consumer goods) in the metropolitan area, since, unlike energy and water, their flows are not accounted for systematically.

Nevertheless, we know that the logistics of material flows require spaces suitable for fostering a more circular economy and a more restricted mobility of goods. Specialised economic activity areas in contact with residential fabrics play a strategic role in this respect.
It should be borne in mind that by 2025, 70% of the waste generated will have to be recycled, which is a long way from the figure of 50% currently processed. On the other hand, positive trends are apparent in the increase in establishments engaged in activities related to the circular economy, and particularly in economic activity areas integrated into the urban fabric, where they now account for more than 20% of the total.

The demand for water was 283 hm3 in the metropolitan area of Barcelona in 2017, which is 40% of Catalonia's total domestic consumption. This demand is mainly met by surface water captured in the Llobregat and Ter rivers, although the aquifers in the metropolitan territory also play a significant role as the source of 20% of the water supplied. Other less important sources are the sea water treated at the desalination plant, the water reclaimed at water reclamation plants (WRP), and bottled water from various sources.

The metropolitan water cycle still has a long way to go in terms of becoming less dependent on the outside world, with the benefits that this would bring.

The use of aquifers, reclaimed water and grey water, which are currently far below their potential levels, must be encouraged. 50% of the water supply could be covered by resources in the metropolitan area.

The current annual demand for energy in the metropolitan area is estimated at 44,786 GWh, which is equivalent to 30% of Catalonia's consumption. This energy is mostly consumed in the form of combustible liquids and electricity, although natural gas also plays a major role. On the other hand, liquefied petroleum gases (mainly butane and propane) account for a much smaller proportion. The metropolitan area of Barcelona generated 38.6% of the electricity consumed within its territory in 2014 while 6.4% of its electricity came from renewable energy sources or was recovered by cogeneration.

The energy cycle must undergo a transition in the coming years, as a result of the current climate crisis. One of the possible areas for improvement is that the metropolitan region has enough potential to cover up to 30% of the energy it currently needs using local renewable sources, because 30% of its urban land has a high potential for capturing solar energy. This land is mainly located in specialised areas of economic activity.

Finally, work must be done towards the territorial integration of the infrastructures that guarantee energy supply. Taking into account the current and planned infrastructures, five strategic areas have been identified for addressing environmental and landscape integration in the metropolitan region and there are 13 others where the potential risks should be considered.