Abstract
Energy security for the EU is a priority of the European Commission. Although both blue and green water resources are increasingly scarce, the EU currently does not explicitly account for water resource use in its energy related policies. Here we quantify the freshwater resources required to produce the different energy sources in the EU, by means of the water footprint (WF) concept. We conduct the most geographically detailed consumptive WF assessment for the EU to date, based on the newest spatial databases of energy sources. We calculate that fossil fuels and nuclear energy are moderate water users (136–627 m3/terajoules (m3 TJ–1)). Of the renewable energy sources, wood, reservoir hydropower and first generation biofuels require large water amounts (9114–137 624 m3 TJ–1). The most water efficient are solar, wind, geothermal and run-of-river hydropower (1–117 m3 TJ–1). For the EU territory for the year 2015, our geographically detailed assessment results in a WF of energy production from domestic water resources of 198 km3, or 1068 litres per person per day. The WF of energy consumption is larger as the EU is to a high level dependent on imports for its energy supply, amounting to 242 km3 per year, or 1301 litres per person per day. The WF of energy production within the 281 EU statistical NUTS-2 (Nomenclature of Territorial Units for Statistics) regions shows spatially heterogeneous values. Different energy sources produced and consumed in the EU contribute to and are produced under average annual and monthly blue water stress and green water scarcity. The amount of production under WS is especially high during summer months. Imported energy sources are also partly produced under WS, revealing risks to EU energy security due to externalisation. For the EU, to decarbonise and increase the share of renewables of its energy supply, it needs to formulate policies that take the water use of energy sources into account. In doing so, the spatial and temporal characteristics of water use and water stress should particularly be considered.
Highlights
In 2015, energy consumption in the European Union (EU) amounted to 1184 million tonnes of oil equivalent (Mtoe), whereas primary energy production was 779 Mtoe [1]
EU level We calculate for fossil fuels and nuclear energy average unit water footprint (WF) amounts that range from 136 m3 TJ−1 for gas, over 249 m3 TJ−1 for oil up to 572 m3 TJ−1 for coal and lignite
Larger average unit WF amounts are calculated for the renewable energy sources reservoir hydropower (9114 m3 TJ−1, due to evaporative losses of water from reservoirs), as well as the biomass resources wood (61 762 m3 TJ–1), 1st generation bioethanol (61 032 m3 TJ−1) and 1st generation biodiesel (137 624 m3 TJ−1)
Summary
In 2015, energy consumption in the European Union (EU) amounted to 1184 million tonnes of oil equivalent (Mtoe), whereas primary energy production was 779 Mtoe (figure S1 is available online at stacks.iop. org/ERL/14/104016/mmedia) [1]. In 2015, energy consumption in the European Union (EU) amounted to 1184 million tonnes of oil equivalent (Mtoe), whereas primary energy production was 779 Mtoe One of the European Commission’s priorities is the Energy Union strategy [2], which focuses on boosting energy security, creating a fully integrated internal energy market, improving energy efficiency, reducing greenhouse gas (GHG) emissions and increasing the use of renewable energy. The EU energy sector is responsible for many environmental pressures, the latter being resource use and pollution [4, 5]. Induced climate change has many impacts, including in the EU [7–9]. Another important pressure, the use of water resources, is generally not considered when formulating energy related policies [2, 3, 10, 11]
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