Energy in numbers - Portugal

Portugal is a country with scarce indigenous energy resources, such as oil, coal and gas, being dependent of external sources to supply its demand. In Portugal, the extraction of coal ended in 1995, when the Pejão mines were closed. However the potential to use renewable energy sources (hydro, wind, sun, biomass and geothermal) is notable, exceeding, in theory, the Portuguese demand (10).

The % renewables with respect to total electricity in 2016 was 55.5% (13).

Geothermal, solar and wave energy

In Portugal, the geothermal energy is only used in Azores, and it is currently in expansion. According to solar radiation data, Portugal receives annually the equivalent to 140 million of GWh, representing a great potential for its utilization through solar thermal and photovoltaic technologies. Similarly, the potential of wave energy in Portugal is considerable, and is being explored though a project in experimental stage (10).

Wind energy

On average over mainland Portugal, wind energy density peaks during winter months and decreases in the warmer months. Future changes of wind energy density over Portugal throughout the twenty-first century have been assessed for the mid-century (2041-2070) and end-century (2071-2100) periods, considering a moderate and high-end scenario of climate change (the so-called RCP4.5 and RCP8.5 scenarios) (16). The largest reductions averaged at yearly and seasonal time-scales are prone to occur over elevated terrain in northern and central-eastern Portugal, and over the southwestern coastal regions. Such decreases are typically larger than 10% for the yearly averaged situation, and they can be larger than 30% during autumn. In contrast, the largest wind energy density increases throughout the year are projected for the central-western region; these positive anomalies are strongest during summer, although their magnitude is projected to be below 10% for all seasons. The authors stress the uncertainties in their results, however: the regional climate models they have used have limited ability to resolve the complex local coastal and topographic effects on wind energy density (16).

Wind power is now (2016) responsible for 20.7% of the Portuguese electricity production. Wind share of total electricity consumption in Portugal was 19.1% in 2016 (13).

Hydropower

Recently the Alqueva Dam in the region Alentejo was completed, creating the largest reservoir of Western Europe. Alentejo is the driest and hottest region in Portugal, and persistent droughts are a problem. The climate and a lack of infrastructure have impeded economic development and isolated the area from the national and European economies. The complex project was made to produce hydroelectric power, irrigation for farms in the surrounding area, as well as a large reservoir (12).

On February 8, 2002, the 96 metre high floodgates of the Alqueva dam were closed. In 2006 the lake was filled to the planned level, with a surface area of 250 km². In 2004, the hydroelectric power station started to work, with a capacity of 240 megawatt. As of 2025 (though the endeavour is already slated to be finished by 2013), the lake should supply irrigation water for 1,100 km² in the Alentejo (12).

Hydropower has contributed 28.1% to total electricity production in 2016 (13).

Vulnerabilities Portugal

The main positive impacts of climate change on the energy sector are (11):

• projection of greater hydroelectric potential in the north;
• reduced energy needs for water heating (for sanitation, swimming pools);
• a greater attractiveness and effectiveness of solar energy systems.

The main negative impacts of climate change on the energy sector are (11):

• increased energy demand from air conditioning in residential as well as service buildings and transport owing to higher summer temperatures, despite better regulations and future technological improvements;
• higher energy consumption resulting in a shift of the peak of energy consumption from winter to summer, placing a heavier burden on the electricity grid.

Vulnerabilities Europe

Supply

The current key renewable energy sources in Europe are hydropower (19.8% of electricity generated) and wind. By the 2070s, hydropower potential for the whole of Europe is expected to decline by 6%, translated into a 20 to 50% decrease around the Mediterranean, a 15 to 30% increase in northern and eastern Europe and a stable hydropower pattern for western and central Europe (1,3,4). In areas with increased precipitation and runoff, dam safety may become a problem due to more frequent and intensive flooding events (5).

It has become apparent during recent heat waves and drought periods that electricity generation in thermal power plants may be affected by increases in water temperature and water scarcity. In the case of higher water temperatures the discharge of warm cooling water into the river may be restricted if limit values for temperature are exceeded. Electricity production has already had to be reduced in various locations in Europe during very warm summers (e.g. 2003, 2005 and 2006) (5,8).

Extreme heat waves can pose a serious threat to uninterrupted electricity supplies, mainly because cooling air may be too warm and cooling water may be both scarce and too warm (9).

Climate change will impact thermoelectric power production in Europe through a combination of increased water temperatures and reduced river flow, especially during summer. In particular, thermoelectric power plants in southern and south-eastern Europe will be affected by climate change. Using a physically based hydrological and water temperature modelling framework in combination with an electricity production model, a summer average decrease in capacity of power plants of 6.3–19% in Europe was shown for 2031–2060 compared with 1971-2000, depending on cooling system type and climate scenario (SRES B1 and A2) (15).

Overall, a decrease in low flows (10th percentile of daily distribution) for Europe (except Scandinavia) is projected with an average decrease of 13-15% for 2031–2060 and 16-23% for 2071-2100,compared with 1971-2000. Increases in mean summer (21 June - 20 September) water temperatures are projected of 0.8-1.0°C for 2031–2060 and 1.4-2.3°C for 2071-2100, compared with 1971-2000. Projected water temperature increases are highest in the south-western and south-eastern parts of Europe (15).

By the 22nd century, land area devoted to biofuels may increase by a factor of two to three in all parts of Europe (2).

Demand

It may become more challenging to meet energy demands during peak times due to more frequent heat waves and drought conditions (1). Strong distributional patterns are expected across Europe — with rising cooling (electricity) demand in summer in southern Europe, compared with reduced heating (energy) demand in winter in northern Europe (7).

Climate change impacts on electricity markets in Western Europe

The expected climate changes in the 21st century are likely to have a small impact on electricity prices and production for the energy markets of Western Europe. This has been estimated by modelling three climatic effects (14):

• changes in demand for electricity due to changes in the need for heating and cooling,
• changes in supply of hydropower due to changes in precipitation and temperature, and
• changes in thermal power supply due to warmer cooling water and therefore lower plant efficiency.

According to the model results each of these three partial effects changes the average electricity producer price by less than 2%, while the net effect is an increase in the average producer price of only 1%. Similarly, the partial effects on total electricity production are small, and the net effect is a decrease of 4%.

The greatest effects of climate change are found for those Nordic countries with a large market share for reservoir hydro. In these countries total annual production increases by 8%, reflecting an expected increase in inflow of water. A substantial part of the increase in Nordic production is exported; climate change doubles net exports of electricity from the Nordic countries, while the optimal reservoir capacity is radically reduced (14).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Portugal.

1. Lehner et al. (2005), in: Alcamo et al. (2007)
2. Metzger et al. (2004), in: Alcamo et al. (2007)
3. Kirkinen et al. (2005), in: Anderson (ed.) (2007)
4. Veijalainen and Vehviläinen (2006); Andréasson et al. (2006), in: Anderson (ed.) (2007)
5. Anderson (ed.) (2007)
6. Rothstein et al. (2006), in: Anderson (ed.) (2007)
7. Alcamo et al., 2007
8. EEA, JRC and WHO (2008)
9. Behrens et al. (2010)
10. Portuguese Environment Agency with the cooperation of Ecoprogresso – Environment and Development Consultants, SA (2009)
11. Portuguese Environment Agency with the cooperation of Ecoprogresso – Environment and Development Consultants, SA (2006)
12. www.eosnap.com
13. www.ec.europa.eu
14. Golombek et al. (2012)
15. Van Vliet et al. (2012)
16. Nogueira et al. (2019)