Portugal Climate Resilience Policy Indicator

• Across all Portugal’s regions, average annual air temperature has risen more than 0.3°C per decade since the 1970s. This upward trend is expected to persist throughout the 21st century, and the number of very hot days and tropical nights is also projected to be higher than during 1971-2000. The temperature rise could affect the country’s energy supply by reducing the generation and efficiency of thermal power plants as well as the electricity grid’s efficiency and maximum transmission. Higher temperatures could also affect energy demand by prompting the wider use of air conditioning, placing stress on the electricity system during extreme heat events.
• Portugal’s average annual precipitation has been decreasing roughly 25 mm per decade since 1970 and is projected to continue declining. Meanwhile, precipitation variability is on the rise. More variability in precipitation patterns may lead not only to longer and more intense droughts, but greater exposure to floods. Changes in precipitation could also affect the energy sector by limiting the amount of cooling water available for thermal power plants and rendering hydropower generation less reliable.
• Portugal prioritised energy sector climate resilience in its latest National Climate Change Adaptation Strategy, supported by actions detailed in the Action Programme for Adaptation to Climate Change as well as municipal plans. Nevertheless, climate resilience is discussed less in national energy plans than in climate plans.

Temperature

Portugal’s average annual air temperature has been increasing since the 1970s across all regions at a rate of 0.3°C per decade, with both minimum and maximum temperatures rising. The number of tropical nights and summer days has also increased, as have the intensity and duration of heatwaves.

This upward temperature trend is projected to prevail throughout the 21st century, such that the country’s average annual temperature in 2100 under a high-greenhouse gas emission scenario could be up to 4°C higher than during 1971-2000. This temperature increase is expected to be especially pronounced during the summer and in Portugal’s inland and southern regions. More very hot days (daily maximum temperature above 35°C) and tropical nights (daily minimum above 20°C) than in 1971-2000 are also projected, and heat waves are anticipated to last longer, especially in the northern countryside, raising the risk of forest fires. Temperatures in Portugal’s Autonomous Island Regions are also projected to exceed 1971-2000 levels (by 2‑3°C in Madeira and 1‑2°C in the Azores).

These temperature changes will likely affect Portugal’s energy supplies, particularly of electricity. According to the National Climate Change Adaptation Strategy’s energy sector report, rising temperatures and more frequent heatwaves could reduce thermal power plant generation efficiency and availability as well as power grid efficiency and maximum transmission. Furthermore, more frequent extreme heat events could interrupt thermal power generation by raising the temperature of cooling water.

Rising temperatures, which have caused Portugal’s number of heating degree days to fall and cooling degree days to increase in the past two decades, could also alter the country’s energy demand patterns. According to the National Climate Change Adaptation Strategy’s energy subgroup report, warming would move peak electricity demand from winter to summer, as warmer average air temperatures reduce energy demand for heating and raise it for air conditioning.

Precipitation

Average annual precipitation has decreased approximately 25 mm per decade since 1970, and rainfall in the last two decades has been particularly low in mainland Portugal. Spring, summer and winter precipitation have decreased while autumn’s has increased, and interannual variability is high, exposing Portugal to a “medium” risk of floods and droughts. The number of extremely rainy days (above the 99th percentile) has increased, especially in southern regions in the past three decades.

Annual precipitation is projected to continue decreasing across the country, despite higher amounts in December and January. As the dry season lengthens from summer to include spring and autumn, lower precipitation and higher temperatures would weaken stream flows and lead to longer and more intense droughts. Furthermore, even though average total rainfall is expected to decline, high interannual precipitation variability, coupled with the increasing share of heavy precipitation events, will raise the country’s exposure to more frequent and intense flooding.

These changes in precipitation may also affect the energy sector. For instance, the Mediterranean drought of 2017 limited Portugal’s hydropower production capacity by lowering the water level in 28 of the country’s 60 reservoirs and raising competition over water use. Thermal power plants made up for the drop in hydroelectric production, which led to greater natural gas consumption and higher wholesale electricity prices.

Tropical cyclones and storms1

Although Portugal’s level of physical exposure to tropical cyclones is estimated to be low, tropical-like and mid-latitude storms in recent years have occasionally damaged its electricity transmission and distribution infrastructure and caused power outages. In October 2018, for instance, storm Leslie uprooted trees and pushed branches onto electricity distribution lines, affecting over 750 000 customers on medium- and low-voltage lines and leaving 300 000 households without electricity. Although there are uncertainties in predicting extreme weather events, storms have been hitting Portugal with more intensity and frequency in recent years and could continue compromising its energy supply stability in the future.

Energy sector climate resilience is a priority area in Portugal’s climate change adaptation policies. Its latest National Climate Change Adaptation Strategy, published in 2015, was initially valid to 2020 but was extended to 2025 with publication of the National Climate and Energy Plan. A section dedicated solely to energy (one of its nine priority sectors) highlights the importance of energy sector adaptation and states that any energy system vulnerabilities may compound effects in other sectors. The strategy underscores the importance of integrated contingency plans to minimise impacts of cascading failures, as well as interconnections between energy sector adaptation and planning in other areas such as land use, water resource management and transport.

The Action Programme for Adaptation to Climate Change (2019) defines nine lines of action focused on key climate impacts. Two of these target wildfires and floods, and they detail specific actions for implementation on the ground for the energy sector. An additional crosscutting line of action includes various measures to support decision-making. For instance, the Action Programme proposes that all energy companies have climate adaptation and contingency plans in place by 2030. More than 50 municipal and inter-municipal adaptation plans back implementation of the Action Programme.

Climate vulnerability assessments by various sectors support development of the National Climate Change Adaptation Strategy and Plan, as does the project Climate Change in Portugal: Scenarios, Impacts and Adaptation Measures (SIAM) conducted in two phases in 2002 and 2006. The project’s second phase explored climate impacts on the energy sector, particularly on solar energy, water availability for electricity generation, and energy demand for heating and cooling.

The National Roadmap for Adaptation 2100 (RNA 2100), launched in September 2020 by the Portuguese Environment Agency, supports implementation and monitoring of the Action Programme for Adaptation to Climate Change and relevant actions of the National Climate Change Adaptation Strategy 2020. The RNA 2100 will set adaptation objectives based on climate risk assessments and will help identify adaptation investment needs as well as costs, including the cost of inaction. In this way, strategic projects and measures will be identified to further support adaptation policies at the practical level. The project is to be completed by December 2023.

Portugal’s National Energy and Climate Plan (NECP 2030) recognises the importance of climate change adaptation and refers several times to the Action Programme for Adaptation to Climate Change. Although NECP 2030 does not offer additional measures to enhance energy sector resilience, it emphasises the synergies between adaptation and mitigation and the need for an integrated approach.