The excellent solar energy availability in Portugal (between 1860 kWh/(m2.year) in the south and 1590 kWh/(m2.year) in the north for solar radiation in the horizontal), gives to Portugal the opportunity to decrease its traditional dependency on energy imports. The imports are coming down in the last years mainly due to wind energy contribution, but also due to a combined contribution of energy efficiency measures and other renewable energy sources such as large hydro, biomass and solar. Since 2010 the dependency of the country in conventional energy imports is below 80%. It reached a minimum in 2014 (70.5%) and a maximum in 2017 of 77.7%. In 2019, the value was 74.2% (General Direction of Energy ).
The large solar resource has always been and incentive to the use of solar thermal collectors and systems, which was initiated in the 1970s. Along the years, the public policies gave, mainly, fiscal incentives to the installation of solar thermal systems for Domestic Hot Water (DHW) preparation. Despite of these incentives, the total collector area installed until 2000 was 219,500 m2 .
In the first decade of this century, public policies were implemented to profit from this resource but imposing the “quality” paradigm in the technology and system installation services. In 2001, a program called “Solar hot water for Portugal”  was implemented, and it introduced the following certification schemes:
for solar thermal collectors and systems, in a very similar way to Solar Keymark, which was also implemented at the same time at European level;
for installers of solar collectors and systems.
In 2002, the Directive 2002/91/EC of the European Parliament and of the Council on the energy performance of buildings, was published and the work of transposition to the Portuguese law was initiated. Benefiting from the work performed in the frame of the program “Solar hot water for Portugal”, the transposition of the directive introduced the obligation of use of solar thermal collectors for hot water preparation in new buildings and large renovations. This obligation was accompanied by the following criteria: only solar thermal systems with certified collectors, installed by certified installers and having six years guarantee, could be accepted in the framework of this obligation.
These policies were important for the growing of the solar thermal market. Some fiscal incentives were also a good support to the growth of the market. Fiscal incentives were directed to families with deduction in the individual income tax but also to corporate income tax (during a few years a very beneficial condition was possible: amortization of investment in renewable energies could be done in four years).
In 2009, a strong incentive program (http://www.paineissolares.gov.pt/faq-mst2009.html) busted the growth of the market specially in the domestic sector (the price of solar thermal systems for family houses could be acquired with a reduction in price from 30 to 60% depending on the typology and size of the system). Deduction in individual income tax could also be applied. In 2010, the incentive was directed to the social-service sector, but the financial crises stopped this incentive in the next years and also stopped the fiscal incentives).
In 2020, a new incentive program “Programa de Apoio a Edifícios Mais Sustentáveis (PAE+S)” aiming to give support to more sustainable buildings was launched and was opened until 31st December 2020. In this program, support to the installation of Solar Thermal Systems for Hot Water Preparation was considered. The systems had to be Class A+. A support up to 70% was considered with a maximum of 2500€. The program also supported other energy efficiency measures such as efficient windows, insulation, PV systems and heat pumps as well as water efficiency use. A new edition of this program (PAE+S2021) is foreseen for 2021 but rules are not yet available.
Statistics on number of collectors installed are not available since 2016. In that year, the installed collector area was around 1,2 million m2 of collectors, mainly in the domestic sector. This puts the Portuguese market on a modest place within European countries (<200 000 m2 annual), although with average installed capacity per 1000 inhabitants of 79.1kWth when European average is of 72.4 (values for 2019 according to “Solar Thermal Markets in Europe - Trends and Market Statistics 2019, ESTIF, December 2020). An annual evolution of the installed capacity of 5% comparing 2019 to 2018 is considered in “Solar Thermal Markets in Europe - Trends and Market Statistics 2019, ESTIF, December 2020.
The national energy and climate plans (NECPs) were introduced by the Regulation on the governance of the energy union and climate action (EU)2018/1999 , agreed as part of the Clean energy for all Europeans package , which was adopted in 2019.
Portugal developed its Integrated National Plan for Energy and Climate (PNEC) for the period 2021-2030 and its final version was approved in July 2020 (Portuguese Ministers Council Resolution nº53/2020, 10th July ).
For solar thermal PNEC indicates:
“In buildings, the solar thermal should coexist with other technologies of great potential and efficiency, such as biomass boilers and heat pumps. Still, it will maintain a significant role in the preparation of hot water, and in addition to other efficient solutions, it is one of the most efficient ways for space and water heating, contributing to the increase of comfort. In the case of industry, the capacity to satisfy low / medium temperature heat needs is expected to grow substantially.”;
and it predicts that solar thermal will contribute with a total of 96, 101 and 104 ktep for 2020, 2025 and 2030, respectively (see Table 9 of PNEC) to the share of renewables in Heating and Cooling, which is considered to be 41%, 45% and 49% of the total energy consumption in 2020, 2025 and 2030, respectively;
and it also considers that solar thermal can contribute to energy needs in Industry in complement to biomass and higher electrification and digitalization of the sector.
Another important document of Energy policy is the “Roadmap for Carbon Neutrality 2050 (RNC 2050) - Long-Term Strategy for Carbon Neutrality of the Portuguese Economy in 2050”  where the same role in foreseen for Solar Thermal.
 ADENE/INETI (2002). “Fórum Energias Renováveis em Portugal – Uma contribuição para os objetivos de política energética e Ambiental”. Eds. Hélder Gonçalves, António Joyce, Luís Silva, ISBN-972-8646-05-4. Chapter “Solar Térmico Activo” (page. 30 to 67), Prepared by Working group coordinated and edited by M. Collares Pereira, and M.J. Carvalho
 Resolution of Ministers Council nº154/2001; Água Quente Solar para Portugal, ADEME/DGE/INETI, Novembro 2001, ISBN 972-8646-02-X
 Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings, withdrawn and replaced by Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings, which was latter amended, as part of the Clean energy for all Europeans package, in 2018 (Directive (EU) 2018/844 of the European Parliament and of the Council of 30 May 2018 amending Directive 2010/31/EU on the energy performance of buildings and Directive 2012/27/EU on energy efficiency).