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)[1], 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 [2]).

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 [3].

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” [4] was implemented, and it introduced the following certification schemes:

1. 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;
2. 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[5], 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[6] was launched and was opened until 31^st December 2020. In this program, support to the installation of Solar Thermal Systems for Hot Water Preparation was considered[7]. 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 [8], agreed as part of the Clean energy for all Europeans package [9], 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, 10^th July [10]).

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” [11] where the same role in foreseen for Solar Thermal.

The solar thermal collector capacity installed in Portugal is in majority directed to DHW applications and is mainly directed to the residential buildings although solar systems are also installed in buildings in the service sector – tourism, public buildings, sport. With a market directed to the single-family houses, it is usual to see the typical thermosiphon system constituted by 4m² of solar collectors and 150/200 liters horizontal storage tank on the roofs, covering, in average, 80% of DHW housing needs. For the collective systems, the average size is 40 m². In 2015, according to APISOLAR, the thermosiphon systems manufactured or imported were circa 22% of the total of solar products. No information is available since 2016.

On the first decade of this century, the main drivers for the expansion of solar thermal market in Portugal were:

a) the regulation on Energy Performance of Buildings, which imposed solar thermal for DHW since 2006 in all new buildings and in building retrofitting with a cost of 25% of the building declared value;

b) a strong incentive program in 2009/2010 connected with interesting fiscal measures.

These measures decreased substantially the final costs of installed systems for end-users.

The regulation on Energy Performance of Buildings is still a driver for the market, specially for new buildings. For old buildings, the support program PAE+S[1], implemented in 2020, can also be an incentive.

An additional program is announced to fight energy poverty. In this program needy families will receive “efficiency vouchers” that will allow to renovate electrical appliances or perform repairs (new insulation, new windows, etc.) that will contribute to a better energy efficiency of the households. Rules are not yet available, and it is not yet possible to know if solar thermal systems are included in the “efficiency vouchers”.

Although much higher numbers have been reported previously due to the peak of Solar Thermal Industry in 2009-2010, it is estimated now that there are around 5 producers (collectors and storage tanks). A major part of commercialized systems (produced and imported) is directed to the Portuguese market and are based on flat plate collectors (98.2% - values for 2015 according to “Solar Thermal Markets in Europe - Trends and Market Statistics 2015, ESTIF, November 2016) and mostly with selective absorbers.[1]

In the 2013 report of APISOLAR, it was estimated 270 workers working directly on the sector, which developed commercial relations with 630 workers. No other source of information is available now. It is possible that a decrease on the employment in this sector was observed between 2010 and 2019, especially due to reduction on manufacturing companies.

Typical specific market prices including installation for different systems are estimated to be:

• Individual domestic hot water system (4m² collector): 1500 - 3000 €
• Collective systems: 500 - 750 €/m²

VAT is presently 23%, including RE technologies, but companies can amortize investment in RE in 12,5 years, reducing by that way the annual taxation which is 21%.

As already referred the quality paradigm was introduced in the first decade of 21st century, not only with the certification of equipment (e.g., Solar Keymark certification scheme) but with the certification of Installers. This is recognized in the Certification Scheme for Energy Performance in Buildings (SCE) [1] where the contribution of Solar Thermal Systems for hot water preparation is considered if solar systems and/or collectors are certified according to the standards EN 12976 and EN 12975, respectively. Also, the installation needs to be performed by qualified professionals [2].

Legislation issued by the Portuguese Parliament in 2018, establishes the Legionnaires' disease prevention and control regime [3]. This Legislation is referred in the recent legislation on the Certification Scheme of Energy Performance in buildings.

In 2019, legislation was published [1] with the rules that allow to classify buildings as NZEB – Nearly Zero Energy Buildings. The verification of these rules is mandatory for new buildings owned and used by public institutions since 1^st January 2019 and for all other new buildings since 1 of January 2021.

In the frame of the Energy Performance Building Directive [2], Portugal adopted a Certification Scheme for Energy Performance in Buildings (SCE) [3] which is mandatory not only for new buildings but also for all the buildings when rented or sold to a new owner. In these situations, when the labelling is attributed, recommendations are given to obtain a higher label. If these measures are applied and correspond to an increase of two labels, a reduction in the taxes to the property can be requested. Information on these benefits is available in https://www.sce.pt/certificacao-energetica-de-edificios/investidores/.

Incorporation of solar technologies for buildings, like passive house and daylighting technologies, are considered in SCE, which has a structure of classification (labelling) favourable to the introduction of those technologies, meaning that, when they are used in connection with solar thermal, it is easy to achieve the highest label. This highest label can then take profit of 25% reduction in the property taxation. Information also available in https://www.sce.pt/certificacao-energetica-de-edificios/investidores/

The regulation on Energy Performance of Buildings is in place and was recently revised [1] to be in line with 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.

There is legislation that imposes that new buildings, from 1^st January 2021 on, shall be NZEB - Nearly Energy Zero Buildings and Solar Thermal is mandatory for DHW preparation.

The obligation to have NZEB buildings in the residential sector may be a factor for introduction of solar passive solutions, as well as higher use of solar active solutions for DHW preparation and climatization.

The trend for electrification will contribute to a tendency to use roof space mainly with PV.

In 2021, a Long-Term Strategy for the Renovation of Buildings (ELPRE) was approved [2] . This Strategy is implemented in the frame of the transposition of Directive (EU) 2018/844 of the European Parliament and of the Council, of 30 May 2018, on the energy performance of buildings and Directive 2012/27 / EU on energy efficiency (Decree-Law nº 101 - D / 2020, of 7 December).

The indicative objectives of renovation of buildings for 2030, 2040 and 2050, considering as base the year 2018 are:

• Renovated building area of circa 363 million m² for 2030, 635 million m² for 2040 and 748 million m² for 2050, corresponding to primary energy savings of 11% for 2030, 27% for 2040, and 34% for 2050

ELPRE will be an important program to raise building renovation rate and construction rate in general.

The tendency for decrease in the construction market observed until 2015, changed and in 2016 and 2017 the number of building permits increased by circa 10% over the previous year and in 2018 this increase was 19.1%. In 2019 the increase on building permits had lower increase rates of circa 4.1% [3].

The increase in construction reflects in the Solar Energy Market due to the mandatory use of Solar Collectors for DHW preparation.

It is also worth referring that the number of permits for refurbishment increased circa 1.4% in 2019 while in 2018 it had an increase of 13.3%. This is in line to the slower increase observed in 2019 for new building permits.

No data available.

In Portugal there is not a “typical” solar building, because there is not yet in the market a large offer for those buildings. But the experience gathered with the construction of the “SOLAR XXI Building” existing on the campus of LNEG in Lisbon, the final costs including 100 m2 of polycrystalline PV façade, is in the order of 800 €/m². This is the price of 2006. It includes straight costs surveillance and excludes terrain of construction.

There is no national R&D programme specific for solar thermal and/or for solar buildings in Portugal. Anyway, universities, research Institutes and enterprises can apply for national programs, where it has been possible to accommodate part of the research and demo needs of solar technologies. Those Programs are managed by:

1. FCT (www.fct.pt) – Science and Technology Foundation which supports graduate education and training, carrier development, research and development grants, research units, etc., in all areas of science and technology.
2. Portugal 2020 (https://www.portugal2020.pt/Portal2020), which sponsors R&D in industry and services, promoted by enterprises that can apply alone, in consortium or subcontract R&D national entities.

Specific private companies develop new solutions for, e.g., Solar Combistores (J. Prior); Collector for façade integration heating air and water (T&T); Medium temperature stationary concentrating collectors for Industrial applications (MCG).

In the frame of projects financed by FCT (Science and Technology Foundation) study of solar thermal collector components durability are being performed by LNEG with the support of Solar Thermal Producers and in cooperation with Universities (Lisbon University – IST and New University of Lisbon – FCT).

Two research infrastructures are now also financed by FCT (Science and Technology Foundation):

1. NZEBLab is coordinated by LNEG and is dedicated to the research on integration of RE in buildings;
2. INIESC is coordinated by University of Évora and is dedicated to research in CSP including SHIP.

In the frame of projects financed by Interreg-Sudoe two projects related to building operation:

1. Sudoket, which the main objective is to enhance the growth and technological leadership of Europe in the “Innovative Buildings” (EI) sector by strengthening research, innovation and development capabilities of solutions based on Key Enable Technologies (KETs);
2. Improvement, which aims  to renovate / convert existing public buildings into nearly zero energy needs buildings, integrating renewable energy micro grids with combined heat, cold and electricity generation and storage systems.

This is not a full list of projects.

Portugal, as a European country is committed to contribute to the targets established in 2030 Climate & Energy framework. The targets for 2030 are now considered in PNEC 2030 (Integrated National Plan for Energy and Climate 2021-2030[1]):

• GHG emissions: -45% to -50%;
• Energy Efficiency: 35%
• Renewable Energies: 47% (estimated to be by sector: 80% in Electricity; 49% in Heating and Cooling and 20% in Transport)

For solar thermal, NEPC 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.

The Portuguese government committed to an overall investment of 3% of GDP by 2030 in R&D and NEPC considers that the part dedicated to R&D in Energy is 0.2% of GDP by 2030.

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” [2] where the same role in foreseen for Solar Thermal.

The Minister of Environment and Climate Action and Secretary of State of Energy are is responsible for Energy Policies.

DGEG (www.dgeg.pt ) – The General Directorate for Energy and Geology (DGEG) is the Portuguese Public Administration Body, in the frame of the Ministry of Environment and Climate Action, whose mission is to contribute to the conception, promotion and evaluation of policies related to energy and geological resources, with a view to sustainable development and guaranteeing the security of the environment. supply. The DGEG's mission naturally includes the need to raise citizens' awareness of the importance of those policies, within the framework of the desired economic and social development for the country, informing them of the instruments available for the execution of political decisions and disseminating the results of its monitoring and execution.

LNEG (www.lneg.pt ) – National Laboratory of Energy and Geology, is a R&D institution, assumed as the interface between research results and economic agent’s community. It works as a consultant for public policies in the areas of energy and geology, environment, sustainability, standardization and certification. LNEG also gives direct support to the State in the areas of international representation and provides the Government of appropriate reasoning on Science and Technology for the sectorial policies. LNEG has an accredited laboratory for testing of solar thermal systems, collectors, and other components (LES) performing tests either directly to industry or to certification bodies, namely, the national certification body CERTIF, in the frame of national and Solar Keymark certification.

ADENE (www.adene.pt ) – Is the national energy agency, an association of private law, non-profit and public utility, whose mission is to develop activities of public interest in the area of energy, efficient use of water and energy. energy efficiency in mobility.

ADENE performs activities of public interest in energy policy and can act in areas relevant to other sectorial policies, when intertwined with energy policy, in connection with the public competent entities. ADENE is the entity responsible by all building thermal performance certification process by delegation of DGEG (Directorate General of Energy and Geology).

The regulation for energy performance of buildings (SCE) was recently revised and the main document was published [1]. Other necessary documents such has the SCE Guide are not yet published but are expected by July 2021.

Meanwhile the former codes, one applied to energy performance of residential buildings (REH) and another applied to energy performance of commercial and services buildings (RECS)[2] are applied.

The REH imposes the usage of solar thermal collectors for hot water production in all new buildings, if there is a good exposition to solar radiation in their cover. The same rules apply to large renovation of existing buildings. Although it is an imposition, it has been accompanied along the last years, by some punctual programs sponsoring the solar thermal systems for buildings of social benefit and for companies when integrated in their overall energy efficiency measures. In the same base punctual interventions in building’s façade had benefit of similar supporting programs.

The mandatory usage of solar thermal in the REH context is accompanied by the obligation of usage of certified collectors according to EN 12975 or EN 12976. This set of items lead, during the last years, to the existence of several courses for designers and installers, promoted by the public and private education sectors. Some universities are also offering now in their civil and/or architectural departments lectures on the solar thermal and solar building design (IST, FCUL, FEUP, FCT/UNL, EEUM, UEvora, UA, UAlg, IPS, etc).

RD&D funding in Portugal is connected to the Programs of FCT (usually for small projects on the fundamental and applied research side coming from universities and research institutes and laboratories) and of Portugal 2020 (for projects led by companies and involving or not public research entities).

The most relevant national associations in the solar heating and cooling field, are:

APISOLAR – Associação Portuguesa da Industria Solar

Was founded in 1998, APISOLAR - Solar Industry Portuguese Association, with the mission to defend, develop and promote of solar photovoltaic and solar thermal, involving industrial manufacturers, importers, exporters, wholesalers, retailers components and accessories, designers, installers, etc. Was very active between first and second decade of XXI century.

APREN – Associação de Energias Renováveis (www.apren.pt )

The Portuguese Association for Renewable Energies (APREN) is a non-profit association, founded in October 1988 with the mission of coordination, representation and defence of the common interests of its Members. APREN Associates are companies holding licenses for the establishment of centrals for renewable electricity production, as well as any natural persons or legal persons interested in the development of renewable energies in Portugal. APREN represents about 90% of the electrical installed capacity produced by renewable sources. APREN participates in the development of energy policies for Portugal, promoting the use and exploitation of renewable resources for domestic electricity production.

APESF – Associação Portuguesa de Empresas do Setor Fotovoltaico (https://www.apesf.pt)

APESF is a non-profit association dedicated to promoting the development and dynamization of the photovoltaic energy market in Portugal, in order to accompany the development that characterizes the sector. The APESF mission is to promote, develop and disseminate the potential of photovoltaic energy, whether at the level of immediate benefit to the producer / consumer, or at the universal level, as a form of clean energy and a measure of energy efficiency.

ZERO (www.zero.ong) is a Non-Governmental Organization (NGO) founded in Portugal at the end of 2015, from the common interest of about a hundred people in achieving sustainable development. It has the ambition to intervene in Portuguese society through a proactive participation in the defense of the values of sustainability, with the understanding that only through the balance between environment, society and economy will it be possible to build a more cohesive, socially and economically world, in full respect for the natural limits of the planet.

QUERCUS (www.quercus.pt) – National Association for Nature Conservation (Associação Nacional de Conservação da Natureza). Quercus is a Non-Governmental Organization (NGO) founded in Portugal October 31, 1985. It is an independent, nonpartisan, nationwide, nonprofit, and consists of citizens who joined around the same interest for Conservation of Nature and Natural Resources and Environmental Protection in general, in a perspective of sustainable development.

DECO - Portuguese Association for Consumer Protection (http://www.deco.proteste.pt/institucionalemedia/ ) defends the rights and legitimate interests of consumers, helping them to solve their problems and to exercise their basic rights: access to information for a better choice, the quality of goods, right to education,  justice,  health and safety. DECO contributes to more informed consumers, more enlightened, more aware, more confident and empowered, and able to be an engine of an innovative and competitive economy.

DECO, and DECO PROTESTE publisher, work closely with similar organizations in Spain, Italy, Belgium and Brazil. It is also BEUC member (Bureau Européen des Unions de Consommateurs), CI (Consumers International) and ICRT (International Consumer Research & Testing).

DECO was involved in two European Projects where Solar Thermal Systems were important subjects (LabelPack A+ (http://www.label-pack-a-plus.eu/) and Clear (http://www.clear-project.eu/))

Passivhaus Portugal Association (http://www.passivhaus.pt/) The Passivhaus Portugal Association was created in 2012 in accordance to the strategy defined by Homegrid and the Passivhaus Institut to implement and develop the Passive House standard in Portugal.

ADENE (www.adene.pt) – National Energy Agency, keeps actualized all-important information (laws, codes, software, certificates, statistics, courses, etc.) related with building thermal certification in Portugal.

LNEG (www.lneg.pt) -The National Laboratory of Energy and Geology, Information on activities, talks open to the public, organization of seminars.