Electricity is transported from the place where it is generated (hydropower and thermal power stations) to other parts of the country via Portugal’s national transmission grid, Rede Nacional de Transportes (RNT). RNT is made up of both high and very high voltage lines distributed all over the country with varying levels of capacity (60 kV, 150 kV, 220 kV and 400 kV). Transformer substations that supply electricity to the power grids at 60 kV are also part of the RNT (REN, 2014).
In Portugal, electricity is supplied by the national electricity utility, Rede Elétrica Nacional (REN), which is a concessionaire of RNT. Created in 1994 as a public utility, REN acts as a systems operator and market operator and is responsible for ensuring the continuous supply of electricity, without interruption. Managed by REN, RNT currently has 6,438 km of power lines, of which 1,301 km operate at 400 kV; 2,717 km at 220 kV, and 2,420 km at 150 kV/130 kV. It also has 47 substations, 7 transmission stations, 1 switching station and has a transformer capacity (both transformers and autotransformers) of 17,667 MVA (REN, 2015).
The installation of high voltage power lines is not without controversy. On the contrary, it has been the strongly contested by a range of social actors who are firmly opposed to their establishment. The main issues raised are in relation to the installation of the lines close to residential areas and their potential impacts on human health.
Since the 1970s, several studies have identified serious threats to the health of populations living close to the electromagnetic fields. However, the World Health Organization (WHO) affirms that there is not enough scientific evidence to prove that there is a direct relation (WHO, 2007). According to the WHO, only very intense magnetic fields, with values above 500 µT, can affect the nervous system, which is not the case of HVTLs that generate magnetic fields of no more than 30 µT (SÁ, 2008). The WHO considers that it is possible, although it has not been proven probable, that low intensity magnetic fields are somehow related to the incidence of cancer (SÁ, 2008). Therefore, in accordance with the precautionary principle proposed at the 1992 Earth Summit (SIMAS, 2010), in 1998, the WHO established exposure limits of 10 kV/m for HVTLs. This limited was adopted by the EU in 1999 and later, in 2004, by Portugal (MAPA, 2014).
Statistics show, however, increases in the incidence of cancer in people living close to HVTLs. Research conducted by specialists at Oxford University concluded that the risk of developing leukaemia is 2.7 times higher among children living 100 m from HVTLs than among children in general (METEO.PT, 2007). Other studies conclude that HVTLs are linked to higher risks of developing brain tumours and long-term exposure can lead to birth defects and premature births. Another public health issue is the impacts caused by low frequency noise, which causes increases in stress, depression, sleep disorders, headaches and epileptic crises (METEO, 2007).
The 1st Meeting on Power Lines and Birds in the country was held in Castelo Branco in 1999 by Quercus and the Portuguese Society for the Study of Birds (SPEA for its acronym in Portuguese). The main outcome of the meeting was the creation of a working group composed of representatives from these two environmentalist organisations, EDP and the Institute for Nature Conservation (Instituto de Conservação da Natureza, ICN). A cooperation agreement was signed in 2003 among the entities involved in the WG.
Concerned with the need to protect birds, the working group carried out an extensive study on bird mortality due to electrocution and collusion in Special Protection Zones and Bird Important Areas. Birds use the infrastructure of HVTLs for landing, as a strategic point for hunting, sleeping and building their nests. Often, while doing so, they come into contact with two conductors of different currents and are electrocuted or run into aerial conductors or ground wires. To conduct the study, researchers travelled 5,000 km on foot, which corresponds to close 500 sections of the HVTL, and noted a high rate of bird mortality along the way (SPEA and QUERCUS, 2005). Earlier studies had already identified the correlation between HVTLs and setbacks in the protection and conservation of various endangered species. The impacts of HVTLs are not limited only to birds, but also mammals in the area such as bats and wolves (REN, 2014).
While there may not be scientific consensus on the matter, there appears to be a strong consensus among civic movements to reject projects that aim to install HVTLs in urban areas.
The effects of prolonged exposure to HVTLs got introduced to the public debate in 2007, when several civic movements all over the country mobilised to contest actions taken by the REN. 2007 was a year of important victories for the movements, namely the alterations to the path of the Silves transmission line and the decision to bury the Trajouce-Fanhões line. These movements demanded that the government take action to change the law and that the REN reduce the values of the electromagnetic fields by up to 500 times. In 2008, the government voted down the draft bill presented by the Bloco de Esquerda (BE) that proposed reducing the limits of exposure to electromagnetic radiation, which would force the REN to bury the lines (ESQUERDANET, 2008).
The same year, the discussion on the risks of HVTLs for the population in urban areas was taken up again in the Assembly of the Republic. More specifically, the topic of debate was the draft bill proposed by the Partido Social Democrata (PSD) in coalition with Centro Democrático Social (CDS), Partido Comunista Português (PCP), Partido Ecologista Os Verdes (PEV) and BE. Deputies from the Partido Socialista (PS) who coordinated the environmental committee’s working group at the time, questioned the bill, primarily in relation to financial issues. It did so after requesting opinions from the REN, the Energy Services Regulatory Authority (ERSE in Portuguese), the National Association of Municipalities (ANMP) and the National Association of Parishes (ANAFRE). According to the PS, answering the question “who will assume the costs of the proposed changes?” is fundamental for the law’s approval. Will these costs be covered by the REN, which will then penalise citizens by raising their electricity bill, or by the government through the state budget? This issue is even more important if we consider that one of the main solutions to the problem of the HVTLs is, in fact, burying them underground. The estimated cost for the Trajouce-Fanhões line alone, for example, is between 20 and 30 million euros (SIMAS, 2010). The draft bill, passed in 2009, establishes: 1) that the government is responsible for defining the minimum distance between buildings and HVTLs; 2) a one-year deadline for the government to complete an assessment of the situation of HVTLs in the country; 3) a two-year deadline for resolving the problems; and 4) a 10-year deadline for resolving all the issues raised (SIMAS, 2010).
In April 2008, several civic movements came together in Cacém to form one single movement - the Movimento Nacional Contra as Linhas de Alta Tensão nas Zonas Urbanas (National Movement Against High Voltage Power Lines in Urban Areas) - with the goal of pressuring the government and organising mobilisations. In addition to the impacts on public health, people directly affected by the HVTLs were concerned with changes to the landscape (many of which were of international interest) and the impacts that they would have on tourism and land values (LUSA, 2008).
Case law on this matter has existed since 1995. The Porto Court of Appeal was a pioneer in this area with its ruling on a case of expropriation and later, in 2001, the one handed down in a common lawsuit. In both cases, after analysing scientific reports, the court ruled that in view of the possible threat that exposure to the electromagnetic fields produced by HVTLs poses to public health and the consequent lowering of land values, mandatory compensation must be paid for the real amount of the buildings that the HVTLs run overhead (METEO, 2007).
According to the law approved in November 2009, which is grounded on the “precautionary principle”, HVTLs can only be built a certain distance from residences in order to protect the population from the impacts of exposure to electromagnetic fields on their health. A second law, enacted in 2010, Law n. 30/2010 of September 2, stipulates that at a certain time of the year, the government must conduct a detailed survey on the situation in the country and in the two years after that, it must present a plan for resolving the problems of buildings erected close to the power lines. It was given a period of 10 years for resolving all the cases (AR, 2010).
Some popular mobilisations against the high voltage power lines were highly emblematic and had international repercussions, as in the case of the Spain-Portugal HVTL. The majority of this line was to be built in Portugal by the REN. The protest began in 2011 and in April 2014, protestors from both sides of the border met on the Melgaço bridge in Minho. The people of Arbo and Minho united in the fight against the installation of the 400 kV HVTL that was to run from the border of Galicia to the Portuguese border (PAeM, 2017).
In the case of the Tunes-Estoi HVTL, the works to connect two substations began in the late 1990s. Licenced in May 1994, they were halted in 2007 by the Albufeira City Council due to the conflict with the population who did not want the transmission towers close to their residences.
Another case was the Foz Tua-Armamar HVTL. The power line was to transport energy produced by the hydroelectric dam in the Alto Douro wine region, declared a world heritage site by UNESCO, which will modify the landscape and affect the wine culture. The Portuguese government received several criticisms from UNESCO for the threats posed by the project to world heritage. Despite the criticisms, the government went ahead with its plans and the construction of the Tua dam is now at an advanced stage.
The case of the Trajouce-Fanhões line in 2008 led Quercus and Olho Vivo to file a complaint with the EU against the Portuguese state for its failure to comply with EU guidelines requiring environmental impact assessments to be carried out for projects to build overhead very high voltage transmission lines. According to these organisations, studies proposing alternative locations for the lines were not carried out, which is mandatory according to EU legislation (PÚBLICO, 2006). The same did not happen with the project for the Cascais, Amadora and Sintra line where the population and environmental organizations demanded the lines should be buried, in a public consultation of these projects.”
In October 2016, the Assembly of the Republic (AR) unanimously approved the BE’s draft resolution that proposed that the law to protect against the impacts of high voltage lines be regulated (ESQUERDA, 2016).
In April 2017, the AR approved the PSD and the BE’s request for a hearing with the president of the REN and the State Secretaries for Energy and the Environment on the path of the very high voltage power lines planned for the municipality of Barcelos. According to an official source from the State Secretary for Energy, these hearings fall under a new working group created by the government in February to study electromagnetic fields and propose the necessary changes to the methodology used for licensing new electricity infrastructure. The working group was to present a report by April 30 (LUSA, 2017) and until today, no information has been released to the public on this.
In May 2017, the president of the Parliament’s Environmental Committee was at a conference organised on this issue in Barcelos, together with MEP Lídia Senra from Galicia, where they defended an alliance between the Portuguese and Spaniards to stop the plans for very high voltage lines in both countries from advancing (ESQUERDA.NET, 2017).
In June 2017, the government announced that it planned to push ahead with the process of regulating the construction of HVTLs as quickly as possible. The proposed regulations on the impacts of electromagnetic fields, drafted by the working group set up at the beginning of the year, are available for public consultation on the website of the Direção Geral de Geologia e Energia (DGEG, Directorate General for Geology and Energy). They propose that new power lines must not be allowed to pass over sensitive facilities, which are defined as: health facilities and schools, day care centres or preschools, retirement homes, asylums, parks, playgrounds, sporting facilities and venues, and residential buildings and houses meant for permanent residence. In cases where other alternatives do not exist, the owner may authorise or refuse to authorise the construction of the line over his or her property. At the same time, REN will have to guarantee a minimum distance between the HV/VHV electric infrastructure and sensitive facilities, and minimise the different kinds of impacts: noise from the electromagnetic fields or social impacts resulting from their installation (LUSA, 2017).
ESQUERDA.NET. Alta tensão: governo recusou alterar lei. Portal Esquerda.net, 27 dez. 2008.
MAPA. Muito alta tensão ameaça norte e Galiza. Jornal de Informação Crítica, 14 jun. 2014.
METEO.PT. Linhas de alta tensão-perigo para a saúde. Site meteopt.com, Diário de Notícias da Madeira, 3 jul. 2004.
SÁ, José Luís Pinto de. 20 perguntas frequentes sobre linhas de alta tensão e saúde pública. Universidade de Lisboa-UL, Instituto Superior Técnico-IST, fev. 2008.
SIMAS, Nuno. PSD avança com lei sobre linhas de alta tensão, PS quer saber quanto vai custar. Público, 5 jul. 2010.
SPEA; QUERCUS. Estudo sobre o impacto das linhas elétricas de média e alta tensão na avifauna em Portugal. Associação Nacional de Conservação da Natureza-Quercus, Sociedade Portuguesa para o Estudo das Aves-SPEA, jun. 2005.
REN. Eixo da RNT entre Vila do Conde, Vila Fria B e a rede elétrica de Espanha, a 400 Kv. Rede Elétrica Nacional S.A.-REN, Estudo de Impacte Ambiental. resumo não técnico, nov. 2014.
REN. Regras de segurança junto a instalações de muito alta tensão e alta tensão. Rede Elétrica Nacional S.A.-REN, 2015.
PORTUGAL. Assembleia da República. Lei n.º 30/2010 de 2 de setembro de 2010. Proteção contra a exposição aos campos elétricos e magnéticos derivados de linhas, de instalações e de equipamentos eléctricos. Diário da República, p.3846-3848, set. 2010.
PÚBLICO. Ambientalistas levam linhas de alta tensão a Bruxelas. Notícias, 19 ago. 2006.
June 30, 2017.
In Portugal, electricity is supplied by Rede Elétrica Nacional (REN, the national electricity company), a concessionaire of Rede Nacional de Transportes (RNT, the national transmission network) created in 1994. REN currently manages 6,438 km of high and very high voltage lines. The installation of HVTLs is being strongly contested by several social actors concerned with their impacts on human health and the environment. Since the 1970s, several studies have identified the serious threats that living close to electromagnetic fields pose to human health. They warn about the need for caution when planning new installations and to regulate the national power grid.