Global warming and energy are two intertwined concepts since the energy sector is responsible for more than two thirds of the global emissions of greenhouse gases (IEA 2017). Energy is also one of the main pillars of society responsible for satisfying most human needs (e.g. lighting, communication, mobility, food and industrial production) are crucial to economic development.
The global demand for energy increased by over 50% between 1973 and 2015 driven by the increased use of fossil fuels which represent more than 81% of the total consumption of primary energy (IEA 2017). Globally, if this trend continues, carbon dioxide emissions will duplicate by 2050 leading to an increase of the average global temperature of at least 6°C compared to pre-industrial levels.
Historical trends show that economic development has been deeply associated with energy consumption. In developed countries, for instance, energy consumption per capita is higher. Notwithstanding, in the last decades we have witnessed a decoupling between energy consumption and economic development due, not only, to structural changes in the economy but also, to the increase in energy efficiency and changes in the energy consumption mix.
The impacts of resource consumption and the associated emissions of energy production/consumption justify its reduction in all sectors of the economy to encourage sustainable economic and social development. To this end it is vital to create an energy system that is safe, affordable and compatible with environmental protection. “Affordable and Clean Energy” is the 7th Sustainable Development Goal of The United Nations. It focuses on the need for a trustworthy, sustainable and modern access to energy at an affordable price for everyone.
Non-sustainable energy systems are responsible for a wide range of negative effects such as natural resource depletion, air pollution, negative impacts on health and on the economy. Moreover, fossil fuel resources, such as oil and natural gas are not equally distributed among regions. This creates a negative effect directly on the energy costs of importing countries. Additionally, these countries are vulnerable in their access to resources due to political instability in some supplier countries.
Socio-economic and behavioral changes as well as the decarbonization of energy systems through low carbon technologies and the improvement of energy efficiency have several benefits. These changes can contribute to the fight against global warming while improving air quality, foster energy safety through the promotion of sustainable energy systems and a diverse, resilient and trustworthy technological portfolio.
Portugal has implemented profound social and economic changes in the last few years and this has positively impacted both the energy system and greenhouse gas emissions. Currently, national energy policies are substantiated by economic rationality and sustainability which translate into energy efficient measures, energy consumption from endogenous and renewable sources and the need to reduce costs (ADENE 2016).
Foreign energy dependency has been declining and dropped by 9% between 2000 and 2015. This decrease was due to its commitment to invest in renewable energy for electric production/generation. Thus, making renewable energy sources the main component of electricity production in Portugal. Consequently, this has led to a reduction of fossil fuel imports (gas and coal). Still, fossil fuel consumption represented 76% (primary energy) in 2015. Though still a high percentage it is below the global average.
In the last semester of 2016 of 21,3 GW of total installed capacity in Portugal: 63% came from renewable energy sources. Hydropower represented 32% and wind power 25%. These are complemented by 25% from fossil fuel sources, mainly natural gas representing 24% and coal at 9% (DGEG 2017).
The transportation sector has the highest energy consumption. It represented 37% of total energy demand in 2015 while industry represented 31% and construction 29%. Notwithstanding, we have witnessed a reduction in consumption in all of these sectors. Energy consumption in industry decreased by 22%, in the transportation sector it fell by 17% and in construction by 15% in the years between 2000 and 2015 (DGEG 2016).
The role of energy system is, therefore, paramount to the path toward carbon neutrality.