TECNICA ITALIANA-Italian Journal of Engineering Science Vol. 64, No. 1, March, 2020, pp. 11-16 Journal homepage: http://iieta.org/journals/ti-ijes The Energy Transition and the Advent of Hydrogen Economy Matilde Pietrafesa DICEAM, Mediterranea University, Reggio Calabria 89121, Italy Corresponding Author Email: [email protected] https://doi.org/10.18280/ti-ijes.640103 ABSTRACT Received: 7 January 2020 Climate change according to almost all experts is a consolidated reality; the responsibility Accepted: 18 January 2020 for these changes in the terrestrial ecosystem is largely attributable to man and in particular to activities related to the use of fossil fuels and deforestation. Keywords: In order to deal with these emergencies, in the near future a new sustainable energy climate change, sustainable energy, paradigm should be established, fully implementing the decarbonization process and based paradigm decarbonization, renewable on distributed micro-generation from renewable energy sources (RES), smart grids, energy energy sources, hydrogen and fuel cells storage and hydrogen. Energy production from RES, characterized by variable temporal availability, unpredictable over time, can efficiently meet the needs if coupled with storage systems (mechanical, electrical, chemical, thermal, biological, etc.): it follows that thanks to its energy performance and its environmental sustainability, the interest in hydrogen as energy carrier (it is clean, versatile and has high combustion efficiency) is growing today. The paper illustrates the characteristics and properties of hydrogen, together with its production and storage techniques and its uses, highlighting how, thanks to its environmental sustainability, it could play the role of energy carrier of the future in the new decarbonized energy paradigm. 1. CLIMATE CHANGE AND THE NEED FOR A NEW contained in the Directive 2009/28/EC, so-called Climate- ENERGY PARADIGM Energy, on climate change and energy sustainability [2], has set three important objectives for 2020: Nowadays almost all climate experts agree that climate change is a consolidated reality, the responsibility for which is largely attributable to man, especially to activities related to the use of fossil fuels, which have caused upheavals of the terrestrial ecosystem, and deforestation. The main among the bodies involved in climate change is the Intergovernmental Panel on Climate Change (IPCC), established in 1988 by the United Nations and the World Meteorological Organization (WMO), which is responsible for the scientific evaluation of these phenomena and their potential environmental and socio-economic impact. Worldwide, the average earth temperature has increased by about 0.8°C since 1880 (Figure 1), while on the European continent there has been a greater raise (around 1.4 °C), and a future increase of 4°C cannot be excluded. IPCC has estimated in 2°C the global average temperature increase, compared to the pre-industrial period, in order to avoid dramatic consequences for the planet [1]. Thus was born the need to take on shared commitments at an international level by directing the energy system on a virtuous path, started in December 2015 with the 21st climate conference held in Paris (COP21) and the Agreement stipulated therein, and to assume the consequent actions necessary to implement it. In Europe, member countries purchase oil from OPEC nations and Russia and still natural gas from Algeria, Norway and Russia itself. To limit this dependence on other states and to reduce carbon emissions, the European Union is incisively encouraging member countries towards a low carbon economy. In particular EU, referring to the third point of the strategy Figure 1. Temperature increase on planet surface 11 • 20% greenhouse gas emissions reduction compared to 1990 sources (small electricity production plants, isolated or • 20% energy production from renewable sources interconnected, placed close to the end user), energy storage • 20% reduction of primary energy consumption compared and hydrogen [5-8]. to 1990. The production from RES, characterized by variable temporal availability, unpredictable over time, can in fact As regards the framework to 2030, moreover, the Directive efficiently meet energy needs if coupled with storage systems requires a further reduction of greenhouse gas emissions, (mechanical, electrical, chemical, thermal, biological, etc.): it bringing it to 40% compared to 1990, and to 27% both the follows that thanks to its energy performance and its increase in the share of energy produced from renewable environmental sustainability, the interest in hydrogen as energy sources and in energy efficiency [3]. energy carrier is growing today [9-11]. This would lead by 2050, according to the expected In particular, one of the most environmentally sustainable European road map [4], to 80% reductions of CO2 emissions techniques for the accumulation of electricity produced from related to the energy sector, including those of the transport renewable energy consists in its use as a primary source for the sector, with electricity consumption from RES equal to 97%, production of electrolytic hydrogen, which is then converted thus establishing a safe, competitive and decarbonized energy back into electricity in fuel cells [12, 13]. system. Production can take place both in large plants and in small generative units close to the end user and can affect multiple sectors (electrical production, transport, air conditioning, etc.) 2. THE DECARBONIZATION PROCESS AND THE [14, 15]. ENERGY TRANSITION TOWARDS A HYDROGEN The fuel cells for its conversion could potentially produce ECONOMY electricity to meet the future needs of humanity, but triggering the transition from the era of fossil fuels to that of hydrogen 2.1 The decarbonization process will not be easy: producing hydrogen is still too expensive, so currently most fuel cells are powered by methane or other The new and sustainable energy paradigm that should be fossil fuels. established in the near future should fully implement a Furthermore, connecting millions of fuel cells to the grid decarbonization process: the term indicates the change in the will not be immediate and will require extremely sophisticated carbon-hydrogen ratio in the temporal succession of the control and distribution mechanisms (smart grids), capable of different energy sources. regulating traffic both in normal and peak periods. Wood, the primary energy source for most of human history, The new energy network will have to be interactive, has the highest carbon-hydrogen ratio, with ten carbon atoms equipped with integrated sensors and intelligent agents to for each hydrogen atom; among fossil fuels coal has the provide real-time information on demand conditions, in order highest ratio, with a value of 2:1, oil has one carbon atom for to allow the flow of electricity exactly where and when it is two of hydrogen, while natural gas has only one to four: this needed. means that energy sources gradually used over time have The problem of the current electricity distribution network, emitted less carbon dioxide than the previous ones. on the other hand, is that of being designed to ensure a one- In the last one hundred and forty years, even if total CO2 way energy flow, from the producer to the end user, so emissions have continuously increased, the carbon emission transforming it into an interactive network of millions of small per unit of primary energy globally consumed has decreased suppliers-users will require enormous efforts. by about 0.3% per year: hydrogen would therefore represent the completion of the decarbonization path, being free of 2.3 Hydrogen as the energy carrier of the future carbon atoms. Its emergence as primary energy source of the future is In the 70s of the twentieth century, in conjunction with the therefore an indication of the end of the long dominance of first oil crisis, the need arose to identify and develop new hydrocarbon-based energy production. energy frontiers, seeing hydrogen as an excellent opportunity In addition to the progressive elimination of carbon atoms, to overcome the dependence linked to fossil fuels. decarbonising has also meant the dematerialization of fuels, During the 1980s the end of the crisis and the collapse of which have gone from solid (wood and coal) to liquid the oil price caused a slowdown in the studies that were being (petroleum), to gaseous (natural gas and hydrogen): hydrogen carried out, but in the 1990s climate changes due to carbon is in fact the lightest and most intangible form of energy and emissions gave new impetus to research: as a consequence of the most efficient in combustion for the same weight (three this, since then the interest in the use of hydrogen is growing, times that of oil). thanks to its environmental sustainability and its energy The transition from solid energy forms to liquid and gaseous performance (it is clean, versatile and has high combustion ones has also made flows into the system easier and more efficiency) [16-19]. efficient: in pipelines oil travels faster than coal in railway Indeed: wagons and gas in pipelines is in turn faster than oil; moreover • its combustion provides only water as a by-product (no it allowed flourishing of technologies, goods and services that greenhouse gases) tend to speed, efficiency, lightness and virtuality. • it is suitable for stationary applications, in transports (vehicles, aircraft, boats), in air conditioning and portable 2.2 The transition to a new energy paradigm