The energy transition from fossil fuels to renewables is already ongoing, but it will be a long and difficult process because the energy system is a gigantic and complex machine. Key renewable energy ...production data show the remarkable growth of solar electricity technologies and indicate that crystalline silicon photovoltaics (PV) and wind turbines are the workhorses of the first wave of renewable energy deployment on the TW scale around the globe. The other PV alternatives (e.g., copper/indium/gallium/selenide (CIGS) or CdTe), along with other less mature options, are critically analyzed. As far as fuels are concerned, the situation is significantly more complex because making chemicals with sunshine is far more complicated than generating electric current. The prime solar artificial fuel is molecular hydrogen, which is characterized by an excellent combination of chemical and physical properties. The routes to make it from solar energy (photoelectrochemical cells (PEC), dye‐sensitized photoelectrochemical cells (DSPEC), PV electrolyzers) and then synthetic liquid fuels are presented, with discussion on economic aspects. The interconversion between electricity and hydrogen, two energy carriers directly produced by sunlight, will be a key tool to distribute renewable energies with the highest flexibility. The discussion takes into account two concepts that are often overlooked: the energy return on investment (EROI) and the limited availability of natural resources—particularly minerals—which are needed to manufacture energy converters and storage devices on a multi‐TW scale.
On the move: The energy transition to renewables has started and the development of solar electricity is much more consolidated than that of solar fuels. The transition process suffers two key constraints, that is, relatively low net energy gains and the limited availability of mineral resources to manufacture converters and accumulators.
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2.
The Hydrogen Issue Armaroli, Nicola; Balzani, Vincenzo
ChemSusChem,
January 17, 2011, Volume:
4, Issue:
1
Journal Article
Peer reviewed
Hydrogen is often proposed as the fuel of the future, but the transformation from the present fossil fuel economy to a hydrogen economy will need the solution of numerous complex scientific and ...technological issues, which will require several decades to be accomplished. Hydrogen is not an alternative fuel, but an energy carrier that has to be produced by using energy, starting from hydrogen‐rich compounds. Production from gasoline or natural gas does not offer any advantage over the direct use of such fuels. Production from coal by gasification techniques with capture and sequestration of CO2 could be an interim solution. Water splitting by artificial photosynthesis, photobiological methods based on algae, and high temperatures obtained by nuclear or concentrated solar power plants are promising approaches, but still far from practical applications. In the next decades, the development of the hydrogen economy will most likely rely on water electrolysis by using enormous amounts of electric power, which in its turn has to be generated. Producing electricity by burning fossil fuels, of course, cannot be a rational solution. Hydroelectric power can give but a very modest contribution. Therefore, it will be necessary to generate large amounts of electric power by nuclear energy of by renewable energies. A hydrogen economy based on nuclear electricity would imply the construction of thousands of fission reactors, thereby magnifying all the problems related to the use of nuclear energy (e.g., safe disposal of radioactive waste, nuclear proliferation, plant decommissioning, uranium shortage). In principle, wind, photovoltaic, and concentrated solar power have the potential to produce enormous amounts of electric power, but, except for wind, such technologies are too underdeveloped and expensive to tackle such a big task in a short period of time. A full development of a hydrogen economy needs also improvement in hydrogen storage, transportation and distribution. Hydrogen and electricity can be easily interconverted by electrolysis and fuel cells, and which of these two energy carriers will prevail, particularly in the crucial field of road vehicle powering, will depend on the solutions found for their peculiar drawbacks, namely storage for electricity and transportation and distribution for hydrogen. There is little doubt that power production by renewable energies, energy storage by hydrogen, and electric power transportation and distribution by smart electric grids will play an essential role in phasing out fossil fuels.
Energy: The hydrogen economy is often proposed by media and also by some scientists as the way out from fossil fuels. Is it an achievable goal? How far are we from it? This Review makes a critical analysis of the use of hydrogen in several different technologies.
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Energy for everybody? The ever increasing world energy demand cannot be satisfied much longer with fossil fuels; alternatives are required to limit the chance of a climate collapse and the spreading ...of wars for natural resources. The 21st century will be largely defined by the way we face and resolve the energy crisis. This is an intricate and fascinating scientific challenge, in which chemistry will play a fundamental role, and also an unprecedented opportunity to shape a more peaceful world.
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Our world is sick because of the bad relationship between human society and the planet and even more because of the discords within human society itself. We are slipping more and more towards ...ecological and social unsustainability. Both scientists and philosophers say it, and Pope Francis highlights these views in the Laudato Sì: " Doomsday predictions can no longer be met with irony or disdain. ... The pace of consumption, waste and environmental change has so stretched the planet’s capacity that our contemporary lifestyle, unsustainable as it is, can only precipitate catastrophes". Here then, as the Pope writes, " bold cultural revolution" is needed.
•Ruthenium tris(bipyridine) is a most influential molecule in contemporary chemistry.•Ru-polypyridine complexes exhibit a unique combination of ground- and excited-state properties.•Ru-polypyridine ...complexes are convenient building blocks in supramolecular photochemistry.•Valuable functions arise from photoinduced energy/electron transfer in multicomponent systems.•Integration with mechanically interlocked molecules can lead to nanomachines.
This review deals with a very peculiar molecule, Ru(bpy)32+ (bpy: 2,2′-bipyridine), and its interaction with photons and electrons. We summarize the properties that make Ru(bpy)32+ and related compounds a unique family of “clever” molecules which find application as components of chemical species capable of processing optical and electrical signals to perform a variety of interesting functions. Examples discussed in the article, that showcase the realization of these concepts with molecular and supramolecular systems, include molecular wires, switches, antennas and mechanical machines.
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6.
Light: A Very Peculiar Reactant and Product Balzani, Vincenzo; Bergamini, Giacomo; Ceroni, Paola
Angewandte Chemie (International ed.),
September 21, 2015, Volume:
54, Issue:
39
Journal Article
Peer reviewed
Open access
See the light of day: Light is the fastest way of transferring energy and information through space, and in chemistry it can perform the dual role of reactant and product. Sunlight, a really unique ...reactant, represents our ultimate energy source. Chemists are engaged in designing systems for the conversion of light into electrical or chemical energy and vice versa to create a more sustainable way of life.
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Photochemical Conversion of Solar Energy Balzani, Vincenzo; Credi, Alberto; Venturi, Margherita
ChemSusChem,
February 22, 2008, Volume:
1, Issue:
1-2
Journal Article
Peer reviewed
Energy is the most important issue of the 21st century. About 85 % of our energy comes from fossil fuels, a finite resource unevenly distributed beneath the Earth’s surface. Reserves of fossil fuels ...are progressively decreasing, and their continued use produces harmful effects such as pollution that threatens human health and greenhouse gases associated with global warming. Prompt global action to solve the energy crisis is therefore needed. To pursue such an action, we are urged to save energy and to use energy in more efficient ways, but we are also forced to find alternative energy sources, the most convenient of which is solar energy for several reasons. The sun continuously provides the Earth with a huge amount of energy, fairly distributed all over the world. Its enormous potential as a clean, abundant, and economical energy source, however, cannot be exploited unless it is converted into useful forms of energy. This Review starts with a brief description of the mechanism at the basis of the natural photosynthesis and, then, reports the results obtained so far in the field of photochemical conversion of solar energy. The “grand challenge” for chemists is to find a convenient means for artificial conversion of solar energy into fuels. If chemists succeed to create an artificial photosynthetic process, “…︁ life and civilization will continue as long as the sun shines!”, as the Italian scientist Giacomo Ciamician forecast almost one hundred years ago.
A leaf out of nature's book: Will photochemists succeed in their grand challenge to find an artificial means for converting sunlight into fuels? Energy is the most important issue of the 21st century. There is a need to find alternative energy sources to fossil fuels. The most promising choice is solar energy. Chemists, by creating new materials and new processes, can play a key role in solving the energy crisis.
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8.
A Providential Last Warning Vincenzo Balzani
Substantia (Firenze),
2021, Volume:
4, Issue:
1
Journal Article
Peer reviewed
Open access
In the past few months a dangerous and highly contagious virus, Covid-19, has been circulating on the spaceship Earth. Waiting to fight it with a vaccine, we defend ourselves with the obnoxious ...weapon of social distancing. According to scientists, the virus passed from wild animals to humans because of one or more of the following mistakes in our relationship with Nature: exaggerated use of resources, environmental degradation, climate change, increasing consumption of animal products, exaggerated anthropization of the soil, loss of biodiversity and the search for wild food by the poorest populations. Viruses are somehow "refugees" of the environmental destruction caused by our aggressiveness. They were fine in the forests and in the bodies of some animals, we gave them the opportunity to multiply.
The pandemic caused by Covid-19 locked us at home for several weeks. Some clever town councillors took this opportunity to offer their citizens cultural pills. In my little town I was asked to ...present a few short lectures on general scientific concepts. I tried to link together four entities of reality (Universe, Light, Earth and Life) showing that reality is much more complex than we think and much greater than us. E.g.: age of the Universe vs age of human civilization (~1.3x1010 vs ~ 1x104 years), size of universe vs human size (~1x1025 m vs ~1 m), velocity of light vs velocity of sound (3x108 vs 3.5x102 m/s), number of stars in the sky (~ 1x1023), number of molecule in a drop of water (~ 3x1021), number of atoms in a human body (~ 1x1027). Although we know reasonably well how Universe, Light, Earth and Life “work”, we are still surrounded by profound mysteries related to the why questions, i.e., the “questions of meaning”, that science cannot answer. Such questions, e.g., why is there the Universe? Why is there Life in this insignificant fragment of the Universe called Earth? Why did the evolution of Life lead to human? What's the meaning of my life? What is the meaning of the Covid-19 pandemic? The answers to the these “questions of meaning”, that cannot be given by science, are discussed in the enciclic Laudato si’ of pope Francis in relation to the ecological and social crisis we are going through.
Planet Earth is a very special spaceship that cannot land or dock anywhere for being refueled or repaired. We can only rely on the limited resources available on the spaceship and the energy coming ...from the Sun. The huge amounts of carbon dioxide produced by using fossil fuels in affluent countries has caused global warming, which is responsible for climate change. Ecological degradation of the planet is accompanied by an increased social disparity. As Pope Francis warns, we are faced with a complex crisis which is both social and environmental. Strategies for a solution demand an integrated approach to combating poverty and protecting nature. If we want to continue living on planet Earth, we must achieve the goals of ecological and social sustainability by implementing three transitions: from fossil fuels to renewable energies, from a linear to a circular economy, and from consumerism to sobriety. Science, but also consciousness, responsibility, compassion and care must be the roots of a new knowledge-based society.
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