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The 2018 edition of the United Nations World Water Development Report stated that nearly 6 billion peoples will suffer from clean water scarcity by 2050. This is the result of increasing demand for water, reduction of water resources, and increasing pollution of water, driven by dramatic population and economic growth. It is suggested that this number may be an underestimation, and scarcity of clean water by 2050 may be worse as the effects of the three drivers of water scarcity, as well as of unequal growth, accessibility and needs, are underrated. While the report promotes the spontaneous adoption of nature-based-solutions within an unconstrained population and economic expansion, there is an urgent need to regulate demography and economy, while enforcing clear rules to limit pollution, preserve aquifers and save water, equally applying everywhere. The aim of this paper is to highlight the inter-linkage in between population and economic growth and water demand, resources and pollution, that ultimately drive water scarcity, and the relevance of these aspects in local, rather than global, perspective, with a view to stimulating debate.

Population growth, even if coupled to economic growth, and resources, were already on a collision course, especially in Africa. The 2019 United Nations World Water Development Report provided a dramatic status of world water, however without questioning the main drivers of an imminent water crisis, that were unbounded, unequal, economic, and population growth, within the context of reducing resources in a finite world. Despite the report was a small step forward in awareness, still, it was not proposing satisfactory remedies. With business-as-usual, without acting on the drivers of water scarcity, regional water crises were inevitable in the next 3 decades, starting from Africa. Constrained by political, financial, and energy burdens, the technological improvements that have helped humanity to deal with the increased demand for water, food, and energy over the last 70 years, were likely not enough to avoid the water crisis. On top of forecast is the Covid19 pandemic. Coronavirus cases are (August 4, 2020) 18,446,065 and fatalities are 697,202 worldwide, and still growing. The containment measures enforced for Covid19 infection following the examples in the United Kingdom have already produced significant damage to the world economy. This will limit social expenditures in general, and the expenditures for the water issue in particular. The water crisis will consequently become worse in the next months, with consequences still difficult to predict. This will be true especially for Africa, where the main problem has always been poverty. There is the opportunity of significant health, food, and water crisis, especially in Africa. While the concepts of washing hands and social distancing that are difficult to apply haven’t produce so far major issues with the Covid19 outbreak in Africa, borders closure, restrictions on movement, and more poverty will translate in a lack of food and water potentially much more worrying than the virus spreading.

Quantum technologies (QTs) hold the promise to transform a wide range of industries, such as computing, communications, finance, healthcare, defense, space, and beyond. Of the various QTs, the most relevant is presently quantum computing (QC), of significant projected market potential, with some estimates forecasting it to reach many billion dollars over the next few years. There are, however, risks to factor, as highlighted in this perspective, the most relevant technical, economic, and societal risks. Those financial and societal are projected to become increasingly relevant phased with the progressing solution of the technical issues. The synergy with artificial intelligence comes with further opportunities as development can be faster and more effective, but also increases risks. AI presents numerous opportunities, but it also comes with several risks and challenges. Some of the major risks associated with AI include bias and fairness, transparency and explainability, job displacement, security concerns, ethical concerns, privacy issues, lack of regulation and standards, and exponential growth and unintended consequences. Balancing the advantages of AI-driven quantum technologies with associated risks presents a significant challenge. It necessitates careful consideration of ethical, economic, and technical aspects to ensure that these technologies are developed and deployed in a manner that is beneficial and equitable for everyone. Graphical Abstract

Silicon carbide has recently surged as an alternative material for scalable and integrated quantum photonics, as it is a host for naturally occurring color centers within its bandgap, emitting from the UV to the IR even at telecom wavelength. Some of these color centers have been proved to be characterized by quantum properties associated with their single-photon emission and their coherent spin state control, which make them ideal for quantum technology, such as quantum communication, computation, quantum sensing, metrology and can constitute the elements of future quantum networks. Due to its outstanding electrical, mechanical, and optical properties which extend to optical nonlinear properties, silicon carbide can also supply a more amenable platform for photonics devices with respect to other wide bandgap semiconductors, being already an unsurpassed material for high power microelectronics. In this review, we will summarize the current findings on this material color centers quantum properties such as quantum emission via optical and electrical excitation, optical spin polarization and coherent spin control and manipulation. Their fabrication methods are also summarized, showing the need for on-demand and nanometric control of the color centers fabrication location in the material. Their current applications in single-photon sources, quantum sensing of strain, magnetic and electric fields, spin-photon interface are also described. Finally, the efforts in the integration of these color centers in photonics devices and their fabrication challenges are described.

Diesel-LNG internal combustion engines (ICEs) are the most promising light and heavy-duty truck (HDT) powering solution for a transition towards a mixed electric-hydrogen renewable energy economy. The diesel-liquid CH4 ICEs have indeed many commonalities with diesel-liquid H2 ICEs, in the infrastructure, on-board fuel storage, and injection technology, despite the fact H2 needs a much lower temperature. The paper outlines the advantages of dual fuel (2F) diesel-LNG ICEs developed adopting two high-pressure (HP) injectors per cylinder, one for the diesel and one for the LNG, plus super-turbocharging. The diesel-LNG ICEs provide high fuel energy conversion efficiencies, and reduced CO2, PM, and NOx emissions. Super-turbocharging permits the shaping of the torque curve while improving acceleration transients. Diesel-LNG ICEs may also clean up the air of background pollution in many polluted areas in the world. Computational results prove the steady-state advantages of the proposed novel design. While the baseline diesel model is a validated model, the 2F LNG model is not. The perfect alignment of the diesel and diesel-LNG ICE performances proven by Westport makes however the proposed results trustworthy.

Steam natural gas reforming is the preferred technique presently used to produce hydrogen. Proposed in 1932, the technique is very well established but still subjected to perfections. Herein, first, the improvements being sought in catalysts and processes are reviewed, and then the advantage of replacing the energy supply from burning fuels with concentrated solar energy is discussed. It is especially this advance that may drastically reduce the economic and environmental cost of hydrogen production. Steam reforming can be easily integrated into concentrated solar with thermal storage for continuous hydrogen production. Steam methane reforming (SMR) is the favored technique to produce hydrogen, well established but subjected to perfections in catalysts and processes. Herein, the decomposition of CH4 in the presence of Ni on TiO2 support is shown. Especially replacing energy supply from burning fuels with concentrated solar energy is avenue to drastically reduce economic and environmental cost of hydrogen production by SMR.

The statistic of wind energy in the US is presently based on annual average capacity factors, and construction cost (CAPEX). This approach suffers from one major downfall, as it does not include any parameter describing the variability of the wind energy generation. As a grid wind and solar only requires significant storage in terms of both power and energy to compensate for the variability of the resource, there is a need to account also for a parameter describing the variability of the power generation. While higher frequency data every minute or less is needed to design the storage, low-frequency monthly values are considered for different wind energy facilities. The annual capacity factors have an average of 0.34. They vary significantly from facility to facility, from a minimum of 0.15 to a maximum of 0.5. They also change year-by-year and are subjected to large month-by-month variability. It is concluded that a better estimation of performance and cost of wind energy facilities should include a parameter describing the variability, and an allowance for storage should be added to the cost. When high-frequency data will be eventually made available over a full year for all the wind and solar facilities connected to the same grid of given demand, then it will be possible to compute growth factors for wind and solar capacity, total power and energy of the storage, cost of the storage, and finally, attribute this cost to every facility inversely proportional to the annual mean capacity factor and directly proportional to the standard deviation about this value. The novelty of the present work is the recognition of the variability of wind power generation as a performance and cost parameter, and the proposal of a practical way to progress the design of the storage and its cost attribution to the generating facilities.

Marine hydrokinetic turbines of MW-level capacity for harvesting oceanic currents are here reviewed. The best design is 3-blades, open rotor, axial flow turbines, of similar design philosophy to wind turbines, which are anchored to the ocean floor. The best locations are those with the oceanic current resource of higher intensity and stability, non-excessive depth of the ocean floor, proximity to shore, and favorable topography. In these locations, marine hydrokinetic turbines may become competitive with other renewable energy alternatives. It is expected that such turbines will be installed and will start producing electricity, within the next decade, working with power coefficients, the ratio of electric power from the turbine to wind power, around 0.45, similarly to wind turbines. This will pave the road for further progress and significant uptake of technology so far of no impact on the global energy mix.