idrogeno verde

Prima di parlare di scelte sostenibili da parte dei governi, si calcolano i vantaggi e svantaggi degli interventi. A livello di ricerca alimentare, le fonti proteiche alternative si sono indirizzate sulle FARMS di insetti. Ma quanto costa un kilo di farina di insetti (grilli, ad esempio)? 70 euro al kilo. Quindi, un pacco di pasta contenente il 10% di farina di insetti dovrebbe costare 7 euro. A livello di fonti energetiche alternative ai combustibili fossili, si parla a fasi alterne della possibilità di usare l'idrogeno, che bruciando non produce anidride carbonica. Il costo dell'idrogeno per uso automobilistico è elevato (17 euro/litro) e manca l'infrastruttura. Inoltre, per la conversione in energia si usano le celle combustibili, un processo che disperde parte dell'energia, invece di motori che brucino direttamente H2, anche se alcuni modelli di auto sono stati prodotti. L'idrogeno si produce con metodi ecologici (green) o non ecologici (Blu) partendo dal consumo di energia convenzionale, che aumenta la CO2. Nessuno fino ad oggi aveva ventilato la fattibilità delle elettrolisi dell'acqua per produrre H2, perchè i catalizzatori usati sono le terre rare come l'iridio. Oltre all'impiego di idrogeno nelle batterie (fuel cells) con efficenza dell'80%, è stato messo a punto da Toyota un motore a indrogeno, motori prodoti dall'azienda Acquarius, basato su un cilindro in cui i pistoni si muovono tra due capi del motore (vedi anche post precedente) Nelle auto elettriche attuali, aplug in, l'alimentazione elettrica viene prodotta a partire da energie non verdi (carbone, biodiesel), quindi non è sostenibile: consumiamo un eccesso di energie tradizionali per alimentare la rete elettrica, quando dovremmo produrre sorgenti di energia pulita. Questo si traduce nella ricerca di fonti di energia alernaive che non producano CO2: nella classificazione dell'idrogeno, H2, se è prodotto a partire da carbone, petrolio o centrali tradizionali, viene chiamato idrogeno blu, mentre dobbiamo puntare su idrogeno verde, produzione in cui le reazioni che permettono l'elettrolisi dell'acqua sono alimentate da energie rinnovabili. le tecnologie per produrre idrogeno verde hanno bisogno di uno scale up industriale, e di abbassare il costo a valle. Finchè sarà venduto a 17 euro/litro, le auto ad idrogeno per fare un pieno in Italia devono arrivare all'unico distributore presente, nel Trentino, e compiere con quel pieno 350/400 km. In Germania esistono almeno una ventina di distributori. Oggi, un articolo che presenta la ricerca del Giappone, RIKEN institute, mostra un nuovo catalizzatore economico che aumenta la produttività dell'elettrolisi di 4000 volte. Researchers led by Ryuhei Nakamura at the RIKEN Center for Sustainable Resource Science (CSRS) in Japan have improved on their green and sustainable method of extracting hydrogen from water by using a custom-made catalyst for the chemical reaction. Published in Nature Catalysis, the study details how they manipulated the catalyst’s 3D structure, which led to improved stability and an increase in the catalyst’s lifetime by almost 4,000%. The findings impact the ability to achieve a lasting and sustainable hydrogen-based energy economy. Water electrolysis using proton exchange membranes is a green electrochemical process for splitting water into oxygen and hydrogen. Hydrogen produced this way can then be stored and used at a later time. For example, when combined with a proton exchange membrane (PEM) fuel cell, the stored hydrogen can be used to power an electric car. However, PEM electrolysis still has limitations that prevent widespread industrial uses such as in power plants. In particular, the necessary chemical reactions happen in a highly acidic environment, and the best catalysts for these reactions are extremely rare earth metals, such as iridium. As Nakamura explains, “scaling up PEM electrolysis to the terawatt scale would require 40 years’ worth of iridium, which is certainly impractical and highly unsustainable. Almost two years ago, Nakamura and his team developed a breakthrough process that allowed acid water electrolysis that did not rely on rare earth metals. By inserting manganese into a cobalt oxide lattice, they created a process that relied only on common and sustainable earth metals. Despite the success, the process was still not as stable as it needs to be in a PEM electrolyzer. Now, they have built on their previous discovery and developed a longer-lasting earth-abundant catalyst. The new catalyst is a form of manganese oxide (MnO2). The key finding was that reaction stability could be increased over 40 times by altering the catalyst’s lattice structure. Oxygen in the 3D lattice structure of manganese oxide comes in two configurations, planar and pyramidal. The planar version forms stronger bonds with manganese, and the researchers discovered that increasing the amount of planar oxygen in the lattice significantly enhanced catalytic stability. They tested four different manganese oxides, which varied in the percentage of planar oxygen. When using the version with the highest achievable percentage, 94%, the critical oxygen evolution reaction could be maintained in acid for one month at 1000 mA/cm2. The total amount of charge transferred in this case was 100 times more than anything seen in previous studies. When tested in a PEM electrolyzer, water electrolysis could be sustained for about 6 weeks at 200 mA/cm2. The total amount of water electrolyzed in this time period, and therefore the amount of hydrogen produced, was 10 times more than has been achieved in the past with other non-rare metal catalysts. “Surprisingly,” says co-first author Shuang Kong, “the improved stability did not come at a cost in activity, which is usually the case. A PEM water electrolyzer that generates hydrogen with an earth-abundant catalyst at a rate of 200 mA/cm2 is highly efficient.” Industrial applications typically require a stable current density of 1000 mA/cm2 that lasts for several years, rather than a month. Nevertheless, the researchers think that tangible, real-world applications will eventually be possible and contribute to carbon neutrality. “We will continue to modify catalyst structure to increase both current density and catalyst lifetime,” says Nakamura. “In the long-term, our efforts should help achieve the ultimate objective for all stakeholders — to conduct PEM water electrolysis without the use of iridium.” Kong et al. (2024) Acid-stable manganese oxides for proton exchange membrane water electrolysis. Nat Catal. doi:10.1038/s41929-023-01091-3 The new manganese oxide catalyst allows this level of production to last for months in a PEM. Proton exchange membrane (PEM) water electrolyzer using manganese oxide.

A photocatalyst developed by researchers at Oregon State University could provide a more efficient route to hydrogen production. Publishing their research in the journal Angewandte Chemie, the researchers say that their photocatalyst is based on a metal organic framework (MOF). The MOF was used to develop a metal oxide heterojunction – a combination of two materials with complementary properties – to make a catalyst that, when exposed to sunlight, could quickly and efficiently split hydrogen from water. The heterojunction features MOF-derived ruthenium oxide and titanium oxide doped with sulphur and nitrogen. The researchers tested a number of heterojunctions, which they call RTTA, with different amounts of the oxides and found that the lowest ruthenium oxide content exhibited the fastest rate of hydrogen production. In just one hour, a gram of RTTA-1 was able to produce more than 10,700 micromoles of hydrogen. The team said the process utilized photons—light particles—at an “impressive” rate of 10%, so that for every 100 photons that struck RTTA-1, 10 contributed to hydrogen production. The researchers said the photocatalyst could enables the high-speed, high-efficiency production of hydrogen, used in fuel cells for cars as well as in the manufacture of many chemicals including ammonia, in the refining of metals and in making plastics. "The remarkable activity of RTTA-1 is because of the synergistic effects of the metal oxides’ properties and surface properties from the parent MOF that enhance electron transfer," said Kyriakous Stylianou, assistant professor in the Department of Chemistry at Oregon State University College of Science. "This study highlights the potential of MOF-derived metal oxide heterojunctions as photocatalysts for practical hydrogen production, contributing to the development of sustainable and efficient energy solutions," Stylianou added. Current catalytic processes for producing hydrogen from water involve electrocatalysis. The sustainability of this route depends on using renewable energy, and to be competitive in the market, the energy must be inexpensive. Producing hydrogen by splitting water through a catalytic process is cleaner than the conventional method of deriving hydrogen from natural gas via a carbon-dioxide-producing process known as methane-steam reforming. Techniques that can bring down the cost of producing hydrogen by splitting water are therefore welcome. Presently, methane-steam reforming produces hydrogen at a cost of about $1.50 per kilogram, compared to about $5 a kilogram for green hydrogen. Stylianou said: "Ruthenium oxide is not cheap, but the amount used in our photocatalyst is minimal. For industrial applications, if a catalyst shows good stability and reproducibility, the cost of this small amount of ruthenium oxide becomes less important." Boosting Photocatalytic Hydrogen Production by MOF-derived Metal Oxide Heterojunctions with a 10.0% Apparent Quantum Yield Emmanuel N. Musa, Ankit K. Yadav, Kyle T. Smith, Min Soo Jung, William F. Stickle, Peter Eschbach, Xiulei Ji, Kyriakos Stylianou First published: 10 July 2024 https://doi.org/10.1002/anie.202405681

COP28 e misure drastiche per fermare il cambiamento climatico

 Anche quest'anno i rappresentanti dei paesi che aderiscono alla  Conferenza delle Nazioni Unite sui cambiamenti climatici si sono riuniti, partorendo un minuscolo, timido topolino. Da una parte riunendosi a Dubai, un paese dell'OPEC al centro della produzione di petrolio, non si poteva sperare molto. Dall'altra, ogni rappresenanza è arrivata a Dubai sul proprio aereo, contribuendo ad un traffico aereo e ad un consumo di carburante inutile.

E' vero, anche io ho avuto le mie debolezze. In un post di due anni fa, ho scritto che le energie rinnovabili possono puntare su nuovi carburanti, sulla bioenergia prodotta da biomasse, ed anche nel post sulle energie nucleari ho fatto riferimenti che collegavano le energie verdi a queste biomasse, da scarti o da coltivazioni. 

E' tutto sbagliato! iIlusorio, semplicistico! fuorviante!

Tutti i combustibili, e le combustioni, che portano alla produzione di CO2, sono da punire, tassare, con sovraprezzo in stile da economia protezionistica (nulla di nuovo, lo facevano in Giappone per sovvenzionare i coltivatori di riso, lo abbiamo fatto in Europa per fermare l'ondata di importazioni di auto giapponesi, lo ha fatto Trump con i prodotti cinesi ed anche europei). Un sovraprezzo non solo per disincentivare il consumo di carbone, benzina, diesel, metano, propano, ossido di carbonio (usato negli USA come gas da cucina) ma per sovvenzionare la produzione di energie verdi (che non aumentano la CO2): idrogeno da acqua (verde), energie del mare e del vento, energie nucleari. Ed anche i consumatori, che invece di pagare pochi spiccioli per un litro di carburante, si troverebbero ad avere quasi gratis l'idrogeno verde (che al consumatore oggi viene a costare 16 euro al litro), penso all'ILVA di Taranto, eda tutte le grandi indusrie che inquinano). Chi usa biomasse come la legna, a kilometro zero, ha diritto ad un prezzo più equo, se non incide il suo trasporto a distanza. Ogni termovalorizzatore che distrugge il solido a kilometro zero va favorito.

La seconda operazione di polizia planetaria è quella di punire economicamente l'uso di armi: ogni bomba, ogni scoppio di impianti che bruciano, mandano in fumo gas, metanodotti, buncker di stoccaggio di petrolio o gas, va sanzionato bloccando le risorse finanziarie del paese colpevole. Di qualsiasi paese o parte.

E infine, sarei molto felice di vedere una bomba atomica  cancellare Israele o almeno la destra estremista  (non voglio aspettare secoli, o che completino la pulizia etnica dei palestinesi. Gesù, ehi palestina, non vedi non senti non fai nulla? fai un miracolo, fai volare un uccellino di creta, che vedano e credano ancora, e si ravvedano)

E una penale a tutte le industrie che vendono armi ed esplosivi, le voglio vedere fallire.

energia nucleare e energie verdi: the good, the bad and the ugly

 Le centrali nucleari sono superate, ma continuano a tenere in piedi progetti per construirle: ma sono proprio convenienti?

una centrale tradizionale consuma una tonnellata di uranio all'anno, se fosse al carbone ne consumerebbe milioni di tonnellate di carbone, molto  più economico ma molto più dannoso, alla salute ed al  pianeta, perchè produce anidride carbonica. Però, Le risorse di uranio, al consumo attuale (non calcolando nuove centrali) saranno esaurite in 45 anni.   Le centrali saranno sicure, ma l'energia recuperabile è poca rispetto a quella che va dispersa (acqua di raffreddamento), le scorie radiattive che vengono prodotte (ogni atomo di uranio da' vita ad isotopi di stronzio ed elementi intermedi pericolosi).

Esisono centrali nucleari su navi, portaerei e sottomarini, come mai sono più controllabili? probabilmente perchè non devono produrre grandi quantità di energia, e le reazioni partono da quantità minime di uranio, più controllabili

Ed il Torio? Reattori nucleari ad amplificazione di energia  affiancato da una sorgente esterna di protoni (sistema noto in inglese come Accelerator-Driven System o ADS), necessaria ad alimentare la reazione nucleare nel nucleo del reattore in sé. Questo, infatti, ha la caratteristica di essere un reattore subcritico, incapace di sostenere autonomamente una reazione a catena e, dunque, di dar luogo a una reazione incontrollata. Per innescare la reazione a catena, esso ha bisogno di essere irraggiato da un potente fascio di particelle proveniente da un acceleratore di particelle (sincrotrone): una volta acceso, il nucleo del reattore rilascia sufficiente energia termica da poter essere trasformata in energia elettrica che servirà ad alimentare l'acceleratore di particelle e a fornire un surplus di energia elettrica destinato all'immissione nella rete elettrica

il torio non dà problemi di scarti radiattivi, e il nocciolo non è soggeto alla fissione incontrollata

le centrali al torio sono costruibili in pochissimi anni, tre-cinque, i prodotti della reazione sono più cisuri, meno instabili.... e costa molto meno dell'uranio, Nobel nel 1984, Carlo Rubbia,  da anni propone di ricavare energia dal Torio, un elemento che non si autoinduce nella fissione nucleare come invece fa l'uranio

 è circa dieci volte più abbondante dell'uranio ed è circa comune quanto il piombo; ne serve 1/1000 rispetto all'uranio che invece va arricchito: ....

un altro aspetto favorevole è a produzione di energia rilasciata lentamente, secondo i consumi e le necessità locali: potrebbe essere abbinato ad un impianto di produzione di idrogeno (idrogeno verde a partire da acqua), in uno scaling up che è limitato dalle dimensioni dei polimeri su cui avvengono le reazioni

tengo a precisare che le auto elettriche, e ciò che viene prodotto  partire da altre energie non verdi , non  è sostenibile: consumiamo un eccesso di energie tradizionali per alimentare la rete elettrica, quando dovremmo produrre sorgenti di energia pulita. Questo si traduce nella classificazione dell'idrogeno, H2, che se prodotto a partire da carbone, petrolio o centrali tradizionali, viene chiamato idrogeno blu, mentre dobbiamo puntare su idrogeno verde, produzione in cui le reazioni che permettono l'elettrolisi dell'acqua sono alimentate da energie rinnovabili. 

ma... queste tecnologie per produrre idrogeno verde ha bisogno di uno scale up industriale, e di abbassare il costo a valle. Finchè sarà venduto a 17 euro/litro, le auto ad idrogeno  per fare un pieno in Italia devono arrivare all'unico distributore presente, nel Trentino, e compiere con quel pieno 350/400 km. In Germania esistono almeno una ventina di distributori.

Oltre all'impiego di idrogeno nelle batterie (fuel cells) con efficenza dell'80%, è stato messo a punto da Toyota un motore a indrogeno, motori prodoti dall'azienda Acquarius, basato su un cilindro in cui i pistoni si muovono tra due capi del motore

per la produzione indusriale su larga scala di idrogeno, sono necessarie strategie di superfici esese catalizzanti, come i polimeri per membrane elettrolitiche del progetto REPHYNE II 

in the Rephyne II project, there are products such as  the world largest polymer electrolyte membrane, or PEM, electrolyser to produce green hydrogen at scale,  a technology at level readiness near realization state

l'idrogeno verde costa attualmente 17 euro per litro, al consumo, ma potrebbe essere una fonte di energia di stoccaggio, prodotto quando se ne produce tanta, e usato quando la richiesta di energia aumenta.... un pò come le batterie che stoccano energia

un sistema innovativo per lo stoccaggio del surplus di energia solare abbinato a impianti fotovoltaici, è una batteria che utilizza anidride carbonica, fatta passare tra un stato liquido a uno gassoso, conserva temporaneamente l' energia mediante  cycling del CO2 da gas a liquido

adopt different innovative hydrogen production technologies of water electrolysis, generate hydrogen by photovoltaic power, and then store hydrogen through suitable hydrogen storage and metal alloy storage, and then generate hydrogen through fuel cells Electricity and heat or other industrial applications, especially to provide low-cost green hydrogen power generation and heating products and services for off grid households and enterprises

Un altro approccio può venire dall'utilizzo di cellette ad alveare basate su composti di nickel

Green Energy & Environment

Available online 27 September 2021

What are Corrected Proof articles?

Research paper

Hierarchical and self-supporting honeycomb LaNi5 alloy on nickel foam for overall water splitting in alkaline media

Thorium, Th 90

named for the Norse god of thunder, is much more abundant than uranium and has 200 times that metal’s energy potential. Thorium is also a more efficient fuel source — unlike natural uranium, which must be highly refined before it can be used in nuclear reactors, all thorium is potentially usable as fuel. Thorium could be used as an energy amplifier in next-generation nuclear power plants. Known as an accelerator-driven system, it would use a particle accelerator to produce a proton beam and aim it at lump of heavy metal, producing excess neutrons. Thorium is a good choice because it has a high neutron yield per neutron absorbed. Thorium nuclei would absorb the excess neutrons, resulting in uranium-233, a fissile isotope that is not found in nature. Moderated neutrons would produce fissioned U-233, which releases enough energy to power the particle accelerator, plus an excess that can drive a power plant.  A network of tiny underground nuclear reactors, maybe producing about 600 MW each....

The Innovation 2, 100180, November 28, 2021

Technologies and perspectives for achieving carbon neutrality

Solar thermal technologies rely on photothermal conversion to achieve heat, steam, and electricity production for C-neutral operations, unlike photovoltaic techniques. When solar thermal technologies, such as concentrated solar power systems, are employed in commercial and residential sectors to replace natural gas as a source of energy, an obvious reduction in both energy consumption of fossil fuels and CO2 emissions has been observed.51,52 Besides photovoltaic and solar thermal technologies, some strategies to convert solar radiation into stable chemical fuels also provide feasible ways for large-scale utilization and storage of solar energy toward energy decarbonization. For instance, great efforts have been made on solar hydrogen production, demonstrating an extremely attractive route to produce hydrogen fuel by adopting renewable solar energy or solar-derived power to electrolyze water.53,54 Note that hydrogen fuel is an ideal clean energy source to deliver C-free emissions, showing a great potential to reduce GHG emissions. Recently, a new concept of liquid sunshine has been proposed for combining solar energy with captured CO2 and water to generate green liquid fuels, such as methanol and alcohol, which may deliver an ecologically balanced cycle between generation and utilization of CO2 in global production systems.55

Solar energy represents an ideal solution tomeet the energy demands in a low-C and C-free society. Owing to the low-operating costs, a series of useful measures based on solar energy techniques are good candidates to reduce C emissions and utilize CO2 to form clean energy storage, thereby playing an irreplaceable role in the realization of C neutrality. The next decades will require accelerated development of advanced energy conversion/storage technologies and large-scale deployment of solar energy combined with clean resources to promote integrated pathways to C-neutral energy systems.

Wind energy

Wind results from the motion of air due to uneven heating of the Earth’s surface by the Sun. This means that wind power could be regarded as indirect solar energy.56 Like solar energy, wind energy will play a critical role in realizing "C peak and C neutrality."

The Earth has abundant wind resources, which are mainly distributed in grasslands, deserts, coastal areas, and islands.57 The site location has a significant impact on the economy, technicality, and implementation of wind energy.

The world attaches great importance to and vigorously supports the development of wind power. However, one of the issues that hinders wind energy utilization is the noise generated by wind turbines. Strategies to reduce or minimize the noise produced by wind turbines and further utilize wind sources sensibly are urgently needed. Another concern with wind energy production is that wind turbines may have an adverse effect on birds via collisions, disruptions, or habitat destruction if they are located inappropriately.

Although the wind resource on Earth is abundant, the uneven distribution of wind resources across the landscape poses a challenge to the transport of electrical energy produced by wind turbines. And the unpredictable nature of winds in terms of speed and direction will result in a variable and unstable phase, amplitude, and frequency for the generation of electricity, which may make it difficult to be integrated into the grid, resulting in a waste of wind energy. The cost of installing awind turbine is currently quite high,which also hinders the widespread adoption of this technology. It is necessary to devote more efforts to exploring and developing wind energy technology to meet the needs of energy users.

Ocean energy

Ocean energy refers to the energy contained in thewater body in the ocean and is both renewable and clean. The ocean energy reserve is enormous globally and is enough to power the entire world. There are typically five different energy forms: tidal energy, wave energy, ocean current energy, thermal energy, and osmotic energy. The tidal, wave, and current energies are mechanical energy. The research of exploiting ocean energy was started a few decades ago. The geographical distribution varies broadly for different energy forms, and the harnessing technologies are also quite different.

Tidal energy is the energy contained in the tide, including the potential energy related to the water level and the kinetic energy of the tidal current. The tide originates from the gravitational interaction of sea water with the Moon or the Sun. Tidal energy is estimated to be about 1,200 TWh per year,which is relatively low among all ocean energy forms58 due to limited locations from where tidal energy can be harvested. The tidal barrage is adopted to harvest the potential energy of tides, which is relatively technologically mature. Early tidal barrages started to operate in the 1960s, and tidal energy now has the largest share of ocean energy being exploited (Khare et al., 2019). Harnessing tidal current power mainly relies on turbines, although other types of devices are also under development.

Wave energy is the kinetic and potential energy in water waves, which is widely distributed. It essentially comes from wind, which transmits part of its kinetic energy to the water at the ocean surface. The potential of wave energy globally is 29,500 TWh per year.59 The technology for harvesting wave energy is less mature than that for tidal energy, and many different types of devices are being tested on a small scale toward commercialization.

The major device forms include point absorber, attenuator, oscillating water column devices, and overtopping devices. Besides traditional large devices using electromagnetic generators, new technologies based on triboelectric nanogenerator networks are also being developed toward effective harvesting of wave energy economically.60

Ocean current energy is reserved in the large circulations of sea water globally. It is the kinetic energy in the water flow. The supply of this source of energy is stable with little fluctuation. It can be extracted using turbines. 

The device needs to be deployed in deep sea and far from the shore; thus, less effort has been devoted to harnessing this type of energy.

Thermal energy originates from the Sun’s irradiation, which heats the upper layer of the sea water, making its temperature different from the water in the deep sea. Such temperature differences can be exploited for electricity generation mainly based on thermal cycles. Due to the high-temperature difference required for improved efficiency, this form of energy ismainly distributed in the tropical region. The potential for this energy is estimated to be 44,000 TWh per year.61 The utilization of this form of energy is still at the research stage by universities and research institutes.

Osmotic energy, also called salinity gradient energy, is the energy that exists between water bodies with different salt concentrations. The salinity of sea water is not homogenous globally; for example, a salinity gradient is formed in estuaries where fresh water meets salt water. The harness of  such energy relies on high-performance membranes that are robust in sea water. Twomain technologies are being tested at present: pressure-retarded osmosis and reversed electrodialysis.59 Osmotic energy is still a conceptual energy source and is not ready for commercialization.

The ocean energy reserve is enormous globally and is enough to power the entire world. Technologies to harvest tidal and wave energy are on the verge of commercialization. Technologies for harvesting ocean current energy, thermal energy, and osmotic energy are still in their early development stage. Major challenges of exploiting ocean energy lie in the economic costcompetitiveness and technological reliability in severe ocean environments.  By overcoming these challenges, ocean energy will provide the world with abundant clean energy.

Bioenergy

Biomass is a renewable source of energy that originates fromplants. The most important sources of biomass are agricultural and forestry residues, biogenic materials in municipal solid waste, animal waste, human sewage, and industrial wastes. Biomass provides 13%–14% of the annual global energy consumption.62 Various processes are used to convert biomass into energy, including the following.

Thermochemical conversion of biomass includes gasification, pyrolysis, and combustion. Combustion produces approximately 90% of the total renewable energy obtained from biomass.63 Pyrolysis can convert biomass into solid, liquid, or gaseous products by thermal decomposition at temperatures around 400
C–1,000
C in the absence of oxygen, producing components such as acids, esters, and alcohols.64 Gasification converts carbonaceousmaterials into combustible or synthetic gas by reacting the air, oxygen, or vapor at a temperature of over 500
C, preferably over 700 oC,  yielding gases such as H2, CO, and CH4.64,65

Chemical conversion converts vegetable oils and animal fats into fatty acid esters through esterification or/and transesterification to produce biodiesel.

The transesterification process is necessary since raw materials are composed of triglycerides, which are not a useable fuel. Triglycerides are converted into methyl or ethyl esters (biodiesel) using amostly alkaline catalyst in the presence of methyl or ethyl alcohol, respectively. Rapeseed oil (accounting for 80%–85%) and sunflower oil (accounting for 10%–15%) are major vegetable oils used for biodiesel production.63

Biochemical conversion converts biomass into liquid fuels (e.g., alcohols and alkanes), natural gas (e.g., hydrogen and methane), different types of bio-products (e.g., carotenoids, omega-3 and omega-6 fatty acids), as well as other chemical building blocks (e.g., acetic acid and lactic acid) using microbes and enzymes as the catalyst.66 The most popular biological conversions are fermentation and anaerobic digestion.

The most common biomass feedstock used for biological conversion is lignocellulosic biomass, such as agricultural and forestry residues. Lignocellulosic biomass is the most abundant and widely available renewable resource in theworld,mainly composed of three heterogeneous biopolymers, namely cellulose, hemicellulose, and lignin. Threemajor steps are involved in cellulosic bioethanol production: (1) pre-treatment, (2) enzymatic hydrolysis, and (3) fermentation. Pre-treatment uses physical, chemical, or physicochemical

methods to improve biomass accessibility by enzymes. Enzymatic hydrolysis splits cellulose and hemicellulose into monomer sugars, such as glucose, xylose, and mannose. The conversion of biomass-derived sugars into ethanol by Saccharomyces cerevisiae has received most research and development efforts. Another method for producing butanol is through fermentation, specifically through an acetone/butanol/ethanol process that

is predominantly carried out by Clostridia strains.67 Anaerobic digestion consists of hydrolysis, acidogenesis, acetogenesis, and methanogenesis. These reactions break down the macromolecules in the biomass into simpler molecules with the generation of biogas in an anaerobic environment. One of the advantages of anaerobic digestion lies in the potential of the biogas to be used directly in ignition gas engines and gas turbines.

Despite the presence of abundant biomass resources, there  is still a need for work on the use of biomass to produce energy, withmain efforts needed to increase productivity and reduce costs to further expand the share of such renewable energy in the total energy consumption.68 Some of the issues that need to be resolved are the high cost of transporting the biomass to the site for bioenergy production through various conversion processes and the sustainability of the production of bioenergy feedstocks.

H2 energy

Hydrogen has been a necessity for industrial use over the past two hundred years. The demand for hydrogen (currently >80 Mt per annum) has grown more than three times since 1975 and continues to rise. Up to now, H2 is almost entirely produced from fossil fuels, consuming around 6% of global natural gas and 2% of global coal, resulting in emissions of around 830 Mt of CO2 per year.69 Recently, hydrogen energy has drawn a great deal of interest because it can be used to establish a fully renewable energy system similar to an electricity grid, providing the sector integration needed for energy system transition and decarbonize energy end uses.70

Hydrogen production using renewable energy has a strong likelihood of both technological and economic viability in the near future. The decreasing costs of renewable energy and the increase in variable renewable  power supplies’ market share have put significant roadblocks in the way of cheap water electrolysis.71 With the fast development of artificial intelligence, deployment and learning-by-doing are expected to reduce electrolyzer costs and supply chain logistics. After H2 production via electrolysis, safe and low-cost hydrogen storage and transportation technology need to be developed.

Hydrogen can be stored in gas, liquid, and solid states.72,73 As of now, none of these technologies are mature for establishing a hydrogen economy. In addition, hydrogen offers the lowest cost option for long-termenergy storage, such as inter-seasonal; however, the ability to store large quantities of hydrogen at low costs with a high safety is still a challenge. Underground H2 storage in large salt caverns and hydrogen transport via existing and refurbished gas pipelines are available at low cost to support long-term energy storage and sector coupling. However, equipment standards need to be adjusted and are also limited by geographical conditions.74,75

Hydrogen fuel cell technologies have developed rapidly and are ready for  commercialization, to the point that we now see commercial sales of hydrogen-powered passenger cars, such as Mirai, Clarity, and Nexo, and heavy-duty vehicles, trains, and ships. The main issue now is to reduce the cost whilemaintaining an acceptable level of durability and efficiency.76 Other opportunities that pay more attention to the handling of energy-intensive commodities producedwith hydrogen—synthetic organicmaterials/pharmaceuticals, iron and steelmaking, building/marine bunkers or feedstock to produce ammonia/methanol, and so on—seem to be prime markets. We now need to develop scale-up technologies, increase energy use/conversion efficiencies, optimize the upgrade of H2 industrial structures, and lower costs to enable widespread use of H2 energy. There needs a long-term devotion to fundamental understanding and development of new strategy/technology and infrastructure.

nuovi carburanti per la green economy

 Il post di oggi riprende il discorso degli inerventi per mitigare i cambiamenti climaici. In paricolare, abbiamo introdotto la produzione di biochar, o carboni vegetali, mediante gassificazione e flash-pirolisi, un processo che produce syngas (ossido di carbonio, idrogeno gassoso, e altri prodotti alifatici). 

Il processo è descritto in questa immagine (6.3)

come materia prima, abbiamo parlato di biomasse vegetali, scarti, segatura, ma anche materiale solido derivante dalla raccolta differenziata della spazzatura.

Molti di questi impianti di produzione su grande scala sono asssociati a finanziamenti EU di progetti pilota. 

Segue presentazione in lingua inglese. Renewable energy sources include wind power, solar power (thermal, photovoltaic and concentrated), hydroelectric power, tidal power, geothermal energy, biomass and the renewable part of waste.

The use of renewable energy has many potential benefits, including a reduction in greenhouse gas emissions, the diversification of energy supplies and a reduced dependency on fossil fuel markets (in particular, oil and gas). Biodiesel life cycle analysis (LCA) shows it affects a 78 % reduction in CO2 (greenhouse gas) emissions relative to petro diesel.

Targets in EU Commission define that only seven-tenths of renewable energy will originate from first-generation fuels. The difference of three-tenths will be made up by second generation fuels, advanced fuels based on waste products and other feedstocks that do not affect food production. That translates in European demand for advanced biofuels to reach 14 billion litres by 2020. Only two types of advanced fuels are capable of large-scale production today in Europe. 

The first one is based on turning waste cooking oil and other fats into diesel. Europe already has 2 billion litres of capacity to process these by-products. 

The second type of plants are producing ethanol from cellulose by enzymatic hydrolysis.

A number of EU projects addressed the feedstock issue, eg. ITAKA project improving the readiness of existing technology and infrastructure: focus on camelina & cooking oil. Oil from plants is extracted, hydrocracked, products are isomerised to obtain paraffins and iso-paraffins.

Several EU projects have been funded to provide solutions to the challenge of feedstock processing.

In one such project, the EMPYRO consortium was led by BTG.Bio-oil, for combined heat and power (CHP) and acetic acid at AkzoNobel Global, The Netherlands, a Multi-national manufacturing corporation, active in healthcare products, coatings and chemicals. The EMPYRO pyrolysis oil plant of Biomass Technology Group in the Netherlands was the first EU plant to sign a long term supply contract of the bio-oil to replace fuel oil. In EMPYRO, full conversion configurations have been estimated for a range of economies of scale, 1 MW, 675 MW and 1350 MW LHV of bio-oil. The economic competitiveness was found to increase with increasing scale. A cost of production of FT liquids of 78.7 Euro/MWh was obtained based on 80.12 Euro/MWh of electricity, 75 Euro/t of bio-oil and 116.3 million Euro/y of annualised capital cost (Ng and Sadhukhan 2011).

In another project, the LED consortium, was led by Abengoa industries. To produce from straw and maize bioethanol and renewable hydrocarbons. The CHEMREC Bio-DME project has been the first project to demonstrate the conversion of black liquor to bio-dimethyl-ether, through the production of synthesis gas which is converted to second generation biofuels. Black liquor is a waste product resulting from the conversion of pulpwood into paper pulp. Dimethyl ether is an advanced biofuel

produced by catalytic dehydration of methanol, or from syngas. Above -25°C or below 5 bar, DME is a gas. Hence its use as a transport fuel is similar to that of Liquid Propane Gas.

InteSusAl is a still ongoing EU project. Three European algae biofuel projects with a common LCA approach. Three large scale algae production facilities are under development. These will be the largest facilities built in Europe; with a productivity of 90 tonne/hectare of dry matter algal biomass per year for each facility (30 hectares totally).

Infinite Fuels GmbH works on the development and market introduction of a unique technology for transformation of renewable electricity, biomass and waste into sustainable hydrocarbons serving as basic chemicals and fuels. The incubator for start ups KIC InnoEnergy Germany, has signed five new German start-ups under its Business Creation Accelerator programme (KIC InnoEnergy’s Highway).

The companies were selected by a committee of experts for their ability to innovate, as well as potential to drive Europe’s move towards sustainable energy with high-performance and efficient products.

Syngas e pirolisi

Lignocellulosic residues are hydrolised into sugars and charcoal, processed into syngas, that together with alcohols are hydrocracked and isomerised to obtain paraffins and iso-paraffins, with aromatics and cyclo-paraffins.

There are several types of biofuels.

SKA are synthetic paraffinic kerosene with aromatics-  as a blendstock with conventional jet fuel.

FSK are Fully Synthetic Kerosene. This fuel falls within the conventional jet fuel specification- to be used as neat jet fuel.

SIP, a synthesized iso-paraffine, C15, is obtained from from farnesan, a sugar molecule ( component for blending with conventional jet fuel)

Hydroprocessed oils and fats (HRJ/HEFA) are converted into kerosene-like fuel (SPK), a synthetic paraffinic kerosene used as a blendstock with conventional jet fuel.

ATJ = fuel produced from C2-C5 alcohols, as single alcohol or multicomponent mixture, into kerosene like fuel and kerosene (SPK, SKA, FSK).

Overview of the process to produce kerosene-like fuel (SPK). Coal and biogas are gassified into syngas, then n-paraffins are synthesised through the Fischer Tropsch (FT) process and hydrocracked and isomerised to obtain paraffins and iso-paraffins as kerosene-like fuel (SPK ). In the FT process, the purified syngas is processed through a fixed-bed tubular reactor where it reacts with a proprietary catalyst to form three intermediate FT products, a Heavy Fraction FT Liquids (HFTL) product, a Medium Fraction FT Liquids (MFTL) product and a Light Fraction FT Liquids (LFTL) product, commonly called Naphtha. The Naphtha is recycled to the partial oxidation unit with remaining tail gas to be reformed to hydrogen and carbon monoxide.

"Production of fully synthetic paraffinic jet fuel from wood and other biomass " BFSJ 612763 is a project in the EU 7th Framework Programme (2007-2013) involving Swedish Biofuels.

Full scale commercial plant size was estimated to be 200,000 ton/y of motor fuel, of which jet fuel would make up 100,000 ton/y. The business plan is to deploy 3 commercial units in the 10 years following the project, subject to market acceptance, safety and financial risks. With a good political and economic environment, up to 600,000 t/y of advanced biofuels can be produced by 2030 using Swedish Biofuels ATJ technology: Production is economic at various production volumes, e.g. processing 2,500,000 m3/y of humid, low grade wood residues. A wide range of biomass suitable for process is available. Biological fuel capacity: 30 t/y (3300 USGallons/y). Jet 14.4 t/y. Gasoline 10.5 t/y. Diesel 5.1 t/y.

A third type of biofuel is under development using municipal solid waste (MSW) as source of lignocellulose.

Key market drivers for waste as feedstock are of various nature, here enumerated: increased scarcity of urban landfill space and societal desire for waste diversion; Turning carbon waste into a useful building block for the chemical and petrochemical industry; low cost, non-land using, unconventional feedstocks for biofuels and renewable chemicals; renewable fuels mandates around the world;

consumer pull for renewable and biobased products; focus on carbon footprint and greenhouse gas emissions reduction.

The potential for transforming garbage (estimated valued are positioned around 254 Million metric tonnes/year in Europe) into chemicals and fuels (375 litres of cellulosic ethanol per metric tonne) is delineated in Figure 6.2.

There are ongoing strategic alliances with EU and partners around the world, by Enerkem biorefineries (full-scale commercial biorefinery in Edmonton, and two facilities in Quebec, Canada), a producer of biofuels and renewable chemicals from municipal solid waste, agriculture biomass, plastics, petcoke, biosolids from pulp and paper industry, forest biomass and wood pellet.

Enerkem has a proprietary clean technology developed in-house. The thermochemical process converts MSW feedstock into low-carbon renewable transportation fuels including jet fuel and diesel.

Fulcrum, US,  is a pioneer in the development of a reliable and efficient process for transforming everyday household garbage into low-carbon transportation fuels including jet fuel and diesel. The low-cost process reduces the dependence on imported oil, create new clean energy jobs and significantly reduce greenhouse gas emissions compared to traditional petroleum production.

Fulcrum has established industrial partnership with US Renewables Group and Rustic Canyon Partners, two leading venture capital firms in the clean energy space. In addition, Waste Management and Cathay Pacific Airways have become equity partners in the Company. Fulcrum ThermoChem Recovery International has licensed to Fulcrum their highly efficient and economic gasification system for the conversion of the carbon rich residues into synthetic gas (syngas) (Figure 6.3). During the gasification process, the prepared MSW feedstock rapidly heats up upon entry into the steam-reforming gasifier and almost immediately converts to syngas. The syngas is further cooled in a packed gas cooler scrubber. The cleaned syngas is then processed through an amine system to capture and remove sulfur and carbon dioxide. The syngas then enters the secondary gas clean-up section that contains compression to increase syngas to the pressure required by the FT process.

The syngas is catalytically converted, thus synthesing the renewable fuel constituents.

Utilizing this transformation process, municipalities will be able to convert the garbage into 30 million gallons per year of clean renewable fuel. A number of facilities are under construction across North America with the annual capacity to produce hundreds of millions of gallons of renewable transportation fuel while eliminating trash landfilled annually across North America.

In 2015 Fulcrum announced that it had awarded an engineering, procurement and construction contract to Abengoa for the construction of the Sierra BioFuels waste to transportation fuels plant.

Abengoa will construct Sierra under the fixed-priced contract that also includes cost, schedule and plant performance guarantees.

In US, United Airlines (UA) has announced the first stable use in the tract from Los Angeles-San Francisco, by as new jet fuelled with bio-kerosene. The required amount of fuel at this stage is 180 million litres each year. In the agreement with UA, Fulcrum will transform Municipal Solid Waste (MSW), cooked oils and fats derived from animal wastes to produce a biofuel that will be blended with traditional fuels.

Aviation Climate Change Commitments are exemplified in Figure 6.4. 

There are several targets to be accomplished, such as an improvement of 1.5% fuel efficiency per year from 2009 to 2020; a Carbon neutral growth from 2020; a reduction of net emissions by 50% by 2050 compared to 2005 levels.

Air transport moves over 2.4 billion passengers annually, dumping 677 million tons of carbon dioxide into the atmosphere. While these emissions are small compared with other industry sectors, these industries have viable alternative energy sources. The power generation industry can look to wind, hydro, nuclear and solar technologies to make electricity without producing much CO2. Cars and buses can run on hybrid, flexible fuel engines or electricity. The primary objective of using biofuel is to

reduce emissions. Carbon Dioxide absorbed by plants during its growth is roughly equivalent to the amount of carbon produced when the fuel is burned. This would allow biofuel to be carbon neutral over its life cycle.

The European Biofuels Flight Path Initiative (EBFPI) and the European Biofuels Technology Platform (EBTP). The EU Commission has launched the EBFPI with the objective to reach the target of using 2 MTons of aviation biofuels in 2020, corresponding to about 4% of EU fuel consumption. By 2015, EBFPI will set up financial mechanisms, secure sustainable feedstock production to feed three refineries, construct three new refineries, and launch biofuel production. By 2018, EBFPI will start regular commercial flights using biojet fuel blends, construct four additional refineries, and construct two additional refineries producing algal and microbial oil-based aviation biofuels. By 2020, a full deployment of at least 2 million tons of biofuels per annum for EU aviation

Sunchem has made an alliance with SkyNRG and South Africa Airlines (SAA) for the exploitation of Solaris. SkyNRG expanded production of the hybrid Solaris as an energy crop that farmers could grow instead of traditional tobacco. South African Airways (SAA), Boeing, and SkyNRG are developing bio-jet fuels. South African Airways (SAS) is partnering with Boeing aerospace company and Amsterdam-based SkyNRG to make sustainable aviation biofuel from a new type of tobacco devoid of nicotine, the

Solaris variety of tobacco, grown in South Africa.

 Resource Technology Strength. 

Bioenergy and advanced biofuel investments are in  progress. 

In the US, Boeing has partnered up with other stakeholders to promote “Farm to Fly” biofuel programs that includes the Midwest Aviation Sustainable Biofuels Initiative (MASBI) along with United Airlines, UOP (a Honeywell company), the Airlines for America (A4A) Inc., the Chicago Department of Aviation, the Federal Aviation Administration (FAA) and the Clean Energy Trust.

The US National Bioeconomy Blueprint is designed to create jobs and stimulate investment by using federal resources to speed the transition from fossil fuel dependency into a more sustainable, healthful and diversified mix of fuels, chemicals and other products.

Boeing has been looking for partners at various levels, including fuel from plants grown in the desert using saltwater, and it is optimistic that a range of bio-kerosene promising to be both cleaner than standard fuels and with a greater energy density, essentially offering more power for less weight, is to be certified for aviation use.

Currently, these alternative fuels for transport are marketed by Neste Oil and by ENI. In 2014, Neste Oil produced approximately 1.3 million tonnes (1.6 billion litres) of renewable NEXBTL diesel from waste and residues. There is a big potential for aviation since three refineries in function, one in Italy, one in Rotterdam and one near Helsinki currently produce around 4 billion liters of bio-kerosene. This amount for aviation corresponds to 2 percent of fuels use globally.

Boeing Airlines have conducted more than 1,500 passenger flights using biofuel since the fuel was approved in 2011. Alternative aviation biofuel reduces carbon emissions by 50 to 80 percent compared to petroleum jet fuel through its life cycle.

Military Certification Constraints

ASTM approval of a synthetic fuel means that blend with synthetic fuel conforming to specification is considered Jet A/Jet A-1 fuel, can be used by any civil aircraft certified for use of Jet A/Jet A-1, and is accepted both within North America and Europe. This, however, does not imply certification for military use. The military is using its own fuel specifications. A military equivalent to Jet A-1 exists (JP-8), and NATO aircraft are qualified on it.

US Armed Forces have introduced advanced regulatory rules so that FT- and HEFA-kerosene have been approved for all military equipment. US Armed Forces increasingly move to include blends with synthetic material in their fuel supply

approval process is coordinated by US standards body ASTM, referring to relevant specification such as ASTM D7566. This defines required properties of blends of conventional (ASTM D1655) kerosene and synthetic material. The specification annexes define required properties of the neat synthetic fuels (currently three), Fischer-Tropsch (FT) with maximum blend ratio 50%; Hydrotreated Esters and Fatty Acids (HEFA) with maximum blend ratio 50%; Farnesane (SIP) with maximum blend ratio 10%. Fuel meeting ASTM D7566 by definition becomes ASTM D1655 kerosene, and can use the same infrastructure as conventional fuel.

Implications for biokerosene. In case of aviation kerosene, registered substance is defined as ‘‘being produced from crude oil sources‘‘. Kerosene not produced from crude oil still needs a separate registration. This makes the process expensive and time-consuming, costing several 100,000 Euros.

Full registration of bio kerosene so far has only been performed by Neste Oil, for HEFA.

Whereas ASTM D7566 conforming blends are within the experience base for conventional kerosene, the synthetic components are dissimilar. Main components of conventional kerosene are n- and iso-alkanes, cycloalkanes and aromatics. HEFA- and FT-kerosene consist almost solely of n- and iso-alkanes. Other pathways currently up for approval produce fuel solely consisting of aromatics, fuel consisting of cycloalkanes and aromatics, or even fully synthetic fuel containing all main components of conventional kerosene (SIP kerosene is an extreme case, consisting solely of C15 iso-alkanes).

In the aviation approach, blend is the key unit. Certification is released on the basis of blend properties, that Need to be within experience base for conventional kerosene. If D7566 conditions are met, blend by definition becomes D1566 fuel. Information of synthetic component is completely lost (US) or only generically preserved (Europe). Properties of individual blend components are defined only for quality control purposes. The rationale is that only the blend will ever end up in an aircraft.

da:

Polronieri P. Tobacco seed oil for biofuels. Pp. 161-187. In: Poltronieri P. and D'Urso O.F.: Biotransformation of agricultural waste and by-products. The  food, feed, fibre, fuel (4F) economy. Elsevier 2016. ISBN 978-0-12-803622-8