Hydrogen economy


he global energy demand is expected to grow significatively in the next decades, driven by economic and population growth.1However, our current energy sector is heavily reliant on fossil-base energy carriers, such as coal, oil and natural gas.

The indiscriminate use of these resources, with consequent emission of green house gases (GHG), is the primary cause for the alarming increase in world’s temperature. In 2021, energy-related carbon dioxide (CO2 – one of the main GHG) emissions reached 36.3 billion tons (6% of the total CO2 emissions), setting a new record, the highest ever.2

In response to this threat of climate change, the Paris Agreement set the goal of limiting the global warming to 2 degrees above the pre-industrial level. A key player in this energy transition is green hydrogen. In fact, a renewed interest in hydrogen, already under the radar as potential alternative energy carrier many years, has surged in the last five years to meet the Paris Agreement. The production of green hydrogen from water electrolysis might also represent a more accessible energy carrier, contrary to a fossil-fuel-based society where inequal distribution of resources and geopolitical instability repeatedly threaten the worldwide stability of the current energy system.

As such, the European Union (EU) has recently set ambitious goals for the next decades aiming to increase the current yearly hydrogen production of about 100 MW, to 40 GW ( ̴ 10 million tons) in 2030.3

Green hydrogen production technologies are currently available at different level of maturity. Alkaline electrolysers (TRL – technology readiness level – 9) and polymer electrolyte membrane electrolysers (TRL 8), and  represent the most promising technology to be used on a large scale in the coming years.4 Other promising technologies are solid oxide electrolysis (TRL 6), natural gas reforming with CO2 capture (TRL 8), biomethane reforming with CO2 capture (TRL 8), low temperature biomass gasification (TRL 7) and high temperature biomass gasification (TRL 6).4 The reported costs for these technologies are presented in Figure 1. Other alternative hydrogen production technologies are also being developed.5,6

Figure 1. Reported costs ranges for upcoming hydrogen production technologies.4

Even we have several technologies which we could be using nowadays as seen in Figure 1, the technological cost needs and related challenges prevent its implementation. For example, the use of alkaline and polymer electrolysis is challenged by the availability of low carbon electricity and as well as its high costs while the implementation of natural gas or biomethane reforming with CO2 capture is challenged by the fugitive methane emissions from the natural gas supply, and the availability of a CO2 transport and storage infrastructure.7,8

Hydrogen has been for long time considered as a promising future green energy carrier, but technological and socio-economical barriers did not allow the H2 economy to be deployed at large scale. Will the next decades be finally the years in which we will witness a full take off of green hydrogen technologies supporting the transition towards a carbon neutral energy system?

We really hope so…

Recent news of interest:

  • European Commission’s Clean Hydrogen Partnership (CHP) has launched a call of proposals offering €300.5m of grants “to support projects that boost renewable hydrogen production, reduce its costs, develop its storage and distribution solutions, and stimulate the use of low carbon hydrogen in hard to abate sectors, such as energy intensive industries, aviation or heavy duty transport”.: Source: https://www.clean-hydrogen.europa.eu/apply-funding/call-proposals-2022/call-proposals-2022_en

  • In the Netherlands, the growth fund programe GroenvermogenNL announced that they will receive extra €500m adding to the existing €338m to: “accelerate the production and use of green hydrogen and related technology in various industrial chains, such as chemistry, kerosene, steel or fertilizer”. Source: https://www.groenvermogennl.org/en/news/500-miljoen-extra-voor-groene-waterstof-en-chemie-via-groenvermogennl


1. IRENA, Global Energy Transformation: A roadmap to 2050, International Renewable Energy Agency, 2018, Abu Dhabi.

2. International Energu Agency (IEA) 2021: “https://www.iea.org/news/global-co2-emissions-rebounded-to-their-highest-level-in-history-in-2021”

3.European-Commission, A hydrogen strategy for a climate-neutral Europe. COM(2020) 2020, 301 final.

4.Van der Spek, M.;  Banet, C.;  Bauer, C.;  Gabrielli, P.;  Goldthorpe, W.;  Mazzotti, M.;  Munkejord, S. T.;  Røkke, N. A.;  Shah, N.;  Sunny, N.;  Sutter, D.;  Trusler, J. M.; Gazzani, M., Perspective on the hydrogen economy as a pathway to reach net-zero CO2 emissions in Europe. Energy & Environmental Science 2022, 15 (3), 1034-1077.

5.Rioja-Cabanillas, A.;  Valdesueiro, D.;  Fernández-Ibáñez, P.; Byrne, J. A., Hydrogen from wastewater by photocatalytic and photoelectrochemical treatment. Journal of Physics: Energy 2020, 3 (1), 012006.

6.Sazali, N., Emerging technologies by hydrogen: A review. International Journal of Hydrogen Energy 2020, 45 (38), 18753-18771.

7.Parkinson, B.;  Balcombe, P.;  Speirs, J. F.;  Hawkes, A. D.; Hellgardt, K., Levelized cost of CO2 mitigation from hydrogen production routes. Energy & Environmental Science 2019, 12 (1), 19-40.

8. Lane, J., Greig, C. & Garnett, A. Uncertain storage prospects create a conundrum for carbon capture and storage ambitions. Nat. Clim. Chang. 2021 11, 925–936.

Ammonia Pollution


eleased data from the European Environment Agency shows how the emissions of most air pollutants are decreasing in the European Union, in contrast to the increasing ammonia (NH3) emissions from the agricultural section, which challenges the EU Member states to meet their air pollution limits.1

Ammonia is one of the most produced inorganic chemicals in the world, with an estimated annual global production of up to 200 million tons.2 Approximately 80% of the global ammonia production is used in the fertiliser industry,2 playing a key role in sustaining the exponential growth in human population in the last 50 years, as seen in Figure 1.3

Figure 1 – Portion of the global population supported by synthetic NH3 (in red), from 1900 to 2015.4

Despite our dependency on ammonia fertiliser, NH3 is a highly toxic chemical and undesirable NH3 emissions into the natural environment are responsible for damaging the biodiversity in aquatic and terrestrial ecosystems, as well as the human health. Exposure to high levels of gaseous NH3 has been associated to adverse health conditions in humans skin, lungs and eyes, and concentrations of about 3000 ppm can be fatal in roughly 30 minutes.5 Gaseous ammonia is colourless and it can combine with other contaminants present in the atmosphere, such as sulfuric dioxide, volatile organic compounds and nitrogen oxides, to form harmful small sized particulate matter, known as PM2.5.6 These PM2.5 can travel long distances (up to 1000 km).7 NH3-derived PM2.5 is responsible for causing adverse health conditions, as cardiovascular disease, asthma, lung cancer and premature death.7

In the past years, the increase in NH3 levels has been widely attributed to farming intensification. In this sector only, NH3 emissions increased by 90% between 1970 and 2005.8 It is estimated that more than 60% of the applied nitrogen-based fertiliser is not used by crops to grow.9 Nutrient loss is a major source of pollution and it is, in different extent, globally widespread. Another major source of ammonia emissions is produced by livestock manure.

In Europe, sixteen out of twenty-eight members had surpassed in 2016  their 2020 ammonia emission limits.10 Among which the most NH3-pollutant countries were in Latvia, Germany and United Kingdom.10

In UK, Northern Ireland (NI) alone is responsible for 12% of the total NH3 emission.11 The majority (94%) of these emissions originates from the agriculture sector, and in particular from cattle, which accounts for the largest portion (69%).12 Most of NI including priority habitats have a nitrogen concentration that causes significant and irreparable ecological damage. Northern Ireland Environment Link (NIEL) reported in 2019 that 90% of NI’s protected habitats, 98% of Special Areas of Conservation and 83% of special protected areas have exceeded critical loads of nitrogen deposition. Moreover, data released by Department of Agriculture, Environment and Rural Affairs (DAERA) shows significantly deteriorating water quality standards, with 95% of lakes not meeting the Water Framework Directive quality standards and nitrogen levels in both river and marine bodies rising in the past years.13

Some of the strategies that have shown to reduce emissions include: reducing food waste, changing crop allocation to maximise the gain in crop yield, investing in agriculture technology, supporting agricultural modernization, and using chemical nitrogen fertilisers effectively and efficiently.9, 10, 12 Ammonia pollution can be as well reduced by improving confined animal buildings and livestock raising techniques, with better design to sequestrate NH3, reducing the hazard for workers and the NH3 emissions to the atmosphere.11 Moreover, a careful slurry management, including artificial floating crust or a fixed cover, can also reduce ammonia emission up to 60%, during the storage.12

Ammonia emissions are a threat for humans and the natural ecosystems. There is an urgent need to reduce the impact of the agriculture sector, which represents the major source of NH3 emission in the natural environment. Further actions need to be implemented to prevent further biodiversity loss, prevent public health, and at the same time enable sustainable development.


1.           Air quality in Europe – 2020 report; European Environment Agency: 2020.

2.           Garagounis, I.;  Vourros, A.;  Stoukides, D.;  Dasopoulos, D.; Stoukides, M., Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook. Membranes (Basel) 2019, 9 (9), 112.

3.           Smil, V., Detonator of the population explosion. Nature 1999, 400 (6743), 415-415.

4.           Erisman, J. W.;  Sutton, M. A.;  Galloway, J.;  Klimont, Z.; Winiwarter, W., How a century of ammonia synthesis changed the world. Nature Geoscience 2008, 1, 636.

5.           Birken, G. A.;  Fabri, P. J.; Carey, L. C., Acute ammonia intoxication complicating multiple trauma. J Trauma 1981, 21 (9), 820-2.

6.           Gu, B.;  Sutton, M. A.;  Chang, S. X.;  Ge, Y.; Chang, J., Agricultural ammonia emissions contribute to China’s urban air pollution. Frontiers in Ecology and the Environment 2014, 12 (5), 265-266.

7.           Asman, W.;  Sutton, M. A.; Schjørring, J. K., Ammonia: emission, atmospheric transport and deposition. New Phytologist 1998, 139, 27-48.

8.           Sommer, S. G.;  Webb, J.; Hutchings, N. D., New Emission Factors for Calculation of Ammonia Volatilization From European Livestock Manure Management Systems. Frontiers in Sustainable Food Systems 2019, 3 (101).

9.           West, P. C.;  Gerber, J. S.;  Engstrom, P. M.;  Mueller, N. D.;  Brauman, K. A.;  Carlson, K. M.;  Cassidy, E. S.;  Johnston, M.;  MacDonald, G. K.;  Ray, D. K.; Siebert, S., Leverage points for improving global food security and the environment. Science 2014, 345 (6194), 325-328.

10.         Giannakis, E.;  Kushta, J.;  Bruggeman, A.; Lelieveld, J., Costs and benefits of agricultural ammonia emission abatement options for compliance with European air quality regulations. Environmental Sciences Europe 2019, 31 (1), 93.

11.         Luke, J.;  Lucy, G.;  Courtney, S.; King, K. Air Pollution Inventories for England, Scotland, Wales, and Northern Ireland: 2005-2019; Department for environment Food and Rural Affairs: 2021.

12.         Code of Good Agricultural Practice for the Reduction of Ammonia Emissions; Department of Agriculture, Environment and Rural Affairs: 2019.

13.         Ciara, B.;  Laura, N.;  James, O.; Ekaterina, G. EJNI Briefing Paper Series Northern Ireland Assembly – Ammonia Pollution in Northern Ireland; Environmental Justice Network Ireland (EJNI): 2020.

Taking a look underwater


hen we think at the sea and the thousands of varied animals living in them, certainly an image pops up in our head: the coral reef. Besides being spectacular and colourful ecosystems, home to very diverse organisms, coral reefs are also source of food, medicine, income and provide coastal defence to more than 500 million people [1]. This outstanding underwater ecosystem, comparable to an underwater rainforest, is today being threaten. This complex system, which can take thousands of years to form, risks to disappear in mass, resulting in an inestimable environmental catastrophe.

Coral reefs are large underwater structures composed of colonies of individual organisms, named polyps. The backbone structure is a robust protective exoskeleton derived by calcium carbonate. The polyps host inside them the zooxanthellae algae, which is responsible for their colours. In this symbiotic relationship, the algae produce oxygen and organic products (main source of nutrients for the coral itself) through photosynthesis from the CO2 and waste provided by the coral. This beneficial cooperation is highly affected by environmental conditions, such as water purity and water temperature.

Different species of coral reefs are found in more than hundred countries all over the planet. They are mostly found in tropical regions, where the right combination of sunlight, water temperature and nutrients allow them to healthily grow at a speed that can range between 0.5 and 10 cm per year. Some of these enormous coral atolls are considered one of the oldest inhabitants of the oceans. One example, the coral triangle, located in the Pacific Ocean around the waters of Philippines, Malaysia and Indonesia, which is recognized as one of the most diverse marine ecosystems on the Earth.

In the past years, thanks to a collaboration between Google Maps and The Catlin Seaview Survey, it was made possible to admire these marvellous ecosystems and to dive into the ocean comfortably from your couch (which can be a real turning point in “Corona-time”, when real life adventures are rarely possible!). For this peculiar project a special underwater camera, Seaview SVII, was designed to acquire unique, stunning imagines in “street-view” mode; now available on Google Maps (https://www.google.com/maps/about/behind-the-scenes/streetview/treks/oceans/). The broadcasting of these ecosystems has great impact in moving the social awareness to an urgent environmental problem, at global scale.

Underwater “street-view” of the coral reef in The Great Barrier Reef available on Google Maps.

When coral reefs are under stress, they expel the zooxanthellae algae, turning white and losing their inner source of nutrients; this is event is referred as coral bleaching. Most of the big scale bleaching events are linked to the increased temperature in the water. The Intergovernmental Panel on Climate Change (IPCC) declared that with an increase of water temperature of just 1-to-2-degrees, the coral reefs would suffer from high mortality rates. In some circumstances, some corals might be able to recover after a coral bleaching event, but this regeneration can take up to 10-15 years. However, repetitive bleaching events over a short period of time result lethal, as corals do not have enough time to recover. The longest bleaching event was reported from 2014 to 2017, were 70% of earth coral reef were damaged [2]. A recent study has stated that heat stress has caused the Great Barrier to lose significant coral population and that the possibility for the recovery of these corals is uncertain due to increasing intensity and frequency of the disturbance events [3].  A different study has also recorded a drop of 89% below historical levels in the number of newly born larval landing on the reefs [4]. Climate change impact on coral wealth also includes weakening of coral skeletons due to water acidification and the reduction of sunlight due to sea level rise. The extent of these events seriously increases the concern among the scientific community.

Picture of a healthy coral (on the left), compared to a bleached coral (on the right), (Source – Great Barrier Reef Foundation, accessed 25th February 2021). 

Scientists around the world are currently working to increase our understanding on coral reef adaptability and restoration. For example, genetics studies are being undertaken with the hope that in the future reefs could be restored with heat tolerant coral [5]. Many innovative and interesting projects have been launched on artificial 3D printed reef structures, with the aim of saving this ecosystem from a complete disappearance. The Caribbean Marine Biological Institute (CARMABI) research station conducted a study to understand where corals prefer to anchor. The highest rate of repopulation was observed for pink and white coloured structures with holes and crevices [6]. Moreover, researchers from Cambridge University and University California San Diego have made 3D scans of living coral and managed to bio-print reproductions using polymers and hydrogels that contain cellulose materials which imitates optical properties of corals [7]. Furthermore, SECORE International is trying to produce cost-efficient 3D printing seeding substrates to improve the survival rate of coral larvae [8].

In conclusion, mass coral bleaching, and consequent deterioration of coral reefs, is one of the consequences of climate change on large scale. This hidden underwater ecosystem is undergoing tremendous changes, which are not as easily observable as other devastating events occurring on the Earth’s surface. It is important to bring scientific and technologic innovations towards rescuing these unique marine ecosystems and their incomparable biodiversity. Until we can mitigate climate change, it is necessary to raise social awareness on the preservation of any threated ecosystems, including the ones hidden from our view.

[1]        Hoegh-Guldberg O, Pendleton L and Kaup A 2019 People and the changing nature of coral reefs Reg. Stud. Mar. Sci. 30 100699

[2]        https://www.scientificamerican.com/article/scientists-are-taking-extreme-steps-to-help-corals-survive/

[3]        Dietzel A, Bode M, Connolly S R and Hughes T P 2020 Long-term shifts in the colony size structure of coral populations along the Great Barrier Reef Proc. R. Soc. B Biol. Sci. 287 20201432

[4]        Hughes T P, Kerry J T, Baird A H, Connolly S R, Chase T J, Dietzel A, Hill T, Hoey A S, Hoogenboom M O, Jacobson M, Kerswell A, Madin J S, Mieog A, Paley A S, Pratchett M S, Torda G and Woods R M 2019 Global warming impairs stock–recruitment dynamics of corals Nature 568 387–90

[5]        https://www.nationalgeographic.com/science/article/scientists-work-to-save-coral-reefs-climate-change-marine-parks

[6] https://www.ted.com/talks/kristen_marhaver_how_we_re_growing_baby_corals_to_rebuild_reefs/transcript?language=en

[7]        Wangpraseurt D, You S, Azam F, Jacucci G, Gaidarenko O, Hildebrand M, Kühl M, Smith A G, Davey M P, Smith A, Deheyn D D, Chen S and Vignolini S 2020 Bionic 3D printed corals Nat. Commun. 11 1748

[8]        https://3dprint.com/217003/3d-printing-restore-coral-reefs/