A completely clean, renewable energy system that can be produced locally and that can easily power heat, energy storage and transportation, and travel — that's the future that promoters of a hydrogen economy envisage.
If it sounds a bit like rocket science, that's because it is. Hydrogen is what's used to fuel rockets — that’s how powerful it is. In fact, it’s three times more powerful as a fuel than gas or other fossil-based sources. And, after use, it’s frequently converted to drinking water for astronauts.
US President Joe Biden has highlighted the potential of hydrogen in his ambitious plans for economic and climate recovery and a number of recent reports have been encouraging about hydrogen’s breakthrough moment, including McKinsey and Company (Road Map to a US Hydrogen Economy, 2020) and the International Energy Agency.
Hydrogen fuel cells provide a tantalising glimpse into our low-carbon future
The McKinsey report claims that, by 2030, the hydrogen sector could generate 700,000 jobs and $140bn in revenue, growing to 3.4 million jobs and $750bn by 2050. It also believes it could account for a 16% reduction in CO2 emissions, a 36% reduction in NOx emissions, and supply 14% of US energy demand.
So how does it work?
Simply put, hydrogen fuel cells combine hydrogen and oxygen atoms to produce electricity. The hydrogen reacts with oxygen across an electrochemical cell and produces electricity, water, and heat.
This is what gets supporters so excited. In theory, hydrogen is a limitless, incredibly powerful fuel source with no direct emissions of pollutants or greenhouse gases.
So what's the problem?
Right now, there are actually a few problems. The process relies on electrolysis and steam reforming, which are extremely expensive. The IEA estimates that to produce all of today’s dedicated hydrogen output from electricity would require 3,600TWh, more than the total annual electricity generation of the European Union.
Moreover, almost 95% of hydrogen currently is produced using fossil fuels such as methane, natural gas, or coal (this is called "grey hydrogen"). Its production is responsible for annual CO2 emissions equivalent to those of Indonesia and the United Kingdom combined. In addition, its low density makes it difficult to store and transport — it must be under high pressure at all times. It’s also well-known for being highly flammable — its use as a fuel has come a long way since the Hindenburg Disaster but the association still makes many people nervous.
A Hydrogen refuelling station Hafencity in Hamburg, Germany. Infrastructure issues must be addressed if we are to see more hydrogen-fuelled vehicles on our roads. | Image credit: fritschk / Shutterstock.com
So there are quite a few problems. What’s the good news?
In the last few years, we've seen how rapidly investment, innovation, and infrastructure policy can completely transform individual renewable energy industries. For example, the IEA analysis believes the declining costs of renewables and the scaling up of hydrogen production could reduce the cost of producing hydrogen from renewable electricity 30% by 2030.
Some of the issues around expense could be resolved by mass manufacture of fuel cells, refuelling equipment, and electrolysers (which produce hydrogen from electricity and water), made more likely by the increased interest and urgency. Those same driving forces could improve infrastructural issues such as refuelling stations for private and commercial vehicles, although this is likely to require coordination between various stakeholders, including national and local governments, industry, and investors.
The significant gains in renewable energy mean that “green” hydrogen, where renewable electricity powers the electrolysis process, is within sight.
The IEA report makes clear that international co-operation is “vital” to progress quickly and successfully with hydrogen energy. R&D requires support, as do first movers in mitigating risks. Standards need to be harmonised, good practice shared, and existing international infrastructure built on (especially existing gas infrastructure).
If hydrogen can be as efficient and powerful a contributor to a green global energy mix as its proponents believe, then it's better to invest sooner rather than later. If that investment can help power a post-Covid economic recovery, even better.
But before proceeding, it is important to first distinguish between the terms ‘primary energy consumption’ and ‘final energy consumption’. The former refers to the fuel type in its original state before conversion and transformation. The latter refers to energy consumed by end users.
Oil consumption is on the decline.
In 2018, UK primary energy consumption was 193.7 m tonnes of oil equivalent. This value is down 1.3% from 2017 and down 9.4% from 2010. This year, the trend has continued so far. Compared to the same time period last year, the first three months of 2019 have shown a declination of 4.4% in primary fuel consumption.
It is also important to identify consumption trends for specific fuels. Figure 1 below illustrates the percentage increases and decreases of consumption per fuel type in 2018 compared to 2017 and 2010.
Figure 1 shows UK Primary Energy Consumption by Fuel Type in 2018 Compared to 2017 & 2010. Figure: BEIS. Contains public sector information licensed under the Open Government Licence v1.0.
As can be seen in 2018, petroleum and natural gas were the most consumed fuels. However, UK coal consumption has dropped by almost 20% since 2017 and even more significantly since 2010. But perhaps the most noticeable percentage change in fuel consumption is that of renewable fuels like bioenergy and wind, solar and hydro primary electricity.
In just eight years, consumption of these fuels increased by 124% and 442%, respectively, thus emphasising the increasingly important role renewables play in UK energy consumption and the overall energy system.
Overall, the UK’s final energy consumption in 2018, compared to 2017, was 0.7% higher at a value of approximately 145 m tonnes of oil equivalent. However, since 2010, consumption has still declined by approximately 5%. More specifically, figure 2 illustrates consumption for individual sectors and how this has changed since.
Figure 2 from UK Final Energy Consumption by Sector in 2018 Compared to 2017 & 2010. Figure: BEIS. Contains public sector information licensed under the Open Government Licence v1.0.
Immediately, it is seen that the majority of energy, consumed in the UK, stems from the transport and domestic sector. Though the domestic sector has reduced consumption by 18% since 2010, it still remains a heavy emitting sector and accounted for 18% of the UK’s total carbon dioxide emissions in 2018.
Therefore, further efforts but be taken to minimise emissions. This could be achieved by increasing household energy efficiency and therefore reducing energy consumption and/or switching to alternative fuels.
Loft insulation is an example of increasing household energy efficiency.
Overall, since 2010, final energy consumption within the transport sector has increased by approximately 3%. In 2017, the biggest percentage increase in energy consumption arose from air transport.
Interestingly, in 2017, electricity consumption in the transport sector increased by 33% due to an increased number of electric vehicles on the road. Despite this, this sector still accounted for one-third of total UK carbon emissions in 2018.
Year upon year, the level of primary electricity consumed from renewables has increased and the percentage of coal consumption has declined significantly, setting a positive trend for years to come.
Today, most rockets are fueled by hydrazine, a toxic and hazardous chemical comprised of nitrogen and hydrogen. Those who work with it must be kitted up in protective clothing. Even so, around 12,000t of hydrazine is released into the atmosphere every year by the aerospace industry
Now, researchers are in the process of developing a greener, safer rocket fuel based on metal organic frameworks (MOFs), a porous solid material made up of clusters of metal ions joined by an organic linker molecule. Hundreds of millions of connections join in a modular structure.
Robin Rogers, formerly at McGill University, US, has worked with the US Air Force on hypergolic liquids that will burn when placed in contact with oxidisers, to try get rid of hydrazine. He teamed up with Tomislav Friščić at McGill who has developed ways to react chemicals ‘mechanochemically’ – without the use of toxic solvents.
The pair were interested in a common class of MOFs called zeolitic imidazole frameworks, or ZIFs, which show high thermal stability and are usually not thought of as energetic materials.
They discussed the potential of using ZIFs with the imidazolate linkers containing trigger groups. These trigger groups allowed them to take advantage of the usually not accessible energetic content of these MOFs.
The resulting ZIF is safe and does not explode, and it does not ignite unless placed in contact with certain oxidising materials, such as nitric acid, in this case.
Authorities continue to use hydrazine because it could cost millions of dollars to requalify new rocket fuels, says Rogers. MOF fuel would not work in current rocket engines, so he and Friščić would like to get funding or collaborate with another company to build a small prototype engine that can use it.
The concept of a hydrogen economy is not new to anyone involved or familiar with the energy sector. Until the 1970s, hydrogen was a well-established source of energy in the UK, making up 50% of gas used. For several reasons, the sector moved on, and a recent renewed interest into the advantages of hydrogen has put the gas at the forefront in the search for green energy.
Confidence behind the viability of hydrogen was confirmed last October when the government announced a £20m Hydrogen Supply programme that aims to lower the price of low carbon hydrogen to encourage its use in industry, power, buildings, and transport.
Hydrogen - the Fuel of the Future? Video: Real Engineering
‘In a way, hydrogen is more relevant than ever, because in the past hydrogen was linked with transportation,’ UCL fuel cell researcher Professor Dan Brett explained to The Engineer. ‘But now with the huge uptake of renewables and the need for grid-scale energy storage to stabilise the energy system, hydrogen can have a real role to play, and what’s interesting about that […] is that there’s a number of things you can do with it.
‘You can turn it back into electricity, you can put it into vehicles or you can do a power-to-gas arrangement where you pump it into the gas grid.’
Engineers say they have demonstrated a cost-effective way to remove carbon dioxide from the atmosphere. The extracted CO2 could be used to make new fuels or go to storage.
The process of direct air capture (DAC) involves giant fans drawing ambient air into contact with an aqueous solution that traps CO2 . Through heating and several chemical reactions, CO2 is re-extracted and ready for further use.
‘The carbon dioxide generated via DAC can be combined with sequestration for carbon removal, or it can enable the production of carbon-neutral hydrocarbons, which is a way to take low-cost carbon-free power sources like solar or wind and channel them into fuels to decarbonise the transportation sector,’ said David Keith, founder of Carbon Engineering, a Canadian clean fuels enterprise, and a Professor of Physics at Harvard University, US.
Fuel from the Air – Sossina Haile. Video: TEDx Talks
DAC is not new, but its feasibility has been disputed. Now, Carbon Engineering reports how its pilot plant in British Columbia has been using standard industrial equipment since 2015. Keith’s team claims that a 1 Mt- CO2 /year DAC plant will cost $94-$232/ton of CO2 captured. Previous theoretical estimates have ranged up to $1000/ton.
Platinum is one of the most valuable metals in the world. Precious and pretty, it’s probably best known for jewelry – and that is almost certainly its oldest use. But its value has become far greater than its decorative ability; today, platinum powers the world. From agriculture to the oil markets, energy to healthcare, we use platinum far more than we realise.
1. Keep the car running
Platinum is needed to make fuel for transport. Image: Pixabay
Platinum catalysts are crucial in the process that converts naphtha into petrol, diesel, and jet-engine fuel, which are all vital to the global economy. The emissions from those petroleum fuels, however, can be toxic, and platinum is also crucial in the worldwide push to reduce them through automotive catalytic converters. In fact, 2% of global platinum use in 2016 was in converting petroleum and 41% went into reducing emissions – a circle of platinum use that’s more impressive than a ring.
2. Feed the world
Nitric acid is a by-product of platinum which is used in fertilisers. Image: Pixabay
Another vital global sector that makes use of platinum catalysts is agriculture. Without synthetic fertilisers, we would not be able to produce nearly as much food as we need. Nitric acid is essential for producing those fertilisers and platinum is essential for producing nitric acid. Since 90% of the gauzes required for nitric acid are platinum, we may need to use more of it as we try to meet the global food challenge.
3. Good for your health
A pacemaker. Image: Steven Fruitsmaak@Wikimedia Commons
Platinum is extremely hard wearing, non-corrosive, and highly biocompatible, making it an excellent material to protect medical implants from acid corrosion in the human body. It is commonly used in pacemakers and stents. It is also used in chemotherapy, where platinum-based chemotherapeutic agents are used to treat up to 50% of cancer patients.
4. The fuel is clean
In addition to powering the cars of the present and reducing their environmental impact, platinum might well be crucial to the future of transport in the form of fuel cells. Platinum catalysts convert hydrogen and oxygen into clean energy, with water the only by-product.
5. Rags to riches
The Spaniards invaded the Inca Empire, South America, in 1532. Painted by Juan B Lepiani. Image: MALI@Wikimedia Commons
Amazingly, despite all this, platinum was once considered worthless - at least in Europe. In fact, it was considered a nuisance by the Spanish when they first discovered it in South America - as a corruption in the alluvial deposits they were earnestly mining and they would quite literally throw it away. It wasn’t until the 1780s that the Spanish realised it might have some value.
Because platinum is essential to so many aspects of our economy, there are concerns about supply meeting demand – particularly as nearly 80% is currently mined in South Africa, which has seen its mining industry repeatedly crippled by strikes in recent years.
Two Rivers platinum mine, South Africa. Image: Wikimedia Commons
Some believe the solution to the issue of supply is space mining, arguing the metal could be found in asteroids.
Others, such as researchers at MIT, are working to create synthetic platinum, using more commonly found materials. Neither approach is guaranteed to work but, given our increasing dependence on this precious metal, we could be more reliant on their success than we realise.