Synthetic fuels – energising the parts green electrification cannot reach?

28 November 2023 By 0

Not everyone can plug into the power grid! Although a fully-fledged hydrogen economy is being developed in the increasingly intense race to reach net-zero emissions by 2050, some hard-to-reach-and-abate sectors will have to rely on carbon-neutral, or even carbon-negative, liquid fuels as an interim or even long-term solution. It is important to plan for their infrastructure now.

It is now overwhelmingly clear that we must cap the release of greenhouse gases (GHGs) wherever possible to put a lid on the soaring temperature rises seen around the world recently, with far worse predicted to follow.

The nub of the problem is that carbon dioxide – and its fellow GHGs including methane – released by both natural and human activities are transparent to the sun’s incoming short-wave radiation. That heats the ground.

Unfortunately, they also block heat reflected back up from the Earth’s surface as infrared long-wave radiation, trapping it in the atmosphere, and preventing it from escaping into space.

Yes, we do need some form of an insulating greenhouse-effect blanket or the planet would be too cold to support many kinds of life. But no, not so much that we are in danger of overheating.

Net-zero – on balance a good solution

The world’s main answer to global warming caused by the fast-growing greenhouse effect is to curb the use of fossil-fuels formed eons ago such as natural gas, oil, and certainly coal.

Instead, we are seeing a transition to low- and zero-carbon renewable sources that harvest sunlight energy differently – like wind and solar – plus hydropower, and a new generation of nuclear energy.

However, it is not physically possible to stop all emissions. Therefore, net-zero means balancing carbon emitted into the atmosphere and carbon removed from it so that the first figure is no larger than the second. Emissions that cannot be stopped must be offset instead.

There is an important additional argument that net-zero alone is not enough, and we must go much further to invent and use technologies that claw back carbon already released into the atmosphere.

The electrification strategy – with one weakness

A primary goal of a swift green energy transition is to produce clean electricity. But this is not a universal solution.

Where fossil-fuels can only be phased out gradually, the vision is to use new carbon capture and storage (CCS) technologies that are gradually being deployed on a large scale.

The number of UK planned CCS projects has risen from 55 to more than 90 worth circa £40 billion in inward investments by 2030, says the Carbon Capture and Storage Association’s (CCSA) new Delivery Plan (https://www.ccsassociation.org/), with enough in the pipeline to capture some 94 million tonnes of CO2 annually – 29% up from 73 million tonnes in 2022.

However, there is one missing component I would like to focus on – synthetic fuels. Where access to clean electricity is not feasible, synthetic products can be a viable alternative.

Their production sits well with the wider goal of converting industrial and community waste streams into clean liquid fuels in the circular economy where one organisation’s waste becomes another’s feedstock – and little is actually wasted.

Velocys – waste-to-jet-fuel

It is important that I mention the Velocys project in northeast Lincolnshire because Enzygo was instrumental in its planning, environmental impact assessment, understanding its complex technical requirements, permitting, plus liaison with local planning officers, councillors, and the community.

Velocys, in partnership with British Airways and Shell, is planning to build a Humberside facility by 2027 that will convert up to 500,000 tonnes of waste into 60 million litres of aviation and road fuel; the company joined Zero Carbon Humber in 2022 https://velocys.com/2022/02/03/velocys-joins-zero-carbon-humber/

Because the project evolved as it was developed, it was essential that planning consent allowed the design team to make continuous adjustments without referring back to the planning authority each time.

With our multi-disciplinary team’s knowledge of local authority professional practices, and their first-hand experience in working with planning officers, we were able to secure this for Velocys.

Sustainable infrastructure

We think our approach and ability to speak the language that a wide range of clients, specialists, and local planners understand, will become increasingly important as we see the rapid development of other sustainable energy industry infrastructure.

This is likely to include the fledgling hydrogen sector, but also carbon capture, utilisation and storage (CCUS) plants when they become commercially viable as the green future unfolds.

Looking even further ahead, other innovative technologies could become commonplace, such as DAC (direct air capture) plants – in effect artificial trees used on a wide scale to help claw back some of the high levels of carbon already in the atmosphere.

Why synthetic fuels just now?

The other fly in the sustainable ointment is that electrification could face potential problems.

Can net-zero be reached by 2050? Will supply-chain shortages slow down electric vehicle (EV) production? There are fears the ‘first global stocktake’ under COP28 in December 2023 will reveal that many countries are not meeting their COP21 Paris climate agreement low-carbon commitments from 2015.

Therefore, I thought it would help to focus on what synthetic fuels are, how they are made, their importance, and they overall part in wider global decarbonisation.

Synthetic fuels explained

Renewable synthetic fuels are seen as a key net-zero technology for the heavy modes of transport like bulk road freight, rail, shipping and aviation.

Terms such as ‘biofuel’, ‘synfuel’, and ‘e-fuel’ are often used interchangeably, but actually have important differences in their production, scalability, and sustainability which can effect planning,

Synthetic fuels are liquid fuels with similar properties to fossil-fuels. However, they are made by copying natural processes using renewable resources.

As a result, their building bricks are the same as for fossil-fuels, and there are synthetic versions of jet fuel, diesel, and gasoline for ordinary planes, boats, trucks, and cars.

Mimicking fossil-fuels with clean results

Fossil-fuels made from hydrogen and carbon chains can create hundreds of different hydrocarbon molecules. The key to synthetic fuels is mimicking this process with a syngas made from hydrogen and carbon monoxide – plus large amounts of renewable energy.

These syngas ‘Lego-bricks’ can then be used to build all the hydrocarbon fuel types mentioned above via an established industrial process that has been used and proved on a large scale for decades.

The difference is that unsustainable feedstocks, such as coal and natural gas, are no longer used.

Types of renewable synthetic fuels

Long-distance transport needs energy carriers with a very high energy density, and relies on liquid fuels that contain 60 to 100 times more energy per unit of mass than lithium-ion batteries.

Batteries are also too heavy and bulky for long-distance aviation, which is why the aviation industry is looking to Sustainable Aviation Fuels (SAF) to reach net zero.

There are currently three ways of making renewable syngas and synthetic fuels: – biofuels from biomass; e-fuels with renewable electricity; and solar fuels from solar heat. All three involve a mixture of hydrogen and carbon monoxide turned into liquid fuels via gas-to-liquid processes.

– Biofuels – biomass-to-liquid

Biomass from sugar cane, corn, green waste, or algae is converted at high temperatures into syngas and biofuels. A drawback is that they may compete with the food industry for arable land.

– e-fuels – power-to-liquid

Renewable electricity is used to splits water into H2 and O2 in an electrolyser; hydrogen mixed with carbon dioxide then forms a syngas in a high temperature ‘reverse water gas shift’ reaction (RWGS).

– solar fuels – sun-to-liquid

Solar fuels are produced using solar heat to drive a thermochemical reactor in which carbon dioxide and water are converted into syngas. Sunny deserts and semi-arid regions with high solar radiation are best. Neither e-fuels are solar fuels are widely available on the market.

How can synthetic fuels be used?

Synthetic fuels can be used in internal combustion (ICE) and jet engines for transport sectors that cannot be electrified. They use the conventional fuel storage and distribution infrastructure.

Are e-fuels suitable for cars? Electrification is acknowledged the way forward here. In fact, e-fuels are incredibly inefficient in passenger cars and need five times more renewable electricity than EVs.

The other view is that the existing fleet of 1.4 billion vehicles with ICEs won’t vanish overnight. If the ultimate goal is hydrogen, synthetic hydrocarbon fuels could be a stop gap.  But an effective hydrogen economy with its own brand new infrastructure could be many years away.

Can petrol be carbon neutral?

Banning new petrol and diesel cars from 2030 – or whenever politically expedient – raises practical questions about the support infrastructure needed by EVs, the heavy EV road weight, charge points, supplying enough renewable power, and the high costs for drivers of maintenance and insurance.

One major bonus is that EVs are much more energy efficient than ICE or hydrogen fuel-cell vehicles, which means that even with electricity from fossil-fuel power stations, CO2 emissions are lower.

Carbon-neutral synthetic fuels offer similar benefits, and given that ‘legacy’ fossil-fuel vehicles may be running for a while, powering them with synthetic fuels could be important in meeting net-zero.

Upcycling proven technologies

I mentioned above that a shortage of agricultural capacity was a major reason why the focus has moved from biofuels to e-fuels as more practical and sustainable. Looking at that shift in more detail has important planning implications.

By re-examining processes like the 1925 Fischer– Fischer–Tropsch process, modern innovators using syngas from a mix of hydrogen and carbon monoxide at high temperature and pressure have created long waxy linear-chain alkenes that can be cracked to the chain length for aviation fuel.

The aim is to improve the Fischer–Tropsch process using sustainable feedstocks such as municipal solid waste or biomass as a low-cost circular feedstock.

But cost is still a problem because no process yet competes with fossil-fuels on price.

What about the batteries?

I can’t finish without a footnote about battery developments for off-grid applications.

When questioned, many motorists list three EV priorities: an extended driving range, a short charging time, and a price on a par with comparable ICE vehicles.

Automakers have been searching for ways to replace conventional lithium-ion (Li-ion) batteries that power most modern EVs with more advanced ‘solid-state’ super-batteries that promise much faster charging and a longer driving range.

After overcoming years of technical hurdles, the first solid-state Li-ion batteries could go into production in the next few years.

Toyota, as the world’s largest carmaker, started to study solid-state batteries in 2012. Since then, nothing much has happened in public. However, Toyota recently announced a ‘technological breakthrough’ that could see it manufacturing a solid-state battery as early as 2027.

The company claims its new battery could give average EVs a range of circa 1,200km – roughly twice that of existing models. Recharged will also be around ten minutes – not quite long enough to grab a coffee!

Contact

I’m always happy to answer questions. To discuss synthetic fuels, or any other planning issues, please contact me directly.

Incidentally, at the top of this article I am grateful to Terry Lovelock for his iconic 20th century Heineken ad campaign strapline – “Heineken Refreshes the Parts Other Beers Cannot Reach”.

Matt Travis, Company Director, Enzygo Ltd