Ten years ago, biofuels were regarded as ideal low-carbon replacements for the liquid fossil fuels that power most of the world’s transport systems. But since then, concerns have grown that first-generation biofuels, which were made from food crops, were not as green as hoped.

Indeed, when all factors relating to their production were considered, several sources (notably biofuels from palm oil, soybean and rapeseed) were found to be more polluting than crude oil and in the case of palm oil, production emitted over 98 per cent of CO2 as extracting oil from tar sands.

On top of this is their effect on food supplies and food prices as well as other considerations including deforestation and the effect on indigenous wildlife, which has occurred in places like Indonesia when planting crops such as palm oil.

Fig 1: while next gen biofuels can be almost carbon neutral, the production of several forms is more polluting than crude oil. Testing is therefore essential if the transport industry is to meet its climate change commitments
Subset of EU data leaked to Euroactiv in 2012

Biofuel development

As of this year, the EU’s scheme for certifying biofuels as sustainable requires fuels from new manufacturing plants to emit 60 per cent less CO2 than regular fuel (up from 50% in 2017 and 35% in 2016). This would eliminate the use of the higher polluting fuels anyway but last year (2017) the EU stressed its objection to the use of palm oil (or more accurately the deforestation that accompanies it) by voting almost unanimously (640-18) to ban the use of palm oil in biofuels.

But while second generation biofuels are significantly less polluting (see fig 1), a 2016 paper in Nature Biotechnology, which looked at the global landscape of biofuel patenting stated “after surging between 2004 and 2008, the invention of biofuel technologies slowed considerably, and in many countries went into decline.”

Currently much of the focus is on algae, which can be genetically engineered to reliably produce fuel in industrial processes – for example this year Exxon Mobil outlined its goal to produce 10,000 barrels of algae biofuel per day by 2025 – but according to a July 2017 UK Government commissioned report by the Royal Academy of Engineering, even the promise of algae remains far off, with the report stating: “Third generation biofuels (produced from microalgae) do not represent a feasible option at present state of development as their GHG emissions are higher than those from fossil fuels.”

In short, there is a significant variation in the ‘green’ credentials of biofuels and without a simple, accurate, cost effective and portable testing procedure in place, the sector will be subject to consumer fraud and commercial malpractice. We believe mid-IR sensors based on PZT pyroelectric materials will provide the best solution for this.

Biofuel in transportation

By 2020, the EU aims to have 10 per cent of the transport fuel of every EU country come from renewable sources – including biofuels. Fuel suppliers will also be required to reduce the greenhouse gas intensity of the EU fuel mix by 6 per cent by 2020 in comparison to 2010.

In addition to this, the Renewable Transport Fuel Obligations order stipulates that biofuel must be blended into petrol and diesel in the UK – today at a rate of 4.75 per cent. In the UK, the rise towards the 10 per cent EU-wide target by 2020 has currently stalled.

And while personal transportation (cars, taxis, buses) is moving towards the elimination of fossil fuels: several major cities including Paris, Oxford and Copenhagen have announced diesel car bans, and the London Mayor is considering a ban on all non-electric cars in the City of London, this is happening slowly and low-pollution biofuels will need to be part of the mix for the foreseeable future. Indeed, a Greenpeace commissioned analysis by the DLR (German Aerospace Centre) announced September 2018 has stated the EU will need to end sales of petrol and diesel cars by 2030, and plug-in hybrids by 2035 if the auto sector can play its part in holding global warming to the Paris agreement’s 1.5oC goal.

According to a researcher behind the 2017 Royal Academy of Engineering report for government, Imperial College London’s Nilay Shah, biofuels will need to be a key part of tackling climate change even with the growth in electric cars because no significant alternatives for liquid fuels are available for aircraft, ships and long-distance HGVs. With Shah telling the Guardian at the report’s launch: “The scope for electrification [was] quite limited for at least several decades.”

Current work is underway, however: British Airways has reopened (after abandoning in January 2016) a scheme to create jet fuel from London’s rubbish; and the US navy has announced aircraft carriers powered by biofuels.

IR testing of biofuels

Not all biofuels are created equal, and as we begin to accept their use in fuels for both cars and long-distance transport, the need for a, detailed fuel characterisation and testing is required, be it to ensure optimum performance, prevent consumer fraud or assess environmental impact.

Passive mid-IR spectrometers – made from PZT pyroelectric materials (see Pyreos offering here) are ideal to analyse the content of biofuels. They can capture a wealth of information, with IR energy from a sample exciting vibrational motions in a molecule’s covalent bonds. These vibrational modes are a unique fingerprint for a specific molecule and give information on its composition and concentration as well as atomic structure and molecular interactions.

This allows them to detect signatures for each type of biofuel and determine either the correct octane of fuel is used, check for the presence of fuel additives like ethanol, or detect adulteration with low-cost but illegal / high-pollution fuels such as palm oil.

The technology is tried and tested, with Parker Kittiwake announcing the ATR in 2017, this analyser has been created for use on board ships to check the condition of engine oil while it is hot and the ship is cruising. The ability to test simultaneously for water content, base number, total acid number, soot loading, viscosity and fatty acid methyl ester (FAME) allows engineers to assess the state of the oil. Frequent testing ensures that unnecessary engine damage due to contaminants is avoided, but also that oil is not changed before it needs to be.

Furthermore, PZT pyroelectric IR sensors are robust, don’t require cooling, are small, have an excellent SNR, are highly sensitive, low-power and scalable. All this means high-density thin-film mid-IR arrays are the key to building an affordable, easy-to-use and effective spectrometer.


With the scope for electrification being limited, at least for several decades, biofuels need to be part of the mix for the foreseeable future if the auto sector is to play its part in holding global warming to the Paris agreement’s 1.5oC goal.

The need to ensure these are as non-polluting as possible must be a priority and mid-IR sensors give us the ability to track chemical fingerprints and quickly, cost effective and easily identify both the mis-labelling of, and adulteration with, lower-cost, higher-polluting biofuels.