How F1 will adopt alternative fuels

In last month's column we looked at the need for F1 not just to embrace environmental sustainability but also to promote, using its sheer persuasive power, the path to an ultra-low carbon economy. This month we'll dig deeper into how we may achieve this, but first we need to expand a little on fuel chemistry.

Many fuels are made of combinations of carbon and hydrogen atoms. One of the most simple comes from combining four hydrogen atoms with one of carbon to give CH4 - a gas known as methane. Ethanol, the most common automotive bio-fuel, is made by combining two carbon atoms, six hydrogen atoms and one oxygen atom to give C2H5OH. Ethanol has the advantage of being easy to make and therefore cheap, but unfortunately it doesn't have the energy content of gasoline.

For every litre of conventional fuel burned we would need to burn 1.5 litres of ethanol to get the same energy. However, accepting that these hydrocarbon fuels can be made from atoms, we can also make the basis of gasoline, which is a substance known as iso-octane. This is made from eight carbon atoms and 18 hydrogen atoms - C8H18. This would then be what is known as a 'drop-in' fuel, meaning it could be used in an existing engine without requiring any modifications. It would still need some additives, but these would be the same as are currently added to conventional gasoline and has a further advantage of not having some of the undesired elements, such as sulphur, in it.

While this may seem the perfect answer unfortunately it's much more difficult, and energy consuming, to make a drop-in fuel than a simple alcohol-type fuel such as ethanol. Equally there are no plants or refineries in the world capable of making enough synthetic fuel, or e-fuel as it's sometimes called, to supply F1 - let alone the larger automotive community.

Although alcohol fuels may not have high energy density they do possess other advantages, such as very high resistance to knock, an uncontrolled and violent ignition that is detrimental to both power and the very structure of the engine.

Let's consider now the engine itself. The laws of thermodynamics show that engine thermal efficiency, in other words its efficiency at converting chemical energy to mechanical energy, is a function of compression ratio.

This is the main reason diesel engines are so efficient. Current F1 engines run very high compression ratios but they're limited by knock. The propensity of an engine to knock depends on the fuel it's run on - and gasoline, while good, isn't the best in this respect.

Tailored fuels, made from advanced sustainable bio resources, matched to engines specifically designed to exploit the characteristics of the fuel could move us forward to the next steps of efficiency. After all, the easiest way to reduce our carbon footprint, and to reduce cost to the consumer, is to reduce the amount of fuel burned no matter what its source.

While much of the low-hanging fruit of engine efficiency has already been harvested, we need to set ambitious targets for the next generation of power units. Just a few years ago 50% efficiency seemed a dream and yet F1 engines have achieved it. When we consider the next F1 engine we need to define targets rather than technologies, and the determination of achieving 60% efficiency is no longer a dream.

It is ambitious, though, and current technology will not get us there. We need to think laterally, to go back to basics and see what technologies will allow us to run higher compression ratios and what will reduce the inevitable losses. For example, should the engine be a two-stroke? Turbocharging, direct injection and plasma ignition could allow a very efficient two-stroke to run with none of the inherent problems of past-generation two-strokes.

More importantly, an engine running on a synthetic ultra-low-carbon fuel with a very high octane rating could run at the sort of compression ratios that engines running on today's gasolines couldn't begin to sustain. Equally we may find traditional poppet valves are no longer suitable since the clearance volume needed for them to open into the cylinder imposes some limitations on achievable compression ratios.

When considering future engine technologies we should also consider a full life-cycle analysis of the power unit itself and the supporting energy source, be it chemical or electrical. We live in a rapidly evolving world and one in which industry must be powered by low-carbon electricity. Once we have that, should we just be using it to charge batteries (which have built in environmental problems) and new infrastructure needs, or should we be using that electricity to synthesise liquid hydrocarbon fuels?

We'll probably need to follow both paths, with full-battery electric vehicles having a role in an urban environment, and low-carbon-fuelled, highly hybridised internal combustion engines powering non-urban light vehicles and all heavy vehicles.

F1 could play a huge role in this transition. It's proven its ability to advance technology readiness levels from experimental to production, and must do so again. It also has the profile to engage the public in these technologies.

The difference this time is that it doesn't have an option. Failure to reduce CO2 emissions will leave the sport as a pariah with no place in modern society.

The next step needs to come with the next generation of power unit. F1 must be the first series to run on 100% advanced sustainable fuels to demonstrate their effectiveness.

The fuel and the engine must be designed in harmony, and hybridisation and electrical systems must be taken to a new level. When a full circular life-cycle analysis is done, F1 must pave the way toward a true net zero carbon society in the transport arena.