Give Me Green, Give It To Me NOW!

Automology's columnist, MAC, continues to weigh in on 'greener' alternatives.   Not a lot of people know this, but good o...

Automology's columnist, MAC, continues to weigh in on 'greener' alternatives.
Not a lot of people know this, but good old Henry Ford ran his cars on ethanol and Rudolf Diesel fired his namesake engine with peanut oil. So, how come both became addicted to ‘rock oil’? To put it simply, they both discovered that with a little refining, you got a better bang for your buck from the stored sunshine in petroleum products. The fact is that the stored energy in hydrocarbons is far greater and the cost to produce is far lower, mainly because much of the hard work of breaking down the cellulose to sugars and alcohol has been done by nature.

With the ever growing threat of the world running out of oil and the cost differential being eroded, there has been a race between oil companies, governments, environmental organisations, academics and even private individuals to produce the successor to oil powered vehicles; these organisations have been spending perhaps billions of dollars to be the first. 

There is now a plethora of alternatives to a straight hydrocarbon burning system, but of course which one is the best and who will determine what powers our cars of the future - you, the car companies or governments - is still to be decided. Currently, the alternative for mainstream, next-generation power for personal automobiles breaks down into the following six basic categories:

Biodiesel. This is a renewable fuel that can be manufactured from vegetable oils or recycled restaurant grease, and is very similar to petroleum diesel but with cleaner burning. 

Pure biodiesel only contains about 86% of the stored energy that petroleum diesel has. In many countries, we have become familiar with signs on pumps that say B20 to about B85. The number stands for the amount of biomass in the fuel, with B20 having 20% and so on. The great thing about biodiesel is that there is virtually no need for any new technology; most diesel engines will run on just pure vegetable oil, although there are issues with the hygroscopic nature of the fuel and the flow characteristics when cold. So perhaps we have started with our winner…

NOT SO FAST! There are grave concerns about the environmental impact of using vegetable oil and how much carbon is released into the atmosphere as a result. Matt Adams believes, “There are two key reasons many biofuels are more polluting than fossil fuels. First, they are often grown where there's rainforest or other land that's high in carbon. This carbon is released when the land is converted. Second, they displace food crops, which have to be grown elsewhere, and these food crops replace carbon-rich environments such as rainforests.” 

So, with biodiesel we may have found a sustainable fuel source with a low entry barrier but we will not have solved the greenhouse gas issue.

Ethanol. This is a renewable fuel made mostly from corn or sugarcane, and are essentially alcohol, hooch, moonshine and the like, and of course most governments have a small issue with that. The great thing about ethanol is that it can be used in a variety of blends depending on the season, from E10 to about E85, and can be delivered via the existing petrol fuel delivery system.

Ethanol actually contains much higher octane and oxygen, which traditionally was a problem as it needed a specialised engine. However, Volkswagen in Brazil decided to create a vehicle that was not wedded to a particular fuel and thus could avail itself to the cheapest fuel source. VW developed new software for the engine’s Electronic Control Unit that automatically adjusted the air-fuel ratio and spark advance, so that the vehicle could run on just about any mixture, from pure petrol to pure ethanol. The first FLEX vehicles were introduced in 2003 and now account for at least 85% of the new vehicle market there.

But ethanol is not without its problems - a litre of ethanol only has 67% of energy content compared to petrol, which means that there is a major mileage penalty for using it.

And don’t forget that we grow the corn where we used to grow food crops; if you are a farmer in the midwest of the USA, you are experiencing grain prices at historic highs. If you are not a midwest farmer, and let’s face it, most of us are not, then this is bad for the food economy, causing the price of such staples as tortillas in Mexico to cornflakes in the USA to climb ever higher. Sugarcane is not much better; this tropical grass is grown in much the same locations as the much vilified palm oil trees and with all the same arguments against it.

Electricity. Okay, so now it starts to become a bit difficult as there really are 3 different primary technologies here.

There is the Hybrid Electric Vehicle (HEV), as typified by Hollywood’s favourite Toyota Prius, which is powered by an internal combustion engine that runs on conventional fuel (usually petrol) and an electric motor that uses energy stored in a battery. The battery is charged by the Kinetic Energy Recovery System (KERS) and/or by the combustion engine.

Then we have the Plug-In Hybrid Vehicle (PHEV) which is pretty much the same as the HEV, but can be plugged in to an external electrical source to charge the battery. The main difference between the PHEV and HEV is that PHEV is primarily designed to run on the battery with the engine kicking in only to generate electricity for the battery when the range is almost exceeded. Some PHEVs are also called Extended Range Vehicles (EREV).

Finally there is the All-Electric Vehicle (EV) which has a battery to store electricity and is charged by plugging the vehicle in, and is sometimes referred to as Battery Electric Vehicle (BEV). EVs have not caught on very well at all, with most consumers suffering from range anxiety. To date, there are few commercially available models, although Nissan is committed to their Leaf EV.

HEVs, on the other, have gained widespread acceptance with even the supercar manufacturers jumping onto the band wagon. But they are not without their sceptics (See: Why You Shouldn't Buy Hybrids Cars). Well known environmental activist and treehugger, Tony Bosworth, maintains that "we need a 21st century energy revolution based on efficiency and renewables, and not more fossil fuel”. So, in other words, we have got to kick our hydrocarbon addiction in favour of non-polluting renewable energy sources. Hybrids just drags on the usage of hydrocarbons and, therefore, are bad.
Natural Gas. This is a surprisingly ubiquitous product and is described as a clean burning alternative fuel that can be used as either Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG). Vehicles using this technology are called Natural Gas Vehicles (NGV).

The gas is readily available through the utility infrastructure in a lot of countries. A simple conversion is all that is needed to change a vehicle over. For fleets of vehicles that are centrally fuelled, CNG is seen as a sensible option whilst for fleets that travel greater distances, LNG is considered the better choice due to the amount of energy that you can store.

The fact is though that most NGVs have a bi-fuel system, that is they can operate either on petrol or natural gas. This gives flexibility, but the tanks for the gas are often placed in the boot space and thus restrict the luggage space dramatically. So where is the flaw on this seemingly great alternative, that is ubiquitous and works with current technology?

As we mentioned already, there is a strong argument that the world needs to develop a renewable fuel system that will not impact the environment. The trouble with natural gas is FRACKING and, as I have previously written, this is not without its issues.

Propane. Also known as Liquefied Petroleum Gas (LPG) or autogas, and contains butane, the stuff we put in throw-away cigarette lighters or in camping gas stoves. LPG has been used worldwide as a vehicle fuel for decades; in fact, it was first created by a Dr Walter Snelling in 1910.

LPG is prepared by refining petroleum or wet natural gas and has a boiling point below room temperature. Thus, it will evaporate rapidly at normal temperatures and pressures, therefore needing special handling considerations and transported and stored in large steel vessels. Once it has evaporated, the gas is heavier than air and thus will seek low points like basements, creating further issues with the use of the product.

So, like CNG before it, the handling problems associated with LPG will probably mean that it never reaches universal acceptance in the same way that diesel or petroleum have.

Hydrogen. Hydrogen, oh hydrogen. It is all around us, all the time; it is in the water that we drink, in the air that we breath, in the food that we eat. In fact, fuel cells powered by hydrogen have the opportunity to revolutionise our transportation system. Just about every major government in the world agrees with me and are pushing for a hydrogen solution for our future transportation requirements.

Hydrogen fuel cells are more efficient than conventional internal combustion engines and produce no tail pipe fumes, except for water that is. The fuel cell system is a radically different system when compared to other propulsion systems, effectively utilising hydrogen on one side and oxygen on the other (explained below).

The hydrogen can come from pure hydrogen stored directly in the vehicle or from a secondary fuel, such as methanol, ethanol or natural gas, all of which carry hydrogen. Fuel Cell Vehicles (FCV) can also be equipped with advanced technologies to increase the efficiency, such as KERS, but all of these vehicles are in an early stage of delivery and, despite the promise, there are two major flaws in the technology ie. the cost of the hydrogen generation in the first place, followed by the cost of developing the distribution and delivery infrastructure.

So, perhaps this will not be the one after all.

How Fuel Cell Vehicles Work

Like EVs, FCVs use electricity to power motors located near the vehicles’ wheels. In contrast, FCVs produce their primary electricity using a fuel cell powered by hydrogen. 

The most common type of fuel cell for vehicle applications is the polymer electrolyte membrane (PEM) fuel cell. In a PEM fuel cell, an electrolyte membrane is sandwiched between a positive electrode (cathode) and a negative electrode (anode). Hydrogen is introduced to the anode and oxygen to the cathode. The hydrogen molecules travel through the membrane to the cathode but not before the membrane strips the electrons off the hydrogen molecules. 

image: wikimedia
The electrons are forced to travel through an external circuit to recombine with the hydrogen ions on the cathode side, where the hydrogen ions, electrons, and oxygen molecules combine to form water. The flow of electrons through the external circuit forms the electrical current needed to power a vehicle.
There probably is no magic wand or one stop solution to the urgent problem of solving the next generation of personal transportation systems, and certainly little consensus on what is the best way forward. Still, what most commentators would agree on is that there needs to be a solution. It is clear that the answer has to be the one that stops the clouds of planet-killing greenhouse gases from being released into the atmosphere either directly or indirectly; it cannot be at the expense of food crops and the creation of starvation, and it must be something that is versatile enough to be applicable to different scenarios.

So, perhaps we do have the solution. Perhaps it is a Plug-In Hybrid with a FLEX engine that has a KERS battery - a PHEVFLEXKERS. Does anyone make them?


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