Yes friends, I have been head down, bum up and studying for an assignment that had a deadline of Friday midnight. I made the deadline with a few hours to spare and it took much longer than anticipated. The course is a Diploma of Carbon Management (DoCM), which I may have mentioned before. It runs from February to November. You can read more about the course at this link to the Swinburne University of Technology.
The last assignment was a cost benefit analysis for carbon emissions abatement. In English, the cost of cutting emissions. I had to prepare analysis on four potential abatement projects for my case study company. Two projects were about fuel switching from Unleaded (ULP) to Liquid Petroleum Gas (LPG) and from Unleaded to E10 (90% ULP + 10% Ethanol) fuel. I discovered a few things that may bust some myths out there regarding fuel emissions.
I learnt that litre on litre, unleaded petrol is more energy dense than either E10 and LPG. To get the true value for either of these replacement fuels, there is quite a bit of maths involved. Firstly you have to convert unleaded fuel to GigaJoules (GJ) to get the energy value. Then you have to calculate the equivalent energy value for the other two fuels. Yes my brain hurt at this stage as well. Let me demonstrate with 10,000 litres of petrol which will take my hybrid car > 175,000 km.
10,000 litres of ULP = 342 GJ of energy. Now to get the equivalent energy to make your car go the same distance, you would need 13053.4 litres of LPG which is less energy dense (and a fuel conversion of course), or 10332.3 litres of E10 which is also less energy dense that ULP.
Now that may seem inefficient, however there are less carbon emissions given off when LPG and E10 are burnt in your engine. As I said, even though the volumes of fuel differ, it will still drive you the same distance due to equivalent energy content. Here are the comparisons for all three fuels and their emissions in metric tonnes of carbon dioxide equivalents (t CO₂-e);
10,000 litres of ULP = 22.8 t CO₂-e
13053.4 litres of LPG = 20.5 t CO₂-e
10332.3 litres of E10 = 20.6 t CO₂-e
So as you can see, by using these alternate fuels to normal ULP you do reduce your emissions by about 10% from the tail pipe. What about the cost I here you say?
Well based on today's average prices for the same energy content (it is all about the energy) here are the results;
10,000 litres of ULP @ A$1.45 = $14,500
13,053.4 litres of LPG @ A$0.55 = $7,179.30 (almost half the cost of ULP energy wise)
10332.3 litres of E10 @ A$1.42 = $14,671.86
So what does that mean? Well, it means that even though E10 may look cheaper at the pump, it cost in this example, $171.86 more to drive the same distance, even though you are lowering your emissions by 10%. On the other hand, LPG still cuts emissions by 10%, but cost $7,320.70 less to drive the same distance. LPG wins hands down, even if you throw in the one off cost of between $2500-$4000 to convert your vehicle to this fuel. This investment would pay itself off within a couple of years.
So if you think you are helping to reduce your personal carbon footprint by using LPG and E10, you can rest assured that you are, however E10 does not make sense financially for just a 10% reduction unless of course you are willing to pay the premium for this reduction as I do. It would be better to catch public transport and make an even bigger difference for far less cost as I also do. I drive the 7km to the train station and catch the train the rest of the 37km to work each day. You and I could even buy a nice bike for the difference it costs us. Then we would save a fortune in emissions and fuel costs!
I hope this post has made sense (kinda anyway), and that you have learn a little something today about energy content of transportation fuels. Just remember, its all about the Joules!