Friday, 12 April 2013

1250 Kms on a single 50 litre tank of Diesel! - Reducing Carbon Impact

One of the largest carbon outputs we create as individuals, is due to our need for transportation. The graphic below from identifies that personal transportation is the largest contributor to personal carbon output next to recreation and leisure and represents 10% of our overall total carbon output.

My wife and I do not do a lot of air travel and we also do not drive long distances. Her work is only 10 km away and the majority of my work is also close by. My vehicle is 22 years old and my wife’s is 9 year old, so we probably buck the trend there as well (would lower the carbon in car manufacturing percentage). We also are home bodies, so I would estimate that our recreation and leisure is a lower percentage. In fact, I would imagine that our total output is much lower than the North American average due to the lifestyle we live and the efforts already in place in our household to reduce our impact.

Breakdown of a typical individual's carbon footprint. (Source: Carbon Footprint)
My vehicle, a 1991 Toyota Hilux Diesel Right-Hand Drive, used to produce 22.2 pounds of carbon per gallon of diesel burned (Ref 1). As I typically travel approximately 7000 miles per year and was only getting 15 MPG(USG), I was contributing a whopping 5.2 tons (10,400 lbs) of carbon to the atmosphere every year.

Well, I am pleased to advise that I have made a major shift in my output and am driving a vehicle I could almost consider carbon free.

You see, I have converted the Hilux to a duel fuel system that allows me to burn vegetable oil. But not just any vegetable oil, I am able to burn USED vegetable oil (Waste Vegetable Oil – WVO). I converted the vehicle last summer, but for technical reasons and oil supply, I have just finished my first session where I was able to fully utilize the WVO system. In typical urban driving (limited highway and no long trips), I was able to travel 1250 km before having to refill the diesel tank.

Some may ask why I don’t just burn the WVO. Well the reason is because the WVO must be heated to achieve the right viscosity before it can be burned in the engine. I have elected to heat the oil using the engine coolant system as I have a weak alternator that would not have stood up to electric resistance heating of the oil flow. Using the coolant at the heat source requires me to start the vehicle on diesel and drive until the coolant temperature is high enough (I wait till the thermostat opens and I see the temp on the dash go to normal operating temps) before switching to the WVO tank. (I have the stock diesel tank and an auxiliary WVO tank) and start burning only WVO. I can leave it on the WVO setting throughout the day as long as the vehicle will not sit for more than 2 hours. If I will be stationary for more than 2 hours or am back home for the day, I then need to switch back to Diesel to purge the WVO out of the engines injector system so that when it is cold the next day, I will not have thick congealed WVO in the engine. I usually start this purge about 2-3 km from home.

Engine compartment contains the heated WVO filter, a 30 plate heat exchanger, and two solenoid valves.
The system has worked well over the last 3 months and is well proven in the industry. In Europe, countries like Germany have formalized the ‘fuel’ and tax it like any other. All of the research I did, showed that the buring of WVO is safe as long as the fuel is properly processed to remove water and particulates and is adequately heated before burning.

For the interim, I am buying my WVO from a local ‘producer’ who collects the oil from local restaurants on the Sunshine Coast and then processes it. This involves letting the oil settle (removes most of the particulate), running the oil through a centrifuge (removes any moisture), and then running the oil through a series of filters down to 10 microns. Once the new house is completed, I will start producing the oil myself. At 50¢ per litre, I am saving 80-90¢ per litre or around $1500 per year. The system only cost $1000 in parts, so I am ahead of the game within about 8 months of typical driving.

So, what does this all mean to my personal output?

Based on 777 miles (1250 km) per 14 gals of diesel burned, my carbon output for just the diesel per year would be reduced down to 2800 lbs or a 73% reduction from my preconversion contributions.

But wait, we are not finished. Vegetable oil as a plant material is often considered carbon neutral as it is just releasing the carbon it already sequestered from the atmosphere. I question this statement, as the growing and harvesting of the seed crop that creates the oil is still a very carbon heavy activity. I would agree that vegetable oil as a food item has the lowest carbon output by a very significant margin when used as a fuel in comparison with all other fuel forms including electricity from the North American Grid. So if I was burning new, unused, vegetable oil, I would need to calculate some contribution to my carbon output.

But I am using used oil, so I am reusing a very low carbon product for the second time. I am reusing something that would otherwise be thrown away. This means that I am receiving a carbon credit in some fashion. I have been unable to find a logical resource that identifies how to calculate this credit. You would need to reduce the credit by the energy it takes to collect and process the waste oil into WVO, but what should the initial credit be? 100% of the carbon output of burning diesel, as this is the fuel being offset? 100% of the carbon created by growing, harvesting, and processing the vegetable oil?

What ever credit is used, you can see that it would quickly take my 73% reduction and increase it quickly to a point approaching 100% or Carbon Neutral.

Even at a 73% reduction however, assuming the WVO comes out neutral (no credit or contribution), this is still a feat I am very proud of. This has been an action that has significantly lowered my personal contribution to this planet and will probably represent the single largest action and carbon reduction I will ever make.

Filling Up Auxiliary WVO Tank in Cargo bay of vehicle

WVO Storage Tank – Can hold up to 1000 liters of Waste Vegetable Oil  

Time for a fill-up - My supplier is delivering another 400 liters
Note: I can provide specifics of conversion for any interested parties. Just leave a comment below with your email address.

References: (1) &