I only do around 2000 miles per year by car. To further reduce carbon emissions and air pollution I’ve been filling up my Golf Tdi mk4 with recycled food oil biodiesel. Crops grown for Biofuels compete with food production for land and water, so can they only be a stop-gap until electric, Hydrogen and other truly renewable fuels take over. However bio-fuels should not be completely dismissed as they bring some environmental benefits.
In use I’ve found no loss of power and the engine runs as smoothly as before. Because biodiesel contains more Oxygen and can clean deposits from your fuel system, it’s recommended to change the fuel filter after the first 1000 miles. My 2002 Golf Tdi is well suited to running 100% biodiesel. Cars from around 2004 usually require a 50/50 blend to protect the particulate filter, but with an older diesel I can use either bio or mineral diesel as needed, the engine management system adapts to these in any proportions without modification. A major selling point of biodiesel is also price, around 30% cheaper at 86p/litre.
Diesel engines can use fuel from a wide range of sources – I know someone who poured 20 litres of Sunflower Oil from Lidl into his tank, then added 20 Litres of mineral diesel, and his van ran perfectly. But modern turbo diesels have complicated engines so I buy EN14214 (EU standard for biodiesel) because having something properly filtered and made to a specific standard should minimise risk of damage.
Recycled biodiesel does have a slight food-oil smell, which is only as strong as the mineral diesel smell I was getting before (and so far I’ve been free of cravings to stop at the nearest chippy as I’ve been driving along). The only real downside is that my car does give off some white smoke (unburnt diesel, likely caused by a leaking injector seal) on starting if the car hasn’t been used for a few days. This is more visible with biodiesel, as it’s slightly thicker than mineral diesel.
The good and bad of biodiesel
Bio-fuel useage is quite low in the UK compared to some European countries, for example 85% of Stockholm’s buses run on biodiesel. More widespread adoption of bio-fuels has been tarnished by the misguided addition of bio-fuel to all UK petrol/diesel around 10 years ago. This created an instant demand, and the horrifying effect of developing nations ripping up rainforest and replacing it with monocultural palm oil plantations to power our school runs and weekly shops1. Deforestation also meant some Palm oil biodiesel may have created 3x more carbon than mineral diesel. Even the sustainability of German made Rape Seed biodiesel on existing agricultural land is lower than was originally thought, possibly as low as 30% sustainability.2
However biodiesel made from recycled oil shouldn’t contribute to deforestation and 30% is better than 0% sustainability. Apart from the provenance issue, one probably reason the UK government hasn’t promoted biodiesel is because it produces more Nitrous Oxides (NOx) up 8% according to a 2016 Defra study3, and NOx is a key measure of EU air quality standards. However the same report estimates Carbon Monoxide and particulate matter are lowered by a third, and Hydrocarbons by two thirds, which is a significant pollution reduction overall.
Although UK government policy from 2001 was to promote diesel, they’re now considering toxin taxes to discourage diesel use. A workmate angrily told me the government lied to us because they knew diesel was dirty. But ministers have admitted they made a mistake and governments rarely take decisions in isolation. I suspect the government consulted the motor industry who would have favoured more diesel because few manufacturers had invested in hybrid and alternative fueled vehicles, but they all knew how to make diesel engines. Diesel is far more efficient than petrol per mile, leading the government to believe they had a quick fix for meeting Kyoto protocol Carbon emission targets. They also believed better engine design and exhaust filtering would create a new generation of ‘clean diesel’ – something we know doesn’t work in the real world.
Maybe time to go electric
It would be great if in a few years time I can preserve some of the energy invested in building and maintaining my car by replacing its diesel engine with an electric motor and batteries, as one garage is doing in Mexico city.
However I’m sure the motor lobby will site safety, and lobby the UK government for scrapage schemes and make buying entirely new vehicles the only option.
If you’re running a business with mostly local mileage, an electric van is a viable option now. I know of one landscape gardening business who ditched their unreliable and expensive diesel van for an all electric Nissan e-NV200. Range is just over 100 miles, so it needs charging every 2-3 days. But per mile fuel costs are less than half the diesel fuel. It always starts, is road tax free and the purchase qualified for a 35% grant from the government. It should also be good for the long-term as the electric drivetrain has fewer moving parts than any petrol or diesel engine to need expensive maintenance once it’s out of waranty.
There is more to gain than just meeting targets with cleaner vehicles. Friends of mine recently visited Tokyo and were surprised by how quiet and clean a city of 13 million people can be, due to high air quality standards and the large number of hybrid and electric vehicles – even on busy streets they could smell flowers by the roadside. The technology is just around the corner to cut pollutants and in so doing make our cities much more enjoyable places to live.