Biodiesel vs Petrol - which is cleaner?

[Marm Toastsmith]

Just had a chat with a neighbour who's bought a petrol hybrid. It's a 10 year old Civic. They're starting to get quite cheap, and I thought it quite a nice thing really...although probably a bit dull to drive. She said she wanted a diesel hybrid on the basis that she could run bio in it...but had to settle for petrol... I argued that petrol was cleaner anyway, she disagreed.

 

Now, I'm pretty sure that biodiesel is cleaner than regular diesel (research and my sense of smell seems to back this up). But vs petrol? What are people's thoughts/experiences/anyone know of any relevant research? Google drew a blank for me...

 

I'm not really thinking of greenhouse gas emissions, neither am I considering sustainability, land use, etc... really just want to know about impact on air quality (in terms of what we have to breathe). So particulates, toxic stuff, etc...

[Rave]

Yes I'd say petrol is cleaner than biodiesel- the smoke out of the back of a diesel running on veg might smell reasonably pleasant but the fine particulate matter still gets into your bloodstream. Small particulates are bad whatever the source- wood burning stoves are also pretty bad for air quality. Plus I think diesels are more prone to creating nitrogen oxides during the combustion process- probably due to higher compression and consequently higher peak temps? AdBlue injection systems deal with them, if they're set up to work properly (unlike most of VW's ).

 

The cleanest car in terms of tailpipe emissions, battery and fuel cell EVs excluded, would be a petrol hybrid running on LPG. Whether it's possible to convert them, what with the complicated engine stop-start stuff etc., I don't know.

[Asimo]

Don't forget the vaste quantity of tractor Fuel and crude-oil fuelled fertiliser that is required to produce the "bio"Diesel.

[Dave_Q]

So, euro for euro petrol is slightly cleaner than diesel, ie for euro 6 the CO and PM levels are the same, but NOx is slightly higher for diesel (0.06g/km vs 0.08 for diesel)

 

But thats on pump diesel.

 

This here bit of study sez that running on bio decreases hydrocarbons, CO, and PM, but increases NOx.

 

https://www.sciencedirect.com/science/article/pii/S0378382012000021

 

As NOx is the main contributor to air quality I'd have to say the pez car is cleaner.

 

Its not really clear cut as a biodiesel car could be made to emit less nox with a calibration change, mainly retarding timing (which top level bio nutters will do on their XUDs).

 

As such the only way to get a real answer would be to do a back to back real world emissions test on the 2 cars.

[GoGently]

Hey Man,  like my car runs on sunflower oil.

[Tamworthbay]

Biodiesel isn’t the way forward, electric with decent range and quick charge is. If we all ran on biodiesel we would probably need half of Brazil to grow the stuff that makes it in.

[Marm Toastsmith]

Biodiesel isn’t the way forward, electric with decent range and quick charge is. If we all ran on biodiesel we would probably need half of Brazil to grow the stuff that makes it in.

 

Yeah, and if we all ran on electric we'd need a shitload more nuclear power plants...

 

But then as I said I'm not really interested in sustainability, land use, etc. here... really just want to know about direct impact on air quality. On that score, sure, electric is cleaner, and I agree that realistically it is going to be the way forward.

 

 

So, euro for euro petrol is slightly cleaner than diesel, ie for euro 6 the CO and PM levels are the same, but NOx is slightly higher for diesel (0.06g/km vs 0.08 for diesel)

 

But thats on pump diesel.

 

This here bit of study sez that running on bio decreases hydrocarbons, CO, and PM, but increases NOx.

 

https://www.sciencedirect.com/science/article/pii/S0378382012000021

 

As NOx is the main contributor to air quality I'd have to say the pez car is cleaner.

 

Its not really clear cut as a biodiesel car could be made to emit less nox with a calibration change, mainly retarding timing (which top level bio nutters will do on their XUDs).

 

As such the only way to get a real answer would be to do a back to back real world emissions test on the 2 cars.

 

Yeah I looked at that article. It's also the specific nature of the particulates that is an issue health wise, apparently.

 

The thing is, Euro for Euro PM levels might be broadly similar, but in the real world tired diesel engines belch black smoke. It doesn't matter what their Euro rating is... Old petrol engines are rarely as bad...

 

I reckon that black smoke is bad whether it's bio or pump diesel.

 

It's probably all moot cos they only test new cars. I'm not about to start driving a new car.

[Cavcraft]

Having found out what goes in bio-diesel, you'll have a job convincing me it's clean.

[Tamworthbay]

Yeah, and if we all ran on electric we'd need a shitload more nuclear power plants...

 

.

No we wouldn’t we would need more renewables, nuclear is dead technology, far too expensive. We need to look to the future not the past or we are fucked. The new generation of renewables are even now cheaper than the the stupid deal we are signed up for with the French nuclear supplier and keeps up self reliant, in a few years that aspect may become more important than any other consideration.

[castros_bro]

It seems the UK is not moving to renewables like some other counties. Without going into it deeply here is a couple of things.

 

Portugal has already managed to produce more renewable energy than it consumes for a complete month though there are caveats  

 

https://www.independent.co.uk/news/world/europe/portugal-renewable-energy-generated-electricity-consumption-march-greenhouse-gas-environment-a8289656.html

 

 

Other countries, some not know for their cutting edge technology, are investing big time.

 

https://www.pbs.org/video/here-comes-the-sun-1519162035/

[DodgeRover]

 

The cleanest car in terms of tailpipe emissions, battery and fuel cell EVs excluded, would be a petrol hybrid running on LPG. Whether it's possible to convert them, what with the complicated engine stop-start stuff etc., I don't know.

Yep there's a few rx400 hybrids on lpg now.

[Marm Toastsmith]

No we wouldn’t we would need more renewables, nuclear is dead technology, far too expensive. We need to look to the future not the past or we are fucked. The new generation of renewables are even now cheaper than the the stupid deal we are signed up for with the French nuclear supplier and keeps up self reliant, in a few years that aspect may become more important than any other consideration.

 

I'm with you in spirit (and buy my electricity from a renewable supplier), but as you point out we are tied in to various nuclear deals for the forseeable future and I suspect that in practice it's likely to be presented as a solution to increased electricity demands as people ditch petrol and diesel. Would be nice if not. At the end of the day it's the desire for weapons that drives the nuclear industry, and until that goes away we're probably stuck with it.

 

Thorium reactors are actually pretty interesting, potentially much safer for a number of reasons, but there hasn't been much research because you can't make bombs out of them. Worth reading up on.

 

Anyway, personally I can't see renewables alone being able to meet the increased demand...assuming we all keep driving as much as we are now, and especially if we want to reduce fossil-fuel based electricity in general. It all adds up to a shit ton of energy, and electric cars will never be truly efficient with transmission and storage losses... As I see it the only real solution long term is to use less energy.

 

In the mean time, what have we decided re Bio vs Petrol?

[Rave]

I reckon if you live in a town or city and are concerned about polluting the air in it, petrol, or better still, LPG. If you do a lot of motorway miles and want to minimise greenhouse gas emissions, bio.

 

Edit: and I'm pretty sure that nuclear weapons have little or nothing to do with the current nuclear power industry. They've had enough enriched uranium and plutonium to lay waste to the entire planet since the sixties. If new nuclear weapons are required they just recycle the material from the old ones, it doesn't go off. Tritium does, but it's not particularly difficult to make, as I understand it.

[DodgeRover]

It does go off though, there's an issue with the lack of material to use in space probes for the radioactive thermal generators as it has pretty much all decayed and no more is being produced. Will go and hit google for the details.

[Marm Toastsmith]

I reckon if you live in a town or city and are concerned about polluting the air in it, petrol, or better still, LPG. If you do a lot of motorway miles and want to minimise greenhouse gas emissions, bio.

 

Edit: and I'm pretty sure that nuclear weapons have little or nothing to do with the current nuclear power industry. They've had enough enriched uranium and plutonium to lay waste to the entire planet since the sixties. If new nuclear weapons are required they just recycle the material from the old ones, it doesn't go off. Tritium does, but it's not particularly difficult to make, as I understand it.

 

I think you're probably right re the fossil fuels. Very sensible answer and one that gives me an excuse to buy some tickets for a diesel roffle...

 

As for the nuclear stuff, hard to say for sure, I could well be wrong. Lots of lies around the industry historically, in the first place reactors were built for weapons, and the tech was driven by that, electricity was essentially a byproduct... still the reactors were presented to the public as having been built to provide a cheap source of clean power... In any case it's a shame that the technology today has been shaped by a need for enriched uranium and plutonium, when e.g. thorium reactors make more sense for power stations (at least in theory).

[forddeliveryboy]

As NOx is the main contributor to air quality I'd have to say the pez car is cleaner.

 

As such the only way to get a real answer would be to do a back to back real world emissions test on the 2 cars.

The BBC did this https://www.bbc.co.uk/news/resources/idt-sh/how_toxic_is_your_car_exhaust with interesting results, not so much that the diesel NOx was lower than the petrol but that they were much lower than expected. It seems diesels running gently (which can be at a steady 85mph) have low emissions, but a delivery driver with a full load and nailing it from one junction (or speed hump) to the next will create NOx max.

 

 

I reckon that black smoke is bad whether it's bio or pump diesel.

It is, but the worst smoke is the invisible sort, if that makes sense. Modern engines, both petrol and diesel, spewing billions of nano-particulates are lethal since they pass through our lung linings.

 

 

Taken in isolation, I reckon there's little in it between petrol and biodiesel emissions all things considered (typically, tailpipe emissions on bio-d are around two-thirds those on diesel, except for NOx). The lack of additives in plant oil fuels compared with what comes from a fuel forecourt probably skews the result for bio-d - benzene in petrol is spewed out of tailpipes, with traces of other nasties to put the boot in.

 

The interesting point is that we're perhaps fixated on exhaust emissions even now they're really low - so low that particulates from tyres, roads and other friction materials already make up over half of all road vehicle PMs. What's in them is even nastier than fuel additive packages, but people are about as interested as they were in exhausts back in 1968.

 

 

The idea we'll need a much bigger supply of electricital energy to power EVs has been sat on by people who should know. Their reckoning is somewhere between 10-20% extra. A smart grid with increased storage including V2G (and using EV power for domestic use at times of peak demand), the efficiencies gained using electric motors and so on mean the increased demand won't be as huge as you'd imagine.

[castros_bro]

The difficult part of the conundrum is trying to get information/data which can be relied on to make decisions. .   The expression "pollutant" is applied to different substances but "they are not all equal" (Quote from G Orwell).  The govmts got buggered by not understanding that   10mg/km of PM10 (diesel black smoke) is not the same as 10mg/km of NOx in terms of damage to life so the big push to stop visible smoke produces unwanted side effects, ie increase of NOx.  By having targets for reducing pollution in one area makes it easy to understand and govmts/media can say "look we are wonderful in achieving this" but if they don't understand even the slightly complex nature of what they are doing in this area then it's a facade  (and it is).

 

The complete package of pollution needs to be taken into consideration, building electric cars or PV-Solar Panels is not pollutant free but can have the effects of moving the pollution production elsewhere and a different pollution so does not register on the great CO2 reduction targets.  Even CO2 as the villein of greenhouse gas emissions is not portrayed properly, the spectrum of methane compared to CO2 means so 

 

   While carbon dioxide is typically painted as the bad boy of greenhouse gases, methane is roughly 30 times more potent as a heat-trapping gas. New research in the journal Nature indicates that for each degree that  Earth's temperature rises, the amount of methane entering the atmosphere from microorganisms dwelling in lake sediment and freshwater wetlands -- the primary sources of the gas -- will increase several times. As temperatures rise, the relative increase of methane emissions will outpace that of carbon dioxide from these sources, the researchers report.

 

so just taking a view on CO2 then basing reduction targets on this missed the real target which is far more complex.

[Junkman]

Biodiesel does nothing to improve© The Climate.

Don't only avoid that shit, boycott it!

[Marm Toastsmith]

Interesting comments guys. I enjoyed that BBC article linked to although it's a shame it failed to accurately compare particulate output between the diesel and the petrol. Would be interesting to look at the broader results from the organisation that did the testing. In the end a depressing (if not surprising) conclusion - i.e. new cars are built to pass the tests rather than actually be less polluting.

 

On a side note it's also a shame that the idea of making vehicles more efficient by saving weight, improving aerodynamics, etc... seems to have gone out of fashion.

 

My gut feeling is that particulates are still a big issue, especially in cities, and especially against a backdrop of a high particulate concentration in the air from building work, demolition, tyres, brakes, Saharan dust, etc... And long term the impacts on e.g. lung cancer are perhaps harder to predict and measure.

 

Basically, it still comes down to drive less, IMHO. But I'm encouraged that the additional power required for EVs is not as high as I'd assumed.

[Talbot]

The fuel that has not been mentioned so far is Methane, specifically CNG. This is absolutely the cleanest-burning fuel you can use in a car, as it's such a lightweight and small molecule that the combustion is as complete as it possibly can be, thereby ensuring that the exhaust emissions are all gasses, with minimal particulate matter generated. The PM's generated by CNG are almost unmeasureable. Most of them come from inadvertent combustion of the engine lubricating oil.

 

It's just a shame that there is bugger all infrastructure for CNG in the UK. It exists to some extent on the continent, and has been used for some public service vehicles in the UK, but it's very very limited.

 

There is also the option to use Bio-Methane, generated from BioGas, which is a product of anaerobic digestion. Completely renewable and is actually an excellent thing, as ensuring that all digestable material is degraded in a digester, and the methane generated then burned actually lowers overall emission to the environment.

 

The infrastructure *could* be put in place to do this.

[Tadhg Tiogar]

The fuel that has not been mentioned so far is Methane....

 

I'm sure we have plenty of livestock that can help with the supply.... Maybe a good advert for increased vegetarianism?

[castros_bro]

The fuel that has not been mentioned so far is Methane, specifically CNG. This is absolutely the cleanest-burning fuel you can use in a car, as it's such a lightweight and small molecule that the combustion is as complete as it possibly can be, thereby ensuring that the exhaust emissions are all gasses, with minimal particulate matter generated. The PM's generated by CNG are almost unmeasureable. Most of them come from inadvertent combustion of the engine lubricating oil.

 

It's just a shame that there is bugger all infrastructure for CNG in the UK. It exists to some extent on the continent, and has been used for some public service vehicles in the UK, but it's very very limited.

 

There is also the option to use Bio-Methane, generated from BioGas, which is a product of anaerobic digestion. Completely renewable and is actually an excellent thing, as ensuring that all digestable material is degraded in a digester, and the methane generated then burned actually lowers overall emission to the environment.

 

The infrastructure *could* be put in place to do this.

 

However,  

 

carbon dioxide is typically painted as the bad boy of greenhouse gases, methane is roughly 30 times more potent

 

also Hydrogen is a clean burn without any producing any CO2 and can be produced n several ways including using excess electricity from renewables when the grid doesn’t need it all. 

[Talbot]

carbon dioxide is typically painted as the bad boy of greenhouse gases, methane is roughly 30 times more potent

What's your point here? If Methane is captured and burned, then it's no longer Methane. If bio-degrading material is left out in the open, said methane ends up in the atmosphere. If the bio-digestion is done in a digester, then the Methane is captured and can be burned, meaning the methane is not relased to the atmosphere, only the CO2 from it's combustion. Hence my point above that CNG from BioDigestion is environmentally beneficial (as opposed to the vast majority of other technologies which are merely environmentally-slightly-less-damaging)

 

also Hydrogen is a clean burn without any producing any CO2 and can be produced n several ways including using excess electricity from renewables when the grid doesn’t need it all.

There isn't any excess electricity from renewables:

 

https://www.gridwatch.templar.co.uk/ and http://gridwatch.co.uk/ both show the same information, but each have better visualisations of some aspects of the national grid. All the Solar and Wind (and BioMass and small amounts of Bio-methane) that is generated in the UK doesn't even cover base load. We are still heavily reliant on Nuclear and CCGT, with a bit of Coal, hydro and bought-in electric from France added to the Mix.

 

What those sites do show, however, is that there is still a massive difference between night-time load and daytime load. Economy 7 storage heating was devised in an attempt to rectify this, but it still makes very little difference.

 

Given that it would be beneficial for the UK Electrical load to be less variable, it would be a very good thing to have lots of electric vehicles plugged in and charging on an Economy-7 style tarriff. This would balance the grid a bit better, and is the ideal time to be charging vehicles. What's needed is cheaper electricity tarriffs which cover the overnight period (E7 is not the bargain it used to be) and electric vehicles plugged in overnight, the charging of which is controlled by turning on or off seperate circuits (exactly how E7 works)

 

Again, the infrastructure is there, but just not implemented.

[forddeliveryboy]

The common sense way forwards for our energy requirements is to

 

1/ reduce demand - our building stock radiates energy in biblical proportions through poor insulation for six months of the year, something often overlooked.

 

2/ use EVs wherever possible, market economics will soon dictate this.

 

3/ build Grid storage and lots of it.

 

4/ continue building loads of renewable energy supplies (market economics again).

 

5/ use excess RE to synthesise propane (it's fairly widely accepted that although it burns marginally less cleanly than methane, methane is such a powerful GG that the inevitable spills rule it out), which can be stored for space heating and used in ICEs.

 

6/ look back in disbelief that we were still setting fire to things to make energy in the early 21st century.

 

 

Some of this will happen, but you've only to observe how the Conservative government continue to pump out money into subsidizing both the dinosaurs of both fossil fuel and nuclear to see how these still enormously powerful bodies may continue to generally make a mess of our descendents' lives.

 

It's only because of the already huge influence of the oil barons early in the last century that the ICE took off as it did - to those used to the relative silence, smoothness and easy power of steam (and electric power) it was a big step backwards on everything other than price.

[richardthestag]

every single taxi in High Wycombeshite is a 'kin Prius on LPG

 

LPG emissions a way lower than same engine running on pez 

 

PLUS as a by product / waste product there is a chance that the carbon footprint is occupied by end product of refinery etc

 

So on that ^ basis oil crops are grown on land that phood crops should be grown on, but because we buy food from overseas because cheaper etc then redundant land* (not used for Golfer) is for sunflowers. Should carbon footprint on a tesblow BLT sandwich that travels 1000s of miles before consumption be offset against biodizzle? 

 

when Mrs thestag pointed out that phood was expensive in farmers market I responded "nope! it is normally priced, spanish grown tomatos are cheaper (and tasteless) but are they?" blah blah 

 

sort out hydrogen/leccy/lpg and reduce reliance on heavy oil and refined fossil fuels.

[Tadhg Tiogar]

….oil crops are grown on land that phood crops should be grown on, but because we buy food from overseas because cheaper etc then redundant land* (not used for Golfer) is for sunflowers housing development.....

 

EFA

 

...and of course, once the arable land is given over to development, you'll never get it back, so you become ever-more reliant on cheap overseas-imported food, which in turn may not stay cheap forever....

 

Are we not holding ourselves to ransom in some way?

[forddeliveryboy]

The only possibility for any biofuel is that made with algae or similar, using land is nuts, even waste land for jatropha or similar.

 

Equally, planting PV arrays to the exclusion of any other land use is crazy, just another sign govt incentives are poorly matched to reality. All the while vast factory and warehouse roofs are empty. Do farmers continue to receive their other raft of subsidies on this land, I wonder?

 

 

Approaching 100% RE is inevitable, it's just likely that we'll take longer than most to catch on given the cosiness our nuclear and FF industries enjoy with Westminster.

 

https://www.renewableenergyworld.com/articles/2016/10/why-everyone-is-talking-about-baseload-power.html

https://www.skepticalscience.com/print.php?r=374

 

The crunch point comes with an extended period of high pressure across Northern Europe in the first three months of the year - freezing fog. It happens roughly one year in ten, I think a reserve of coal/oil should be used in these situations with appropriate stack scrubbing if synthesised LPG stores aren't sufficient.

 

 

PS thorough recycling of an old car's plastics and circuit boards would have a massive effect on TheEnvironment.

[Talbot]

The real problem is this:

 

 

Utterly unsustainable.

[Talbot]

methane is such a powerful GG that the inevitable spills rule it out)

The massive and widespread use of natural gas would suggest that statement is wrong.

 

That said, the amount of natural gas that is currently intentionally vented to atmosphere is absolutely criminal, and simply ensuring that all methane captured is burned rather than released would make a difference in the concentration of methane in the atmosphere.

[somewhatfoolish]

I'm with you in spirit (and buy my electricity from a renewable supplier), but as you point out we are tied in to various nuclear deals for the forseeable future and I suspect that in practice it's likely to be presented as a solution to increased electricity demands as people ditch petrol and diesel. Would be nice if not. At the end of the day it's the desire for weapons that drives the nuclear industry, and until that goes away we're probably stuck with it.

 

Thorium reactors are actually pretty interesting, potentially much safer for a number of reasons, but there hasn't been much research because you can't make bombs out of them. Worth reading up on.

It's impossible to make weapons grade fissile material in a nuclear power station without lighting the invisible neon sign alerting the fun police at the IAEA that you're being a naughty boy. The UK finished making weapons grade material officially in the 1970s, although I suspect we mostly stopped in the 1960s as it's an expensive business. Thorium is a very interesting possibility, the prospect of reliable and plentiful energy for thousands of years is enticing; the technology remains to be developed though, steps are being made in several places, Canada, India and China being the obvious ones with others like Norway, the Czech republic being in the pack. Moltex were briefly based in the UK but their experience with the UK Office of Nuclear Regulation caused them to get on the plane to Canuckistan.

 

Anyway, personally I can't see renewables alone being able to meet the increased demand...assuming we all keep driving as much as we are now, and especially if we want to reduce fossil-fuel based electricity in general. It all adds up to a shit ton of energy, and electric cars will never be truly efficient with transmission and storage losses... As I see it the only real solution long term is to use less energy.

 

Every major advance mankind has made since Ugg mastered the art of fire has been predicated on increasing intensity of energy use and use of more dense energy sources; I don't expect this trend to change any time soon. Individual technologies improve and become more efficient but new uses for energy emerge, along with an expanding population mean that the world deficit in energy generation is not going away. The late Hans Rosling did a good pocket guide to global energy use and needs, it's on yootoob.