Are Diesels "Green"?

[BSRU]

By accident caught a few minutes of Watchdog last night, some guy complaing about his Fiat 500 diesel.

It was very strange to hear that he had bought it as a city car, for small journeys and that is was a "green", environmentally friendly, car. Apparently new diesel cars have a special filter to enable them to meet EU emission targets but this makes them unsuitable for just short journeys.

Since when have diesels been considered "green"?
A recent news item from Bristol stated that nitrogen dioxide levels were way over designated EU safe levels, the main cause being the increase in diesel vehicles and the only solution to solve the problem is to reduce the number of diesel vehicles.

 

[snorri]

"Green" means just what you want it to mean.

 

[ThePainInSpain]

Wasn't it only a few years ago that we were encouraged to buy diesels in preference to petrol engines. They were greener and far more efficient. Even the price of diesel fuel was considerably lower than petrol.

Now, well what a surprise, the reverse is supposedly true.

 

[XmisterIS]

Hydrogen Fuel Cells for the win, IMHO!

 

[User482]

Diesels, on average, emit less CO2 than petrol, but higher levels of nitrogen dioxide and particulates.

Regarding the article about Bristol - all major UK cities have the same problem, and have done for many years. It's odd that the BBC has just realised! That said, they're greatly exaggerating: only one monitoring site in Bristol exceeded the annual mean objective for more than 12 hours, in the whole of 2010.

"Green" cars are simply those which are driven less...

 

[User482]

Hydrogen Fuel Cells for the win, IMHO!

They're good for local air quality, but making the hydrogen requires enormous amounts of energy.

 

[BSRU]

Hydrogen Fuel Cells for the win, IMHO!

Swindon currently has the only hydrogen refuelling station in the country.

 

[Night Train]

'Green' is a catch all meaningless term that seems to carry more weight then it should.

My diesel car is green, metalic emerald green. However, it does produce less CO2 then many cars and it also does a lot more miles per gallon of fuel then the manufacturer suggests.

I think if you want a clean diesel then get a euro 6 lorry.

 

[Hacienda71]

If you use bio diesel in your car then it is almost non reliant on fossil fuels. Although riding a carbon bike could actually take fossilized carbon out of atmospheric circulation........... so you need to go out and buy a Pinarello Dogma

 

[XmisterIS]

They're good for local air quality, but making the hydrogen requires enormous amounts of energy.

True, but then I'm thinking of the sun (vast amounts of energy) + the sea (vast amounts of water and energy) = easily derived hydrogen ... All we need now is some bright spark to design a solar-powered "hydrogen mine" that can be floated out to sea and sit there converting water to hydrogen and oxygen all day long, powered only by the sun and wave action. It could be as big as you please if it is floated out into the Atlantic somewhere where it won't be a nuisance to shipping.

And the oxygen released into the atmosphere won't be a problem, the hydrogen gets burned in the car, so it balances the oxygen out.

At least that's how it works in my naive little world - I sure there is some kind of physics gremlin that says "Oh! No, you can't do that!"

 

[Night Train]

The problem with bio diesel is that, with increasing use, food crop land is being turned over to fuel crops.
It would be better if food crop waste was used but the lower grade fuel isn't as desirable to the oil companies.

I tried B100 on my car and while it worked with virgin veg oil it, used oil nearly destroyed the fuel system.
The fuel economy was also much poorer.

 

[User482]

True, but then I'm thinking of the sun (vast amounts of energy) + the sea (vast amounts of water and energy) = easily derived hydrogen ... All we need now is some bright spark to design a solar-powered "hydrogen mine" that can be floated out to sea and sit there converting water to hydrogen and oxygen all day long, powered only by the sun and wave action. It could be as big as you please if it is floated out into the Atlantic somewhere where it won't be a nuisance to shipping.

The difficulty is that there's no plausible scenario in which we could harness enough renewable energy to replace fossil fuels for transport, industry and domestic use. The unpalatable truth is that we need to use much, much less.

 

[Night Train]

True, but then I'm thinking of the sun (vast amounts of energy) + the sea (vast amounts of water and energy) = easily derived hydrogen ... All we need now is some bright spark to design a solar-powered "hydrogen mine" that can be floated out to sea and sit there converting water to hydrogen and oxygen all day long, powered only by the sun and wave action. It could be as big as you please if it is floated out into the Atlantic somewhere where it won't be a nuisance to shipping.

You'd need to start with making efficient solar photovoltaic panels first.
Then there is the problem of transporting it. You don't get much hydrogen in a tanker and compressing it to make it more energy dense take more energy.
Wouldn't like to see a shipwreck full of hydrogen.

Mid Pacific might be less busy then mid Atlantic.

 

[Night Train]

The difficulty is that there's no plausible scenario in which we could harness enough renewable energy to replace fossil fuels for transport, industry and domestic use. The unpalatable truth is that we need to use much, much less.

That's why we should be cycling more on old steel bikes rather then buying new ones made with exotic materials.

 

[XmisterIS]

You'd need to start with making efficient solar photovoltaic panels first.
Then there is the problem of transporting it. You don't get much hydrogen in a tanker and compressing it to make it more energy dense take more energy.
Wouldn't like to see a shipwreck full of hydrogen.

Mid Pacific might be less busy then mid Atlantic.

Yeahbutt ... worrabout just transporting it in a pipeline layed along the seabed? No need to compress it then. And I recall seeing something on the TV a few years ago about a metal matrix that could hold hydrogen in a very dense form, without the need to compress it - you just pump hydrogen into the matrix and it binds chemically to it - pass a current through it to release the hydrogen.

I don't know how advanced that technology is now, though.