Diesel might be a good transition fuel as we move towards electric cars. I read somewhere that the analogy is that diesel engines now are around where gas engines were in the 80's in terms of the tech in them. I'd love to see a boom in diesel tech, it's already getting good.
Hmm. That's probably selling diesels a little short, or overstating their potential. Current diesels, technology-wise, are easily on par with current petrols.
Mid- to long-term, I see two problems with diesels in cars.
1) They're going to get very expensive. Several automakers in Europe - where diesels are most popular - are dropping diesels from their smaller cars as it's just not worth the trade-off any more. They were already a little more expensive to make but tighter emissions regulations mean they're costing a fortune to build to modern standards. That cost has to be passed on to the consumer, and in a small car, even one that does say 80 mpg, it just isn't worth it - since a small petrol car can do 65 mpg and cost $2,000 less per car to build.
2) As diesel becomes ever more important in goods transport, particularly in huge markets like the U.S, Russia, China, India etc, it's going to put a bit of a squeeze on the market for the fuel. I've heard rumours (and I stress
rumours, as in "I heard it, haven't corroborated it, and have no sources to call upon") that in as little as 15-20 years time the price of diesel is going to rise much more steeply than that of petrol, and may even be rationed.
I'm a bit "meh" on diesels anyway (for cars at least - the diesel aircraft Keef mentioned above seem pretty cool), from both a petrolhead and an environmental standpoint.
On the former, I've never driven a diesel that sounded as good as a petrol and few are particularly responsive to throttle inputs. Some of this is down to modern throttle mapping which makes diesels feel punchy at about a third throttle but then they rarely continue that punch when you really put your foot down. Even the fast ones I've driven are like this - yet in the equivalent petrol, the harder you go the better they get.
Then of course there are all the added complications the average diesel has - high-pressure fuel rails, urea injection (in some), particulate filters, dual-mass flywheels... a good ol' Mercedes mechanical injection diesel from the 80s might go on forever, but some of the modern ones worry me from a longevity standpoint.
On the latter, they simply aren't as clean as petrols. And I don't just mean CO2*, but more noticeable stuff like particulate matter and oxides of nitrogen - responsible for asthma, heart disease, smog, those sort of things. I live in a country where diesels are unfortunately very popular, and I don't like breathing that crap in, frankly.
*
CO2 is an odd one with diesels. Diesel has a higher energy content than petrol, so produces more CO2 per unit of volume. But they tend to be more economical, so overall CO2 is lower on a window sticker. But a 40 mpg petrol produces less CO2 than a 40 mpg diesel.
