Some interesting reflections on the use of "Diesel" in recent debates. Considerable negative press around particulates and NOx. There is no doubt that fumes and particulates can harm the lungs, and that we still do not fully understand the impacts of these. However, diesel engines are very efficient and power the worlds transportation, whether it be marine engines, train traction units or HGV. The unit fuel consumption per item delivered is considerably lower than that of petrol, even for road transportation. Because diesel involves less refining, the production costs vs. petrol are also lower, and thus the impact on the carbon footprint. The point here is to look at diesel from a "Lean" perspective, i.e the value add quotient.
I am therefore glad to see that the debate is moving away from diesel vs. petrol, to a different question. Should we be using diesel for road cars ? There have been recent improvements with AdBlue and filtration, but these are really "bolt-ons", not fundamental improvements. With engine development for both diesel and petrol cars, we are getting closer to the ultimate theoretical thermodynamic efficiency. The recent development of the combustion chamber for the Mercedes F1 car is a step forward. We should not lose the impetus for sustainable fuels, even if they may be less thermodynamically efficient. It is also good to see that in the Netherlands they are powering their electric trains with wind turbines . Gas turbines are being used for ships, and huge LNG tankers are using their cargo to fuel the tankers. The fuel bleed keeps the cargo at temperatures to ensure it stays as a liquid. This is another great example of "Lean" thinking. Until we have alternative fuels cracked, we will have to accept diesel is an efficient fuel for mass transportation of goods, and people.