# When and why did diesel fuel get so cheap? **URL:** \ **Category:** Factual Questions\ **Created:** [July 20, 2015, 9:51pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731 "2015-07-20T21:51:02Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Greg\_Charles](https://avatars.discourse-cdn.com/v4/letter/g/839c29/32.png) [@Greg\_Charles](https://boards.straightdope.com/u/Greg_Charles)\ **Post date:** [July 20, 2015, 9:51pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/1 "2015-07-20T21:51:02Z")
I remember not so long ago that diesel fuel was marginally more expensive than regular unleaded. Now it seems to be fully $1.00 per gallon less, at least at gas stations in my area. Why the big change? ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 20, 2015, 10:13pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/2 "2015-07-20T22:13:15Z")
That’s apparently a California thing. According to the U.S. Energy Information Administration, diesel is running about 10 cents cheaper than gasoline nationwide, this week. A month ago it was only 4 cents cheaper. So the trend has been downward for diesel. In California, diesel on average costs $3.11 per gallon where gasoline averages $3.95 per gallon. On the west coast, without including California, the average for diesel is $2.87 and gasoline is $3.15. Nationwide, gasoline is $2.88 and diesel is $2.78. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [July 20, 2015, 10:14pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/3 "2015-07-20T22:14:09Z")
Even though the price of crude oil has crashed, refinery issues in California have created a bottleneck on gasoline supply. With diesel, that’s not a big deal because they can import it from other states but they can’t with gasoline because of the unique additive blend required by the state government. ---
**Author:** ![Doug\_K](https://avatars.discourse-cdn.com/v4/letter/d/b5ac83/32.png) [@Doug\_K](https://boards.straightdope.com/u/Doug_K)\ **Post date:** [July 20, 2015, 10:18pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/4 "2015-07-20T22:18:52Z")
I’m trying to remember when diesel got to be more expensive. In the 80s and 90s, diesel was always 10 percent or so less than unleaded. ---
**Author:** ![DinoR](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dinor/32/2821_2.png) [@DinoR](https://boards.straightdope.com/u/DinoR)\ **Post date:** [July 20, 2015, 11:04pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/5 "2015-07-20T23:04:36Z")
> [@Doug\_K](#): > > I’m trying to remember when diesel got to be more expensive. In the 80s and 90s, diesel was always 10 percent or so less than unleaded. In 2006, the US implemented [ULSD rules](https://en.wikipedia.org/wiki/Ultra-low-sulfur_diesel) (Ultra Low Sulfur Diesel). From the linked wiki page > [@](#): > > The transition to ULSD is not without substantial costs. The US Government has estimated that pump prices for diesel fuel will increase between .05 and .25 per gallon as a result of the transition. And, according to the American Petroleum Institute, the domestic refining industry has invested over $8 Billion to comply with the new regulations. That is an explanation for at least part of the shift. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [July 21, 2015, 12:08am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/6 "2015-07-21T00:08:51Z")
diesel is $0.10 or so more per gal. than regular, at least in Michigan. ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [July 21, 2015, 2:02am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/7 "2015-07-21T02:02:13Z")
I live in CA and have a diesel. I started a related thread, which never really got much of an answer, about why the price of diesel is so variable compared to gasoline. There are times when one station will have it priced above premium while a nearby station will have it well below regular. I believe it was mentioned that diesel tends to be more expensive than gasoline because most of the oil refined in the U.S. is “sweeter” and contains less of the stuff used to make diesel. I’m probably mangling that explanation and anyway I’m not sure how relevant it is to the current prices, which seem to be generally low. ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [July 21, 2015, 2:18am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/8 "2015-07-21T02:18:30Z")
Diesel is way more expensive than regular in Arizona. Regular is $2.43 a gallon while diesel is $2.69. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [July 21, 2015, 2:36am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/9 "2015-07-21T02:36:38Z")
There never seems to be a correlation. Sometimes diesel is more expensive, and some times it’s less expensive. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 21, 2015, 3:10am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/10 "2015-07-21T03:10:57Z")
> [@cochrane](#): > > Diesel is way more expensive than regular in Arizona. Regular is $2.43 a gallon while diesel is $2.69. Not near me. Diesel is at least 10¢/gallon cheaper these days. Which really ticks me off, because for all the years I had an F-350 Diesel, it was substantially more expensive. ---
**Author:** ![48Willys](https://avatars.discourse-cdn.com/v4/letter/4/db5fbb/32.png) [@48Willys](https://boards.straightdope.com/u/48Willys)\ **Post date:** [July 21, 2015, 8:16am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/11 "2015-07-21T08:16:24Z")
Some of the cost fluctuation comes from winter blend vs summer blend in diesel. Right now diesel distributors are supplying the summer blend, which, around here, is around $0.85 a gallon cheaper then the winter blend. In cold temperatures, diesel fuel flows like honey instead of flowing like very thin 5wt oil. The fuel pump is not be able to deliver it to the injectors. The injectors can not atomize it. The engine dies & can not be restarted. Truckers hate it when that happens. They could freeze to death. The solution is to have two blends of diesel fuel, one for summer & one for winter. The winter blend has to have additives that address the issue of diesel jelling at low temperatures. It costs more to make the winter blend. That cost is passed on to the users. ---
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [July 21, 2015, 8:34am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/12 "2015-07-21T08:34:28Z")
Same thing has happened in the UK [http://www.bbc.co.uk/news/business-33594585](http://www.bbc.co.uk/news/business-33594585) ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [July 21, 2015, 10:00am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/13 "2015-07-21T10:00:47Z")
> [@beowulff](#): > > Not near me. > Diesel is at least 10¢/gallon cheaper these days. > Which really ticks me off, because for all the years I had an F-350 Diesel, it was substantially more expensive. I wonder what could account for the difference in price? I’m in Tucson, and I just rechecked several stations near me, and diesel is about 25¢ more expensive. ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [July 21, 2015, 10:57am UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/14 "2015-07-21T10:57:57Z")
I just filled my tank yesterday. $3.299 for diesel, while 87 octane was $3.579. I’m loving the lower cost. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 21, 2015, 1:17pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/15 "2015-07-21T13:17:08Z")
> [@beowulff](#): > > Not near me. > Diesel is at least 10¢/gallon cheaper these days. > Which really ticks me off, because for all the years I had an F-350 Diesel, it was substantially more expensive. Economics 101 - Supply and demand. The demand dropped when you go rid of that truck and the price dropped correspondingly. :D;) ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [July 21, 2015, 1:19pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/16 "2015-07-21T13:19:09Z")
[**This article**](http://www.cga.ct.gov/2006/rpt/2006-R-0556.htm) touches on some of the things up-thread. It’s a .gov site, but that doesn’t mean it’s not from the Big Oil lobby … Diesel prices tend to go up in fall because of farmers harvesting their fields, and stay high in winter because of home heating oil demands … makes sense to me and it is a .gov site so it’s got to be true. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [July 21, 2015, 2:07pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/17 "2015-07-21T14:07:27Z")
> [@watchwolf49](#): > > [**This article**](http://www.cga.ct.gov/2006/rpt/2006-R-0556.htm) touches on some of the things up-thread. It’s a .gov site, but that doesn’t mean it’s not from the Big Oil lobby … > > Diesel prices tend to go up in fall because of farmers harvesting their fields, and stay high in winter because of home heating oil demands … makes sense to me and it is a .gov site so it’s got to be true. it is likely true. #2 Diesel and home heating oil are the same base fuel, though heating oil doesn’t have the 15 ppm sulfur limit and is dyed red to discourage people from trying to run it in their cars/trucks. Kerosene is also a middle distillate like diesel but a bit lighter. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [July 21, 2015, 3:35pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/18 "2015-07-21T15:35:45Z")
It was about 2 cents higher for Diesel on I-45 between Houston and Dallas on Sunday- $2.49 vs. 2.47 per gallon. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [July 21, 2015, 3:51pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/19 "2015-07-21T15:51:18Z")
> [@jz78817](#): > > it is likely true. #2 Diesel and home heating oil are the same base fuel, though heating oil doesn’t have the 15 ppm sulfur limit and is dyed red to discourage people from trying to run it in their cars/trucks. Kerosene is also a middle distillate like diesel but a bit lighter. OTOH, I’ve been known to say this as a possible reason for summer price drops in diesel fuel. But if I look at a multi-year chart of diesel prices, it doesn’t stick out. If it is a factor, it seems to be swamped by other considerations. Yeah, I grew up in an area where oil heat was common (it’s practically unheard of the western US), and everybody knew you could fill a diesel up with home heating oil, but “don’t get caught”. Of course, a lot of the farmers I had for neighbors got fuel without road tax, both diesel and gasoline, for their farm equipment. And I think every one of them filled the family car from it, too. Even ones who were scrupulously honest in every other way you could think of. The standard statement is that “jet fuel is kerosene”. Again, same base fuel, but I don’t know how well an airliner would run on thousands of bottles of kerosene of the type sold for space heaters. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [July 21, 2015, 4:41pm UTC](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731/20 "2015-07-21T16:41:05Z")
> [@yabob](#): > > The standard statement is that “jet fuel is kerosene”. Again, same base fuel, but I don’t know how well an airliner would run on thousands of bottles of kerosene of the type sold for space heaters. Jet-A is basically kerosene, but it has additive packages required for aviation use. just like #2 road diesel and heating oil being the same base fuel, but road diesel requiring further de-sulfurization and additives such as lubricity enhancers and anti-gel. [Next page](https://boards.straightdope.com/t/when-and-why-did-diesel-fuel-get-so-cheap/725731.md?page=2)