I have recently become intrigued with kerosene and its use in home heating. Part of this interest stems from the fact that one of my nephews dabbled for a while in the art of fire breathing which uses kerosene as well as my interest in the history of the oil industry which I share with students in the Energy and Sustainability MBA program at Franklin Pierce University via Daniel Yergin’s book, “The Prize,” which is a well-written account of the oil industry.
Jeddon Mooiman showing off his fire breathing skills.
Kerosene (known in the UK and many of the old British colonies as “paraffin”) was the first crude oil distillate that made its way into common use. It came into commercial production in the 1850s and quickly displaced the whale oil that was used for lighting at that time. Kerosene has a long history of cooking and heating applications and is still extensively used in Africa and Asia as a cooking and lighting fuel. Today, the largest use of kerosene is as aviation fuel.
When I was growing up in Africa, a lot of cooking in rural areas was done on kerosene-fired Primus stoves, such as the one shown in the figure below. The basic design for this kerosene stove comes from 1892 and the and has not changed much since then. Many of these units, or similar ones, are still in service in Africa and Asia. In fact, these were the stoves of choice for many of the polar expeditions and when Hillary and Tenzing ascended Everest for the first time in 1953.
When crude oil is distilled, the kerosene fraction boils off before the diesel/ home heating oil (HHO) fraction. As a result, kerosene is a little less viscous and slightly more volatile than diesel and the hydrocarbons in kerosene typically contain 9 to 16 carbons, whereas diesel contains hydrocarbons with 10 to 20 carbon atoms. (The exact blend of hydrocarbons depends on the source of the crude oil used in the refining process as well as the type of refining process used.) One of the best features of kerosene is that it stands up to colder temperatures much better than diesel. At very low winter temperatures diesel and HHO fuels can start to become slushy as the longer chain hydrocarbons begin to gel, forming waxes, which can plug up fuel lines and filters, causing heating furnaces to shut down. These waxes start to appear at temperatures known as the cloud point of the fuel. As temperatures continue to drop below the cloud point, more wax is formed and the fuel can become so slushy that it will not even flow. This is known as its gel point. Home heating oil has a cloud point of 9 to 10oF but kerosene will only begin to cloud at -40oF. With its lower cloud and gel point, kerosene is often blended into transportation diesel in the winter months to ensure that the diesel does not gel in the tanks of trucks and other heavy equipment. Aircraft flying at high elevations are subject to very low temperatures and the aviation fuel variant of kerosene, jet fuel, is therefore ideally suited to this low temperature environment and application.
It is the cold temperature stability of kerosene that accounts for its frequent use as a home heating fuel for mobile or manufactured homes. In mobile homes using oil heat, the fuel storage tanks have to be located outside of the residence where the fuel is subjected to the cold winter temperatures. Here in, New England, where temperatures regularly reach single digit temperatures, having typical #2 HHO in an outside storage tank could be problematic for heating units.
Many of us with typical stand-alone homes give little thought to mobile homes and their particular heating challenges. It turns out that mobile housing units are a large part of the NH housing stock and it is estimated that there are ~30,000 units in NH (5.7% of the 519,000 residences). This means that there are many NH residents who are obliged to use kerosene due to the need to locate the storage tank outside of the home. The problem is that kerosene is the most expensive of the commonly used home heating fuels. As shown by the NH data in the figure below, kerosene is consistently more expensive than regular #2 HHO - typically costing about $0.50/gallon more. (As an aside, on an energy content basis, the most expensive way to heat is with electricity, then propane, and then kerosene, followed by regular HHO. See my Under Pressure and Closer to Home posts.)
These higher fuel prices clearly impact those least able to afford it. Moreover, it has been reported that mobile homes built before 1980, which comprise a large part of NH mobile home stock, have, due to poor insulation, an energy consumption per square foot that is 53% higher than other types of homes. With the combination of higher energy consumption and higher fuel prices, it is clear that folks living in mobile homes are deeply impacted by cold weather and home heating expenses: lower income families who live in mobile homes therefore spend a larger portion of their income on heating expenses compared to families living in better insulated residences. For this reason, weatherization programs directed at improving the insulation of these mobile homes, such as was carried out recently in New Hampshire, should be encouraged.
Many of us are familiar with self-standing kerosene heaters such as those shown below. There is the torpedo type one often finds on construction sites or in warehouses or the stand-alone type one might find used for supplemental or backup heat in backwoods cabins, workshops or barns. The appeal of these types of kerosene heaters is that many designs do not require electricity to operate – some rely on wicks to draw kerosene to the combustion area and some, like the primus stove pictured above, require a manually pressurized fuel tank. Some modern stand-alone kerosene heaters have electrical fans to blow the warm air into the room but the main feature of these stand-alone heaters is that they aren’t vented. As such, the combustion products, largely water vapor and carbon dioxide, are released into the heating space. The danger is that improperly adjusted kerosene heaters can release the highly poisonous carbon monoxide, which could have deadly consequences. Any home or enclosure using a kerosene heater should, as a matter of course, be fitted with a carbon monoxide detector. Moreover, a window should be always opened a crack to allow some circulation and to prevent the buildup of carbon dioxide and other combustion products.
The kerosene-based home heating systems installed in mobile homes are not the unvented types shown above; modern units are fan-driven ducted systems which discharge combustion off gases directly outside. These are similar in design and configuration to home heating systems that use regular HHO.
Two grades of kerosene are available for sale. There is K-1 kerosene which low in sulfur (<0.05%) and higher sulfur K-2 kerosene (<0.5%). For unvented heaters, the K-1 grade is the recommended type. The K-2 grade is the type that is often used in mobile homes with vented heating systems. Like untaxed HHO, kerosene used for home heating purpose is dyed red to distinguish it from its taxed transportation equivalent
Data on kerosene sales for home heating applications is tracked by the Energy Information Agency (EIA) and historical data for NH is presented in the chart below. We noted in an earlier post that current HHO sales were off about 55% from their 2004 highs. We also see a decline for residential kerosene sales - but here the drop off is of the order of 90%! NH kerosene sales continue to decrease – consumption has decreased from 7 million to 2 million gallons per year just since 2010. (As a comparison, bear in mind that the HHO consumption in NH is of the order of 100 million gallons per year.) I am pretty confident that these numbers do not reflect a decrease in the number of mobile homes. Instead they indicate that folks living in mobile homes are making choices regarding their use of expensive kerosene.
Source: EIA, NH Residential Kerosene Sales
This is not just a NH phenomenon. Residential kerosene sales are down across the entire US. This decrease intrigued me and so I chatted to a number of folks involved in the NH kerosene business and asked them about the decrease in kerosene sales data. As is typical in a case like this, there does not appear to one single reason for the decrease in usage. Instead a number of factors are at play but they are largely price-driven. Here is what I have learned:
- Kerosene is more expensive than regular HHO so mobile home residents have sought alternatives. For a typical 180-gallon delivery, a resident can save $90 by getting HHO instead of kerosene. The low temperature clouding and gelling problems with outside storage tanks in winter can be combated by the addition of anti-gel additives that reduce the cloud point. These additives can cost $10 to $30 per tank and so there are savings for the resident. However, some oil suppliers have expressed concerns about poor mixing of the additive in a typical oil tank and question the effectiveness of these additives.
- Some oil dealers will supply a blend of expensive kerosene and lower cost HHO to lower the cost of a heating fuel delivery. In these circumstances, it likely that the kerosene content gets lumped in with the oil numbers when data is reported - which then artificially decreases the kerosene consumption numbers.
- Some kerosene users will switch back and forth between kerosene and HHO during the year to reduce their heating bills and will use kerosene only in the very cold winter months.
- Many mobile home owners have converted old kerosene-based heating systems to electrical space heaters or propane systems. Sometimes these changes are done based on the belief that propane systems are better and some are driven to do so because they live in a community that does not allow the installation or replacement of an outside kerosene storage tanks.
- The number of oil dealers supplying kerosene has declined. Fuel storage facilities, along with the associated tanks, pumps and piping are expensive, and many dealers have found maintaining kerosene inventories, along with the related storage and transportation logistics, unattractive in the face of declining sales.
In my last post, I noted that HHO is a dual purpose fuel. It is used as for home heating and, in its low sulfur diesel form, it is used for transportation: it is often the larger transportation market dynamics that ends up dictating the price for HHO. Kerosene is similarly a dual purpose fuel used for home heating and transportation. As noted earlier, in winter kerosene is added to diesel in order to extend the temperature range of the fuel. Far more significant, however, is its use as an aviation fuel. To give you a sense of the US market, in 2012 21 billion gallons of jet fuel were consumed, compared to 81 million gallons of kerosene consumed for home heating, commercial, industrial and farm use. The jet fuel market is 260 times larger.
In making inquiries about why kerosene is more expensive than regular HHO, it turns out to be more of a supply issue. Only about 10% of oil refinery production, see the table below, ends up as kerosene. This limits its availability and, on top of that, the strong demand for jet fuel continues to increase.
Kerosene, in its jet fuel formulation, has another important use: it is used to generate electricity. A few weeks ago, PSNH reported that they were requested to fire up their 20 MW jet fuel generators located at the Merrimack station in Bow, Groveton and Tamsworth. This is generally a rare event and was driven by the lack of natural gas availability for power generation. The challenge with these oil-fired generators is that the jet fuel is expensive compared to natural gas and coal so that they are really only backup units used to meet high peak demand operations. Some operations have converted their oil-fired backup units to run on cheaper natural gas. High oil prices also led to some operators reducing the amount of oil in their storage tanks, which left the region short of oil-fired backup generating capacity during the 2012/2013 winter when it was needed.
This winter, ISO-NE, the regional body responsible for coordinating the entire New England electricity market, instituted a Winter Reliability Program in which ISO-NE procured additional generating capacity from oil-fired operations such as PSNH. ISO-NE paid participants in the program ~$0.60/gal to keep fuel oil in storage to be available when requested. This program has been effective this winter and oil-fired backup capability has been available when needed. The chart below shows the generation of electricity in New England from different sources during the month of January 2014. Natural gas and nuclear generate most of the electricity in the region but the early January cold snaps had oil-fired generators kicking in (shown by the light blue line) and during the very cold weather towards the end of January, oil-fired generators were producing a lot of the region’s electricity. In fact, on Jan 24, 2014, oil was supplying 14% of the region’s electricity, as measured on a daily basis.
We have covered a lot of ground on this post, ranging from Primus stoves to PSNH’s use of kerosene to generate electricity, but here are the main takeaways regarding kerosene usage in NH:
- Kerosene is a versatile fuel which is very useful in low temperature applications, such as blending with diesel in winter and for mobile homes with outside fuel tanks. However, its main use is as an aviation fuel.
- Kerosene is ~$0.50/gal more expensive than HHO as a home heating fuel in NH.
- Use of kerosene as a home heating fuel has plummeted over the past decade, driven largely by price.
- Kerosene is a useful back-up fuel that can be used to generate electricity when natural gas supplies are constrained or prices get too high.
- Finally, if you are planning a traverse of the South Pole or an ascent of Everest, you may want to start scouring yard sales for old Primus stoves.
Until next time, remember to turn off the lights when you leave the room.
Franklin Pierce University
Click on this link to receive email notifications for Energy in New Hampshire updates
Click on this link to receive email notifications for Energy in New Hampshire updates
(*Kerosene Hat – The title of Cracker’s breakthrough 1993 album. I always enjoyed this group as I found many of their songs clever, catchy and some quite dark. Even though this tune is from their previous album, this is my favorite Cracker tune, Teen Angst. As an old folkie I love the “what the world needs now is another folk singer like I need a hole in my head” sentiment.)