A number of factors are driving the need for very clean fuel. The major factors are:

  • Very difficult exhaust emission standards
  • A growing shortage of service technicians to repair increasing complex and sophisticated equipment
  • The cost of failures caused by dirty fuel. These failures result in downtime and loss of machine productivity.

What Is Clean Fuel?

The question of what is clean fuel has been the subject of debate for many years. Until recently, the definition of clean fuel was “Clear and bright”.

What does that mean?

How clear? How bright?

There is only one acceptable and meaningful way to measure and discuss fuel cleanliness. That is ISO cleanliness level.

What do we mean today when we say “Clean fuel”?

Bulk fuels are simply not delivered to sites at these cleanliness levels. Further confusion is introduced when sites attempt to determine fuel cleanliness by bottle sampling. The only reliable way to sample fuel is in dynamic flow with a laser particle counter. Contaminated fuels and the associated cost of failures is something which can be controlled or eliminated by the effective use of bulk filtration.

Follow this link to read entire white paper: Cat Bulk Filtration Paper

Report on Corrosion in Systems Storing and Dispensing Ultra Low Sulfur Diesel (ULSD), Hypotheses Investigation

Final Report,
September 5, 2012
Prepared by Battelle Memorial Institute, Columbus, OH

Clean Diesel Fuel Alliance
Mr. Prentiss Searles
American Petroleum Institute
1220 L. Street, NW
Washington, DC 20005-4070

Executive Summary
Corrosion in Systems Storing and Dispensing Ultra Low Sulfur Diesel (ULSD), Hypotheses Investigation

Severe and rapid corrosion has been observed in systems storing and dispensing ultra low sulfur diesel (ULSD) since 2007. In addition, the corrosion is coating the majority of metallic equipment in both the wetted and unwetted portions of ULSD underground storage tanks (USTs). To investigate the problem in an objective manner, multiple stakeholders in the diesel industry, through the Clean Diesel Fuel Alliance, funded this research project. The design included the identification of retail fueling sites and the development of an inspection and sampling protocol to ensure uniform and thorough inspections of USTs. Fuel, water bottoms, vapor, bottom sediments, and scrape samples were taken from six sites: one that was not supposed to have symptoms (but did to a much lesser degree) and five that were to have the severe corrosion. Then, samples from the inspections were analyzed for genetic material and chemical characteristics. These data, in combination with information on additives, have allowed Battelle to draw conclusions with respect to three working hypotheses.

Specifically, the hypotheses are:

  1. Aerobic and anaerobic microbes are producing by-products that are establishing a corrosive environment in ULSD systems;
  2. Aggressive chemical specie(s) (e.g., acetic acid) present in ULSD systems is(are) facilitating aggressive corrosion; and
  3. Additives in the fuel are contributing to the corrosive environment in ULSD systems.

All of the sites inspected contained microbes, although at different abundances. The dominant organism identified from three of the sites, Acetobacter, has characteristics pertinent to the corrosion observed in all of the sites, such as acetic acid production, ethanol utilization, low pH requirements, and oxygen. Although geographically on opposite sides of the country, from different fuel suppliers, and of relatively new construction materials, the presence of the organisms was relatively uniform. The traditionally expected hydrocarbon degrading organisms were found in insignificant abundances. This indicates that the inspected ULSD USTs are selective environments for these specialized, acetic acid producing organisms. Of note from the chemical analyses is that acetic acid was found to be ubiquitous (water bottoms, fuel, vapor, and scrapings) in all of the sites inspected. In addition, ethanol was unexpectedly identified and measured at five of the six sites. Components necessary for the organisms identified to proliferate were analytically determined to be present in the majority of the samples: trace amounts of ethanol, low pH, oxygen, and water were present in the diesel USTs inspected.

Finally, although additives could play a role in the corrosive environment, it is unlikely that they are the primary cause of the observed corrosion.

This project was designed to objectively investigate multiple hypotheses as to why ULSD USTs have been experiencing severe and rapid corrosion. The in-depth site inspections were performed on a limited number of sites and therefore may not be representative all of systems experiencing this phenomenon. Although it cannot be stated with statistical significance, ingredients necessary for the observed and chemically determined corrosion in this environment were present at the inspected sites. The most obvious issues causing this problem were the focus of this research and the development of corrosion at different sites could also be influenced by other factors (environmental, geographical, seasonal, etc.) not discussed in this report. The project final hypothesis for this investigation is that corrosion in systems storing and dispensing ULSD is likely due to the dispersal of acetic acid throughout USTs. It is likely produced by Acetobacter bacteria feeding on low levels of ethanol contamination. Dispersed into the humid vapor space by the higher vapor pressure (0.5 psi compared to 0.1 psi for ULSD) and by disturbances during fuel deliveries, acetic acid is deposited throughout the system. This results in a cycle of wetting and drying of the equipment concentrating the acetic acid on the metallic equipment and corroding it quite severely and rapidly.

The subject of this review is diesel fuel – its performance, properties, refining, and testing. A chapter in the review discusses diesel engines, especially the heavy-duty diesel engines ised in trucks and buses, because the engine and the fuel work together as a system. In addition, because environmental regulations are so important to the industry, the review examines their impact on both fuel and engine.

When the Lights Go Out…
it’s Too Late to Clean Your Tanks

Most Emergency Power and Engine Performance failures start in the Fuel Tank and are caused by the inherent instability of fuel.

Fuel degradation is a natural process that causes the formation of sediment, tank sludge and acid. It starts at the refinery and continues until the fuel has been used. Heat, pressure, temperature changes, water and microbial contamination accelerate the fuel breakdown process.

The mandated use of biofuels has caused a dramatic increase in fuel re-polymerization. This is causing rampant filter plugging, fuel injection system failures and a significant reduction of stored fuel shelf life.

Advancements in engine and injection system design demand perfect fuel. However, changes in fuel production methods combined with the use of biofuels are seriously endangering engine performance and the reliability of critical power. Traditionally, the solution has been to periodically replace stored fuel and clean tanks. This is a very expensive and only a partial solution at best.

AXI provides equipment based on its unique and innovative approach to fuel quality optimization, maintenance and tank cleaning to improve the stability, filtration and combustion of fuel.

Implementing AXI’s Green Clean Certified® equipment and fuel maintenance programs will eliminate the need for periodically cleaning tanks and replacing fuel. Optimizing and maintaining fuel quality preserves its integrity. It extends filter change intervals, protects engines and injection systems and reduces harmful emissions.

AXI Fuel Quality Optimization, Maintenance & Tank Cleaning provide Reliability and Protection of Engines & Turbines far beyond traditional filtration & separation.

Data Center Knowledge Magazine, 7×24: Generators Are Key to Improving Reliability   By Rich Miller, November 15, 2011

When it comes to reliability, diesel generators are far and away the most important pieces of equipment in a data center, and regulatory mandates on fuel may be creating new problems that could raise generator failure rates.

Those were the key points made by Steve Fairfax, President of MTechnology, in a provocative keynote presentation Tuesday at the 7×24 Exchange Fall Conference in Phoenix. Fairfax, whose firm does “science risk” consulting work for both vendors and end users, said in-depth analyses of failure rates in data center components and systems yields counter-intuitive results, especially when it comes to maintenance.

“Generators are the most critical systems in the data center,”

said Fairfax, whose studies of failure data found generators played a role in between 45 and 65 percent of outages in data centers with an N+1 configuration (with one spare backup generator).

“Reducing generator failures has more than 10 times the impact of reducing other component rates. This is where you should be focusing your attention – on generators. That’s what will take you down.”

Fairfax identified three key threats to generator reliability:

  • fuel quality problems due to old fuel mixing with newer fuel
  • quality issues with new Ultra-Low Sulfur Diesel and biodiesel fuels
  • wear and tear from efforts to start cold generators as quickly as possible

Fuel Tanks and the “Diesel Solera”

Fairfax said the leading problem with generators is not the failure to start, but the failure to run properly once the generator has started. A key factor in the “failure to run” scenario is fuel quality.

Fairfax highlighted a phenomenon he calls the diesel “solera,” a term for the process for aging wine by mixing small amounts of older vintages with newer wine. While the solera process can help improve wine, it can introduce reliability challenges when it occurs in a tank of diesel fuel – which happens when older fuel remains in the bottom of a tank when it is refilled.

“Every year we take some of the diesel fuel out and add fresh fuel,” said Fairfax. “When was the last time you emptied that tank and cleaned it out?”

Ultra-Low Sulfur Diesel and BioDiesel

Another factor is the regulatory requirement to use Ultra Low-Sulfur Diesel Fuel (ULSD). While ULSD improves the emissions profile of generators, Fairfax said data center operators should pay close attention to fuel quality and tank conditions. Ultra-Low Sulfur Diesel is less stable than older distillate diesel fuels, he said, with a maximum storage time of 6 months. “Stabilizers can extend that, but then you have an interesting chemistry experiment going on in your diesel tank,” said Fairfax, who says this could result in a higher incidence of leaks and accelerated wear on seals.

Fairfax offered three recommendations on managing this challenge:

  • Empty and inspect fuel tanks whenever possible.
  • Change your generator testing policies. “Test them as you will run them,” said Fairfax, who said tests should run for 24 to 72 hours to simulate an extended utility outage, which will draw down diesel supplies in ways not seen in shorter periods.
  • Sample your diesel fuel on a regular basis to track fuel quality.

Biodiesel, which is mandated in several states (including Massachusetts, Washington and New Jersey), poses additional challenges. “Biodiesel has a completely different chemistry” than older diesel fuels, said Fairfax, who said biodiesel can dissolves sediments that could clog filters, and has even worse stability than ULSD.

10-Second Start Times

Fairfax noted the NFPA guide to Emergency Power Supply Systems calls for generators to be able to start in 10 seconds for life safety applications. While not all data centers are required to adhere to this, many follow the NFPA guidelines by default. Farfax said Mtechnology’s research found no basis for the 10-second guidance, which he said places high stress on the generators that can shorten lifespan and impact reliability. The 10-second target requires cold equipment to start with a wide-open throttle, creating the highest possible thermal and mechanical stress.

“You get a huge benefit by reducing stresses. One of the best things you could do to improve the reliability of generators is to increase the start time to 30 seconds.”

Unfortunately, a general consensus about diesel fuel being “good for life” is a common idea, but this belief is a myth. Many have found this out the hard way, especially in electric power generation. In order to avoid untimely shutdowns, it is imperative that a systematic approach be in place to avoid contaminated fuel.

With today’s fuel injection systems operating at such high pressures, utilizing extremely fine tolerances, the days of poor contamination control are over. Today’s injectors are extremely vulnerable, subject to wear and premature failure as diesel fuel ages and is not maintained properly.

Poor fuel maintenance can also lead to clogging and blockage of fuel filters. This can slow or even stop the flow of fuel, leading to engine starvation, injector damage, poor performance, and ultimately engine shutdown.

Unlike on-highway trucks and off-road machinery that consume fuel relatively quickly, diesel gensets store large amounts of fuel for extended periods. Stored diesel fuel can present symptoms of fuel degradation in as little as six months. In some applications, the genset will see very little use, allowing the fuel to age. This increases the formation of sediments and bacteria in the fuel. In these cases especially, it is critical that this energy source be maintained.

A few things to consider when maintaining the integrity of your diesel fuel supply:

  • Have fuel samples been taken from three locations (bottom, middle, top) of tank, and evaluated to properly identify fuel quality?
  • Have bacterial and fungal growth inhibitors been added to help combat the effects of fuel being stored for extended periods?
  • Does the fuel supply have its own filtration? Does it have the ability to filter down to 0.5 microns under pressure, as well as a fuel/ water separator to aid in the effort to ensure clean fuel delivery?
  • Has there been a thorough inspection of the fuel tank, including interior video inspection, complete equipment inspection (connections, gauges, monitoring devices) as well as identifying non-compliance issues?
  • Are proper contamination control precautions being taken when replenishing fuel supply? It is important to ensure that the fuel that is received is from a reputable source, who also takes the proper precautions to ensure quality fuel delivery.

Utilizing these maintenance measures will contribute to the longevity and performance of your investment. A failure due to neglect should not be an option, and is easy to avoid if the proper procedures are put into place.

SINGAPORE (Reuters) – Indonesia’s inability to meet the rising energy needs of its businesses, from steelmakers to hotel resorts, threatens to put the brakes on growth in Southeast Asia’s largest economy.

The recent update of Indonesia’s sovereign debt rating by Fitch to investment status should help attract more investors. But analysts and industry watchers fear wasteful subsidies and rampant corruption will reduce crucial investment in the infrastructure needed to supply power.

“Indonesia is not fulfilling its full potential because of these energy and infrastructure problems,” said Erman Rohman, director of economic programs in Indonesia at The Asia Foundation, a San Francisco-headquartered nongovernmental organization.

“A business can’t grow when it is facing blackouts a few times a week,” he said.

Almost half of 13,000 companies surveyed by the foundation in 2010 and 2011 experienced power outages at least three times a week.

Indonesia is the world’s largest exporter of coal and the third-largest exporter of liquefied natural gas (LNG), but almost one-third of its citizens have no access to electricity. In outlying regions such as Papua, the figure rises to more than half.

A World Bank report for 2011 ranks Indonesia 161st among 183 countries in the ease of businesses getting reliable electricity supply, down three places from the previous year. In this category, Indonesia has received worse grades than Congo and Albania.

Recurring blackouts this year have forced hotels on the resort island of Bali to rely on diesel generators for back-up power, which costs more than regular power supplies.

“The situation has improved, but there are still blackouts from time to time. We have to use diesel which is more expensive and adds to our costs,” said a senior executive at a Bali hotel.

Due to poor transport links in the archipelago of more than 17,000 islands, movement of coal is hampered by lace of railroads. A lack of pipelines is on reason why only a small percentage of Indonesia’s rich natural gas deposits are being utilized to power industries at home.

“Indonesia needs to improve access to energy for the smaller islands to diversify the sources of growth now concentrated in greater Jakarta and Java,” said Ferry Wong, head of research at Citigroup Securities Indonesia.

Indonesia’s GDP is expected to grow by 6.3 percent next year, according to the country’s central bank, while electricity demand is forecast to rise a robust 6.2 percent, the Economist Intelligence Unit (EIU) estimates.


Heavy spending on subsidies and problems with land acquisition have held back investment in infrastructure.

Analysts say that with Indonesia growing at more than 6 percent a year, it needs to spend the equivalent of 5 percent of its gross domestic product a year to keep up with growing infrastructure needs.

While a newly-passed land acquisition law makes it easier for developers to secure land to build ports and power stations, there is political and public opposition to tackling subsidies.

The country’s utilities sell power to end-users at subsidized rates of $70-$75 a barrel of crude oil, well below market prices of $95-$105 a barrel, said Citigroup’s Wong.

“If oil prices continue to rise, this will be a risk to Indonesia’s economy because it puts a strain on the budget.”

Finance Minister Agus Martowardojo said on December 13 that this year’s fuel subsidy bill will total 168 trillion rupiah ($18.5 billion), up from the budgeted figure of 129.7 trillion rupiah because of increased demand and higher-than-expected average oil prices.

The government plans to remove fuel subsidies in April for private cars in Jakarta and Bali, but the selective nature of the cuts is likely to limit their effectiveness.

“Motorcycles are exempt from the subsidy (cut), and there are roughly 10 times more motorcycles than cars being sold in Indonesia,” said Martin Adams, an EIU energy analyst in Hong Kong.

State utility PLN cannot cover costs at current tariffs, which the government has been reluctant to raise, capping the power firm’s ability to fund investment, analysts said.

There are plans to raise electricity tariffs in 2012 by an average 10 percent on average for most customers, which would cut an estimated $1.1 billion from the state subsidy bill. But there is no certainty rates will be raised. Early this year, the government proposed a 15 percent hike, but the legislature thwarted the plan.


Underinvestment at the lower levels of government is also a problem, with only 14 percent of local government budgets allocated to infrastructure, compared with 60 percent for personnel, a study by the Asia Foundation shows.

“For road and bridge programs, the average funding allocated was only… around a quarter of the amount needed for periodic maintenance alone,” said the report, “Local Economic Governance 2011”, based on a survey of almost 13,000 businesses conducted for the foundation by Nielsen Indonesia.

Corruption is also a problem, and one that has been exacerbated by Indonesia’s decentralization after longtime strongman Suharto resigned in 1998. Unlike during his tenure, officials in local governments far from Jakarta have the power to permit or block projects, and some provincial civil servants have grabbed the chance to enrich themselves.

“The situation is worse than I had thought, people are paying up to $10,000 to $15,000 just to get these jobs, although their annual pay is just 10 percent of that,” said Rahman.

Bribery also puts off foreign investors at a time when Indonesia is seeking $100 billion of private investment to overhaul its creaking transport network.


In recent years, Indonesia has shifted away from using oil towards gas to generate power as rising crude oil prices boosted subsidy bills and the country became a net oil importer in 2004.

PLN plans to cut oil’s share of the energy mix to 3 percent by 2013, from about 20 percent now. Analysts estimate that producing power from oil-based fuels costs it $15 per million British thermal units (mmbtu), but gas-fired power plants would only cost $12 per mmbtu.

But the lack of gas supply has prevented companies from taking advantage of the lower-cist fuel source, since producers earn more from higher-priced exports.

Gas shortages forced Krakatau Steel, Indonesia’s largest steelmaker, to shelve plans to expand production capacity, President Director Fatwa Bujang said this month.

In response to the shortage, the government in July freed private firms to import natural gas for the first time.

Indonesia will export 362 LNG cargoes this year, down 15 percent from 2010. It is building LNG import terminals with nearly 10 millions tons of capacity to meet demand.


The PLN, where Nur Pamudji was appointed as director last month, wants to boost the national electrification ration to more than 73 percent next year, from below 69 percent now.

To reduce blackouts, the utility plans to add 10,000 megawatts (MW) of generation capacity by 2014 to the existing 30,000 MW.

But even if realized, Indonesia’s energy woes could still cap its economic growth in the short term.

“The government realizes that it needs to remove subsidies, improve the business environment, install more generation capacity and extend the grid, but these are all long term undertakings and we can expect only gradual movement,” said EIU’s Adams.

(Additional reporting by Reza Thaher; Editing by Clarence Fernandez and Simon Webb)

©Thomson Reuters 2011 All rights reserved.

The treatment of carbon based fuels with AFC-705 has a significant effect on trace sulfur combustion chemistry. In diesel engines, gasoline engines, and open flame applications (boilers) the use of AFC-705 treated fuel will significantly reduce sulfur oxide (SOx) emissions, and related sulfur acid corrosion problems.

AFC-705 does not react with the sulfur in the fuel nor does AFC-705 have any effect on the sulfur content of the fuel. AFC-705 does not effect fuel specifications at recommended treatment levels. Fuel containing one percent sulfur prior to AFC-705 treatment will still contain one percent sulfur after AFC-705 treatment. However, the use of AFC-705 will determine where the sulfur ends up and what its chemical state will be after combustion.

The combustion of sulfur in fuels invariably leads to the formation of sulfur dioxide S + O2 ® SO2 (1) and sometimes sulfur trioxide 2SO2 + O2 ® 2SO3 (2). Sulfur trioxide formation is catalyzed by vanadium pentoxide (V5+). This is the most stable oxidation product of vanadium, when vanadium containing fuels are burned in air 4V + 5O2 ® 2V2O5 (3). The catalytic effect is thought to relate to the reversible dissociation 2V2O5 ® 2V2O4 + O2 (4) at temperatures between 700O-1125O C. The sulfur trioxide reacts with water vapor to form sulfuric acid SO3 + H2O ® H2SO4 (5) which is primarily responsible for acid corrosion problems in combustion equipment.

AFC-705 affects the production of gaseous SOX emissions. It enhances the formation of CO2 during the combustion phase thus limiting the amount of SOX produced during the exhaust phase. The increased production of CO2 reduces the amount of excess O2 available for other reactions. The difference in the amount of CO2 produced during the combustion and the exhaust phases correlates to a temperature differential. This temperature differential results in lower exhaust temperatures and shorter heat transfer times.

Minerals contained in fuel are generally oxidized to metal oxides during the combustion process. When vanadium is oxidized to V5+the production of sulfur trioxide increases due to reversible dissociation, and sulfuric acid is ultimately formed. The use of AFC-705 inhibits the formation and reversible dissociation of V5+ during the exhaust phase by limiting the available O2, high temperatures, and time periods needed for these reactions to occur.

This greatly reduces the catalytic effect V5+ has on the formation of Sulfur trioxide and thus the formation of sulfuric acid. By reducing the catalytic effect of vanadium, AFC-705 promotes the combination of SOX compounds with other minerals in the fuel such as Na and Ni. This leads to the formation of stable mineral salts and mixed mineral sulfates found in the clinker or fly ash.

In this manner, AFC-705 decreases the gaseous sulfur emissions by increasing the particulate portion of the combustion residue products. AFC-705 treated fuels will therefore show slightly higher sulfate content in the ash than untreated fuel.

Fuel Breakdown By-Products

Least understood is the natural process whereby organic fuels break down. Diesel and other fuels are naturally unstable, and actually less stable today due to modern refining techniques (catalytic cracking) that are designed to produce more fuel per barrel. Most major oil companies have documented on their Web sites that 6 to 12 months is the useful shelf life for their products, but the deterioration process starts as soon as the products leave the refinery.

This fuel breakdown is a process where agglomerating hydrocarbon chains bond together to create larger clusters. These larger compounds, present even in what visibly appears as clear and bright fuel, do not burn as efficiently. This incomplete combustion robs fuel economy, leaves carbon deposits on injectors and raises emissions, often with visible smoke and soot.

As the process continues, with even larger compounds being formed, the fuel begins to appear “dirty.” Eventually it progresses to forming sludge that falls to the bottom of the tank. This clotting fuel is the material that is commonly clogging fuel filters and shutting down generators. Often it may happen when a tank gets low and new fuel is poured in, agitating the sludge and dispersing throughout the fuel, releasing the threat that had been lying dormant. Or maybe the new fuel delivery came from such an agitated tank upstream in the supply line.

The Bottom of the Barrel

Water and tank sludge, of course, drop to the bottom of the tank, and a too-often overlooked but critical concern is that any tank cleaning be done properly by getting to the bottom of the tank. Access is frequently a limiting factor, but an inspection port can be installed to alleviate this problem. Similarly, when installing a recirculating conditioning and filtration system, the pickup tube into the tank is optimized when near the bottom (not using the fuel system’s draw, which is several inches higher to avoid the very substances you wish to collect).

Take the Test

Any generator that is in a critical application ought to be a candidate for a routine fuel testing service, probably on a quarterly basis. All the talk about fuel quality means little if you don’t have a benchmark to measure from. Be sure to get your samples from both a midpoint and the bottom of the tank.

Put Fuel Maintenance into the Vocabulary

Too often, fuel condition is overlooked, mostly out of ignorance of the issue. When that happens, the extreme of fuel removal, replacement, and possibly extensive tank cleaning or even tank replacement, is the cost. That is, if you’re lucky and didn’t have a generator failure in a real emergency situation. Only the business in question can determine the cost in the case of a total failure. But, generally, they wouldn’t have a generator if total power loss was an acceptable outcome.

It is crucial that disaster-planning professionals become aware of the need for a fuel maintenance routine to assure the survival of critical systems in the event of an emergency. PEI members are perfectly positioned to advance this educational effort. It can also represent a value-add service, as well as potential source of revenue and profits. Perhaps most important, you will be participating in raising overall organizational survivability and reducing the human suffering and loss of life in the midst of the worst of catastrophes.

WaterCondensation, Leaks, Fuel deliveryCombustion/Injector problems, Corrosion, Saturates filters, Supports microbial growth at bottom of tankFix flawed tanks, Water eliminators, Periodic tank cleaning, Automated conditioning and filtration system, Some additives can deal with small (normal) quantities
Microbial GrowthArrives through air or water, Requires water to thriveMultiplies and produces waste matter, Clogs filters, By-product is corrosiveBiocide – only if highly advanced state, Periodic tank cleaning, Automated conditioning and filtration system
Particulate MatterFaulty tank breather, Tank corrosion, Fuel delivery, Tank installationAbrasive wear and tearFiltration through: Periodic tank cleaning, Automated conditioning and filtration system
Fuel Breakdown By-Products (most tank sludge)Natural deterioration process of all organic fuels, Accelerated by heat, temp changes, pressure, presence of waterIncomplete combustion, Carbon deposits on injectors, Poor fuel economy, High emission levels (often visible smoke and soot), Filter cloggingProcess reversal through conditioning in some: Tank cleaning systems, Automated conditioning and filtration system, Chemical breakdown with additives

What do all of these true stories have in common? Poor fuel quality. In all of these cases, poor fuel quality shut down emergency standby power generators exactly when they were being counted on in the middle of a disaster. And the number of hurricanes, wildfires, blackouts, floods, earthquakes and the like in recent years has added significantly to the lore, though most are closely guarded stories and a PR person’s nightmare.

The frightful truth is that many emergency generators—an organization’s last line of defense in a catastrophe— will not perform as expected if and when that time comes. This article will share some insights into the issue to hopefully raise the percentage of emergency backup power systems that will operate as planned when needed.

At its essence, poor fuel quality is about what ends up in fuel that doesn’t burn well, and the complete story will surprise even veteran operations managers. Diesel fuel contaminants should be grouped into the following categories: Water; Microbial Growths; Inorganic Particulate Matter; and naturally forming Fuel Breakdown By- Products. The origins of them all can be traced to either a site-specific problem or in a fuel delivery from upstream in the supply chain.


Water is a widely acknowledged concern, but it need not be a problem as long as some manner of routine fuel maintenance is performed. If a tank is well-designed and is in good condition, with no means of water leaking in at the site, then only small amounts of water should be present. Water appears quite normally in most tanks through condensation.

This water can be removed easily through the use of a wide range of solutions that include absorptive eliminators and filters, coalescers, centrifuges and the like. All mobile tank cleaning systems used by tank cleaning services and permanently installed conditioning and filtration systems utilize one or more of these approaches and are effective at removal of normal levels of water content. A quality multi-spectrum additive often includes an emulsifier which can also pass small quantities through the system.

Microbial Growth

Microbial contamination (bacterial and fungal growth) is the most frequently mistaken problem. It only exists where there is water for it to grow in, so if you are diligent in carrying out a fuel maintenance program, you should never see the problem. Where it does exist in a long-ignored tank, microbes feed on the fuel, multiply and excrete waste products, all of which will end up clotting in your filters. These by-products are highly corrosive and pose a threat to many tanks.

The problem is that clogged filters are widely misinterpreted as containing microbial products, when they actually most often are deteriorated fuel by-products (sludge). This leads to endless streams of toxic biocides being needlessly dumped into tanks, which, when mistakenly used, make the problem worse. Often the result is diesel fuel now so spoiled that it needs to be disposed of and replaced, a costly and unnecessary consequence with serious environmental impacts. Not to mention that it may have sidelined the generator for several days. Again, take care of the water, and you’ll never need a biocide.

Inorganic Particulate Matter

Other particulate pollutants in diesel fuel are mostly dirt, rust and other metallic particles that find their way into the fuel either during the many tank transfers that occur in the supply chain or from a corroding tank somewhere along the line. It is infrequent that the level of particulate matter is very high and is generally welltreated through conventional filtration that accompanies a standard tank cleaning system or onboard permanent tank-side solutions.