Stored fuels are mostly diesel and/or biodiesel blends stored in large and small tanks for use in stand-alone generators, vehicles and boats. Some power plants that run on coal or natural gas also store #2 diesel fuel to have onhand as a start-up fuel to get their turbines going again after a planned or unplanned shutdown.
Fuel storage is an integral part of the energy plans of many businesses and most fleets and municipalities. It's also important for families that may be counting on a generator for use after a storm. Stored fuels have to be available for use at a moment's notice (whether after a hurricane emergency or just simply for when a long-haul truck pulls up to fill up). These business and organizations rely on the stored fuels to maintain the same consistent quality over the weeks and months of storage as when they were put in as fresh fuel.
Maintaining fuel storage quality is therefore essential to the plans of any business or group storing fuel in tanks. Maintaining the stored fuel quality means preventing oxidative fuel breakdown (breakdown through oxidation) from exposure to air and light, preventing hydrolytic breakdown through exposure to water, and keeping the storage tank free from microbes.
Oxidative breakdown can be prevented through preventive treatment with fuel stabilizers that interrupt the chain of oxidation reaction that happen in the fuel upon exposure to air and elements containing oxygen. Hydrolytic breakdown can be prevented by controlling the buildup of water within the tank, which is sometimes inevitable depending on how long the fuel is stored.
More seriously, the build-up of water is a big problem for fuel storage because it gives an avenue for microbes to invade, thrive and grow in the tank, destroying the fuel quality and rendering it almost useless for the future purpose the fuel storer has for it. And when this happens, an infestation is difficult to get rid without using a biocide to kill the microbes.
The biocide issue is a key distinction that fuel consumers may not be aware of. Fuel additives that control water are used by a lot of people. And this is an important step toward minimizing the conditions most commonly associated with microbes to grow and multiply and thrive. But sometimes these microbes still do find their way in, and when this happens, a biocide is needed to kill the microbial colonies. At this point, you cannot get rid of the infestation without using a biocide.
Stored fuels represent a significant financial investment for many companies, municipalities and fleets, and families with tight budgets. No fleet or fuels manager wants to have to go through the headache of figuring out what they're going to do with several thousand gallons of wrecked fuel. So it makes prudent sense, from a financial and operational standpoint, to undertake good housekeeping and preventive measures to keep the fuel quality from degrading.