Central Oil Storage

Central oil storage (COS), or central storage, is the term used for a communal heating system pioneered in the middle of the twentieth century.

The concept was simple and effective, using oil (usually kerosene, but sometimes gas oil) in the way that natural gas is used today – it being fed from a central source and metered into individual dwellings on a housing estate. The concept was popular with major oil companies such as Shell and BP. Each householder was obliged to use their oil from their tank, unlike the situation where a consumer owns their own tank and is free to shop around for the best deal.

A typical COS example follows :

Oil would be delivered by road tanker and discharged into a tank capable of holding, say, 5000 gallons. This oil would then find its way into each house, initially through a master pipeline, which then subdivided underground with a branch leading into each property. Each property was provided with a meter located on an outside wall which was read whenever necessary.

A 5000-gallon tank would usually be installed on an estate numbering up to 50 or 60 properties, although they ranged from a low of about 12 up to a high of in the thousands. The majority of tanks were situated above ground in an elevated position. This meant the oil could flow into each house under the influence of gravity. Other tanks were situated underground and were equipped with an electric pump, usually feeding oil to a small 'header' tank, again in an elvated position, to allow gravity to work its magic.

The level of oil in the tank would be checked regularly and new supplies ordered as and when necessary. Therein lies one potential problem with this system – it was possible, through negligence, for the tank to run dry, resulting in a number of properties being left with no heat.

From the early 1980s, their owners began to close down COS sites. The huge increases in the price of oil had led many customers to convert to gas, solid fuel, or even to install their own oil tank in their garden. With fewer and fewer users per site, and maintenance costs remaining the same, the oil companies went through a closure programme, resulting in few sites still being operational in the new millennium.

As at early 2008, the ownership of many sites is unclear. Sites have been sold through a number of companies which have then been closed down, often immediately. This presents problems for householders and local authorities alike, for when a site experiences a problem – such as an unsafe bund wall, or even a leak – there is no one to pursue with a view to getting things put right.

Having visited many sites in South East England, the author believes that such problems will become more common as sites get older and older but receive no maintenance.