Firm services, also called uninterruptible services, are services, such as

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

(firm power) and

natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

supplies, that are intended to be available at all times during a period covered by an agreement. Also, the service is not subject to a prior claim from another customer and receives the same priority as any other firm service. Conditional firm service is similar to firm service in that it is reserved and has priority over interruptible service. However, it can have restrictions, such as times when it would be curtailed before firm service but after interruptible service. The cost per unit with this service is called a firm rate or uninterruptible rate. The opposite of firm service is non-firm service, also called interruptible service or as-available service. The cost per unit for this service is called a non-firm rate or interruptible rate. The interruptible load is the portion of a utility's load that comes from customers with interruptible service. Firm service cannot be interrupted during adverse conditions, such as periods of high demand. However, firm service may also refer to service that is covered by a long-term

contract A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to tran ...

, such as a year or more. There are extreme cases when firm services may be interrupted, such as emergencies and when system reliability is threatened. Services to homes and small businesses are usually firm. Some businesses that cannot afford interruptions also have firm service. Businesses that can afford to have services interrupted or that can significantly reduce their consumption when notified by the provider can get better rates by having non-firm service. Customers that have non-firm service may have a low level or baseline firm service that is guaranteed so that they do not have to shut down completely. Firm and non-firm service is also available for companies that rent or lease

pipeline Pipeline may refer to: Electronics, computers and computing * Pipeline (computing), a chain of data-processing stages or a CPU optimization found on ** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...

electrical transmission Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a ''transmission network''. This is d ...

capacity. Firm service for natural gas pipelines and electrical transmission lines often include two charges. The first is a reservation charge related to how much capacity the customer reserves. This charge is paid regardless of how much capacity is actually used. The second charge is based on how much capacity is used. Interruptible rates are volumetric, being based only on the volume of gas or electricity delivered.

References

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Energy Information Administration - Natural Gas GlossaryFederal Energy Regulatory Commission - Reliability

Federal Energy Regulatory Commission -Docket No. RP04-328-001Federal Energy Regulatory Commission - Cost of Service
* ttp://www.energy.ca.gov/2006publications/CEC-500-2006-038/CEC-500-2006-038.PDF California Energy Commission - Rate Structures for Customers with Onsite Generation

References

See also