(a) In this section, “service site” means facilities or buildings operated by a public retail customer or a group of adjacent facilities or buildings operated by a public retail customer within one contiguous geographical area.
(b) Unless the utility is prohibited by other law from providing the service and if sufficient pipeline capacity is available on an existing facility of the utility to provide the service, a gas utility or municipally owned utility may not refuse to provide service to a public retail customer at a service site, at rates established as provided by Subsection (c), the following services:
(1) the sale of gas;
(2) the transportation of an annual average of 25 million British thermal units or more each day of gas that is:
(A) taken as a royalty in kind; and
(B) owned by the state or managed by a marketing program operated by the state or by a state agency; or
(3) a combination of the services described by Subdivisions (1) and (2).

(c) A utility shall provide a service described by Subsection (b) at rates provided by a written contract negotiated between the utility and the state or a state agency. If the utility and the state or state agency are not able to agree to a contract rate, a fair and reasonable rate may be determined for the public retail customer, as a rate for a separate class of service, by the railroad commission or, for municipally owned gas utilities, by the relevant regulatory body under this chapter.
(d) In this section, “public retail customer” has the meaning assigned by § 101.009.