Single-shaft combined cycle packs power in at low cost

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Power (New York)

OSTI ID:215491

Swanekamp, R

Worldwide demand for combined cycle (CC) powerplants has grown exponentially over the past decade, and most forecasts call for the boom to continue. Reasons, by now, are clear: the CC powerplant--in its basic form, a gas turbine exhausting into a heat-recovery steam generator (HRSG) that supplies a steam turbine--is the most efficient electric generating system commercially available today. It also exhibits capital costs significantly lower than competing nuclear, fossil-fired steam, and renewable-energy stations. In addition, its low air emissions, water consumption, space requirements, and physical profile are no trifling advantages in an era marked by tough permitting and siting processes. A relatively recent advance that may further cement the CC`s front-running position is combining the gas turbine, steam turbine, and electric generator on a single shaft. Locking together the turbines and generator to form one single-train operating system promises to simplify plant design and operation, and may lower first costs. Trade-offs of the single-shaft approach, however, include the need for higher starting power and less operating flexibility, particularly if no synchronous clutch is used between the gas and steam turbine. Also worth noting: the arrangement takes away the phased construction option where a simple-cycle gas turbine is installed first and the steam cycle is added later. But depending on project specifics, the rewards of the single-shaft CC can outweigh its drawbacks, as a look at several recent installations reveals in this article.

• OSTI ID: 215491
• Journal Information: Power (New York), Journal Name: Power (New York) Journal Issue: 1 Vol. 140; ISSN POWEAD; ISSN 0032-5929
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
COMBINED-CYCLE POWER PLANTS
DESIGN
ECONOMICS
ENERGY EFFICIENCY
MECHANICAL SHAFTS
TURBOGENERATORS