Every component of your control system – from controllers, I/O cards and network equipment to computers and software – has an expectant lifecycle. If any component of the control system is at or near its end-of-life phase, the potential risk for production shut-down is significantly increased. Therefore, it is critical to know the age of all components of your control system, whether your system hardware and software are still supported by the manufacturer and the availability of spare parts so that you can avoid costly unplanned downtime.
In a day and age when technology is advancing more rapidly than ever before, the success of manufacturers and power plant owners has become increasingly reliant on facilities’ ability to execute changes quickly, efficiently, and cost-effectively.
This is particularly true in the process control realm, where a significant increase in both the number of solutions available on the marketplace, along with the capabilities they offer, has provided plant operators with the opportunity to continuously optimize their operations at a relatively low cost.
In recent years, turbine inlet air chilling (TIAC) has become a highly reliable method of enhancing power plant performance by increasing the output and efficiency of combustion turbines during periods of high ambient temperature. This is typically achieved either through mechanical or absorption chilling and involves supplying chilled water (or an alternative fluid) to the heat exchanger in the filter house of the combustion turbine, thereby cooling the inlet air which raises its density and increases mass flow rate through the compressor.
Not Just More Megawatts, Better Megawatts: The Case for Combined Cycle Output Augmentation in a Low Power Price Environment
Currently, the fragmented U.S. wholesale power markets do not face a scarcity of megawatts, as evidenced by the North American Electric Reliability Corporation’s (NERC) recent Summer Reliability Assessment and reported by Public Power Daily here.
However, this does not suggest turbine inlet air chilling (TIAC) is not a valuable resource for U.S. power generators. TIAC quickly elevates a combined cycle unit’s productive capacity during challenging ambient conditions. The benefits of the additional megawatts produced from low-heat rate/low-cost generation resources may be evaluated on a relative (better) or absolute (more) basis.
Ambient conditions have a significant impact on the operation of natural gas power plants. This is largely due to the fact that as temperature and humidity rise, air becomes less dense and mass flow rate through combustion turbines decreases.
Inlet cooling has become a popular method for boosting power output by lowering the temperature of air before it enters the turbine’s compressor. Plant operators today have the option of using any number of cooling/chilling techniques for reducing air inlet temperature – two of the most common of which are turbine inlet air chilling (TIAC) and wet compression.
Both TIAC and wet compression offer distinct advantages that make them more or less suitable for use depending on the specific needs of the facility. Understanding what those advantages are is essential to making the right decision when choosing which method to employ, thus ensuring optimal use of capital budgets.
More than 10 years ago, power plants were traditionally stick-built, with each building custom designed and made for that particular plant. The major benefits of this approach were maintenance access and lowest equipment pricing, since a substantial portion of the work was being completed in the field.
While both Supplementary or Duct Firing and Turbine Inlet Air Chilling (TIAC) are solutions to offset the megawatt output degradation of gas turbines when ambient temperatures rise, the two technologies take very different approaches. With TIAC, the combustion gas turbine inlet air is chilled. In the case of duct firing, injection of fuel is utilized to increase the temperature and mass flow rate of the exhaust gases.
Rather than competing, the two technologies – duct firing and turbine inlet cooling – can actually complement each other when used correctly.
For maximum power output, power plant owners can utilizing the reliable power augmentation provided by TIAC, and balance the requirements with duct firing. This scenario allows them to produce the required power at the lowest possible heat rate.
The changes in U.S. electricity supply and usage levels are rapidly reshaping utility load profiles and thus generation and transmission requirements for both new and existing resources.
The recent discovery of relatively cheap natural gas in the U.S. and growing use of the fuel as a baseload power generation source has also coincided with the rapid adoption of renewable resources in many parts of the U.S. These new components of the electricity supply stack continue to displace more traditional and older forms of baseload power generation, coal and nuclear units, for both economic and public policy motivations. Unfortunately, these growing pieces of the U.S. generation supply side all are subject to weather related intermittency.
The market for liquefied natural gas (LNG) is booming. International LNG trade is expected to exceed $120 billion this year, making it second only to oil as the most valuable world commodity, according to Goldman Sachs Group.
Demand for the product positions the United States – with its abundant natural gas — nicely to build an LNG export market. This is a big switch from a decade ago when the U.S. was experiencing tight energy supplies and thought by now it would rely on foreign LNG imports.
As a result of the industry shift, we are seeing keen market interest in development of liquefaction plants in the U.S. (and other parts of the world). The nation now has plants under construction to produce 44.1 million tons per annum (MTPA) of LNG and has proposed an additional 268 MTPA of capacity.
LNG plants can cost in excess of $8 billion to site, develop and build. So efforts are underway to make these new plants as cost-effective as possible – which is one of the reasons why the LNG industry is examining Turbine Inlet Air Chilling (TIAC).
To call water a hot commodity is an understatement. From controversial water trading to desalination, a slew of efforts are underway to solve water scarcity issues in many regions of the world. Some, like the massive undertaking by Israel to reuse wastewater and desalinate water from the Mediterranean Sea, are having an impact. But as population and urbanization continues to grow worldwide, so does water consumption, and, naturally energy use.
Water and energy are closely tied. Consider that thermoelectric power plants – which currently provide the vast majority of US electricity — consume a lot of water. In fact, the power industry is one of the largest water users in the United States.
Presently, in the US, coal plants are being displaced by natural gas plants. However, gas turbine efficiency is the lowest when the demand for power is the highest, during hot summer months. To offset this negative effect of high ambient temperature, gas turbine inlet air can be cooled via mechanical chillers.