Polar Works-Inlet Cooling Technology Overview-Polar Technology vs. Fogging

Polar Technology vs. Fogging

If there is a spectrum of inlet cooling technologies, then fogging is at one end of that spectrum, and Polar Works is at the opposite end.

So if fogging is successful and widely implemented, why is it good to be the "Polar" opposite of it? Simple: because the addition of the Polar Works system to a power plant is the closest that you can come to adding a new generating plant, without adding a new stack, transmission line, control room, etc. The Polar Works system makes so much additional power that our only natural competition is duct-firing.

While fogging provides power at the lowest first capital cost, you never know exactly when you're going to get that power, or how much of it you'll see. Most advocates of fogging rate their system at fairly absurd ambient temperatures, often in excess of 110 degrees. While that makes sense in places like Nevada and Arizona, it doesn't make much sense in Miami, Houston, or Atlanta. If you look at the operating profile of your power plant, how many real additional MWHr's do you expect to make off your fogging system over the course of a year?

Here's an example. Let's look at a common plant configuration, two "F" technology gas turbines in a reheat combined cycle, making a nominal rating of 500 MW, in Norfolk, Virginia. Norfolk is chosen because it has an annual average temperature of 59 degrees F, so it represents something of an ISO location. A plant at this location should more or less average out over the course of a year at its "nameplate" rating.

On a typical July afternoon, that same plant with evaporative cooling will enjoy as much as a 12.3 MW increase in incremental power from a standard fogging system with an 85% effectiveness rating. This incremental power is measured against what the base plant would have produced without any cooling system at all. The Polar Works equipped plant will enjoy a 112.7 MW incremental increase at the same conditions.

Still not convinced? This plant will see maybe an additional 28,765 MWHr's per year of incremental power from the Fogging system. The Polar Works equipped plant will enjoy 678,687 additional MWHr's per year.

This means that the annual average output from the fogging system is less than 3 MW, with an annual average capacity factor of about 27%.

The annual average output from the Polar Works system is 77 MW, and has an annual average capacity factor of 69%.

What can the fogging system do at the ISO rating of 59 degrees F? In theory, it could make maybe 5 or 6 MW's, but will more likely make nearly nothing at all. While the Polar Works system will still be making 76.8 MW! In fact, the Polar Works Inlet Cooling System is the only system available that can be rated at the standard 59 degree ISO conditions in a meaningful way!

So, which technology has the lowest installed cost per annual average kW? That distinction still falls to the fogging system, at about $150 / kW. Expect that the Polar Works system will cost maybe three times that amount. That is still much less than the cost of the bare combined cycle plant, so the addition of Polar Works to a new plant can actually decrease the per-kW cost of the new plant, while significantly increasing the plant's operating margins.

How do standard (50 degree F) refrigeration systems fare in this kind of comparison? Not too well, at over $700 per annual average kW, with an annual average capacity factor of only 31%.