1 

## Water and Energy

## Water Conserving Cooling

Status and Needs Energy-Water Needs Western Region Workshop Salt Lake City January 10 – 11, 2006 John S. Maulbetsch Maulbetsch Consulting3 

## We’re here to talk about....  Water-Energy trade-offs • A big, multi-faceted problem  More people/more water/more energy  My intent • Take a narrow slice and simplify it  Use less water to generate electricity4 

## Why is this easy?  We know where the water gets used

– Cooling: condense steam from the turbines  We know how we do it now

– Usually wet cooling towers  We have technologies that use less water

– Commercially available, proven technologies

– Can reduce plant water use by 80 to 90+%5 

## So what’s the problem?  It almost always costs more  How much more depends on • Type of plant • Climate at plant site • Cost of fuel • Price for electricity (especially at peak times)6 

## The rest of the talk  Show you some cooling systems  Present some cost comparisons  Show some advancements that may help reduce cost7 

## Cooling systems

 The old movie ---once-through cooling  Common practice ---wet cooling towers  Water conservers ---dry cooling/air-cooled

condensers8 

## Once-through

to HRSG Cold CW Hot CW CW Pump(s) Exhaust Steam

to HRSG Cold CW Hot CW CW Pump(s) Exhaust Steam
Water source— ocean, river, lake, etc9 

## Wet cooling tower Fans Cooling Tower

Blowdown Makeup Fans Cooling Tower

Blowdown Makeup Hot CW

Cold CW Ambient air from condenser
to condenser10 

## Wet cooling tower11 

## Air cooled condenser

Fans
to HRSG Exhaust steam Air Cooled Condense r

Fans
to HRSG Exhaust steam Air Cooled Condenser

Ambient air from steam turbine

to boiler or HRSG13 

## Cooling system costs  Capital costs  Operating costs • Cost of power for pumps and fans • Cost of water • Cost of maintenance  Penalty costs • Effect on plant efficiency • Cost of reduced output on hot days14 

## Trade-off/ optimization

0 1 2 3 4 5 6 7 8

0 1 2 3 4 5 6 7 8 9 10 Size of Cooling SystemCost Capital Costs Penalty Costs Total Costs15 

## Cost differentials  Increased capital cost---500 MW plants

0.4% to 12.5%  Increased cooling system power

0.5 to 3.0 MW  Increased plant heat rates 0.4 to 4.0 %  Increased power production costs

1.9 to 4.9%Capital Cost---500 MW Steam Plant

280,000,000 290,000,000 300,000,000 310,000,000 320,000,000 330,000,000 340,000,000 350,000,000

Once-through Wet Dry Cooling System TypeCaptial Cost, $ Base +.43 % +12.6 %Hot Day Heat Rate Increase---500 MW Steam Plants

0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10%

Once-through Wet Dry Cooling System TypeHeat Rate Increase, %18 

## “Equivalent” cost of water 

##  $3.50 to $6.00 per 1,000 gallons  $1,000 to $2,000 per acre-foot19 

## Some things that might help....  

### Use a little bit of water a little bit of the time

– Hybrid (wet/dry) systems

– Spray enhancement  Recover some of the water from wet systems  Marley’s Air-to-Air ® 

### concept20 

## Hybrid wet/dry systemTucuman 450 MW Combined Cycle (Argentina) PAC SYSTEM® (Air Cooled Condenser & Wet Cooling System)22 

## Spray enhancement  Spray water into inlet air stream of air-cooled condenser  Low capital cost approach  Low annual water use  Reduce inlet temperature by 5 to 10 F  Restore “hot day” capacity loss24 

## Marley Air-toAir ® Condensing Media Ducting Wet Fill Cool Ambient Air Cool Ambient Air Hot Water Condensing Media Ducting Wet Fill Cool Ambient Air Cool Ambient Air Hot Water25 

## Possible retro-fit26 

## Finally....  Is the prize worth the price?

– Your call

– Very site specific  Is this a good way to do it?

– I state without proof • About the same as reclaimed water use • Cheaper (now at least) than “water-free” renewables (wind or solar)