# Presentation: 270959

## Energy System Research and Testing (Conversion) Activities at NREL

- Gerry Nix
- March 20, 2003

## Goal:  Reduce Cost of Geothermal Electricity by at Least 1¢/kWh

- Make the Plant **Less Costly** – Reduce Investment
- Make the Plant **Perform Better** – Higher Efficiency, Greater Output
- Make the Plant **More Robust** – Harder to Break
- Make the Plant **Easier to Operate** – Reduce Costs via Automation and Instrumentation
- Make the Plant **Easier to Maintain** – Better Materials and Designs

**Time Frame is in the Next 5 to 7 years for Implementation**

## Cost Reduction Targets

- Binary Plants – Better Cycles (NREL, INEEL)
- Enhanced Heat Transfer (NREL, INEEL)
- Better Materials (NREL, BNL, INEEL)
- Innovative Components (NREL, INEEL)
- Better Instruments (INEEL, BNL)
- Additional Revenues (BNL, LLNL)

## Low-Temp Resources are More Common

- 83% of the sites require binary plants (also, EGS/HDR will most likely need binary plants)
- And 50% of the available energy is below temperatures requiring binary plants (170C)

- Frequency of occurrence and energy of hydrothermal convection systems identified by the USGS in 1978

- Polymer corrosion barrier coatings:
*Prevent* corrosion of geothermal plant equipment
*Reduce* maintenance expenses

*Steam vent at Cove Fort after 5 years of use*

**Better Materials **

**Approach is to use inexpensive coatings with special properties on inexpensive base materials, with performance equivalent to exotic alloys**

## Extensive Field Testing

- (Mammoth, Cove Fort, CalEnergy)

## Large Life Cycle Cost Savings

## Collaboration with Curran, Int.

- New Plant Built for PPS Business
- Perfected Electrostatic Application
- R&D 100, FLC Awards

## Future Work

- Perform Long-Term Testing of Operating Equipment
- Evaluate at Temperatures to 350°C
- Expand Number of Test Sites and Partners
- Test New, Thin Coating for Finned Tubing Exposed to Brine Spray

## Why Improve Heat Rejection?

- 90% of geothermal heat is rejected; condensers make up 20-30% of plant cost
- Plant power will increase 1% for every1oF drop in condenser outlet temperature
- Output of air-cooled plant can drop more than 50% in summer, when electricity is highly valued
- Water cooling can greatly reduce reservoir pressure (The Geysers)
- Western states face water shortages – air cooling most likely required for new plants, including EGS and HDR

## Air-Cooled Condenser Research

- _Transpired and Tabbed Fins_

**Innovative designs     **
**Increase performance by 30%**
**CRADA with manufacturer (SRC)**

_**Bottom line**_**: Improved heat transfer reduces heat exchange area,**
**and can reduce cost of electricity by 0.5 cents/kWh**

## Advanced Fins ITS Test Results

**Latest tab fin shows about 40% more heat transfer at the **
**Same fan power with only 11% reduction in air flow, plan is**
**To fabricate prototype and test at ITS**

## Fin-on-Plate Air-Cooled Condenser

- Test Setup

## Fin-on-Plate Condenser, 36% higher heat transfer coefficient for the same pressure drop

- Potential Industry Partners for Manufacturing; Linde, GEA Rainey, API Heat Transfer
- Carry out field testing in collaboration with Exergy
- Work with Experts in HX area (Prof. Ken Bell)
- Collaboration with HTRI

## Evaporative Enhancement of Air-Cooled Condensers - Measurements at Mammoth

**Munters increased net power output 62% (800 kW to 1,300 kW**
**At 78****°F ambient**

## Summary of Heat Rejection R&D Benefits

- Increasing heat transfer on air and tube sides 30% can reduce electricity cost by 0.5 ¢/kWh
- Evaporative enhancement and trim condenser concepts can potentially double output of air-cooled plants on summer days; payback for retrofit can be < 3 years depending on water and electricity costs

## Innovative Components - Separators

- Separators disengage solids and liquids from vapor.
- They may also be used to separate NC gases.
- Poor performance results in costly damage to turbo-machinery.
- An industry-wide assessment of separators is needed to reduce O&M costs.
- NREL brings advanced tools such as CFD (computational fluid dynamics) to industry
- Partnership with Two-Phase Engineering

## Well Test Plume Path lines

## Separator in Operation

## “DIRECT USE” - Applications Other Than Generating Electricity at Temperatures Under 250°F

- Heating and Cooling
- Aquaculture
- Industrial Process Heat
- Agricultural Process Heat
- Spas, Pools and Bathing

**Two Activities:**
**  ****Direct Use Field Verification Projects**
** ****Direct Use Technical Support, Testing and Evaluation, **_**OIT and WSU**_

**OIT: **_**web hits: 2,000,000+ , in-person or  phone assistance requests: 2000+**_

## Direct Use Projects

| PROJECT | Location | Phase I | Description | STATUS |
| --- | --- | --- | --- | --- |
| SKS Management | Home Valley, WA | $75,000 | Space heating, water heating and spa heating for a resort to be built-out in several phases | Phase I study I progress. Problem encountered with drilling an injection well |
| I’SOT | Canby, CA | $63,800 | District and water heating system project for a complex of 32 buildings totaling 44,000 sq ft | Phase I study completed. Environmental Assessment completed and FONSI received; Preparing to implement Phase II |
| City of Klamath Falls  | Klamath Falls, OR | $25,300 | Expansion of the city’s district heating system into a new downtown area and increasing its efficiency to serve new customers from the existing wells | Phase I study being completed; 100% design review for proposed Phase II project to be conducted in April |
| University of Idaho/Idaho Water Resources Research Institute
 | Boise, ID | $74,998 | Geothermal-driven absorption cooling system for a new office building at the University | Phase I study completed. Geothermal-driven absorption cooling was found not to be cost-effective |
| AmeriCulture | Animas, NM | $75,000 | Use of direct use geothermal system to expand existing tilapia and add new business of growing fish to market size | AmeriCulture is seeking funding mechanism for Phase I |

**Direct Use Projects**

## Small Scale Field Verification Plants

- Kalina Cycle – Plant to be built via Exergy to provide cost and performance data, support to DOE-GO
- Mixed Working Fluid Binary Plant – Evaluation underway (Power Engineers) of a potential plant at Empire to provide cost and performance data
- DOE assumes a significant portion of the risk

##        Geothermal Communications

_**Objective**_**:**
**- Educate all stakeholder groups about geothermal energy, and****- Convey the **_**mainstream**_** potential of this exciting technology**

***Geothermal Today – all audiences***

***Quarterly GRC Bulletin Inserts – ******industry audience***

## Web Sites

***Web Sites***

***GPW State Fact Sheets – ******GPW stakeholder audience***

***GPW Native American Poster***

***GPW ******State Posters***

***Exhibits and Displays***

## NREL ESR&T Summary

- It is Possible to Reduce COE by 1¢/kWh
- Opportunities Exist for Quick Returns, 5 to 7 yrs to Implementation
- Program is on the Way to Success, ala Direct Contact Condenser, PPS
- All Activities are in Partnership with Industry
- Proper Technical Areas are Targeted
- Cost-Effective R&D Underway, guided by Extensive Systems Analyses
- Promoting Direct Use is Important