View source for GHC BULLETIN, JUNE 2004 - EMPIRE ENERGY LLC, A Case Study

http://www.energy.wsu.edu/documents/renewables/2GeoHeat%20Bulletin_July04.pdf

www.energy.wsu.edu/documents/renewables/2GeoHeat%20Bulletin_July04.pdf

EMPIRE ENERGY, LLC 

- A CASE STUDY - 

R. Gordon Bloomquist 

Washington State University Energy Program 

Olympia, WA 

Empire Energy, LLC 

LOCATION 

Empire Energy, LLC is part of the Empire Group of 
companies including Empire Research and Empire Farms. 
Facilities owned by or to which Empire Energy supplies 
energy include an approximately 3.6-MWe net geothermal 
binary power plant and an onion/garlic dehydration plant 
operated by Empire Farms (Figure 1).  Both facilities are 
located in the San Emidio Desert in northern Washoe County, 
Nevada.  The site is located just south of Empire and Gerlach, 
and approximately 100 miles (161 km) north of Reno, 
Nevada.  The power plant was constructed by ORMAT Energy 
Systems and went online in mid-1988.  The plant consists of 
four 1.2- MWe ORMAT energy converters (OEC) designed to 
produce 3.6 MWe of net power at a design temperature of 
285oF (141oC).  The dehydration plant, originally built by 
Integrated Ingredients, was dedicated in May of 1994.  The 
dehydration unit uses approximately 800-1200 gpm (50.47- 
75.71 L/s) of 298oF (148oC) geothermal water for the four- 
stage dryer.  Present, capacity of the dehydration plant is 
75,000 pounds (34,019 kg) of onions per day or 85,000 
pounds (38,555 kg) of garlic (Stewart and Trexler, 2003). 

RESOURCE 

The San Emidio geothermal area is located within 
the Basin and Range Physiographic Province.  The distinctive 
features of the province are isolated, longitudinal fault-block 
mountain ranges separated by long, alluvial-filled basins.  It 
is adjacent to the northern end of the Lake Range.  The 
geology is dominated by a thick sequence of Tertiary lava 
flows, ash flow tuffs and volcaniclastic sedimentary rocks that 
accumu-lated on an irregular surface of Mesozoic 
metamorphic base-ment (Stewart and Trexler, 2003).  Within 
the San Emidio Desert, the Tertiary rocks are covered by a 
layer of lake beds.  A discontinuous line of hydrothermally 
altered rocks marks the boundary of the desert on the east 
(Mackelprang, et al, 1980).  The northern portions of this 
zone show intense silificants and calcium carbonate deposits 
which, to the south of the zone, is marked by fumaroles, acid 
leaching and some deposits of native sulfur (Mackelprang, et 
al., 1980).  Mapping has identified four north-south striking 
faults and one southwest-northeast striking fault in the area of 
geothermal development.  The faults appear to have between 
1,000 and 2,000 ft (305-610 m) of vertical offset (Stewart and 
Trexler, 2003). 

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