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Sun and Steam Power the Nevada DesertIn the US State of Nevada, energy and environmental engineering firm Solargenix Energy 

is developing a significant solar power plant, one of the largest built worldwide in the last

15 years. The plant adds important capacity to state utilities’ obligation to increase power

generation from renewable sources. Using parabolic trough technology, the electricity 

 will be produced by a 72-megawatt (MW) Siemens steam turbine-generator.

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The word ‘vast’ is perhaps inadequate to describe Nevada’s desert.

Its sheer scope, breadth and expanse are daunting. The mind can

play tricks when judging distance. What looks to be a mile or

so down the highway can suddenly turn into a 30-minute drive.

Of course, this being desert land the climate and landscape can be

extremely inhospitable. The southern region of Nevada, part of 

the Mojave Desert, has both mountainous and flat or uneven bush

land, where away from the main towns you’d be hard pressed to

find a living soul. It is also hot, with minimal rainfall and maximum

sunshine every year.

Twenty miles from the bright lights, big city attraction of ‘Fabulous’

Las Vegas is the quieter and more relaxed Boulder City. Originally

created in the 1930s as a home to the construction workers that

built the nearby Hoover Dam, Boulder is the city with the largest

geographical area in Nevada. Curiously, it is also the only city in

the state with no gaming.

In keeping with that tradition, exploiting the potential for solar

power generation on ideal terrain and climate is anything but a

gamble for the city. In fact, in these environmentally conscious

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Power by the Public Utility Commission of Nevada. The approval

allowed Solargenix to proceed with the development of its 64-MW

solar power plant.

Put simply, the plant uses solar parabolic trough technology to re-

flect the sun’s heat onto oil-filled reception pipes running through

the mirror collectors. The synthetic oil is passed to heat exchangerson the power island, which transfer the heat to generate steam for

the turbine.

Capturing the sun via this process is known as concentrating solar

power (CSP). It uses curved (parabolic) mirrors to concentrate solar

radiation on a thermally efficient receiver running the length of 

the trough. The receiver consists of a specially coated absorber tube

embedded in an evacuated glass envelope. Absorbed solar radia-

tion warms up the heat transfer oil flowing through the tube to al-

most 400°C (752°F). The system also uses a tracker, so that the lineof the sun can be followed throughout the day. German company

Schott AG is the manufacturer of the receiver tube technology, and

for Nevada Solar One, Solargenix is using 19,300 of these units.

POWER ISLAND

For the power island, Solargenix awarded a contract to market-lead-

ing Siemens Power Generation in August 2005 for a high efficiency

direct reheat SST-PAC-700RH steam-turbine generator set. The con-

tract has also included stand-alone Simatic S7 control systems and

installation and commissioning support plus staff training. The

72-MW SST-700 turbine has been manufactured at Siemens’ facility

in Finspong, Sweden. It is a dual-cased geared engine using one

high pressure (HP) and one low pressure (LP) module. The steam

turbine was delivered to site mid November, and the plant itself 

should be commissioned in April 2007.

Steam is generated via the heat exchangers at 700°F/1,250 psia.

 After passing through the HP turbine it is taken back into the steam

generator for reheating and bringing LP steam up to 700°F again.This will further reduce the oil temperature back to the solar collec-

tors and improve the overall cycle efficiency of the plant.

The reheated steam is now admitted into the LP turbine to further

generate power; it then enters a vacuum condenser where remain-

ing steam is condensed to be pumped back into the steam genera-

tor again. This careful use of water is vitally important considering

the desert location and value of water sources. It has also been a

consideration for the plant’s cooling towers. But Solargenix is justi-

fiably proud of the fact that the plant has no water discharge.

Supplementing the heat cycle is a small, natural-gas-fired auxiliary

boiler, which will be used at times when the sun’s radiation is not

times using Southern Nevada’s ample sunlight to provide electricity

for 40,000 local homes is a sound energy policy that allows utilities

to edge closer to legislative requirements for renewables.

RENEWABLE PORTFOLIO STANDARD

In 1997, the State of Nevada adopted a Renewable Portfolio Stan-

dard that placed a mandate on the two utilities —Nevada Power andSierra Pacific Power—to use renewable energy to provide a mini-

mum percentage of electricity consumption. A revision to that state

law in 2001 meant that this amount should increase by 2 percent

every two years. Each phase can be broken down as thus: 7 percent

in 2005, 9 percent in 2007, up to 15 percent by 2013. A further

amendment in 2005 saw the obligation rise to 3 percent every two

years culminating in a 20 percent share for renewable energy

generation by 2015. Investment in energy efficiency measures was

also added to that renewable portfolio standard.

 A crucial part of the legislation expands the state’s commitment to

solar power so that the technology provides 5 percent of renewable

energy projects. The Nevada Solar One project currently under con-

struction will go some way to supporting that ideal. In addition, the

US Department of Energy (DoE) has issued a report that identifies

suitable land and solar resources in Nevada that could produce

over 600,000 MW of electricity using concentrating solar technolo-

gies. Currently, Nevada’s power consumption is less than 3 percent

of this resource capacity. The DoE report also claims that the eco-

nomic benefits far exceed the cost to develop this clean renewable

energy source.

ELDORADO VALLEY

On a 400-acre site in Boulder City’s Eldorado Valley—just off the

Route 93 highway linking Las Vegas and Phoenix— is a solar power

complex that, once complete will be the third largest in the world.

Solargenix Energy, Inc, a leading energy and environmental engi-

neering company headquartered in North Carolina, is developingNevada Solar One. Earlier this year, the Spanish renewable energy

firm ACCIONA Energía S.A. purchased 55 percent of Solargenix.

It is the skill, engineering and solar know-how of Solargenix and

 ACCIONA that drives the scheme, with more than a little help from

the prime mover of course—a Siemens SST-700DRH industrial

steam turbine-generator.

The first stone for Nevada Solar One was laid at a special ceremony

in February this year. This followed a long period of gaining plan-

ning permission and securing financing and tax incentives from

the Nevada Commission on Economic Development. In September

2005, Solargenix announced the approval of amendments to their

power purchase agreements with Nevada Power and Sierra Pacific

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tion workers removed about three rattlesnakes a day. There were

also tarantulas and “hundreds” of black widow spiders presenting,

if not a danger, then at least a distraction to meticulously sort out.

IMPRESSIVE

To give some idea of the scale of the plant, from the sites’ overall

area of 400 acres, 251 are taken up by the solar array system. At a

distance (and again we come to the sheer expanse of the Nevada

desert) the plant looks like a small, flat, white mass. When the sitedraws closer its enormity is jaw-dropping; hundreds of huge CSP

troughs with crystal clear mirrors reflecting the desert with a burst

of deep blue and sandy brown colours. It is immensely impressive.

 As is the steam turbine solution that Siemens has provided for what

was originally a tricky conundrum for the heat cycle of the Nevada

Solar One plant. Producing a quality, proven product at low in-

vestment and life-cycle cost and one that has been manufactured,

shipped and installed to meet customer commitments for on-time

delivery, power output and availability is further testimony to

Siemens’ solutions for every turbine application.

available, or during cleaning of the solar mirrors. The cycling capa-

bility of the plant is significant when dealing with likely variables

in steam temperature and pressure.

The steam turbine is coupled to a generator, which produces elec-

tricity at 13.8 kilovolt (kV), 60 Hz. Power is then stepped up by a

transformer, to be distributed to the grid at 230 kV from the huge

switchyard. With a separate (and unconnected) combined-cycle

power plant adjacent to the solar plant this section of the desert isa curious mixture of bush land and a sea of transmission towers.

WILDLIFE

Of course, working with this terrain has been another interesting

aspect of the project groundwork. With a rocky, uneven surface, not

to mention shrub and bush land, clearing 400 acres is a consider-

able task. And there have been other factors to take into account.

Despite the harsh environment, there is wildlife that adapts to its

surroundings and survives in the desert. On the road down to the

site it is not uncommon for roadrunners to dart across the tarmac.

But not all creatures great and small are particularly friendly. As

a Solargenix official confirms, during the ground clearance opera-

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Designed by Venezuela’s state-owned oil company as a part of a vast new natural gas

transportation system, a brand-new 300-km pipeline is being built to link the country’s west-

ern region with the existing gas infrastructure and the rich, but scattered, reserves from

producing wells in the central and eastern regions. As well as making this clean, low-cost

fuel available to many Venezuelans for the first time, the pipeline will enable gas to be

used to boost oil production from mature wells. As part of this complex US$520 million proj-

ect, Siemens is supplying a total of ten gas turbine-powered compressor trains, which will be installed by a Siemens-led consortium in compressor stations along the new pipeline.

Power in the Pipeline

Covering a total area about two-and-a-half times the size of Ger-

many, Venezuela is located on the northern tropical Caribbean

coast of South America. The diversity and sheer beauty of its land-scape so impressed the fifteenth century explorer Christopher

Columbus that he called it the Tierra de Gracia—Land of Grace— 

which has become the country’s unofficial name. In contrast to its

soaring mountains, the world’s highest waterfall, tropical forests

and silver-sandy beaches which make Venezuela a magnet for

tourists, the country’s burgeoning economy is based principally

on the oil and gas industry.

BIG OIL

With proven oil reserves of around 76 billion barrels, Venezuela is

ranked as one of the world’s largest producers. However, a number

of the largest fields have been exploited for decades, with some of 

the oldest wells in continuous operation for almost 100 years, and

production levels are now falling rapidly. Natural gas, co-produced

with oil from existing wells as well as from more recent finds both

onshore and offshore, is also currently being produced at an annual

rate of nearly 30 billion cubic meters, a large proportion of which is

being re-injected into fast-depleting oil reservoirs to increase their

production. In combination, this vital industrial sector accounts forsome eighty percent of the country’s export revenues and about a

third of its total earnings.

GOING FOR GROWTH

 Although the country has enormous reserves of natural gas, a lack

of adequate infrastructure, such as a national grid-system for

the transportation of bulk supplies of natural gas or an established

country-wide distribution network serving urban and rural con-

sumers, has meant that Venezuela has been unable to exploit this

resource to its full extent. Today, as the price of oil continues to

rocket, the country’s economy is booming with real growth in GDP

approaching 10 percent, allowing previously shelved governmentplans for expansion to be reactivated.

In 2004 the state-owned oil company Petroleós de Venezuela S.A.

(PdVSA) awarded contracts to three local companies for the first

stage in the construction of a huge new undertaking, the 300-km

Interconnexion Centro Occidente (ICO) pipeline, known as the ICO

project. This complex infrastructure project, due for completion

in 2007, will connect gas-producing wells in the eastern and central

regions with existing wells and new gas transmission systems in

western Venezuela, partly to boost oil production and also to bring

natural gas to consumers in that part of the country for the first

time. A 106-km pipeline providing a connection between natural gas

fields in Falcon state and the PdVSA Paraguana refinery complex,

one of the largest in the world, has already been completed and will

soon be delivering between 10 and 100 million cubic meters of gas

per day, increasing progressively until it reaches 100 to 300 million

cubic meters of gas per day.

PICKING THE PATH

One of the largest and most challenging pipeline projects ever un-

dertaken by PdVSA, the ICO system for the bulk transnational

transportation of natural gas, was originally planned nearly 20 years

ago. The giant new line now under construction will comprise 230

km of 30-inch (762 mm) diameter and a further 70 km of 36-inch

diameter (914 mm) pipe. The pipe is formed from special high-

tensile steel capable of withstanding internal pressures of more

than 4,600 bar, reducing both wall thickness and the number of 

welds, and is being used for the first time in Venezuela. Buried at a

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shipped to site via the Siemens facility in

Houston, Texas, where the compressor

trains were assembled and specially pack-

aged for operation in a tropical environ-

ment. Three units are being installed at the

Morón compressor station, four at Los Mor-

ros and a further three at Altagracia. The en-

tire turnkey contract is being carried out by

a local consortium headed by Siemens S.A,

partnered by Caracas-based Jantesa, which

has responsibility for engineering and pro-

curement, with Confurca headquartered in

Ciudad Ojeda undertaking civil works. Siemens will also provide

full maintenance services for the turbocompressors over a four-

year contract period. The compressor stations will be monitored and

controlled remotely through an optical fiber data-communications

network being supplied by Siemens S.A. The stations will be linked

to the primary control room at Anaco and with a secondary con-

trol system in Caracas.

IMPROVING LIVES

 Although Venezuela’s investment in the ICO pipeline is intended to

boost the national economy through increased oil and gas produc-tion, the vast, long-distance construction project is also aimed at

providing major social improvements for the

widely scattered, mainly rural communities af-

fected by the project. In line with the govern-

ment’s demand that no less than ten percent of the

entire project value must be returned to the com-

munities involved, PdVSA is not only ensuring that

gas will become available as a low-cost fuel for a

large number of people for the very first time, but

is undertaking a far-reaching social initiative affect-

ing communities along the whole length of the

pipeline. “This is the nicest and most exciting part

of this project,” says PdVSA Project Manager

Richard Tahan. “We are now able to improve the

lifestyle and raise the standard of living for literally thousands of 

people, providing new facilities in areas ranging from entire towns

and villages, to scattered farms, communities and even isolated

dwellings.”

FISHING, FARMING AND FAMILIES

Richard explained that the initiative is being split into four sectors.

“The first will involve building and repairing roads, building new

local medical centers, improving existing schools and re-housing

widely separated and outlying families who currently live within

2.5 km on either side of the pipeline, in modern new housing.” Hepointed out that the pipeline project involves installing electrical

power, drilling wells for water for hydro-testing operations and

installing the Siemens data-communications network. “Because all

these utilities are already being installed along the route of the

pipeline, it is quite easy for us to provide modern facilities for peo-

ple in the vicinity. They will not only be supplied with drinking

water and mains electricity, but will also have full access to tele-

phones and a broadband connection to the internet,” said Richard.

The second sector will include the development of the fishing

industry in the coastal area of Rio Seco, with the provision of fresh

drinking water and mains electricity, but also including the con-

struction of refrigerated storage and ice-making facilities to support

the local shrimping industry. The third and fourth sectors will cov-

er the modernization and expansion of locally-based agriculture in

both the Altagracia and Los Morros areas. In addition to increasing

production and efficiency, additional investment in the agricultural

and farming industry will provide future employment for local peo-

ple currently employed on the construction of the ICO pipeline.

WIN-WIN FOR SIEMENS

The Anaco project represents not just a major contract win for

Siemens, but marks a significant step forward in the further devel-

opment of the company’s oil and gas business in Latin America.

The ability to demonstrate successful implementation of both in-

dustrial gas turbines and latest-generation gas compression

solutions under a turnkey contract in a tropical environment is

providing a benchmark against which competing products and

suppliers are measured and a win-win solution for Siemens and

customers alike.

”We are able to improve the standard ofliving for literally thousands of people,

providing new facilities to towns andvillages, to scattered farms, communi-

ties and even to isolated dwellings.”Richard Tahan, Project Manager, PdVSA