Article: Nevada Solar One Project: The Biggest Concentrating Solar Power (CSP) Plant in the World

Nevada Solar One Project (NSOP) is indeed the biggest CSP plant installed in the world in the last 19 years and the third biggest in absolute terms behind the two 80 MW facilities constructed in the Mojave desert in the early 1990s.  CSP technology uses thousands of mirrors to reflect and concentrate sunlight onto a central point to generate heat, which in turn is used to generate electricity.

Slide1

Sixteen million solar panels blanketing large pieces of land and covering roofs of homes and businesses were installed in the United States in 2012, when 3.3 gigawatt of the solar equipment materialized to representing a 76 percent annual growth.

Cumulatively, the country had about 7.2 gigawatt of solar generation capacity from solar panels by the end of 2012, according to a report by GTM Research the Solar Energy Industries Association. That capacity doesn’t mean consumers could tap that much power from solar power projects. The amount of production depends on whether the sun is up and unobstructed by clouds.

1.     BACKGROUND:

Total energy consumed per capita (2011) in Nevada was 233 million Btu which ranks 42 at the national basis.  Here are some energy related stats last updated in July 2012 by US Energy Information Administration:

  • More than 90 percent of the energy Nevada consumes comes from outside the State;
  • The 400-mile UNEV pipeline, opened in 2012, lets petroleum products from Salt Lake City area refineries flow to Las Vegas.  Previously, Las Vegas obtained petroleum products only from three California pipelines;
  • Nevada generated two-thirds (67 percent) of its electricity from natural gas in 2011;
  • Nevada ranked second in the Nation in net electricity generation from both geothermal and solar energy in 2011.  9.1 percent of Nevada’s net electricity generation came from those two sources; and
  • The State’s Energy Portfolio Standard requires 25 percent of electricity to come from renewable energy resources by 2025.  In 2011, 16 percent of net electricity generation came from geothermal, solar, and hydroelectric power sources.

The following tables illustrate Nevada’s economy according to US Energy Information Administration:

No

Population and Employment Nevada U.S. Rank Period

1

Population 2.8 million 35 2012

2

Civilian Labor Force 1.4 million 33 May-13

3

Per Capita Personal Income $ 37,361 38 2012

 

No

Industry Nevada U.S. Rank Period

1

Gross Domestic Product $ 130.4 billion 32 2011

2

Land in Farms 5.9 Million Acres 37 2007

3

Market Value of Agricultural Products Sold $ 0.5 billion 46 2007

The following represents the consumption of energy in Nevada for 2011:

  • Residential                  156,088 billion Btu;
  • Commercial                 119,583 billion Btu;
  • Industrial                     159,482 billion Btu; and
  • Transportation             197,365 billion Btu.

                TOTAL                      632,518 billion Btu

The following graph illustrates another view of the consumption:

Slide2

According to a Forbes article, Las Vegas uses 5,600MW on a summer day and is expected to use 8,000MW by 2015. It’s hard to determine how much the strip uses by itself, but the article says that the casinos consume 20 percent of the city’s entire electricity demand.  Of course, not all of the casinos in Vegas are on the strip, but on the other hand the strip has more on it than just casinos.  Call it a wash and say the strip uses 20 percent.

Here are a couple of interesting predictions related to the consumption of electricity which were made by Alfredo Fernandez, an architecture professor at the University of Nevada at Las Vegas, in 2006:

  • Each new resident will need 20,000 kWh of electricity a year.  That will be 400,000 megawatts at a cost of $40,000,000 a year producing 160,000 tonnes of carbon dioxide (CO2) per annum. But that is at a time when Wall Street Analysts predict that the $60 barrel of oil will be $300 a barrel by 2015 energy running costs may be five times higher- $200,000,000 a year at a time when many of the median income visitors will no longer be able to afford the air flights in; and
  • The total electricity output generated by the Hoover, Parker and David Dams is only 200,000 megawatts in a good year.  So the new development will need yet more power. They are already building two more coal power stations.  They are also commissioning the Solar One 64 megawatt solar generator in the Nevada Desert but even with this they still will not have the generating capacity to keep the lights on in the new development let alone the rest of the Strip.

It’s true that the amount of electricity generated by NSOP may not be enough to meet the future electricity demands in order to keep the lights on in Vegas but Nevadans cannot afford to stop exploring the possibilities of generating electricity wherever and however they can.  More importantly, generating electricity by solar power is also environmentally prudent as it’s a clean source and helps avoid CO2 emissions.  Perhaps the simplest way to define solar is “relating to or derived from the sun or utilizing the energies of the sun – solar eclipse.

2.     SOLAR HISTORY:

The history of solar power is a long one. The Sun was worshiped by many ancient civilizations.  Ancient Egyptians built places to live that allowed stored energy from the sun during the day, and a heat release during the night.

Slide3

This kind of architecture heated homes at night while keeping the temperature low during the day.  Egyptians also used the sun as part of their mummification process, using the sun to dry dead bodies. The Egyptians used a form of passive solar power.

Native Americans also built houses that used passive solar power. Houses were built into the side of cliffs or hills to allow storage of heat during the day, and a release of heat at night.

Slide4

3rd Century B.C., Greek soldiers with the help of Archimedes, focused light on a Roman fleet by using mirrors. The Romans were invading a port city that did not have defenses ready for the attack. The mirrors were used to concentrate the energy of the sun, and cause the fleet’s sails to burn. The Romans retreated and the Greeks were able to prevent the invasion. The Greeks used passive solar power.

A historical writer in 100 A.D. by the name of Pliny the Younger built a house in the northern part of Italy that had mica windows in one room. This one particular room demonstrated solar heating in that its mica windows stored heat, and later gave it off. This room was useful because the added heat it generated lessened the amount of wood that had to be burnt.

In 1891 the first commercial solar water heater was patented by the father of American solar energy, Clarence Kemp.  William J. Bailley of the Carnegie Steel Company in 1908 invented a solar collector with copper coils and insulated box.  In 1958, a smaller satellite of US Vanguard was powered by a less than one watt power solar cell.

From the 1960’s to the present oil prices play an important part of the economics of solar power and other alternative energy forms.  In the 1960’s cheap imported oil was the main energy competitor to solar power and restricted the overall solar technology market.

During 1973 – 1974 the oil embargo allowed opportunity for solar power to flourish. The US Department of Energy funded the Federal Photovoltaic Utilization Program that began installation and testing of over 3,000 PV systems.

In the mid 1980’s incentive for business led to around 150 businesses for manufacturing industry with annual sales of $0.8 billion.

Slide5

Gulf War of 1990 renewed interest in solar power as an alternative to oil and petroleum products.  Mid 1990’s have few tax credits and incentives for solar electric homes or heating systems, yet approximately 1.2 million buildings in the US are solar heated.

International markets and foreign investments especially from Germany and Japan took off in 1970, but continue to be major factors in the solar energy market.

3.     NEVADA SOLAR ONE PROJECT:

“Nevada Solar One represents our bid to excel in new technologies to produce clean and sustainable energy, with an emphasis on economic viability, technological competence and the capacity to be replicated on a large scale in locations around the world,” said Jose Manuel Entrecanales, Chairman and chief executive of ACCIONA, the Spanish company that designed and built the solar power plant and will operate it.

“We also chose Nevada for the outstanding commitment of this state to the development of sources of renewable energy,” he said.

The duration of the project was 16 months and it went online for commercial use on June 27, 2007 with a nominal capacity of 64 MW and maximum capacity of 75 MW spread over an area of 400 Acres.  Electricity production is estimated to be 136 GWh annually.  Just to put it in a proper perspective, it will supply electricity equivalent to 15,000 households.  The projected CO2 emissions estimated to be 134 million kilowatt hours per year which is equivalent to taking approximately 20,000 cars off the road annually.  The project required an investment of $266 million USD.

The Nevada Solar One power plant was built in Boulder City’s Energy Resource Zone.  In order for a permit to be granted for a plant development in this zone, plans for renewable generation are required. The NSOP was accepted as part of a larger project initiated by Duke’s Energy, who hoped to build facilities which could generate 1 Gigawatt of electricity in the El Dorado area.

Slide6

During peak hours it uses specialized technology to track the movement of the sun and adjust the mirrors to concentrate the rays accordingly. The amount of the technology used is astounding, with almost 200,000 mirrors reflecting the sun’s rays onto approximately 20,000 tubes which lay in parabolic troughs. A liquid which transfers heat flows through the tubes and then is turned into steam which powers a turbine. This turbine is linked to a generator which produces the electricity.

Slide7

Many hopes are held for the future.  Nevada has abundance of sun and land and, in theory, has the ability to generate around 600 gigawatt of electricity by using the same technology that Nevada Solar One uses. It has been enthusiastically theorized that, with a massive expansion of solar plants in the Energy Resource Zone, the area could provide enough electricity to power the whole of the United States of America. In comparison, similar facilities operating in the Mojave Desert have generated a capacity of 354 megawatts since 1984.

Slide8

The solar power plant is not 100 percent renewable, but has a 2 percent fossil fuel back-up from a small natural gas heater, used to prevent the water from freezing, and to continue generation during cloudy days and peak demand periods. Nevada state law does not allow more than 2 percent fossil-fuel back-up, so this plant uses much less than other Mojave Desert CSP plants in the Mojave Desert of California and Arizona. Operation and maintenance (and profits) are by the Spanish company Acciona Energia. The energy is sold to Nevada Energy (NV).

The electricity is purchased by NV Energy under a 20-year power purchase agreement. The purchase helps the utility offset the requirements for the production of electric power from renewables – 20 percent of the electricity consumption in 2013, with 5 percent exclusively from solar energy.

February 18, 2010 – The Spanish Company, Acciona, expanded its Boulder City, Nevada, parabolic trough solar thermal plant as the Department of Energy awarded it a $2.9 million grant.  The grant for Acciona comes in lieu of the tax credit the company would have gotten for expanding its plant. The grants allow developers to recoup 30 percent of the cost of construction.

4.     CONCENTRATING SOLAR POWER (CSP) TECHNOLOGY:

CSP technology is designed to produce electricity by concentrating solar energy in a single focal point.  This concentrated energy is used to produce steam, heat up fluids, and activate turbines that produce electricity.  CSP uses mirrors or lenses to concentrate a large area sunlight or solar thermal energy onto a small area.

CSP is being widely commercialized and the CSP market has seen about 740 MW of generating capacity added between 2007 and the end of 2010.  More than half of this (about 478 MW) was installed during 2010, bringing the global total to 1095 MW.  Spain added 400 MW in 2010, taking the global lead with a total of 632 MW, while the US ended the year with 509 MW after adding 78 MW, including two fossil–CSP hybrid plants.  The Middle East is also ramping up their plans to install CSP based projects and as a part of that Plan, Shams-I the largest CSP Project in the world has been installed in Abu Dhabi, by MASDAR.

Slide9

CSP growth is expected to continue at a fast pace. As of April 2011, another 946 MW of capacity was under construction in Spain with total new capacity of 1,789 MW expected to be in operation by the end of 2013.  A further 1.5 GW of parabolic-trough and power-tower plants were under construction in the US, and contracts signed for at least another 6.2 GW.  Interest is also notable in North Africa and the Middle East, as well as India and China.  The global market has been dominated by parabolic-trough plants, which account for 90 percent of CSP plants.

CSP plants use direct solar radiation.  They operate best when located in arid and hot areas within an area of 35 Celsius degree (95 degree Fahrenheit) on both sides of the Equator. These “hot spots” are distributed around the globe and cover land on all continents (except for Antarctica): In the Middle East, North Africa, South Africa, Australia, the south-west of the United States, parts of South America and central Asian countries from Turkey to parts of India and China.

CSP has the potential to become a keystone of future energy systems, as it is one of the cleanest suppliers of base load for electrical power networks.  Main components of CSP plants include the following four elements:

  • The concentrator, which focuses the sunlight on a specific zone;
  • The receiver, which sits on the focus area of the concentrator. The concentrated sun radiation produces very high temperatures on the receiver;
  • Transport media and/or storage: A medium (e.g. thermal oils, water, salt or air) is heated within the receiver and then transported to a storage facility or directly to a conversion unit; and
  • The conversion unit (electric power plant), which uses the energy contained in the hot transport medium to generate electric power.

Slide10

Many different types of systems are possible, including combinations with other renewable and non-renewable technologies.

The important consideration, in order to be able to generate power, even in the absence of direct solar radiation (i.e. on cloudy days or at night), plants can be fitted with a thermal storage system or have the option of dual operation.  Under dual operation, a fuel combustion system is used to maintain a continuous supply of heat. This means that the conversion unit can be powered by fossil fuels, biogas or biomass in order to provide fixed capacity at any time.

5.     CONCLUSION:

It is true that CSP technologies are some of the cleanest options for power generation and overall greenhouse gas emissions are marginal but the water requirements may become controversial in some specific cases.  For instance, the cooling towers at Nevada One Solar evaporated huge amounts of water from the Colorado River to cool the steam cycle.

This “wet-cooled” solar thermal plant uses 400 acre-feet of water per year, about 6 acre-feet of water per MW. To put it another way, coal fired power plants use 110 to 300 gallons per megawatt hour; a nuclear plant uses between 500 and 1100 gallons/MWh; and a solar parabolic trough plant uses 760 to 920 gallons/MWh. Solar thermal power plants, like coal, natural gas, and nuclear plants, boil water into superheated steam, which then turns turbines to generate electricity.  The steam must be condensed back into water in cooling towers, and this is where most of the fresh water is used up in wet-cooled systems.  Waste heat is dissipated in steam evaporated off into the air.  For NSOP, the water comes from Lake Mead through negotiation with Boulder City’s supply.  The Colorado River is already strained in allocations for multiple states and cities.

Slide11

The Sierra Club says it will try to push for dry-cooled, “air-cooled” solar thermal plants in the California deserts, which however, are less efficient.  In an attempt to save water, these kinds of solar thermal power plants use dry desert air instead of water to cool the operation.  But this will greatly increase building costs because enormous cooling towers need to be constructed.  Also relying on air to cool would not cool the water circulating through the plant to a low enough temperature for peak performance, decreasing the efficiency of the plant.

The Bureau of Land Management (BLM) has received 130 applications for large-scale photovoltaic and concentrated-solar projects on 1 million acres of land in the West.  In response to the concerns over water shortages and habitat destruction BLM decided to take a cautious route when approving applications for solar projects, announcing it would accept no other applications for large-scale solar projects on its western lands pending the completion of an Environmental Impact Statement.

The delay raised the ire of Senator Harry Reid (D-NV) and the solar industry, so BLM reversed its decision, and will continue accepting applications for industrial-scale projects with no plan for how to allow such drastic water consumption.

Resources:

  1. Forbes – US Solar Market Grew 76 percent;
  2. Nevada State Profile and Energy Estimates;
  3. US Energy Information Administration;
  4. US Energy Information Administration – Consumption;
  5. Climate Change Denial;
  6. The History of Solar Power;
  7. Nevada Solar One Powering America;
  8. Acciona Gets Federal Grant to Expend;
  9. Utility Case Studies – Nevada Solar One;
  10. Wisions – Concentrated Solar Power; and
  11. Wikipedia – Concentrated Solar Power.

Leave a Reply

Your email address will not be published. Required fields are marked *