These 258,000 mirrors comprise the core of the largest operational concentrating solar power (CSP) plant in the world, providing heat for 100 MW of solar generation, coupled with 50 MW of natural gas generation.
The desert sands outside of Madinat Zayed are a red-orange in color, as though infused with cinnamon. 120 km southwest of Abu Dhabi in the harsh interior of the Arabian Peninsula, the small town has mostly been a stopover point for workers in the region’s booming oil and gas industry.
However, another kind of power has arisen here. In the rolling sands a few kilometers outside of town a large fence surrounds the equivalent of 340 football pitches, filled with huge, curved mirrors that reflect sunlight onto tubes.
These 258,000 mirrors comprise the core of the largest operational concentrating solar power (CSP) plant in the world, providing heat for 100 MW of solar generation, coupled with 50 MW of natural gas generation. But perhaps more important than this record size is its presence here, in the oil-rich United Arab Emirates (UAE), as the first large solar plant of its kind in the Middle East and North Africa (MENA) region.
For these reasons, Solar Server brings you the Shams 1 Solar Energy Center as our April 2013 Solar Energy System of the Month.
Solar in MENA?
There is an economic logic to solar and other non-fossil fuel forms of electricity production in the MENA region, based on oil and gas production, which Solar Server covered in a July 2012 report.
Nations in the region currently supply petroleum and gas for electricity production and direct use at a vastly discounted rate, as a form of subsidy to their citizens. In oil producing nations this represents an enormous opportunity cost in lost revenues to state oil companies, as the less oil and gas these nations burn, the more that they have for sale on the international market.
As a result the MENA region has been looking at solar power for some time, and there has been an informal international competition to build the first and the largest solar plant. Three utility-scale hybrid CSP/natural gas plants were commissioned in 2010 and 2011 in North Africa, in Morocco, Algeria and Egypt. However, in all of these plants the CSP was a smaller add-on to natural gas generation, at most 17% of the total capacity.
For years there was the question of which nation would build the first big plant based mostly or entirely on solar power. That the UAE was the first to accomplish this says a lot about the nation’s political will and organizational efficiency, in a region where such projects often don’t proceed on time.
However, even under the best circumstances building a CSP plant is a time-consuming endeavor, and it took three years to build the Shams 1 plant.
Masdar and Sheikh Zayed
The UAE has a unique long-term perspective on energy, which is epitomized in the work of the Abu Dhabi Future Energy Company, also known as Masdar.
Masdar has a history of leadership in bringing solar technology to the region, including commissioning of a 10 MW PV plant in 2009. However, solar energy is only one of the areas that Masdar is active in. The company is also pursuing sustainable development and energy-efficient building science through the Masdar City project, as well as wind projects, biofuel research, and a host of other sustainable energy solutions.
Masdar is a subsidiary of the Mubadala Development Company, an investment vehicle of the Abu Dhabi government focused on diversification of the nation’s economy. As such, it is a concrete manifestation of a vision to use the nation’s petroleum revenues for economic diversification.
In the UAE, this work has roots going back decades, and the nation’s founder, the late Sheikh Zayed bin Sultan Al Nahyan, is often cited as a primary influence. Not only did Sheikh Zayed oversee the transition from society of desert herders to a modern nation based on mineral wealth, but his progressive ideas about education, development, economics and the environment remain sources of inspiration and guidance.
Sheikh Zayed began wildlife preservation in the nation, forbade gas flaring, and emphasized the need to diversity the UAE economy beyond oil and gas. “Right from the start, Sheikh Zayed realized intuitively that the natural resources will not last forever,” noted Masdar CEO Dr. Sultan Ahmed Al Jaber in a message on the 40th anniversary of the founding of the UAE.
“His messaging to his government and to his people was continuously stressed on diversifying the sources of income and initiating economic projects to provide a better life for UAE citizens, along with the preservation of nature and the environment. He has, thus, laid the foundations of ‘sustainable development’ through practice even before it became a familiar term.”
Sunshine and gas
Masdar formed the Shams Power Company with veteran CSP builder Abengoa and oil company Total, with Masdar taking a 60% stake and Abengoa and Total 20% each.
Masdar has worked on other ground-breaking CSP projects, including collaborating with Sener on the Gemasolar plant, which served as Solar Server’s June Solar Energy System of the Month.
The plant that Shams Power Company built is not only a first for the MENA region, but also represents an innovation in CSP technology, one that speaks to the relationship with fossil fuels.
Like Gemasolar, Shams 1 is dispatchable, but not through storage. Instead, the incorporation of 50 MW of natural gas generation allows Shams 1 to operate at night or in cloudy periods, and supply power to the grid on demand.
It is unclear why this was necessary, as the nation’s oil and gas generation should supply plenty of operational flexibility. Shams Power notes that this removes the need for parallel generation, and it also makes the plant’s design highly replicable for other regions, where dispatchability is in high demand.
Masdar is exploring molten salt as an energy storage option at other plants, but at the time of the design of the Shams 1 project the technology was still seen as being risky. “Storage with molten salt has many advantages, as we are demonstrating at our Gemasolar and Valle 1 and 2 projects in Spain,” notes Shams Power Company General Manager Yousif Al Ali.
“However, as we began to conceptualize the design for Shams, molten salt storage technology was not sufficiently commercialized and was considered as unnecessary risk for the lenders, especially when considering the availability of locally-sourced natural gas.”
Gas-boosted CSP and the world’s largest CSP turbine
However, dispatchability is not the only purpose of integrating natural gas. As with other parabolic trough CSP plants, the highest temperature steam that can be generated by the fluid which is heated in the solar field is 380 degrees centigrade. At Shams 1, natural gas “boosters” super-heat this steam to 540 degrees at 120 bar. Masdar says that increases the steam cycle efficiency from 0.33 to 0.39, and thus greatly increases the plant’s overall efficiency.
Both this higher steam temperature and the size of the plant necessitated a special turbine design. Shams Power Company contracted MAN Turbo to supply a custom, 220-ton, 125 MW steam turbine, which is the largest single-casing turbine ever built for a CSP plant.
MAN Turbo says that this turbine can work both in “boost” and solar-only modes, under a range of steam temperatures and pressures. The turbine is further designed to allow for a large number of cold, warm and hot start-ups with rapid start-up times, including an insulating layer on the turbine’s casing that preserves as much heat as possible in the turbine overnight, allowing for a faster and smoother start in the morning.
The steam is recovered after use through a dry-cooling process. This uses less water than wet-cooling a key consideration for the extremely arid environment.
Finally, the plant stresses operational self-sufficiency, and includes seven days of diesel backup fuel in the event of a problem in the solar field or interruption of natural gas supplies.
Another technical problem for the plant was dust. The winds that blow across the open desert carry with them fine abrasive dust particles, moving the dunes slowly and at times building to fierce dust storms. As most of the world’s CSP has been built in Spain and the relatively calm Mojave Desert in California, this was a relatively new problem for the Shams team.
Shams adapts to this using two mechanisms. First, the company built a seven meter-high fence around the plant, to keep out direct winds and shifting dunes. Second, like many parabolic trough plants Shams’ cleaning system for the troughs involving trucks with robotic scrubbing arms to clean the mirrors. In Shams, the number of trucks and frequency of cleaning cycles was increased.
“Innovative solutions like these more than overcome the loss of efficiency due to dust and prove that building CSP plants in desert environments is not only possible, but smart,” notes Shams Managing Director Yousif Al Ali.
Electricity and economic development
Masdar estimates that the Shams 1 plant supplies enough power for 20,000 homes. At 100 MW, the plant currently represents 1% of the generating capacity on the nation’s electricity grid.
The building of the USD 600 million plant has had other impacts. By Shams Power Company’s estimate 66 UAE companies were involved in the project, many of which did not exist before the project. Abengoa CEO Santiago Seage notes the ability to source parts and labor locally as an advantage of CSP.
“Much of the other equipment that you see here has been either manufactured or re-tooled locally,” notes Seage. “In terms of employees, a third of the employees, more or less, are local. It has an impact in the economy that goes way beyond that of other renewable energy sources.”
Masdar is now focused on a number of other projects, including a nuclear power project in Abu Dhabi’s Western Region, with the goal of meeting the growing nation’s appetite for power.
Masdar, Abengoa and Total have not disclosed future plans for CSP in the UAE, though Masdar is investigating CSP use for enhanced oil recovery. Masdar CEO Dr. Sultan Ahmed Al Jaber has also said that the company will be making an announcement regarding the 100 MW Noor 1 PV project later in 2013. Regardless, the impact of Shams 1 can be seen in other regional developments.
In the three years that Shams 1 has been under construction, much has changed in the world and the global solar industry. Notably, the price of PV has fallen precipitously, a number of CSP companies have gone bankrupt and the Desertec initiative has lost key supporters.
However, MENA nations continue to move towards solar, with or without Desertec. Morocco has chosen a consortium led by Saudi Arabia’s ACWA Power to build a 160 MW CSP plant in Ouarzazate, and the nation of Saudi Arabia has announced plans to procure 41 GW of PV and CSP by 2032.
Along with Masdar City and Masdar’s other clean energy projects, Shams 1 stands as a beacon for the MENA region and the world, with Abu Dhabi leading the way towards more diversified economies, lasting prosperity and an environmental balance for the region.
In the words of Sheikh Zayed: "We must not rely on oil alone as the main source of our national income. We have to diversify the sources of our revenue and construct economic projects that will ensure a free, stable and dignified life for the people.”
Christian Roselund, http://www.solarserver.com