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Solar Challenge

The technology continues to make rapid advances in cost and efficiency

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Dubai's 13MW Solar Park
Dubai's 13MW Solar Park

A recent report by Swiss bank UBS made the astonishing claim that solar technology is advancing at such a speed that large-scale, hydrocarbon-fired power stations could become all but obsolete within the next 10 to 15 years.

Steeply declining battery and solar systems costs and the development of electric vehicles will soon enable users to generate their own electricity.

By 2020, a home solar pack combined with a small-scale battery storage system and electric car could pay for itself within six years, the Zurich-based investment house said in the August report titled ‘Will solar, batteries and electric cars re-shape the electricity system?’

“By 2025, everybody will be able to produce and store power. And it will be green and cost-competitive, ie, not more expensive or even cheaper than buying power from utilities,” the report says, adding that many power plants retiring in the future will not be replaced. The revolution is likely to be start in Europe, particularly Germany, Italy and Spain.

Recent discussions about solar have centred around whether it can gain market share from other sources of power generation at the utility level, so the UBS claims will no doubt come as a shock to many involved in the large-scale production of energy.

The fast developing regions of the world continue to build large hydrocarbon-fired power plants to meet their soaring energy demands and, in the Middle East, solar has yet to make a major impact. So has solar technology really advanced to the point that it threatens other forms of powergen with extinction in the near future?

The technology
The two major types of solar technology are Solar Photovoltaic (SPV) and Solar Thermal (ST). “At the most elementary level, technologies utilising light from the sun for power generation are commonly referred to as Solar Photovoltaic Systems (SPV) and those using the heat from the sun are referred to as Solar Thermal (ST) systems,” explains Abhay Bhargava, regional head - energy & environment practice, MENA, at analysts Frost & Sullivan.

“In SPV systems, solar cells generate direct current (DC) power when exposed to sunlight. Arrays of solar panels are used to convert this power into a usable amount of DC electricity. Depending on the application, the DC electricity is used or converted to alternate current (AC) using solar inverters.

“In solar thermal, incident radiation from the sun is concentrated or magnified using arrays of mirrors. This incident radiation is concentrated onto a receiving device that consists of a heat transfer medium that collects the power so it can be used directly as thermal energy or to generate electricity. The heat can also be stored to produce electricity for a few hours after sunset.”

Falling costs
Advances in technology are constantly bringing down the cost of solar power thus making it more competitive. The relative cost of solar compared to other sources of generation can vary from country to country based on a number of factors. Figure 1 shows costs in India, where solar power production is relatively high compared to the Middle East.

“While solar energy is perceived to be more expensive currently, in the long run, solar tariffs are expected to decrease or remain steady, backed by increasing efficiency, and the declining cost of production (especially, the cost of polysilicon),” says Bhargava.

“On the other side, tariffs for conventional sources of generation are expected to either stay stable or increase, depending on subsidisation policies and demand-supply equations for hydrocarbons.”

CSP too expensive?
Concentrated solar power (CSP), the main type of thermal solar power, has gained a foothold in the Middle East through the development of the 100MW Shams 1 plant in western region of the Emirate of Abu Dhabi. The facility is 60% owned by Masdar, 20% by Spain’s Abengoa and 20% by French energy major Total. Saudi Arabia has also announced plans to develop a huge amount of solar power, much of it based on CSP technology.

Victor Martinez, senior technical manager, at Saudi Arabia-based First National Operation & Maintenance (NOMAC), explains the origins of CSP.

“There are currently four main types of CSP technologies: parabolic trough, fresnel linear reflectors, dish-engine systems, and central receiver systems (also called Solar Power Towers). Parabolic trough is the most mature with a significantly greater operational record. It is considered the most established and bankable technology choice for solar thermal plant so far.

“First technical scale demonstrations of CSP date back more than 100 years but the first successful large scale projects were completed in the 1980s in California, USA, where nine parabolic trough power plants (SEGS) with over 354 MW of total installed capacity are feeding summer-peak power to the grid.

“As a result of the comprehensive operating experience made with the SEGS, parabolic trough has been optimised significantly. The second generation of CSP plants have been developed in Spain, USA, India, South Africa with significant improvement in the solar field and steam cycle performance.”

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Photovoltaic v CSP
Global installed capacity of PV far outweighs CSP and that can mainly be attributed to the much lower cost of PV sourced power. Imtiaz Mahtab, executive vice president at Air Liquide MENA and vice president of the Middle East Solar Industry Association (Mesia), says PV has the edge over the rival technology for large scale usage.

“The key advantage of PV is significantly lower operation and investment cost versus that of CSP. In addition, CSP requires lots of water for the cleaning as well as cooling compared to PV, which is problematic given CSP plants are built where water resources are scarce, though progress has been made in dry cooling.

“The main advantage of CSP is storage, and dispatchable power, and hence better grid stability,” he adds.

“However as the development of storage and smart grid management would further put pressure on CSP, it should be looked at as having niche area applications such as retrofitting existing steam turbines or hybridisation with fossil fuels to offer dispatchable power when it is needed.

“Further, in addition to electric generation, the thermal energy that is produces (through receivers and mirrors), could be used to generate steam for various industrial or mining applications.”

PV leads the way
First Solar is a leading manufacturer of solar PV modules as well the developer of Dubai’s 13MW Solar Park. The company has overseen a steady improvement in the efficiency of its Cadmium Telluride (CdTe) cells to the point where it recently hit 21%, and it expects the gains to keep on coming.

“Photovoltaic conversion efficiencies have improved substantially over the past few years,” says Matthew Merfert, technical director, Middle East. “Take, for instance, the fact that Solar Cells Inc. - the start-up that would eventually become First Solar - produced the FS50 module with an efficiency of 6.9% in 1995.

“Less than 20 years later, our Cadmium Telluride (CdTe) cells have achieved a certified world record-breaking efficiency of 21%, which is higher than the decade-old multicrystalline silicon record. Looking ahead, the potential for CdTe improvement is very encouraging and we have upped our targeted entitlement in our efficiency roadmap from 23% to 25%, which will match the world record for monocrystalline silicon research cell efficiency.

The cost of electricity of a particular generation source is calculated using the Levelised Cost of Electricity (LCOE), Merfert explains. In its simplest form, the LCOE of a power plant is the cost of building and operating the plant over its lifetime, divided by its total energy output over that lifetime.

Merfert adds: “At the moment around the world, there are over 2GW of permitted CSP projects that are being re-permitted to have the sites converted to PV, indicating that PV is, in fact, extremely price competitive, not only with CSP but also with conventional fuels on a Levelised Cost of Electricity (LCOE) basis.

“For solar PV plants, the cost of capital currently represents the single largest financial component of an average project, accounting for as much as 36% – and often more - of the LCOE, depending on market conditions,” Merfert says.

“On our part, we’ve contributed significantly towards lowering the LCOE of PV energy through the cost and efficiency improvements we’ve made to our module technology and also by reducing the Balance of Systems (BoS) requirements.”

The Middle East challenge
Middle Eastern countries are yet to install solar power on a wide scale, but that may have more to do with local regulations and government policies than the unique technical challenges that the region poses.

“The region’s unique geological and environmental conditions, evolving regulatory frameworks and the fact that we’re building solar power plants on a scale that is unprecedented in the region, creates both challenges and opportunities,” says Merfert.

“That said, we were able to complete the 13MW Dubai solar power plant to DEWA’s exacting specifications, ahead of schedule and with a flawless safety record, and we expect to repeat that achievement in Jordan in our 52.5MW tracker project.

“There is also a general tendency to exaggerate the impact of the region’s environmental conditions – primarily heat, dust and humidity – on solar plants.

“But I can say with confidence that soiling, temperature, and humidity performance are no longer a major cause for concern for our photovoltaic plants.”

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