GlassPoint - Enclosed Trough Technology
GlassPoint’s enclosed trough technology uses sunshine to produce zero-carbon steam. Lightweight curved mirrors are suspended and protected inside a greenhouse. The mirrors track the sun throughout the day, intensely focusing its heat onto pipes containing water. The concentrated sunlight boils the water to generate steam for use in many industrial processes.
Products Details
The greenhouse protects the mirrors from the elements: wind, rain, sand, and dust. The greenhouse enclosure makes the solar thermal system much lower cost to build and much lower cost to maintain. An automatic washing machine cleans the greenhouse roof, maintaining optimal performance in dusty and remote conditions. These innovations allow GlassPoint solar steam generators to deliver steam at costs competitive with natural gas in most sunny locations around the world.
GlassPoint solar steam generators integrate seamlessly with existing industrial processes, producing steam to customer specifications. The systems are designed and built in compliance with rigorous Health Safety and Environmental (HSE) standards, meeting or exceeding customer safety standards and ensuring safe, trouble-free operations.
Lowest Cost
In many parts of the world, GlassPoint solar steam generators can deliver steam at costs comparable with steam made by burning natural gas. In the graph below, the price shown for GlassPoint and conventional solar is the “gas equivalent price” taking into account the total cost of ownership over a twenty year period, including both capital expenditure and operating expenses.
Proven Glasshouse Reduces Costs, Improves Efficiency
GlassPoint is the only solar thermal design that brings the solar collectors indoors. The self-contained glasshouse delivers foundation, structure and protection in one. This enables a number of cost and efficiency breakthroughs that far outweigh the efficiency losses caused by being inside the glasshouse structure.
Glasshouses have been mass-manufactured for the agriculture industry for decades, and they are deployed all over the world in all sorts of weather conditions. Thanks to decades of continuous improvement, the glasshouse structure is highly optimized to reduce cost and maximize the transmission of sunlight. GlassPoint leverages this mature supply chain to deliver the lowest cost of steam.
Lowest Capital Costs
The glasshouse creates an indoor wind-free environment, allowing a reduction in the amount of raw materials used throughout the entire system. Enclosed trough mirrors are made of ultra-light, razor-thin material. The mirrors are suspended from the glasshouse ceiling and controlled by small, inexpensive positioning systems and motors.
In all other solar designs, each individual mirror is exposed to the force of the wind. These designs require additional steel for support and durability and more concrete to create a stable foundation. As a result, a solar field made of exposed troughs typically weighs more than 30 kilograms per square meter of mirror. In contrast, the GlassPoint solar field, including the glasshouse enclosure, weighs less than 5 kilograms per square meter.
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Lowest Operating Costs
The glasshouse is equipped with an automated washing machine that washes the glasshouse each night to restore full optical efficiency. Robotic washing requires zero operator intervention and can recycle the vast majority of the water, further reducing costs. Learn more about operating advantages.
GlassPoint steam generators are designed to oilfield standards, using the same feedwater and much of the same equipment, including identical boiler tubes, controls and piping. This significantly reduces costs of water treatment, integration and maintenance. Learn more about oilfield integration.
Highest Efficiency
By eliminating the force of wind on the mirrors, GlassPoint increases optical accuracy. Higher accuracy enables a smaller receiver tube relative to the size of the mirrors, resulting in a higher “concentration ratio” and improved thermal efficiency.
Energy loses due to mirrors bending in the wind is a significant challenge in the Middle East, where wind speeds can be 10 times higher than those in Spain or California where most other solar thermal systems are deployed. In Oman, 90% of the available solar energy is delivered during wind speeds above 4 meters per second, compared to only 30% in Spain. Performance modeling shows that exposed solar designs could experience a drop in performance of 8% to 14% when operating in these high wind speeds.
Soiling from sand and dust also leads to significant performance drops. Operating data from solar projects in the Arabian Gulf revealed a week of unwashed mirrors decreases output by more than 15%. High winds and high soiling also lead to mirror degradation from sand abrasion, resulting in additional loses. Download Menasol presentation.
The glasshouse enclosure enables GlassPoint systems to not only survive these challenging conditions, but also maintain the highest operating performance in the following ways:
- Avoiding mirror distortion caused by wind allows a smaller receiver tube relative to the size of the mirrors, resulting in a higher “concentration ratio” and improved thermal efficiency
- Automated roof washing keeps the glasshouse clean, reducing loses from soiling
- The height of the glasshouse roof reduces the risk of sand abrasions, reducing loses from degradation over time
These improvements in performance far outweigh the losses caused by transmission through the glasshouse roof and shading from the glasshouse structure.
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Lowest Construction Costs
GlassPoint builds its solar fields in glasshouse blocks using a series of standardized steps to avoid custom project costs and delays. Most of the system is comprised of prefabricated components that can be easily assembled onsite. The mirrors can be lifted by hand and easily installed with minimal overhead lifting and work at height. Together, these methods improve safety, speed deployment and reduce construction costs.
Sealed from Dust
Many of the world’s oilfields are located in deserts where blowing sand and dust create unique challenges for solar power. By bringing the solar collectors indoors, GlassPoint has overcome this longstanding hurdle. GlassPoint’s technology is proven to withstand harsh deserts environments, producing solar steam even in the toughest operating conditions.
Self Cleaning Glasshouses
Unlike all other CSP technologies, GlassPoint has brought its solar collectors inside a commercial glasshouse. The glasshouse creates a wind-free environment, protecting the mirrors and other delicate components from dust, dirt, sand and humidity. This is especially important in the Middle East, where sandstorms are common year-round.
GlassPoint solar steam generators include a proven, robotic cleaning system that automatically washes the roof of the glasshouse at night. The system recaptures wash water in the gutters, which is filtered and reused to minimize water consumption.
Real-world operating data from solar projects in Oman and the United Arab Emirates reveal that soiling can reduce performance by an average of 2.5% per day. If the optical surfaces are left unwashed for a week, performance drops by more than 15%, underscoring the need for daily wash cycles. Exposed solar designs often rely on manual washing systems, which can be unsafe for operators and impractical at scale. In remote oilfield locations, manual washing will significantly increase operating costs.
Proven Desert Performance
In a recent Middle East dust storm where winds exceeded 53 km/h (33 mph), a GlassPoint solar steam generator continued to operate, producing steam for the entire day. Optical performance was completely restored overnight after one wash cycle where layers of accumulated sand were removed from the glasshouse. The following day, the solar EOR facility exceeded performance targets, producing more than 100% of steam output models.
Protected from Soiling
GlassPoint’s enclosed trough design dramatically reduces energy losses from soiling. The glasshouse roof is six meters above ground level and experiences half the soiling rate of surfaces one meter above grade. More than 90% of the sunlight used to produce steam enters through the roof of the glasshouse, where soiling levels are the lowest.
GlassPoint maintains a pristine environment inside the glasshouse by injecting dehumidified and filtered air to preserve an internal pressure that is higher than the exterior atmosphere. The difference in pressure expels sand and debris through any small gaps in the structure, preventing sand and dust from entering.
In other solar designs, the mirrors and positioning systems have no protection from these outdoor elements. If faced with a sandstorm, the solar collectors would quickly cover in sand and operations would be idled. In addition to increased downtime, losses due to soiling are a significant challenge for designs where the mirrors, the key optical surface, are located close to ground level. Not only will these systems require more frequent cleaning, it also puts them in the “abrasion zone” for high-speed wind blown sand particles. The sand abrasions would degrade the surface of the mirrors in just a few years, reducing performance and increasing maintenance costs.
Oilfield Integration
GlassPoint solar steam generators seamlessly integrate with existing thermal enhanced oil recovery (EOR) surface facilities. GlassPoint systems use the same feedwater and produce steam with the same quality, temperature and pressure as steam produced by burning natural gas. However, Instead of using flames to heat water and generate steam, GlassPoint’s technology uses concentrated sunlight.
Reduce EOR Gas Consumption by 80%
Reduce EOR Gas Consumption by 80%
To maintain steam injection around the clock, solar steam is injected during the day, and steam produced by burning natural gas is injected at night. Studies from Petroleum Development Oman and Stanford University found that solar could provide up to 80% of a field’s annual steam requirements, significantly reducing the amount of gas consumed for EOR. Their research proved that variations in daily steam cycle did not impact oil production, as long as the annual steaming rate remained constant. Therefore, it’s more economical to increase steam injection during the day when it’s sunny out, and reduce the amount of gas-fired steam used at night. Download SPE paper.
Conforms to Oilfield Best Practicies
Once-through steam generators (OTSG) have been used for decades in heavy oilfields worldwide and define best practices for thermal EOR operations. GlassPoint engineered its systems as a solar-powered OTSG, incorporating the same boiler tubes, sensors, pumps and controls used by gas-fired steam generators. As a result, GlassPoint minimizes changes to existing surface facilities, significantly reducing integration costs.
In a standard OTSG oilfield produced water that ha...
In a standard OTSG oilfield produced water that has been minimally treated and softened is fed to the boiler and converted directly to steam. GlassPoint steam generators operate on the same softened feedwater, meeting the American Petroleum Institute’s standard for direct steam generation (API 11T). As the water passes through the boiler tubes, concentrated sunlight heats the water to generate steam. The steam is fed to the field’s central header and steam distribution network to multiple wells within an oilfield. The solar steam generator has a fully automated control system that enables remote operations from a computer.
All other concentrating solar thermal systems were originally designed for electricity generation and do not meet the same oilfield standards. These older solar designs use stainless steel boiler tubes, which are chemically incompatible with oilfield water. Expensive water treatment facilities and working fluids are required to interconnect with the oilfield. The need for pure, demineralized water can quadruple water treatment costs—adding up to a dollar per barrel to a field’s operating costs.
Standard Block
GlassPoint optimized its steam generators for thermal EOR operations, adopting many of the same design, engineering and construction best practices used by the oil and gas industry.
Scale to Customer Specification
GlassPoint deploys its solar steam generators in standard glasshouse blocks to meet the thermal needs of any oilfield. Each glasshouse generates 85 MMBtu/h (28 MWt) of steam at peak output. Blocks are designed to be replicated and scale from one to several hundred for flexible siting on active oilfields.
GlassPoint systems are designed to deliver steam for the duration of a field’s thermal EOR operations, which often lasts for several decades. As fields mature, the steam is redirected to new reservoirs.
The glasshouse blocks have high energy density, co...
The glasshouse blocks have high energy density, covering 96% of the land area with mirrors. Since the materials used in an enclosed trough are so low-cost, it is more cost-efficient to pack the collectors tightly together into a smaller space. The additional energy generated during peak sun hours, when the sun is high in the sky, far exceed any losses from shading caused by neighboring mirrors during the low sun hours. As a result, the enclosed trough offers the highest steam production per unit of land of all solar thermal designs. Compared to exposed trough systems, GlassPoint steam generators produce three times more steam per unit of land.
Achieving high energy density is vital for EOR applications because steam needs to be produced close to the oil field. The low energy density of older systems means that steam has to be transported longer distances reducing steam quality and increasing costs.
Designed for Safety
Safety is at the heart of all GlassPoint operations. Standard blocks were designed to minimize risks at each stage of construction. Careful engineering has reduced overhead lifting and work at height, component fabrication is completed without mechanical aids and no flammable liquids are used. By designing its systems for safety from the ground up, GlassPoint has achieved a strong safety record at each of its projects and operations worldwide.
Sequenced Deployment
GlassPoint uses a “factory line” approach for deploying its solar steam generators, a proven method for building large-scale projects in the oil and gas industry. The construction process is broken into standard steps and then developed in a continuous sequence. Specialized teams move from block to block completing a specific task then relocating to the next. For example, one team is solely responsible for glazing the glasshouse, whereas another team is skilled in mirror installation. Each stage of the process optimizes expertise to speed deployment, control costs and ensure consistent quality. Since several blocks are built in parallel, injecting solar steam can start as soon as the first block is completed.
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