About SolarWorld

America's solar leader for more than 35 years.

Solar Manufacturing Value Chain

SolarWorld owns the full solar value chain – from polysilicon to complete solar power systems

Between its manufacturing hubs in Hillsboro, Ore., and Freiberg, Germany, SolarWorld undertakes all phases of solar panel production in the value chain from polysilicon, the main initial input, to complete solar electric systems. Very few solar electric technology companies in the world can claim to be fully integrated manufacturers. Most rely on outside sources for wafers, cells, laminates, or solar panels. A fully integrated company such as SolarWorld can control product quality from beginning to end. Its ownership of the complete production chain, in strictly controlled manufacturing environments, ensures its customers receive quality products that will produce clean energy for decades.

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Silicon rock

Bell Laboratories, the R&D powerhouse built by the former Bell Telephone Co. monopoly in Murray Hill, N.J., is widely credited with the technological breakthrough that set the course for the solar power industry’s modern development. In the early 1950s, researchers there figured out how to harness the photoelectric effect using silicon as a semiconductor. The discovery made silicon the primary raw material for the mainstay crystalline silicon solar power technology through today.

Silicon rockAs a matter of technology, industry and sustainability, silicon has much to recommend it. As the chief historical element in both the solar and semiconductor industries, silicon has a deep and broad track record as an extremely safe and well-understood industrial supply, which has afforded huge experience in the marketplace. In the solar industry, this track record reaches back about 60 years. The industry also has yet to run out of ways to continually advance power density – the electrical power output per square inch of solar panel – through research and development. Finally, silicon is the most prevalent, and therefore sustainable, solid element on Earth. It’s found in sand, quartz and many rocks. Lying just under foot most anywhere, silicon won’t run out.

More precisely, the industry uses a material called polysilicon, a manufactured good that results from a high-purity production process. As a producer that manufactures in the major markets where it sells, SolarWorld taps silicon supplies in the U.S. and European markets, using reliable producers that meet the West’s high standards of production safety, quality, labor and environmental stewardship.

But SolarWorld does not plan to depend on those sources alone. In fact, it is extending its vertical integration further upstream, as it participates with the Qatar Foundation in a joint venture to establish the first polysilicon refining plant on the Arabian Peninsula as soon as 2014. The operation there will be uniquely positioned to take advantage of domestic supplies of both fuel and silicon in more sustainable refinement.

Solar wafers

Silicon wafer

SolarWorld has been one of the largest manufacturers of solar silicon wafers worldwide, and the company has produced a range of both mono-crystalline and multi-crystalline solar wafers. In this way, SolarWorld is positioned to meet customer-specific requirements. In recent years, it has invested more heavily in new, more cost-effective silicon-crystallization technologies.

Wafers are further processed to make solar cells – not only within the company but also by customers worldwide.

At the U.S. headquarters plant in Hillsboro, Oregon, the company historically has concentrated on producing mono-crystalline technologies. The know-how embedded in the U.S. branch of the company is based on more than 35 years of experience.

The company’s counterpart division in Freiberg, Germany, produces wafers and ingots exclusively from poly-crystalline, providing the overall company with the flexibility it needs to maximize technological and market requirements.

Silicon waferIn the U.S. market, SolarWorld has applied the Czochralski method to produce its mono-crystal ingots. Within a furnace, a seed crystal featuring the desired crystal orientation is lowered down atop molten silicon. Under the right conditions, high-purity silicon begins freezing onto the seed while matching the orientation. The seed and silicon crucible are turned in opposite directions, and the seed is elevated, or pulled, to form a cylindrical crystal – like pulling a candle from melted wax. It takes about 3½ days to produce a single crystal of about 5 feet long and 8 inches wide.

In the poly-crystalline process, silicon, melted inside square molds, is allowed to freeze from the bottom up. As it returns to a solid form, the silicon forms a patchwork of crystal lattices, providing the resulting blocks with a poly-crystalline pattern.

Both types of ingots are then sliced into very thin discs, or wafers, with help from wire-cutting technology. After cleaning and intensive final checks are completed, mono-crystalline and poly-crystalline wafers from the basis for production of solar cells. The physical semiconductor quality determines the attainable efficiency in the manufacture of the solar cells.

Solar Cells

Solar cell

The solar photovoltaic cell is the individual building block of a solar panel. Think of it as a tiny power plant, and the panel is a miniature power network, combining 60 cells. SolarWorld Industries America Inc. is by far the largest producer of solar cells in the Western Hemisphere.

Solar cellThe cell starts as a thin silicon wafer, whose silicon crystal was doped, or impregnated, with another element, boron, to produce a positive electrical orientation. In the cell-manufacturing process, one surface of a wafer is doped with another element, phosphorus, to create a negative orientation. The resulting juncture between the two – a positive-negative, or P-N, junction – constitutes the pivotal atomic-level mechanism that enables sunlight to activate an electronic exchange among the two layers, kick-starting a flow of electricity when the cell is linked into a circuit. 

Metallic lines, also known as fingers and bus bars, are printed onto the surface of the cell to collect the electricity and feed it through a panel and on through a circuit, whether connected into the electric utility grid or within an off-grid solar system. 

Finally, cells are treated with anti-reflective coating, giving them their dark purple color. Because SolarWorld is completed vertically integrated – from silicon crystallization all the way through engineering, procurement and construction of utility-scale solar systems – the company controls each output for the next input. SolarWorld’s vertical integration, combined with its exclusive focus on solar, makes it unique among the West’s major solar-industry producers.

Solar panels

Solar panel

Solar cells are merged into larger units – the panels – in panel-assembly production. They are framed and weather-proofed. The solar panels are finished products, ready to generate power. Sunlight is converted into electrical energy in the panels. The resulting direct current produced is converted into alternating current by the inverter so that it can be fed into the public grid or, if the unconverted electricity remains in the house, it can be used directly.

Solar panels are manufactured in Hillsboro, Oregon, and Freiberg, Germany.

Solar panelA solar panel, or module, is a term for a unit that can be electrically connected, consisting of many solar cells, with weather protection (glass), embedding and framing. The direct current produced by the module is converted to alternating current with the help of a device known as an inverter. The resulting alternating current can be fed into a public power grid.

Solar systemsComplete solar power solutions

SolarWorld pioneered the practice of tailor-designing installation plans and assembling all components for specific solar installations. The company ships its resulting Systems Solutions turn-key solar systems straight to job sites, including all components that electrical contractors will need to install systems.

These components include not only solar panels, inverters and solar mounting solutions, but also the right type and number of nuts, bolts and conduit. The company even includes diagrams for site-specific wiring and mounting.

With Systems Solutions, electrical installers save time on procurement and design and work on projects directly with the manufacturer. In turn, the company designates trained and proven installers as SolarWorld authorized installers.