Glass and Solar Energy

Glass has an important role to play in the development of the growing Solar Energy sector. We supply products for all three of the leading technologies, converting power from the sun into clean renewable energy.

Depending on the type, a photovoltaic panel will typically roduce enough power in around two years to offset the energy used in manufacture. In other words, during its life cycle, a solar panel can produce over 15 times the amount of energy used to make it.

Between 2000 and 2010, global photovoltaic (PV) demand grew at a compound annual rate of 50 percent, rising from 280 MW to over 17 GW (EPIA). Despite the global downturn and reductions in some government incentives, solar volumes actually increased in 2009-2010. This was mainly due to the reduced cost of solar electricity, but also driven by our technological advances, helping our customers manufacture increasingly efficient modules.

Glass is an integral and important element of photovoltaic solar panels. To increase efficiency, low-iron glass, which is more expensive, but clearer than ordinary glass, is increasingly specified. Anti-reflective coatings can also increase the amount of usable solar energy. Our high-quality products are used in the three leading solar technologies aimed at converting solar energy into electricity: thin film photovoltaics, crystalline silicon photovoltaics and concentrated solar power applications.

In addition to the generation of electricity, our glass products are also used in solar applications that generate hot water. We have been closely associated with the leading companies within the crystalline silicon and thin film photovoltaics industries for a long time. This collaboration resulted, in part, from the historical expertise in on-line coating of both Pilkington and NSG. This has enabled us to become the worldwide leading producer of high-quality, high-volume Transparent Conductive Oxide (TCO) coated glass, with manufacturing sites in all main regions. We have been a technological leader in low-iron glass compositions for 25 years.

Glass is an integral and important element of solar modules, used to convert solar energy into electricity. In traditional photovoltaics, the solar cells may be encapsulated using toughened high-transmission glass, which protects the cells from the elements.

During its life cycle, a solar panel can produce over 15 times the amount of energy used to make it. Increasingly, electrically-conductive glass is used in photovoltaic modules as the front contact of the solar cell, to form a system which generates a direct electrical current.

Globally, governments have established policies and incentives to promote renewable energy production. For example, in June 2009, the European Renewable Energy Directive came into force. Carbon-trading schemes encourage CO2 reductions, adding further impetus to the development of renewable energy options. In March 2011, China adopted its 12th Five-Year Plan, intended to cut its overall carbon footprint. Solar Energy is expected to grow significantly in China, with a target of 10 GW installed capacity by 2015. In the United States, various programs and policies are in place to promote the development of renewable energy supplies, such as the SunShot initiative, designed to make solar energy cost competitive with other forms of energy by the end of the decade.

Our products support the three leading solar energy technologies. As solar energy costs fall, generous incentives are no longer essential. Solar energy is now approaching grid parity in several countries and is expected to play a significant role in global renewable energy supplies.

Thin film photovoltaic solar modules

Thin film photovoltaic modules produce power at low cost per watt. They are ideal for large scale solar farms, as well as Building Integrated Photovoltaic applications (BIPV). They benefit from generating consistent power, not only at elevated temperatures, but also on cloudy, overcast days and at low sun angles.

Thin film photovoltaic modules consist of a stack of extremely thin photosensitive layers sandwiched between a top TCO coating and a back contact. The photovoltaic layers are laminated between a TCO coated front glass such as NSG TEC™, and a low-cost backing material, such as standard or thermally-strengthened Pilkington Optifloat™ clear glass.

With our advanced technology, coating properties can be ‘tuned’ to a wide variety of Thin Film PV technologies, including silicon and cadmium telluride-based.

Crystalline photovoltaic solar modules

Developed from the microelectronics technology industry, crystalline silicon (c-Si) is the most widely used solar technology. Due to their high efficiency, crystalline silicon modules are best suited to applications where space is at a premium.

The glass type normally used for this technology is low-iron rolled glass, such as Pilkington Sunplus™, often in toughened form, combined with an anti-reflective coating, to ensure that the maximum solar radiation reaches the PV cells. It is also possible to use low-iron float glass such as Pilkington Optiwhite™.

Concentrated solar power applications

Concentrated solar power technology uses mirrors to concentrate sunlight. The high performance mirrors are manufactured using metallic reflective coatings and weather protective paints deposited onto very high-performance low-iron float glass. Pilkington Optiwhite™ S is an ultra-clear float glass with very low-iron content and its high solar energy transmittance makes it ideal as a base substrate for mirrors used in concentrated solar power applications.