To achieve energy self sufficiency, the ZEB is powered by a broad spectrum of solar panels installed at many locations in the building. It is 100% clean renewable energy. 

The generation of solar power can be broadly divided into 2 parts. Grid tied photovoltaic account for most of the solar panels and is connected to grid supply. Surplus power generated by these solar panels would first be distributed to the rest of BCA Academy before any excess is supplied back to the grid. If insufficient power is produced, then grid supply will provide for ZEB, so that user comfort and function are never compromised.

Standalone photovoltaic are not grid connected and supply power directly to specific functions in ZEB such as the visitor centre solar charging kiosk.

 

Photovoltaic Principles

Photovoltaics are best known as a method for generating electric power by using solar cells to convert energy from the sun into electricity. The photovoltaic effect refers to photons of light knocking electrons into a higher state of energy to create electricity. The term photovoltaic denotes the unbiased operating mode of a photodiode in which current through the device is entirely due to the transduced light energy. Virtually all photovoltaic devices are some type of photodiode.

Solar cells produce direct current electricity from light, which can be used to power equipment or to recharge a battery. The first practical application of photovoltaics was to power orbiting satellites and other spacecraft, but today the majority of photovoltaic modules are used for grid connected power generation. In this case an inverter is required to convert the DC to AC. There is a smaller market for off grid power for remote dwellings, roadside emergency telephones, remote sensing, and cathodic protection of pipelines.

Cells require protection from the environment and are usually packaged tightly behind a glass sheet. When more power is required than a single cell can deliver, cells are electrically connected together to form photovoltaic modules, or solar panels. A single module is enough to power an emergency telephone, but for a house or a power plant the modules must be arranged in multiples as arrays.


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Photovoltaic Technology

(Only silicon and thin film systems have been adopted. Non silicon or 3rd Gen PV have not been installed)

  • Silicon Wafer (widely known as 1st Generation PV)
    • Most efficient system
    • Started in the 1950s
    • Less surface area needed to generate electricity
    • Characterized by large-area, high quality cells based on silicon wafers (monocrystalline and polycrystalline).
    • Most expensive to manufacture
    • Suitable for rooftops and integration into building façade and skylight
    • Widely used and most mature technology
    • Module Efficiency: 12% - 20% achievable

 

  • Thin Flim (widely known as 2nd Generation PV)
    • Flexible and lightweight
    • Aesthetically pleasing
    • Suitable for rooftops and integration into building façade and skylight
    • Cheaper (less material needed) but less efficient
    • Example includes amorphous silicon, cadmium telluride and copper indium gallium diselenide (CIGS)
    • Module Efficiency: 8% - 12% achievable

 

  • Non Silicon (widely known as 3rd Generation PV)
    • Technology not fully mature
    • Flexible and lightweight
    • Aesthetically pleasing
    • Suitable for integration into building façade and skylight
    • Aims to attain higher efficiencies and lower costs than the 1st and 2nd generation PV
    • Examples include dye-sensitized solar cells, polymer solar cells and nanocrystal cells
    • Module Efficiency: 30% for lab tests


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