BIPV: A Future Tech or a Myth?
4th December 2017
Sun has been shining since four billion years and would continue to shine for more 5 billion
years. The sun's energy falling on earth for a day is enough to power the earth for the entire year.
Mankind has tried to capture this energy by means of photovoltaic cells/ modules. There has been a
lot of development in solar modules on its efficiency and power output and many application
specific products have been developed. Building Integrated Photo Voltaic (BIPV) had been developed
and put to use in the late 19 th century. BIPV as the name suggest are solar PV module which is
completely integrated with the architecture of the building. BIPV can be easily installed on the sides
of the building replacing the primitive materials while maintaining the aesthetic look of the building.
Figure 1: BIPV installation on an office (Source: Google Images)
With a target of 100 GW of solar power by 2022, it is important to explore all the possible avenues of solar plant installation.While the country has been steadily moving towards the target, still a lot needs to be done. The main component of the power plant i.e. solar modules (currently in use) may not be compatible to the site all the times. The solar module (currently in use) hasthe following limitations:
- Dependence on direction of installation: As we had mentioned in our previous article "Orientation & Positioning of solar module" the currently used solar has to be installed only in south direction and at tilt angle equal to the latitude of the location for optimal power generation from the module. Any change in this parameters would lead to reduction of solar irradiance on the panel (figure 2) and hence the power output. Additionally the conventional solar module only requires direct solar irradiance for power generation.
Figure 2: Effect of direction and orientation on solar irradiance (Source: Econet)
- Dedicated area requirement: A solar plant as we know require a dedicated shadow free area for its lifetime (25 years) and such land cannot merely be used for any other activities. A solar plant to deliver 1 kW of power output requires 10 m2 of area. Such dedicated area requirement while easy to get in small towns are very difficult and costly in urban areas. Additionally the area available may not be sufficient to power the energy needs of the buildings or may not be a feasible option due to their limited size
Figure 3: A solar rooftop plant
- Power mismatch: Due to land constraints, there has been an increase in building height to accommodate more families. Such increase would lead to an increased power demand of the building. The traditional solar power plant due to limited rooftop space (due to faade and super structure) can just offset the power demand by a marginal amount. Additionally, with introduction of concept like green buildings and/or net zero energy buildings, it is important to offset such power requirement.
BIPV can be installed on all the sides and the fa-ade of the building. This is because unlike the traditional solar modules, BIPV modules are able to generate power by both direct and diffused radiation. Additionally as mentioned above the increased height of the building would lead to high energy demand and require additional sources to offset its power requirement. Such building structures however have high fa-ade surface area to roof surface area making installation of BIPV a feasible option for offsetting its major chunk of power requirement.The BIPV modules have the following advantages:
- Can be used on any building: BIPV can be used on an already constructed buildings and/or buildings which are relatively old. This is because such buildings may not have enough (shadow free) rooftop area for installation of PV modules or adding solar rooftop may compromise the safety of the roof. Such buildings may opt for BIPV where modules are directly stuck/ installed and the building may utilize the energy produced from such plant.
- Increased power output: The BIPV modules can be used to get additional power output. Additionally using bifacial cells in the module utilizing the reflected light at the inner surface of the building. Such modules can provide an additional power of upto 30% enabling the consumer to maximize the benefit of such module.
- Thermal insulation:In addition to generating power BIPV panels (as they are sandwiched between glasses) can be used to provide thermal insulation. This requires the BIPV panels to be sandwiched by double or triple glazing structures by filling air (or anynon conductive gas) between them. This would provide the thermal insulation comparable (superior in some cases) to the traditionally used thermal insulators.
- Other advantages: The initial cost of BIPV may be offset by reducing the amount spent on conventional building materials and labour that would normally be used to construct that part of the building. Once the building is in operation, there are additional savings as the sunlight generates electrical energy. BIPV are available in various colours maintaining the architectural integrity of the building. BIPV modules can comparably (to the regular construction material) reflect sound (noise) based on its construction.
The BIPV technology as mentioned above has added advantages when compared to the traditional solar modules. However, they are not common to our sight (when compared to traditional modules) because of the following reasons:
- Heavy initial cost: One of the most important factors for adapting any technology is the cost associated with it. With the cost of solar plant (using traditional solar plant) touching a mere INR 2.44/ kWh (refer)it has become crucial that other solar technologies are at par with this cost. However BIPV solar modules are costly by more than 2.5 to 3 times the traditional solar module.
- Require adequate protection: The BIPV modules (as we saw in earlier figures) are installed generally outside the building with some installed vertically. This makes them prone to heavy mechanical stress due to wind forces. Additionally few of those modules are only supported by the surrounding modules (and not by a proper supporting mechanism) making them extremely vulnerable. This requires the modules to be extremely sturdy while maintaining the aesthetic look of the building. Such modules are not always available making it an impossible installation.
- Social adaptability and subsidy issues in India: While the country boasts close to 15 GW of grid connected solar installations, adaptability of new technology like BIPV has been an issue. One factor that can be attributed to such adaptability is that the country's infrastructure in not yet been fully developed to adapt such technology. Additionally various countries like USA, China, EU has already declared attractive policy for adaptation of BIPV while India is yet to do so. While there is an uptake of a typical type of BIPV module in India, the full range of BIPV modules are yet to see the bright side of the day.
The figure below shows few installations of BIPV modules on buildings. As evident, there is no standard design for such modules as they are site specific. Additionally these modules can be customized based on the Architectural design of the building or could be made to be in sync with the building (if the building is in planning stage). Also, these modules are perfect match for low (direct) irradiance locations and they can be installed in any orientation. Such modules are already installed in various parts of Europe, USA, China, etc. and are perfectly in sync with the local grid while powering the building. India can utilize such modules (instead of traditional solar PV) in (relatively) low irradiance sites like North Eastern India. Additionally government can also provide financial incentives for such modules giving BIPV the much needed push.
Figure 4: Few installations of BIPV (Source: Google images)
Waaree is capable of producing BIPV module with the standard (and few customized) power requirements. We also have a range of flexible, low weight, peel-and-stick flexible modules which use a patented technology. They can be customized according to the consumer requirements based on their area or power. They can also be integrated with your building based on its size.
Figure 6: Building Integrated PV Merlin modules
Let us all pledge to make solar energy the primary source of energy in the near future.
RAHE ROSHAN HAMARA NATION