According to a recent study, building-integrated photovoltaics (BIPVs), if installed on windows of buildings could yield energy savings of up to 20%. Climate Control Middle East spoke to Mohammad Katanbaf, Architect, Design Division, KEO International Consultants, to explore key issues surrounding BIPVs and the roadmap that lies ahead of the technology.

What is the range of energy savings that buildings fitted with BIPVs can achieve?

In general, the savings will vary between five per cent and 20%. The range will depend on several criteria, including:

• Type of photovoltaic (PV) cells – whether thin film or crystalline
• Method of integration – façade or roof
• Orientation and inclination of the PV cells
• Proper maintenance of cells to avoid performance reduction
• Proper ventilation to keep good air flow, hence avoiding overheating

How do sand and humidity in this region affect the efficiency of the panels? What measures can be taken to remedy these problems?

Both sand and humidity have a negative effect. On one hand, the temporary instabilities caused by dust or sand deposited in the PV array or, in case of rainfall, clouding the surface (aka caked surface) lower the efficiency. On the other hand, permanent disturbances (the wear and tear of the panel itself), particularly caused by large particles in sandstorms that break the fragile glass surface, reduce performance and electricity output. One method of avoiding this problem is through the use of nano-coating with self-cleaning and hydrophobic properties. This can stop dust build-up and keep panels clean, hence maintaining their efficiency and ensuring that the maximum amount of electricity is produced.

How much more expensive are BIPVs compared to traditional solar panels?

Since BIPVs replace conventional building envelope systems, while solar panels are additional components to existing building skin, naturally their prices will vary. Unfortunately, I cannot give you an exact number. BIPVs are roughly twice as expensive as conventional solar panels. For exact figures, you will need to contact the suppliers.

Are customers more conscious of the price of BIPVs instead of the energy savings they may bring?

Yes. Most, if not all, clients consider payback scenarios before investing in the panels. Such economic analysis takes energy savings into consideration. But it is mostly driven by capital cost.

What measures are you planning to take to promote the use of BIPVs? Will a feed-in tariff scheme help in encouraging the market to choose BIPVs?

One way of promoting BIPVs is raising their aesthetic appeal. If the façade integration is more seamless and innovative, such that it strengthens the architecture, then this will work in favour of such alternative façade. This said, the best driving force is economic incentives and government-backed policies that enforce them.

Mohammad Katanbaf has published the results of his study on BIPVs in the January edition of the journal Engineering.