Unsurprisingly, solar PV has been the fastest growing energy source given its recent cost reductions and technological progress. One prominent example of this technological progress is building integrated photovoltaics (BiPV). Whilst optimizing available space, they are also aesthetically pleasing. In this article, we will take a closer look at BiPV and summarise the most important aspects.
What is BiPV?
BiPV is a newly emerging term within the PV industry. It refers to any photovoltaic material which is replacing conventional building materials such as glass, facades, roofs, or skylights, just to name a few. Has BiPV evolved as a potential technology capable of revolutionising the PV and buildings sectors? Let’s take a look.
Why do we need BiPV?
Solar photovoltaics are well-known for being a working solution for buildings to reduce their reliance on the electricity grid and move towards a prosumer-driven society. A problem that rooftop solar faces, however, is the limited space available for modules.
Further, with climate goals and a continually growing energy demand, we are all called upon to act and reduce our carbon emissions. One way to achieve this is to reduce the energy balance of our own homes. With the available innovative technologies, this has never been easier.
In addition to this, as of this year, the EU Building Directive requires newly constructed buildings to have a settled energy balance. This means, the buildings sector needs to reduce its CO2 emissions, whilst further contributing to power generation and energy storage.
Below is an example of how BiPV can achieve the above goals whilst still being aesthetically pleasing.
Nevertheless, this is not an exhaustive example of all the possibilities to date. For example, we could do the fencing with bifacial PV modules and substitute the glass with solar glass.
The advantages of building integrated photovoltaic
The advantage of photovoltaics integrated into buildings is primarily the generation of electricity close to consumption. This combats challenges around land use and social acceptance of solar plants.
“If we produce electricity where it is also consumed, we don’t have to expand the power grid as much to distribute the electricity within the country. And if the technology blends aesthetically into the architecture, it won’t be perceived as a foreign body in public spaces.”, said Dr. Tilmann Kuhn, Head of Group Solar Building Envelopes, Deputy Head of Department Energy Efficient Buildings, Fraunhofer ISE.
In addition to electricity generation, BiPV also serves simultaneously as sound and weather protection, thermal insulation, or shading elements.
The hard facts
As with most innovations, a major concern is costs.
The table below compares the price per square meter of BiPV roofing components and regular roofing, where we can see that BiPV is still more expensive than regular components. However, this is before opportunity costs and savings due to generated electricity.
The source for the following tables has been the PV Status Report 2020 from SUPSI, University of Applied Sciences and Arts of Southern Switzerland and the Becquerel Institute: Building Integrated Photovoltaics: A practical handbook for solar buildings’ stakeholders.
The table below now compares the component costs for facades of BiPV and regular facades, where costs differences appear to be less signficant than with roofing.
Another aspect though are system costs. Again, the table below compares BiPV as well as regular roofing. On top of that, Building Attached PV (BAPV) systems are part of this graph.
And here are the system costs in comparison.
Competitiveness of BiPV
Another interesting comparison is looking at LCOEs as LCOEs give a good overview of the actual costs per unit, kWh.
Suppose the compensable electricity price (the amount of money saved on the electricity bill for each self-consumed kWh) is above the LCOE price. In that case, each self-consumed electricity unit generates more savings than the system has cost to build. Comparing these to electricity prices lets us determine whether the BiPV system will become profitable before the systems lifetime ends.
In other words, it is cheaper to build a BiPV system and use the electricity generated than to build a regular house and buy electricity from the grid operators. This remains true throughout all 8 European countries in the study.
Another important aspect is system lifetime. BiPV is said to have the same life expectancy as regular PV modules. This happens to be 30 years and is in line with regular building material facades and roofs.
For NPV calculations and amortization calculations, the above values are of big interest. When looking at the table below, all parameters illustrate a positive NPV, which means that BiPV is economically feasible. Consequently, this proves that BiPV should be used instead of regular building materials.
The first graph is for roofing, the second for facades across different countries.
In most cases it already makes sense to use BiPV instead of regular building materials, and that is before any other unquantifiable aspect of BiPV.
Additionally, a study from Gholami & Røstvik “Economic analysis of BIPV systems as a building envelope material for building skins in Europe” illustrated that the BIPV system as a building envelope material for the whole building skins could reimburse not only all the investment costs but also become a source of income for the building.
In summary, there is enormous potential for BiPV, especially in markets with higher solar irradiation. As with all new technologies, costs will drop as efficiency increases, posing an even better case for BiPV. Nevertheless, this cost reduction won’t be as fast moving as the one seen for regular solar PV modules due to the uncomparable economies of scale effects. This is due to there being limited possibility for utility scale projects.
In a nutshell, if you are interested in doing some good for our environment whilst increasing efficiency, then BiPV is a good option for you.