Trillion-scale Building-Integrated Photovoltaics (BIPV) Explosion! A Comprehensive Overview of Project Plans, Application Design, and Investment Returns

This document contains 35 pages. The above are only screenshots of the PPT content. To download the complete set of materials, please add my WeChat or other methods to obtain them:

Please add WeChat to obtain the above materials or to join the low-carbon group

 

 

Building-Integrated Photovoltaics (BIPV) integrates photovoltaic components with building materials, transforming traditional buildings into energy-efficient buildings that can generate electricity, thereby driving the transformation of buildings from energy consumption to energy saving and energy production.

In 2022, the Ministry of Housing and Urban-Rural Development and the National Development and Reform Commission jointly issued the "Implementation Plan for Carbon Peak in the Urban and Rural Construction Field," which clearly states: Promote the construction of building-integrated photovoltaics. By 2025, the photovoltaic coverage rate of newly built public institution buildings and newly built factory rooftops will strive to reach 50%.

According to calculations by Everbright Securities, the total potential installed capacity of BIPV is approximately 1500-2000 GW, corresponding to a market size of 7.5-10 trillion yuan!

In today's article, I will detail the design process, application forms, and project return calculation content of BIPV projects. I have found 5 plans to provide to friends for reference, helping everyone understand the entire project process.

 

Table of Contents

1. Practical BIPV Project Plans

2. Four Major Application Forms of BIPV

3. Design Principles of BIPV Projects

4. Investment Return Analysis of BIPV

 

01

Practical BIPV Project Plans

1. BIPV Project Installation Plan

Swipe left and right to view more

2. BIPV Project Design Plan

Swipe left and right to view more

3. BIPV Project Technical Plan

Swipe left and right to view more

4. BIPV Project Return Calculation

Swipe left and right to view more

5. BIPV Project Case Introduction

Swipe left and right to view more

02

Four Major Application Forms of BIPV

With the rapid development of the construction industry and the ingenious ideas of architectural designers, the forms of building envelopes are becoming increasingly diverse. As a deeper manifestation of building envelope structures, building-integrated photovoltaics has also appeared in a variety of application forms on buildings. Below are several application forms of BIPV in buildings for your reference.

Skylights: Ideal lighting, high power generation efficiency;

Curtain walls: Good demonstration effect, diverse forms, beautiful;

Sunshades: Both shade the sun and generate electricity to supplement energy;

Guardrails and floors: Make full use of space, easy and convenient to install.

Application of BIPV in Buildings

 

1. Photovoltaic Glass Curtain Wall

Install photovoltaic curtain walls in the interlayer areas of glass curtain walls with sufficient lighting and facade areas that require shading design, integrating building decoration, building shading, and power generation. Its structural principle is exactly the same as that of a glass curtain wall, and the curtain wall form can be made into various forms such as full hidden frame, full bright frame, and semi-hidden frame.

The photovoltaic glass curtain wall system can be customized according to the project or the original curtain wall system can be structurally modified; the back of the photovoltaic panel can be lined with different colors to adapt to different architectural styles. The photovoltaic curtain wall integrates power generation, sound insulation, heat insulation, and decoration functions, combining photoelectric technology with curtain wall technology, representing a new direction in the development of curtain wall technology.

It collects, converts, stores, and transforms natural light through solar cells and semiconductor materials, and finally connects to the building's power supply network to provide reliable power support for the building.

Photovoltaic Curtain Wall Node Diagram

 

2. Photovoltaic Glass Skylight

Glass skylights are components of buildings. As the span of buildings becomes larger and larger, the indoor lighting needs of buildings cannot be met by building curtain walls and windows, and glass skylights need to be set up on large-span roofs for indoor lighting. The innovative design combining photovoltaic glass components with skylights allows green building design to be integrated into the entire construction process.

Structurally, a horizontal hidden vertical bright semi-hidden frame design is adopted. For those with fire protection requirements, the fire protection requirements of the building roof must be met. For photovoltaic skylights without fire protection requirements, point-supported glass skylights and aluminum alloy frame glass skylights can be used.

Photovoltaic Skylight Node Diagram

 

3. Photovoltaic Guardrail

Guardrails are important protective components of building safety protection facilities. In locations with good orientation and sunlight, using photovoltaic glass instead of common glass, metal, etc., can not only meet safety protection needs but also utilize solar power generation, killing two birds with one stone; the innovative design combining photovoltaic glass with railings is structurally safe and reliable, and the perfectly hidden lines and junction boxes are more beautiful and the construction is simple and convenient.

Photovoltaic Guardrail Node Diagram

 

4. Photovoltaic Awning

Photovoltaic awnings are one of the most promising forms of building photovoltaic applications in the future, with the following three points:

At a reasonable installation angle, it is conducive to the photovoltaic components receiving the maximum amount of solar radiation, improving the photoelectric conversion efficiency; it can block sunlight from entering the room, which is conducive to controlling and regulating the indoor temperature, reducing the air conditioning load of the building, and playing a role in energy saving and emission reduction; photovoltaic components, as a new type of building shading component, can save shading materials and enrich the building.

Photovoltaic Awning Node Diagram

 

03

Design Principles of BIPV Projects

The design of a building-integrated photovoltaic system can be mainly divided into the design of the photovoltaic system and the design of the building system.

The design of the photovoltaic system combines the specific on-site scene with the power requirements of the load side. Based on the solar energy resources and temperature and other environmental factors at the project location, the appropriate solar cell array is calculated, and the corresponding equipment capacity is matched to achieve the economic rationality and feasibility of the overall system.

The design of the building system is that as part of the building structure, it needs to meet the requirements of use performance, and secondly, it needs to meet the requirements of structural stability, economy, and aesthetics.

 

1. Design Principles of Photovoltaic Systems

The design process of a solar power grid-connected generation system mainly includes electrical, thermal, electrostatic shielding, and mechanical disciplines, among which the key process is to analyze the on-site environmental resource conditions, match the power demand, and balance the system.

The overall design principle of the system is to determine the most economical system combination under the premise of maximizing power generation.

Analyze power demand, environmental resources, and the selection of major equipment; use professional simulation software for simulation and comparison and verification. Input data mainly includes:

Insolation at the installation location

Insolation on the tilted surface of the array

Environmental temperature parameters

System voltage

Load energy demand

Controller adjustment characteristics and parameters

Characteristic parameters of solar photovoltaic battery modules

System power supply reliability and power supply availability

The results are calculated using computer simulation methods, mainly including:

Tilt angle and azimuth angle of the solar cell array

Number of solar photovoltaic battery modules

 

2. Design Steps of Solar Power Generation System

Step 1: List basic data

Geographical data mainly include Address, longitude and latitude, and elevation.

Local meteorological data: mainly includes monthly average total solar radiation, direct and scattered radiation, annual average temperature and highest and lowest temperatures, continuous rainy days, maximum wind speed, and special climate conditions such as ice and snow. Generally, accumulated meteorological data from the past 20 years is selected.

Step 2: Calculate daily radiation and array tilt angle

Meteorological stations generally only provide horizontal plane total radiation, direct radiation, and scattered radiation, which needs to be converted into solar radiation on the inclined plane combined with the project's inclination angle.

Step 3: Estimate the solar cell array

Calculate the monthly total radiation using the annual average monthly horizontal plane direct and scattered solar radiation, then calculate the annual average daily total solar radiation and the power generation of the solar cell array.

Step 4: Determine the power capacity of the solar cell array

According to the current, voltage, and power data of the solar photovoltaic array, and referring to the performance parameters of the host equipment, select the appropriate equipment Model and quantity.

 

3. Design Steps of Solar Power Generation System - Design Aspects of Building Structure System

Building-integrated photovoltaic systems can be installed on the roofs of industrial buildings to replace the original enclosure structure, adding power generation functions to the factory roofs. According to the different product structures, the mainstream products are divided into: building solar photovoltaic laminated glass, component type, water diversion rack, and metal backplane type.

(1) Building solar photovoltaic laminated glass

 

 

Building solar photovoltaic laminated glass products integrate solar cells and one or more layers of glass. The structure is composed of upper and lower layers of glass encapsulating the solar cells, and the glass and solar cells are connected by an internal thermoplastic film. It is the smallest power generation unit that can independently provide DC output.

Specifically, it can be divided into two forms according to the combination method of solar cells and glass: laminated to glass with interlayers and directly installed in the cavity of multilayer glass units.

The panel material uses double-layer glass. The Model, Size, and related parameters of the glass can be customized according to the building requirements. It can be a composite of ordinary tempered glass, ultra-white tempered glass, low-e glass, colored glass, etc., and can also be compounded from basic units into better-performing single-layer hollow, laminated vacuum glass types.

The intermediate layer encapsulation material should choose polyvinyl butyral (PVB), which is mainly composed of resin, plasticizer, and other materials. It has the characteristics of transparency, heat resistance, cold resistance, moisture resistance, and high mechanical strength, and has a service life of 50 years with the building .

 

(2) Integrated component type of crystalline silicon photovoltaic and pressed steel plate

 

The crystalline silicon photovoltaic component and roof pressed steel plate integrated component mainly includes crystalline silicon solar power generation components, pressed steel plates, and connecting parts between the two, referred to as the component-type building-integrated photovoltaic system. Structurally, it can be a complete whole and maintain structural connection characteristics when subjected to external loads. It can be the smallest power unit for independent application.

The core of this system's photovoltaic roof is, from top to bottom: purlin, insulation cotton, waterproof breathable membrane, slidable support, pressed steel plate, and photovoltaic components. It is compatible with the concealed and exposed insulation systems and installation methods of conventional industrial plant purlins.

The photovoltaic component uses 2mm tempered glass, front EVA film, high-efficiency monocrystalline Perc cells, polyolefin elastomer encapsulating insulation film (POE), and tempered glass.

At the same time, the component support structure changes from the traditional four-point support to a strip support with a span of every 30cm, making the component force more balanced, greatly reducing the component hidden cracks caused by external forces during use, and achieving a reliable guarantee of the system power generation.

The metal roof system uses 0.6mm thick aluminum-zinc plated steel plate with a full-length type, that is, from the ridge to the eaves, a full-length whole steel plate is used without overlapping, which can effectively reduce the risk of leakage caused by overlapping seams. The longitudinal lap of the pressed steel plate adopts a 360-degree upright locking edge technology to ensure reliable and leak-proof connection between the steel plates; in addition, butyl glue is filled in the locking edge gap, which can effectively prevent seepage caused by capillary phenomenon.

 

(3) Water diversion bracket type

The water-guiding bracket building-integrated photovoltaic system mainly consists of horizontal and vertical water guide troughs, conventional solar panels, fixed pressure blocks, rubber strips, and edges, meeting the basic requirements of building waterproofing, anti-settlement, and anti-expansion. It can also withstand high wind loads, snow loads, has good lighting and ventilation performance, and is also heat-insulating, heat-preserving, shockproof, and waterproof, making it relatively easy to maintain during the later operation stage.

The roof's water-guiding function mainly relies on natural drainage from the surface of the components. A small amount of water flows to the drain trough below under the effect of pressure difference, and then is discharged through the vertically intersecting horizontal U-shaped waterproof trough and vertical W-shaped water guide trough. The short side of the component's horizontal contact is fixed with a pressure block, and the long side of the component's longitudinal contact is fixed with a T-shaped rubber strip. The water guide trough can also serve as a fixture for the solar panels.

 

(4) Metal Backsheet Type

The metal backsheet type building-integrated photovoltaic system uses a galvanized aluminum alloy backsheet for the solar panel, forming a latch structure, replacing or covering the roof's installation method.

Among them, the front of the solar panel uses tempered glass with a 3600Pa positive static load, a photovoltaic power generation layer in the middle, forming a non-combustible composite material structure with external dimensions of 2100*1400mm.

In summary, the currently applicable building-integrated photovoltaic systems for industrial plant roof types are mainly divided into four categories: building solar photovoltaic laminated glass, integrated component type, water-guiding bracket type, and metal backsheet type. With technological advancements, there are completed cases of each product available for research.

 

04

BIPV Investment Return Analysis

1. Payback Period and Rate of Return

A simple model is constructed to calculate the investment economics of typical commercial BAPV/BIPV photovoltaic roofs. It is assumed that the investor and electricity user of the photovoltaic roof are the same entity, and all photovoltaic power generation is self-used.

Due to the gaps between photovoltaic components in the actual installation of BAPV, the actual effective power generation area will be lower than that of BIPV under the same conditions. We assume that the actual effective power generation area proportion of BIPV is 95% and BAPV is 85%.

The project construction period is 0.25 years, and the operation period is 25 years; the power generation efficiency of photovoltaic components decreases by 5% in the first five years and then decreases linearly at a rate of 0.5%/year, with a total decrease of 14% in 25 years; in terms of subsequent maintenance costs, BAPV is 0.06 yuan/watt·year, and BIPV is 0.04 yuan/watt·year. In addition, the BAPV project needs to replace the color-coated steel roof once after 15 years of operation, with a cost of 300 yuan/㎡; in terms of electricity price, the average industrial electricity price of 0.73 yuan/kWh is used.

Assuming the installation of a 2000㎡ photovoltaic roof, the estimated power generation in the first year of completion is 298,000 kWh for BAPV and 380,000 kWh for BIPV.

If the owner initially chooses to invest entirely with their own funds, the estimated payback period for the BAPV project is 5.87 years, IRR=15.25%, and the estimated payback period for the BIPV project is 5.87 years, IRR=16.36%; if the owner chooses loan investment, with an annual interest rate of 6% and a loan term of 5 years, the estimated payback period for the BAPV project is 7.32 years, IRR=34.02%, and the estimated payback period for the BIPV project is 7.31 years, IRR=35.33.

 

2. Impact of Excess Grid-Connected Proportion on Investment Returns

If the owner cannot consume all the power generation, or if the photovoltaic investor and the building owner are not the same entity, part or all of the project's power generation needs to be grid-connected and sold. Since the current price of excess grid-connected photovoltaic power generation is generally lower than the industrial electricity price, the higher the proportion of excess grid-connected power, the lower the return rate of the rooftop photovoltaic project.

Assuming that the tax-inclusive price of excess grid-connected photovoltaic power is 0.42 yuan/kWh, if the proportion of excess grid-connected power is 20%, the payback period of photovoltaic projects with self-owned funds will be extended to 6-7 years; the payback period of photovoltaic projects with loan investment will be extended to about 8 years. If the photovoltaic investor is not the building owner and chooses to sell all the power generation to the grid, the payback period for self-funded BIPV investment is about 10 years, and the payback period for loan investment in BIPV projects exceeds 13 years.

 

That is, the higher the proportion of self-used power generation in industrial and commercial building photovoltaic projects, the better the investment returns.

According to the current energy consumption of industrial and commercial buildings in China, the power generation of building photovoltaic projects is still not enough to cover the electricity consumption of the building itself. Taking a typical four-story commercial building in China as an example, with a floor area of 34,300㎡, the monthly electricity consumption is about 1.61 million kWh. If BIPV photovoltaic renovation is carried out on its roof, the estimated monthly power generation is only about 480,000 kWh.

Therefore, the power generation of building photovoltaics can basically be consumed by the building itself, and there is no need for grid-connected sales. It is expected that in the short term, most building photovoltaic projects will be mainly self-used.

 

3. Impact of Sunshine Hours on BIPV Project Investment Returns

The annual average effective sunshine hours of the photovoltaic project location will directly determine the amount of photovoltaic power generation and is an important factor affecting the return of photovoltaic roofs. The regions with the longest annual average effective sunshine hours in China, such as Xinjiang and Tibet, can reach more than 1600 hours, while the shortest regions, such as Chongqing, have only about 700 hours.

Taking the BIPV project as an example, assuming that the local annual average effective sunshine hours are 800 hours, the payback period for self-funded investment is 7.49 years, and the payback period for loan investment is 9.35 years. If the annual average effective sunshine hours are 1300 hours, the payback period for self-funded investment is 4.42 years, and the payback period for loan investment is 5.51 years.

 

 

4. Impact of Construction Cost on BIPV Project Investment Returns

In 2021, the average bid price for domestic distributed photovoltaic EPC projects was around 4 yuan/watt, with the highest bid price in 2021Q4 being 4.75 yuan/W and the lowest price being 3.32 yuan/W. From some rooftop distributed photovoltaic projects in February 2022, the unit price is between 3.42-4.95 yuan/W.

If the average quotation for domestic building photovoltaics further decreases to 3 yuan/W in 2025, assuming that the domestic industrial electricity price remains unchanged in the future, then by 2025, the payback period for self-funded BIPV photovoltaic roof projects can be reduced to 4.67 years, and the internal rate of return is expected to reach more than 20%; the payback period for loan-invested BIPV photovoltaic roof projects is expected to be 5.82 years, and the internal rate of return exceeds 60%.