Photovoltaics to power up change

Buildings constructed with solar panels in place could ease energy concerns

When seen from a distance, the huge factory of Changshu Longteng Special Steel in Changshu, Jiangsu province, impresses many people.

With a width of up to 234 meters and a height of 58 meters, the workshop with its arched roof is larger than the National Stadium, also known as the Bird's Nest, in Beijing.

However, the complex is important for more than just its size. In addition to providing shelter from the wind and rain like other buildings, it can generate 48.5 million kilowatt-hours of electricity a year, meaning it can meet the annual power demand of more than 9,100 people. Last year, China's per capita power consumption stood at 5,317 kWh.

Moreover, covered by 68,000 monocrystalline photovoltaic panels, the factory can help reduce carbon dioxide emissions by about 38,000 metric tons a year.

Completed last month, the factory is just one of the latest examples of Building Integrated Photovoltaics, known as BIPV in the industry, as China works hard to achieve its climate targets of peaking carbon dioxide emissions before 2030 and realizing carbon neutrality before 2060.

According to the Action Plan for Carbon Dioxide Peaking Before 2030, unveiled in October by the State Council, China's Cabinet, the country will promote the use of renewable energy in buildings and expand the integration of photovoltaics into buildings.

By 2025, renewable resources will account for 8 percent of the alternative to conventional energy used in buildings, the plan said.

The country will also strive to reach 50 percent photovoltaic coverage on the roofs of newly constructed public buildings and factories.

Currently, almost 20 percent of China's carbon dioxide emissions are generated by the operations of buildings. That means making use of roofs and facades for the development of solar energy is a viable approach to reduce emissions, according to experts, who said that compared with other developmental approaches, BIPV is greener and safer.

However, China still needs to reform the construction standards for BIPV modules, or panels, to unleash its huge potential and help the country reach its climate targets.

According to the China Association of Building Energy Efficiency, 4.9 billion tons of carbon dioxide were generated in the country in 2018 by building processes, from producing construction materials to construction and operations.

Meanwhile, the operation of buildings generated roughly 2.1 billion tons of emissions, accounting for 22 percent of the country's total that year, it said.

Chen Pengfei, president of the BIPV section at LONGi Green Energy Technology, a leading industry player, said that for decades, China has mainly depended on the development of energy-efficient buildings to reduce energy consumption.

As standards have regularly been upgraded since the 1980s, "there has been no further potential to tap into traditional technologies for energy-saving buildings", he said.

Against this backdrop, the development of solar energy in buildings has a big role to play in further reducing emissions.

Secondary approach

In addition to BIPV, another viable approach to develop photovoltaic power is Building Applied Photovoltaics, or BAPV, where the modules are fixed to existing surfaces post-construction.

However, BAPV may result in more safety hazards and construction waste compared with BIPV, Chen said. The facades and roofs of many buildings may be plagued by water leaks, rust and damage, especially those made from metal on buildings in the industrial and commercial sectors, he said.

Moreover, BAPV will create more hazards, such as corrosion, and is also more prone to wind damage, he said. Entire facades may have to be repaired and the photovoltaic power system dismantled in no more than 10 years, he added.

Designed and constructed with the same service life as the buildings, BIPV can be resistant to water, fire and wind for 25 to 30 years.

With no need to repair the facade and dismantle the module in just eight to 10 years, it can prevent a large amount of construction waste, Chen said. Many BIPV products can be stamped on, making it unnecessary to provide maintenance routes, he added.

That means that in buildings of the same size, BIPV can have 15 percent more installed capacity, making it more possible for them to not only power themselves but also sell green electricity to other people.

Despite being advanced last century, the BIPV concept was only commercialized in China in 2020.

"In recent years, many photovoltaic and construction companies have entered the sector, but the industry is still in the initial development stage," Chen said.

He added that one of the challenges is that developers of BIPV projects need expertise in both photovoltaic systems and construction work.

"Only with a design that can integrate photovoltaic and building systems into a safe and efficient entirety can BIPV have a service life of 25 to 30 years as claimed," he said.

However, he believes that the country's preferential policies will result in the BIPV market experiencing a sharp rise in demand in the long run.

His view was endorsed by a recent report from GF Securities.

"Considering the large size of China's manufacturing industry and the world's high demand for its products, it is not easy to effectively realize green development and carbon reduction in the short term in the industry. Carbon reduction in the building sector, which is more flexible and has fewer hindering factors, has drawn more attention," the report said.

In June last year, the National Energy Administration published a notification on piloting the rooftop development of distributed solar energy at the county level. The document is expected to greatly expand the market for photovoltaic power generation on buildings, it said.

Driven by preferential policies and the boom in photovoltaic generation, "BIPV will embrace an enormous market," the report said.

GF Securities estimates that China's total addressable market will reach 23 billion yuan ($3.5 billion) this year, and following continuous increases, it will expand to 86.6 billion yuan in 2025.

Liu Jimao, assistant president of Zonergy, a new energy conglomerate, said some reforms are still needed to address factors hindering BIPV development in China.

"BIPV is developing very slowly in China, where its market is less than 10 percent that of BAPV," he said.

Among the obstacles is the fact that in China, BIPV modules need to apply the construction standards used for glass curtain walls, he said. This makes the cost too high if the modules are used to replace the color steel tiles commonly used for rooftops. If the modules are used to replace the glass curtain wall, they only generate a very small amount of power.

To boost BIPV development in China, Liu suggested reforming the standards for BIPV modules.

With costs, practicality and safety as major concerns, different technical standards should be adopted in accordance with application scenarios, he said, adding that he believes such reform would bring a "prosperous future" for BIPV.

Zhang Lei, a postdoctoral researcher at Peking University, believes BIPV is embracing huge development opportunities.

He noted that the increasingly improved policy system, proactive government guidance and the consistent growth of China's PV market are all providing impetus for the development of BIPV.

He added that about 2 billion square meters of new buildings are constructed in China every year, which offers huge market potential for BIPV.

He said that as local governments work to achieve the country's climate targets "it's exactly the right time for the construction sector to develop BIPV technologies on a large scale".