On the morning of September 25, at the Yangcao Village drying center in Huangjing Town, Taicang City, Suzhou, Jiangsu Province, workers were dismantling old equipment like diesel combustion chambers from 10 grain dryers. Before the autumn harvest, these dryers will be equipped with air-source heat pumps to achieve green grain drying. That same day, Li Junnan and Ma Yucheng, staff from the Huangjing Power Supply Office of State Grid Suzhou Taicang Power Supply Company, visited Yangcao Village to understand its electricity needs.

Drying is a crucial step in ensuring a successful harvest and getting every grain safely into storage. The moisture content of rice entering storage must be around 14.5 percent. If the moisture is too high, the grain is prone to sprouting or mold; if it's too low, the grains can easily crack and break during processing. When using diesel for drying, the heat level cannot be precisely controlled, leading to uneven heating of the grains which affects quality. Furthermore, diesel drying involves open flames, posing a fire risk.

"Compared to diesel, electric drying using air-source heat pumps offers advantages such as no open flames, zero emissions, and easy control, making it safer, more environmentally friendly, and energy-efficient," explained Yu Xiaomao, Director of the Marketing Department at State Grid Suzhou Taicang Power Supply Company. After the transformation, operators simply need to pre-set values like the target moisture content, pour the harvested grain into the intake hopper, and press the start button. The machine then automatically completes the processes of screening and drying. "Sensors in the dryer continuously monitor the moisture content," Yu added. "Once it reaches 14.5 percent, the dryer stops automatically, achieving automation, green transformation, informatization, and intelligent operation."

However, switching from diesel to electric is not a simple task. The procurement of new equipment and the necessary increase in electricity capacity requires an investment of at least 2 million yuan, which raised concerns for some villages planning the upgrade.

In 2022, to promote the construction of drying centers using clean heat sources, State Grid Suzhou Taicang Power Supply Company conducted in-depth research into the heat sources used for grain drying across Taicang. Addressing user concerns, they proactively engaged with the local Agriculture and Rural Affairs Bureau and innovatively introduced an overall leasing model for "power distribution equipment + air-source heat pumps." This "lease-to-own" approach significantly reduces the initial investment cost for users. The transformation costs were initially covered by the Suzhou Agricultural Development Group Co., Ltd., with village collectives making annual installment payments. The power supply company provides the electricity connection services.

To date, Taicang has built 30 drying centers with 354 dryers. Of the original 146 diesel dryers, 94 have been upgraded. State Grid Taicang Power Supply Company has added a total power supply capacity of 8,350 kVA for these projects. The overall proportion of dryers using clean heat sources has now reached 85.31 percent. The aim is to achieve full coverage of clean heat source dryers across the city by the end of 2026.