Clean energy is becoming a priority as countries commit to being carbon-neutral by 2050. A serials of cutting-edge technologies are proved crucial in efforts to reduce greenhouse gases as nations are targeting the big pie of green energy.

China is also striving to achieve its own green and sustainable development goals.

Boasting of world's first renewable energy flexible direct current (DC) grid project, river water-powered air conditioner, improved carbon capture technology, smart port and world's largest hydro-solar power station, the country is on track to embrace a more eco-friendly future. 

Giant new energy 'power bank'

The Zhangbei renewable energy flexible direct current (DC) grid project, the world's first of its kind, went fully operational in 2020 in north China's Hebei Province.

Independently developed by China, all core technologies and key equipment of the project were applied to achieve a green Olympics in 2022, making the 2022 Beijing Winter Olympic Stadium the first Olympics venue with 100 percent clean energy power supply in history.

It can deliver 14 billion kilowatt-hours of clean electricity annually, which is equal to one-tenth of the total electricity consumption of Beijing for a whole year. That is to say, one out of every 10 lights in Beijing is lit by the clean energy from the Zhangbei project.

It is also capable of saving 4.9 million tonnes of standard coal and cutting 12.8 million tonnes of carbon dioxide emissions every year.

Compared with alternating current (AC) and conventional DC, the flexible DC transmission technology features strong controllability, fast power adjustment speed, and flexible operation mode, which is considered to be the "golden key" to solve the problem of large-scale consumption of new energy.

The secret of clean energy generation lies in a pumped storage power station inside the project.

With water as the medium, electric energy and potential energy are converted into each other in a lifting room of the power station, consuming surplus wind, solar, and green power in the Zhangbei area, while maintaining the safe operation of the power grid, just like a huge "power bank."

Liu Jindong, deputy director of the Maintenance Department of State Grid Xinyuan Hebei Fengning Pumped Storage Co., Ltd., told China Media Group (CMG) that the two ends of the unit are connected to the upper and lower reservoirs through pipelines. To put it simply, when there is plenty of power generation, the pumped storage power station uses excess electricity to pump water from low places to high places, and converts electric energy into potential energy of water.

"During the peak period of electricity consumption, the potential energy of water is converted into electric energy through power generation, and then transmitted back to the grid for everyone to use," said Liu.

River water-powered air conditioner

In Nanjing, an east China city in Jiangsu Province, traditional air-conditioning units have disappeared in some large public venues, replaced by the River Water-Powered Air Conditioner.

As the name implies, it uses the Yangtze River water as the source of cold and heat, enjoying the "green" cool breeze from the Yangtze River without traditional external air conditioners or cooling towers.

The Yangtze River is the longest river in China with an approximate length of 6,300 kilometers. It is also the third-longest river in the world after the Amazon River in South America and the Nile River in Africa, and ahead of the Mississippi River in the U.S.

The secret of using Yangtze River water for cooling is hidden in the river water source heat pump system in the energy station.

The manner draws water from the Yangtze River and transports it to the energy station to absorb the heat of tap water, reducing the temperature of tap water to a minimum of five degrees Celsius.

The cooled tap water is sent to the heat exchange station of the public buildings, where it exchanges heat with the air-conditioning water. The temperature of the air-conditioning water drops, and it is sent to each floor to blow out cold air.

Fan Kefei, secretary of the Communist Party of China (CPC)'s branch commission with Nanjing Jiangbei New District Public Holdings Group Co., Ltd., told CMG that "in the summer, we replace air-conditioning water with river water to exchange heat. In the winter, the process is completely reversed to heat the region. The energy station only exchanges heat, without consuming water and changing water quality."

Compared with traditional central air conditioner installed for a building, this new method, which adopted by our local civic center, the art museum, and service trade building in the new district, can save energy by 30 percent, said Tan Jin, assistant general manager, State Grid Nanjing Power Supply Company.

Carbon capture technology     

Carbon Capture Usage and Storage (CCUS) is a technology that can capture and make effective use of the high concentrations of carbon dioxide (CO2) emitted by industrial activities. Consequently, it has a key role to play in decarbonization and the addressing the challenge of global climate change.

On the Liaohe Oilfield of north China's Liaoning Province, there lies a carbon dioxide capture liquefaction station covering an area of only 8,800 square meters.

Such a small-scale carbon dioxide capture liquefaction plant can capture and process 57,000 tonnes of carbon dioxide per year, which is equivalent to the annual carbon dioxide absorption of 3.167 million trees.

In a low-temperature liquid state, the carbon dioxide is being transported in a pipe and then sent to the crude oil formation more than 4,000 meters underground by high-pressure pumps.

The carbon dioxide will make crude oil fluffy, fluid and easy to be collected, enhancing oil recovery efficiency for the oil workers.

Such method can increase the recovery rate by at least 18 percent, and truly turn waste into treasure, said Wu Yi, chief technical expert of the Liaohe Oilfield.

China's first CCUS project for a coal power plant was launched in the Shengli Oilfield in east China's Shandong Province in 2012 by Sinopec.

China's first million-tonne-scale CCUS facility, which was also built by Sinopec, was put into operation at the end of last August. The company said it could reduce carbon emissions by one million tonnes per year, the equivalent of planting nearly nine million trees.

The country's first offshore million-tonne carbon storage project was put into operation on June 1 in the South China Sea, according to the China National Offshore Oil Corporation (CNOOC). The project is designed to store a total of more than 1.5 million tonnes of CO2, which is equivalent to planting nearly 14 million trees.

Smart low-carbon Yangshan Port

Shanghai's Yangshan Deepwater Port, the world's largest automated container terminal, started operation in 2017, with a loading and unloading capacity of 26,000 Twenty-foot equivalent units (TEUs) for a day and night.

Liu Changman, general manager, Shandong Container terminal Branch, Shanghai International Port Group (SIPG), told CMG that "in the past, everything had to be done by workers. Now that these manual jobs have been automated, the level of efficiency is much more stable. Also the computer designs the routes to move the containers, and these will be the shortest routes with as little shifting of other containers as possible."

The project uses automated handling equipment designed and manufactured in China, including all loading and unloading equipment, a bridge crane, an automated guided vehicle and a rail-mounted gantry crane.

Now, the 945,000-square-meter automated yard at the terminal is "empty," and only automatic guided vehicles shuttle back and forth loading containers.

With domestic-developed technology which runs the systems, the unmanned terminal has reduced labor costs by 70 percent, while increasing productivity by 30 percent, said the operator of the port.

As a transfer node in the supply chain, ports account for about three percent of the global greenhouse gas emissions. Among them, port operations, loading and unloading equipment, and transport vehicles are all fuel-consuming.

Now, the bridge cranes, rail cranes, and automatic guided vehicles used in the Yangshan Port are all driven by electricity, which completely eliminates the exhaust emission problems of wharf loading and unloading, horizontal transportation, and yard loading and unloading, with minimized environmental noise.

Moreover, the port created a shore power supply system for large cargo ships to automatically switch to the electric energy system after docking, without continuing to consume fuel. Technologies such as energy-saving new light sources and solar auxiliary heating have made this a new low-carbon benchmark for ports.

World's largest hydro-solar power station

The world's largest and highest-altitude hydro-solar power plant, which generates power through a water-light complementary manner, entered full operation in China last month.

With an unprecedented installed capacity scale of 1 million kilowatts for a hydro-solar power grid, it can fully charge 15,000 electric vehicles with a range of 550 kilometers in just one hour. 

The plant, situated in the Yalong River Basin of the Tibetan Autonomous Prefecture of Garze in southwest China's Sichuan Province's Yajiang County, will cover the needs of 700,000 households for a whole year with its annual generating capacity of 2 billion kilowatt-hours (kWh). 

With a reliance on sunlight to generate electricity, the power generation of PV stations fluctuates between day and night amid weather events. The hydropower component can help to regulate all instability in such supply manner, therefore, providing stable and high-quality clean energy.

Being the first phase project of the Yalong River's Lianghekou Hydropower Station, which was put into operation in March with a total installed capacity of three million kilowatts, electricity generated by Kela will be connected to the Lianghekou and then integrated into the power grid. The two will help to shape a grand renewable energy base.

Upon completion, the Yalong River Clean Energy Base, with an installed capacity exceeding 100 million kilowatts and annual power generation of around 300 billion kWh, will be sufficient to serve 100 million households for a year, ultimately emerging into one of the world's largest green, clean, and renewable energy bases. 

(CGTN's Liu Tianwen, Chen Yurong also contributed to the story.)