Against the backdrop of global climate change and increasingly severe resource and environmental pressures, sustainable development has become a common pursuit of governments and enterprises around the world. As a core part of urban infrastructure, the green transformation and sustainable development of the water industry plays a vital role in promoting the green development of the entire society.

Water companies usually need to operate 24 hours a day, consume huge energy, and electricity bills become the highlight of operating costs, often accounting for more than 70%. Faced with the challenges of the "dual carbon" goals, water companies urgently need to explore a new low-carbon and environmentally friendly path that can both save energy and reduce emissions and reduce energy costs in order to achieve cost reduction and efficiency improvement.

Against this background, energy storage technology and water management, as two important directions in the fields of energy and water resources, are gradually showing great potential for cross-border integration.

Recently, the "Photovoltaic + Energy Storage + Water" project of Songxian Yinji Waterworks Yidong Water Plant was put into use, setting a successful example for the industry.

It is reported that the project makes full use of the roofs of the water plant buildings and idle sites, and installs 141 solar panels with a total area of ​​438 square meters, generating up to 99.405 kWh of electricity. At the same time, it is equipped with two energy storage cabinets with a storage capacity of 466 kWh, realizing daily charging and discharging. Through the operation mode of "self-generation for self-use + valley charging + peak discharge", the average monthly photovoltaic power generation of Yidong Water Plant reaches 24,000 kWh, and the peak discharge of energy storage is 12,000 kWh, accounting for 45.5% of the total monthly electricity consumption, effectively reducing the electricity cost.

Why does water service need "energy storage"?

The water service system includes multiple links such as water supply, drainage, and sewage treatment, and each link consumes a lot of energy.

Specifically, the water supply system requires pumping stations to lift water sources to treatment plants and then transport them to users through pipelines; the drainage system requires pumping stations to lift sewage from low-lying areas to sewage treatment plants; the sewage treatment process requires a lot of electricity for biological, chemical and physical treatment. With the acceleration of urbanization and population growth, the energy demand of the water system continues to rise, bringing huge pressure on energy supply and environmental protection.

The emergence of the "photovoltaic + water" innovative cooperation model aimed at reducing energy consumption, reducing emissions and achieving sustainable development has given the water system a new idea for "green development".

A professional organization has calculated that if each water plant in my country builds an average of 5MW photovoltaic power stations, the total scale can reach nearly 25GW, which will provide water plants with clean and reliable energy and effectively alleviate their energy consumption pressure. Not only is the market prospect broad, but it is also an important development direction of "energy +" for water companies.

In addition, water companies have the advantages of a large area, many idle areas, and stable corporate attributes, which is indeed an ideal place to build distributed photovoltaic power stations. In fact, more and more water companies have begun to install photovoltaic panels inside water plants, using clean energy from photovoltaic power generation to meet their own energy needs, which not only reduces operating costs but also improves the environmental image of the company.

Do you think there is no "energy storage"?

In fact, energy storage technology also plays a vital role in water and photovoltaic systems.

Due to the intermittent and unstable nature of solar energy, photovoltaic panels will have power fluctuations and supply and demand imbalances during power generation. Energy storage technology can solve the problems of power fluctuations and supply and demand imbalances by storing excess electricity and releasing it when needed, thereby ensuring the stable operation of water facilities.

It is specifically applied to three modules.

First, the pump station is an important part of the water system, and its power consumption accounts for a large proportion of the energy consumption of the entire water system. The traditional operation mode of the pump station is often to start and stop control according to the change of water level. This method is not only energy-intensive, but also easy to cause impact on the power grid. By introducing energy storage technology, power regulation and peak-shaving and valley-filling of the pump station can be achieved.

Secondly, sewage treatment plants are another major energy consumer, and their energy consumption is mainly concentrated in the aeration, mixing and sludge treatment links in the biological treatment process. Traditional sewage treatment plants usually use a constant aeration volume and mixing speed, which not only consumes a lot of energy, but also has unstable treatment effects. By introducing energy storage technology and intelligent control systems, energy optimization management of sewage treatment plants can be achieved.

Finally, water systems may encounter various emergencies and failures during operation, such as power outages and equipment failures. These events and failures often have a serious impact on the normal operation of water systems and even cause water outages. By introducing energy storage technology and backup power systems, the emergency response capability and reliability of water systems can be improved.

Active exploration of photovoltaic storage + water services

At present, the photovoltaic storage + water services model has been implemented in many places.

The "water-photovoltaic-storage" integrated green energy system of Shenzhen Shenshui Longgang Water Group has been implemented in He'ao Water Plant. It is understood that the project integrates green facilities such as low-head power generation, solar photovoltaic power generation, and distributed energy storage to achieve self-production and utilization of clean energy. The system can generate 390,000 kWh of electricity per year, providing more than 22% of the water plant's annual electricity consumption, saving about 480,000 yuan in electricity bills and reducing about 540 tons of carbon dioxide emissions.

Taiyuan Water Plant in Anyang City, Henan Province, built a sewage treatment plant energy storage power station project, using the peak-valley electricity price difference within the plant area to save comprehensive electricity bill benefits, achieving an annual discharge of about 640,000 kWh, and saving about 600,000 yuan in electricity bills in the first year.

The energy storage power station project of Hanzhong Yangxian Water Co., Ltd. has a project scale of 0.72MW/1.548MWh. It can not only effectively balance the load of the power grid, improve the reliability and stability of power supply, but also optimize the power quality in the water treatment process, and promote the water industry to develop in a more environmentally friendly and efficient direction.

The Xincheng Water Environment Treatment Center in Huzhou City, Zhejiang Province built a "photovoltaic + energy storage" power station. The photovoltaic system of the project adopts the "self-generation and self-use, surplus power to the grid" mode, which can provide about 313,000 degrees of clean electricity per year; the energy storage system is equipped with a standard liquid-cooled energy storage cabinet and adopts the "two charging and two discharging" operation mode to achieve peak shaving and valley filling on the user side, reduce electricity costs, improve power quality, and optimize the configuration of light storage resources.

There is also an urban water supply system. It is understood that a certain city water supply system uses energy storage technology to optimize the power regulation and water supply strategy of the pump station. By introducing energy storage devices and intelligent control systems, the on-demand start and stop and power regulation functions of the pump station are realized. During the off-peak period of the power grid load, the energy storage device is used to store excess electricity; during the peak period of the power grid load or when the pump station needs to operate at high power, the energy in the energy storage device is released to supply the pump station. After one year of operation, the energy consumption of the city's water supply system has been reduced by about 20%, and the electricity bill has been reduced by about 15%, while the water supply security and stability have been improved.

In general, with the deepening of global sustainable development and green transformation, the market opportunities for energy storage + water services will be broader. On the one hand, the water industry's demand for efficient and sustainable energy solutions continues to grow; on the other hand, the application of energy storage technology in the water sector will continue to expand and deepen.