In the previous article, we mentioned the strong complementarity between electricity and heat. Today’s article will explore its advantages and multiple possibilities in more depth through practical testing of thermoelectric technology.
Practice of Thermoelectric Synergy
- New Energy+Heating
According to the curve test conducted by Pinggao Electric on the participation of electrode boilers in peak shaving and frequency regulation, Dr. Zhao Wenying stated that electrode boilers can not only achieve peak shaving and heat storage using valley electricity, but also make a very good contribution to frequency regulation. From the curve in the figure below, it can be seen that the change in electrode boiler load can well follow the fluctuation of wind power output, and this second level response time scale can theoretically participate in the power frequency regulation market. Therefore, electrode boilers are excellent flexible loads for the power grid.
- Thermal Power Flexibility Transformation
Dr. Zhao Wenying pointed out that the flexibility transformation of thermal power was vigorously promoted by the country during the 13th Five Year Plan period, but the construction of the electricity market during the 13th Five Year Plan period is still relatively lagging behind. During the 14th Five Year Plan period, the country once again explicitly proposed the goal of adding 200 million kilowatts of coal-fired power flexibility transformation, with a focus on the flexibility transformation of 300000 kilowatt level and some 600000 kilowatt level coal-fired units in the “Three North” regions. From the perspective of the external environment, the construction of the electricity market, whether in the medium to long term or in the spot market, including the auxiliary service market, has a good policy environment for its market-oriented mechanism. Therefore, the flexibility transformation of thermal power has good economic viability during the 14th Five Year Plan period, and will be promoted faster compared to the 13th Five Year Plan period.
From the perspective of specific technical routes, the most important aspect of flexibility transformation in thermal power is to use terminals with thermal storage tanks to achieve thermal electric decoupling of thermal power units and deep peak shaving of thermal power.
- Thermal Power Extraction And Energy Storage
Dr. Zhao Wenying also introduced another new technology – thermal power extraction and energy storage. The traditional flexible transformation route mainly involves adding electric heating and thermal storage equipment to the terminal, which to some extent relies on coal-fired power generation to generate electricity, which is then converted into heat. From an energy perspective, this approach results in certain waste. However, due to the storage of high-temperature steam, steam extraction and energy storage do not result in significant energy loss from the perspective of energy conversion. In the future, it can be used to extract and store energy for millions of units in the southern market, which is a very good choice to improve the flexible adjustment capability of millions of units.
Dr. Zhao Wenying stated that after extracting steam, the peak power generation capability of coal-fired units can be achieved by adding a small steam generator unit. He pointed out that the current power system has a strong demand for peak capacity, but whether it is planning and constructing new units or using energy and heat storage methods, how can we meet about 10% of the peak load? Dr. Zhao Wenying believes that from an economic perspective, this is a very good choice. So from the perspective of the construction of future new power systems, steam extraction and energy storage is a very promising technological route, but the implementation of demonstration projects and other aspects are still being promoted.
- Cold Storage Technology
When it comes to cold storage, Dr. Zhao Wenying stated that it has a wide range of applications in the southern region, including the industrial and commercial markets. As shown in the project case above, traditional refrigeration units are used, and the working hours of the units are relatively dispersed without obvious peak valley differences. After adding cold storage, most of the working time of the units is concentrated in the evening valley electricity, which has a significant effect on saving electricity costs. We have also made a rough calculation, and after implementing cold storage in different regions, the average electricity cost can be saved by about 40%. Compared with the electricity prices of industry and commerce, many industrial and commercial scenarios may achieve investment payback in about 1-2 years, so the economic benefits are still very significant
In terms of policies, Dr. Zhao Wenying has submitted a report to the relevant regulatory authorities on policy recommendations for the heat source side, heat network side, and user side, and actively called for the introduction of relevant industrial policies.
The current “two joint ventures” refer to “coal+coal-fired power” and “coal-fired power+new energy”, and an additional “joint venture” should be added. In the future, “new energy+heating” will also be a new and important joint venture method to assist in the consumption of new energy and system peak shaving and frequency regulation. We must regard heat and cold storage as very important forms of energy storage, actively promote relevant technical solutions, and promote the implementation and landing of projects.
