Professor Liu Dunnan: Flexibility resources under the energy internet

China Energy Storage Network: Over the past decade, many countries have been exploring energy development models that combine Internet technology with renewable energy technology, trying to build a new era of energy where everyone is a producer and consumer. In China, the combination of Internet technology and energy is still in the exploratory stage. New energy technology, intelligent technology, information technology, and network technology are constantly breaking through and integrating. Accordingly, under the premise of ensuring energy security, the integration of resources of government departments, energy companies, Internet companies, financial institutions, and industry associations is crucial. Government policies should follow the development of energy Internet and introduce supportive and guiding policies in a timely manner. In 2015, "Internet +" was written into Premier Li Keqiang's government work report, which means that "Internet +" has become an important strategy for national economic and social development. Against this background, on February 24, 2016, the National Development and Reform Commission, the National Energy Administration, and the Ministry of Industry and Information Technology jointly issued the "Guiding Opinions on Promoting the Development of "Internet +" Smart Energy" (hereinafter referred to as the "Opinions"), which carried out a top-level design at the national level for the future period of work, divided the stages, and proposed key work tasks.

Focusing on the development of energy Internet, the guiding opinions put forward ten key tasks. Among them, Task (I) promoting the construction of intelligent energy production and consumption infrastructure and Task (II) strengthening the construction of multi-energy coordinated integrated energy network are important infrastructures of energy Internet, providing important physical facilities and equipment foundation for the flexibility of energy supply and demand system; Task (III) promoting the deep integration of energy and information and communication infrastructure is the physical connection of infrastructure in energy Internet, providing the basis for the flexibility of multi-energy interconnection, intercommunication, complementarity and exchange in energy supply and demand system; Task (IV) creating an open and shared energy Internet ecosystem provides a good environment for the existence and development of resource flexibility under energy Internet; Task (V) developing energy storage and electric vehicle application new models Energy storage is the most important flexibility resource. The development of energy storage technology directly determines the level of resource flexibility. At the same time, electric vehicles are demand-side resources based on incentive response and are a form of existence of flexibility resources; Task (VI) developing new models of smart energy use focuses on flexibility resources and proposes several ways to obtain flexibility resources; Task (VII) cultivating green energy flexible trading market models provides solutions to the development of flexibility resources and investment recovery issues; Task (VIII) developing energy big data service applications provides an environment and development direction for the informatization development of flexibility resources; Task (IX) provides technical support for the development of flexible resources in promoting key technologies of energy internet. Task (X) establishes the direction and goal of flexible resource development by building an internationally leading energy internet standard system.

In order to help industry peers understand the core spirit, connotation and extension of the Opinions in a more in-depth and systematic way, this micro blog invites one of the authors of the Opinions, Associate Professor Liu Dunnan of North China Electric Power University, to write an article to interpret the Opinions in detail. Please continue to pay attention. The following is the first article in the series of interpretation articles.

Flexibility resources under the energy internet

Liu Dunnan

Energy Internet Research Center of North China Electric Power University

Introduction ​

On February 24, 2016, three ministries and commissions issued the Guiding Opinions on Promoting the Development of "Internet +" Smart Energy. Focusing on the development of energy Internet, the Guiding Opinions put forward ten key tasks. Among them, in Task (six) of building a new model of user-autonomous energy services, flexibility resources were mentioned in particular.

It can be seen from the ten major tasks of the Guiding Opinions that flexibility resources are present throughout the entire construction and development process of the Energy Internet and are a kind of iconic resource under the Energy Internet. This article will conduct an in-depth analysis and interpretation of the definition, characteristics, problems faced in development, and future development direction of flexibility resources.

1. What are flexibility resources?

Flexibility resources refer to resources that can increase the flexibility, elasticity and agility of the energy supply and demand system and serve the dynamic supply and demand balance of the energy consumption system. The system can achieve its own supply and demand balance through the rapid and accurate regulation of flexibility resources, while meeting the diversified energy supply and demand requirements.

Under the energy Internet, multiple energy sources interact flexibly, energy demand continues to diversify, and the proportion of renewable energy consumption is getting higher and higher; this leads to increased instability in the energy supply and demand system and increased difficulty in balancing the system; in order to meet diversified energy demand and achieve a high proportion of renewable energy consumption, the amount of flexibility resources required is gradually increasing; the continuous increase in flexibility resources will make the energy supply and demand system more flexible, resilient and agile.

2. Characteristics of flexible resources

1 Physical characteristics

1) Timeliness of regulation

Flexible resources should be able to respond to control commands in a timely manner without delays or lags.

2) Wide range of regulation

Flexibility resources should be resources that can significantly adjust the increase or decrease of energy load to meet the balance and stability requirements of the system.

3) High regulation speed

Flexible resources should be able to achieve large-scale regulation of energy load in a short period of time, that is, resources with a large rate of increase or decrease in energy load per unit time.

4) Can be translated

Flexible resources should be resources that can achieve time and space shifting of energy load while keeping the total energy consumption unchanged.

2. Economic characteristics

Acceptable economic cost. Flexibility resources should be resources with acceptable economic cost when regulating the balance between energy supply and demand.

3. The existence form of flexibility resources

Under the energy internet, the energy supply and demand system will be a complex of “source-grid-load-storage”. Flexibility resources exist in different forms on the four sides of the energy supply and demand system:

1. Source side

That is, on the energy supply side, taking the power system as an example, flexibility resources mainly include: ① deep peak-shaving units of thermal power; ② large hydropower with long-term regulation capabilities; ③ large thermal power units with segmented regulation of coal mills.

2. Network side

That is, on the energy transmission side, flexibility resources mainly include: ① multi-level two-way coordinated scheduling; ② multi-time scale scheduling transactions; ③ multi-energy complementary scheduling transactions; ④ micro-balanced scheduling of centralized optimization and decentralized optimization; ⑤ a multi-energy convergence interconnection network.

3. “Lotus” side

That is, on the energy demand side, flexibility resources mainly include adjustable and incentivized demand-side resources, mainly electric vehicles.

4. Storage side

That is, on the energy storage side, flexibility resources mainly include: ① various types of energy storage measures and equipment; ② pumped storage, etc.

4. Problems with current flexibility resources

Under the Energy Internet, there are still many problems related to flexibility resources:

1) Technical issues

Under the current energy Internet, there is a lack of flexible conversion technology between multiple energy sources, and the technologies in energy routing and energy distribution are still immature.

2) Economic issues

Under the current energy Internet, firstly, in most cases, the regulation cost of flexible resources is higher than the gain under regulation, which is unacceptable; secondly, there is a lack of effective investment return channels for flexible resources, which limits their development; thirdly, due to the different types of demand for flexible resources, it is difficult to reflect economies of scale.

3) Policy and market environment issues

Taking the power grid as an example, currently most ancillary services of flexibility resources are free, there is no ancillary service market, the flexibility resources have not been commercialized, the value of flexibility resources in the system has not been restored, and there is no established pricing mechanism and evaluation mechanism to measure their economic value. Therefore, it is difficult to reasonably determine their actual value.

5. Enlightenment from the development of flexible resources

Under the energy internet, the demand for flexible resources is increasing, while the existing problems are still serious. Therefore, the development of flexible resources should be promoted: