Two major technology models of energy Internet: smart grid and smart energy network

Energy Internet is one of the hottest topics in China's energy and related industries today, especially after "Internet +" has become a trend of the times, people are eagerly looking forward to the "integration" of energy and the Internet, opening up a new path
for China to promote the revolution of energy production and consumption mode and achieve sustainable energy development.

Unfortunately, the concept of energy Internet has been controversial
since it was introduced to China.
There are many insights in different understandings, but they are also mixed with some misunderstandings, which have affected the development of
China's energy Internet industry to a certain extent.
In order to deepen and unify the understanding, in today's new situation of "Internet +", it is necessary to re-understand
the energy Internet with a rational attitude.
Starting from the analysis of the background of the concept of energy Internet and the reasons for ambiguity and misunderstanding, this paper conducts in-depth research on the connotation of energy Internet, technical model, relationship with smart grid, and how to express it in the way of "Internet +", and puts forward new insights
.

1.
Energy Internet is an ambiguous concept

As a professional term, the Internet refers to the information sharing network
that covers the whole world formed by the interconnection of countless computer networks.
The combination of energy and the Internet constitutes the concept of "energy Internet", which was officially proposed by American economist Jeremy Rifkin in the book "The Third Industrial Revolution
".
Rifkin said that economic and social changes in history are inseparable from the two major factors of the energy revolution and the communication revolution, and it is their occurrence and combination that triggered a new round of industrial revolution
.
A revolution is emerging to replace fossil fuels with renewable energy, and the communications sector has also seen a great revolution in the past 25 years, the Internet revolution, which prompted him to associate
the energy revolution with the Internet.
He believes that the integration of Internet technology with renewable energy can transform the global electricity grid into an energy sharing network, enabling hundreds of millions of people to produce renewable energy in their homes, offices, factories and share
it with others.
This shared network works like the Internet, where decentralized renewable energy flows freely across borders, just as information flows freely over the Internet, and each self-generating generator becomes a node
in a continent-wide, borderless green power network.

This is the earliest and most "authentic" idea
of the energy Internet.
There is no doubt that this idea is in line with the direction of the energy revolution and is very good, but it cannot fail to point out that there are technical errors that cannot be ignored: the working principle of the energy sharing network (i.
e.
the grid) and the Internet is not similar but very different, and energy (electricity) cannot flow
freely around the world like information 。 In fact, because the structure, function, technical characteristics, transmission mode and carrier of the power grid and the Internet, as well as the physical laws followed by the operation are completely different, the transmission of electricity in the power grid is subject to much more and greater constraints than the transmission of information in the Internet, not only voltage, frequency, power balance, power loss, transmission capacity constraints, but also transient, dynamic, thermal stability and other safety and stability limit restrictions, so it is difficult for power to interact freely
between any two nodes like information 。 It is a misleading or misunderstanding to think that as long as the power grid continues to expand, the realization of global grid interconnection will solve the problem of transmitting electricity from one point to any point; Even in the distant future, the application of superconducting transmission in the power grid is as common as the application of optical fiber in the Internet today, and it cannot be fully achieved
when the DC grid is used as the main backbone network frame.

In addition, because electricity has the characteristics of homogeneity, one-time consumption, and cannot be repeatedly "shared" (information has the characteristics of personalization, long-term storage, and repeatable sharing), it is also determined that electricity does not all need to be transmitted
between any two nodes like information.
There is no boundary, Internet-like energy sharing network, and no energy (electricity)
that can be freely transmitted within any range without constraints.
However, if only in a local area, such as a community or a city or even a larger area, in accordance with the objective law of power grid operation and according to the needs and characteristics of electricity load, the overall planning and construction of various distributed power sources, energy storage devices, microgrids, distribution networks and backbone networks, while using advanced information and automatic control technology for intelligent collaborative dispatching management, it is possible
to realize Rifkin's vision.

It must be admitted that as a translated Chinese phrase, the energy Internet is an ambiguous concept
.
If the "Internet" here is regarded as the professional term Internet, the literal meaning should be "the Internet that transmits energy", which is obviously not technically valid
.
If "Internet" is regarded as a common Chinese term rather than the Internet, the energy Internet can be regarded as "the interconnection network of energy"
.
Under this premise, there are two different understandings: one is that all kinds of energy, such as hydro, nuclear, wind, solar, natural gas, and coal are converted into electricity, and then they must be integrated into the power grid, so the power grid is a natural energy Internet; Second, it is believed that the real energy Internet should be a comprehensive energy network
including power grids, oil grids, gas grids, and heat grids.
Although both understandings make sense, not treating the "Internet" as the Internet is clearly inconsistent with the original meaning of the concept
.
This kind of trouble caused by the difference in the law of language expression is objective, so it is necessary
to unify the understanding through careful discussion.

2.
The connotation of energy Internet and the idea of new energy revolution

Because the idea of the energy Internet was technically questioned, Jeremy Rifkin, an economist, later explained that the proposal of the energy Internet was mainly based on philosophical and economic thinking, and he admitted that the energy Internet is not a new energy technology model or system, but only a new energy economic idea
.
This is a very important explanation, which can be said to be a key to correctly understanding the essence and connotation of the concept of the energy Internet, but unfortunately Rifkin's explanation has been almost completely ignored
.

The idea of new energy economy is essentially the idea
of new energy revolution.
According to Rifkin's exposition and the practical experience of energy revolutions in various countries in the world, its main points can be summarized as follows: First, the new round of energy revolution is an irresistible historical trend, the purpose of the energy revolution is to gradually replace fossil energy with renewable energy, prevent the deterioration of the earth's ecological environment, and achieve sustainable
development of energy and mankind.
Second, the mode of energy production and consumption will be integrated into the Internet concept and modern information technology, the development of renewable energy will be mainly distributed, the public is both a consumer of energy and a producer, and the world will usher in a new era
of green, decentralized, diversified and democratic energy.
Third, the traditional power grid with centralized, vertical and unidirectional characteristics will be transformed into a relatively decentralized, flat and two-way interactive new power grid, and at the same time, the traditional power grid company will also transform from a single top-down power supplier to a service provider including energy information, and users to jointly manage energy production and consumption
.
Fourth, the greening of energy needs to go through a mixed energy period of fossil energy and renewable energy, we must make full use of modern information technology, use intelligent means to coordinate and control the development and utilization of various types of energy, optimize energy allocation, and maximize energy utilization
.
Distributed energy production methods and energy democratization will create millions or even tens of millions of jobs for society and become an important pillar
of the third industrial revolution and the new economy.

It is not difficult to see the essence of the idea of the new energy revolution, that is, to achieve green, efficient and democratic energy by integrating the Internet concept and modern information technology into the energy revolution, and the concept of energy Internet is the concentrated embodiment
of this idea.
Therefore, the connotation of energy Internet can be expressed as "integrating the Internet concept and modern information technology in planning and construction, and realizing low-carbon, green energy, efficient, decentralized, intelligent and democratically utilized energy transmission and allocation network"
.
The construction of the energy Internet is to build an energy network
that meets the requirements of this connotation.

3.
Smart grid is the main technical model of energy Internet

Smart grid (SmartGrid, or smart grid) is a new generation of intelligent grid
integrated into the Internet concept, with "green and efficient" as the goal, two-way interaction and flattening as the main features, and supported by modern information and energy storage technology.
Smart grid has a narrow sense and a broad sense, narrow smart grid refers to low-carbon green small and micro grids based on distributed power generation, which can operate alone or be connected to the large grid
.
Smart grid in a broad sense refers to the entire regional and national low-carbon green grid with centralized power sources
.
The unique functions of the power grid and the irreplaceable status and role of smart grid in energy greening determine that smart grid is the main technical model
of energy Internet.
In fact, Jeremy Rifkin's "energy-sharing network" envisioned in his book The Third Industrial Revolution refers to the smart grid
.

The relationship between the energy Internet and the smart grid is the relationship between connotation and extension, and the smart grid is the extension
of the concept (connotation) of the energy Internet.
They can also be regarded as the relationship between macro guiding ideology and specific technical models, the concept of energy Internet reveals the development direction of energy and power grid, and smart grid construction provides specific technical solutions
.

At present, most of the domestic research on the energy Internet actually belongs to the category of smart grid construction, such as distributed energy access to the grid, operation control and interconnection of microgrid, integration and utilization of demand response resources, construction and operation of electric vehicle charging and discharging facilities, intelligent household electricity consumption, and the research and development and construction
of energy (electricity) routers 。 These contents are either based on the power grid, the object, or themselves are a part of the power grid, a facility, no matter how they are integrated into information technology, no matter how high the degree of integration of their information and power facilities, the purpose is to make the power grid better green, flexible, intelligent and efficient
.

One situation worth pondering is that not only is there no debate about the energy Internet in Europe and the United States, but this concept
is rarely used in practice.
For example, there is also a book on the theme of the new energy revolution in the United States, called "Reinventing Energy: Business Solutions for the New Energy Century" (Chinese translation published in June 2014), written by the famous energy expert Emery Lovins
.
In the book, he analyzes the path that the United States should take to reach 80% of the total electricity demand from renewable energy by 2050, and affirms the role of smart grids in reshaping energy and accelerating the transformation of traditional power systems, but never mentions the concept of
energy Internet.
Looking at the situation in Germany, it can also be found that almost all the energy Internet things talked about in China are included in
their smart grid construction.

Chinese was also full of enthusiasm for the smart grid (SmartGrid), but it seems that overnight this enthusiasm has turned to the energy Internet, and the reason is that there is a big deviation
in the construction of China's smart grid.
It must be pointed out that the construction of smart grid is proposed in the context of a new round of energy revolution, so it is not a simple continuation and improvement of the original automation and intelligent construction of the traditional power grid, but a profound change
in the green and democratic traditional power grid.
However, due to the current smart grid construction in China, which is basically based on the intelligent construction of traditional power grids, many people have misunderstood
.
Another important reason is that the construction of smart grids has been hijacked by AC UHV
.
Over the years, the construction of power grids in most areas of China has been centered on the construction of AC UHV power grids, and the construction of power grids is basically subject to and serves this center, and the construction of smart grids is not excluded
.
Since we cannot see the important role that smart grid construction should play in promoting China's energy greening and democratization, improving energy utilization rate, and promoting the development of distributed energy, countless people with lofty ideals who take the energy revolution as their responsibility naturally pin their hopes on the energy Internet, and do not hesitate to return to the source and set sail
again.
In fact, this is a situation that should not have happened, and it is both lamentable and praiseworthy
.

4.
The second technical model and the "Internet +" expression

Smart grid is the main technical model of the energy Internet, but it is not the only one
.
Since the greening of energy cannot be achieved overnight, especially in China, the period of mixing of renewable energy and fossil energy may be longer
.
In order to improve the comprehensive utilization efficiency of various types of energy and promote the better and faster development of energy in the direction of low-carbon and green, there is no doubt that the energy Internet has a second technical model, which is the smart energy network
。 The network is a comprehensive energy network including distributed energy conversion and storage facilities composed of transmission and distribution network, natural gas network, cold and hot gas network, etc.
, through overall planning and construction, the use of modern information technology and intelligent control technology for collaborative scheduling and management, timely provision of gas, electricity, cooling and heat of multiple varieties of energy, mutual assistance and complementarity to meet user needs, to achieve energy cascade utilization and intelligent matching between production capacity and energy consumption, to maximize the comprehensive utilization rate
of energy.

Both smart energy grid and smart grid are technical models of energy Internet, but they have different
emphases.
Smart grid takes power system as the research object and greening as the main goal; The smart energy network focuses on the mutual conversion of various energy sources and the synergy and complementary advantages between various energy networks, and the main goal is to maximize the utilization rate of energy and the proportion
of clean energy consumption.
In a park, a town, or a larger area, what kind of technical model is used in the construction of the energy Internet needs to be determined
according to local conditions and the actual available energy resources.
It is certain that with the advancement of renewable energy conversion, utilization and storage technology, as well as the continuous improvement of energy greening, smart grid and smart energy network will develop
in the direction of merging into one to form a new comprehensive energy supply system.
At present, the construction of smart energy network in the form of "pan-energy network" has achieved gratifying results and valuable experience
in some places.

The two technical models of the energy Internet can be expressed in a similar way in today's "Internet +" era, making it more modern.

Among them, the smart grid can be expressed as "green grid + Internet", and the smart energy network can be represented as "energy grid + Internet"
.
The advantages of this representation are: First, the concept is clear and pertinent
.
The word "Internet" in each expression cannot be interpreted
in any way other than the Internet.
In the expression of the smart grid, the word "green" is added before the power grid, which points out the essence of the smart grid and helps people grasp the right direction
in the construction of the smart grid.
In the expression of the smart energy network, the term "energy grid" is directly used to indicate the basic characteristics of the second technical model of the energy Internet, avoiding unnecessary misunderstanding
.
Second, it highlights the characteristics and difficulties of the research object
.
"Green grid" and "energy grid" are both networks, and they are the "integration" of the two networks, which undoubtedly have considerable complexity, emphasizing that "network" can remind people that they cannot solve the problems
by dealing with the general "Internet +" method.

In addition, it should be noted that the reason why "+ Internet" is used instead of the expression "Internet +" is because when the object of "Internet +" is also a network, if "Internet +" is put first, it is easy to misunderstand the information network as a network that plays a leading role, which may lead to the reversal of the main and auxiliary in the construction practice of the energy Internet and go off course
.

5.
Conclusion

The two technical models of the energy Internet are smart grid and smart energy network, which are both extensions
of the concept of energy Internet.
In the field of engineering and technology, there is no abstract energy Internet, and there is basically no other technical model
other than smart grid and smart energy network.
The construction of smart grid and smart energy network includes the use of Internet technology to establish a modern energy trading market and its marketing model conducive to clean energy consumption, energy conservation and user cost reduction, which can be combined with energy demand side management to achieve relevant requirements and goals
by carrying out research and practice on topics such as "Internet + power" and "Internet + power + heat".

In order to eliminate the misunderstanding of the smart grid, so as to unify the understanding, form a joint force, and promote the great development of China's energy Internet industry with scientific, pragmatic and innovative smart grid construction practice, it is very necessary to rename the smart grid (SmartGrid) to "smart grid", so that the name of the two technical models of the energy Internet is: smart grid and smart energy network, not only more coordinated, but also more accurately reflect the essential attributes
of the energy Internet.

(The author, Wu Anping, is the former deputy chief engineer of Southwest Electric Power Design Institute)