The underlying core technology of the Bitcoin system - blockchain, as a decentralized (open, flat, equal, and system structure without compulsory central control) database technology, has begun to enter people's vision in recent years. As a product of the "Internet +" smart energy that integrates multiple energy sources, information physics, and diversified markets, the energy Internet has also received widespread attention from the academic and industrial circles. "Internet+" smart energy is trying to establish "a new form of energy industry development that deeply integrates the Internet with energy production, transmission, storage, consumption and energy market", and realizes "equipment intelligence, multi-energy collaboration, information symmetry, supply and demand dispersion, flat system, and open transactions". Blockchain technology itself is innovating the traditional Internet pattern and model, and promoting efficient operation of transactions, certification and other aspects with the guarantee of trust as the core. Similarly, blockchain technology will also promote the coordination of multiple forms of energy and various participants in the era of energy Internet, promote the further integration of information and physical systems, and achieve diversification and low-cost transactions.
Blockchain is a data structure formed by orderly linking blocks. Blocks refer to a collection of data, and related information and records are included in it, which is the basic unit that forms the blockchain. The special data structure organization form of blockchain makes blockchain technology have four main features: decentralization, transparency, contract execution automation, and traceability. The characteristics of blockchain technology are similar to the concept of energy Internet to a certain extent, see Table 1.
Table 1 Blockchain technology and energy Internet concept
2Dimensions of application of blockchain technology in the energy Internet
The core function of blockchain technology is to not rely on centers or third-party institutions to ensure the authenticity of data, break the barriers of trust, greatly reduce the trust cost that needs to be paid for business development, and promote efficient business development. The technical characteristics of blockchain are consistent with the concept of energy Internet, making blockchain have the potential to become one of the important technical solutions in the energy Internet in the future. As shown in Figure 1, the application of blockchain technology in the energy Internet can be summarized and analyzed from three aspects: functional dimension, object dimension and attribute dimension.
Figure 1 Application of blockchain technology in the energy Internet
In the functional dimension, the blockchain decentralized data storage model and technology naturally include transparency and traceability, so it is very suitable for occasions such as authentication and exchange that originally required third parties to organize and guarantee. Blockchain can achieve trust and self-organization mechanism, so it does not require the existence of third-party institutions, which is of great significance to the future energy system under the "Internet thinking". Specifically, it will play a huge role in the measurement certification of energy and emissions, market transactions of energy and its derivatives, organizational coordination of multiple energy forms and multiple entities, and energy financing.
In the object dimension, traditional energy systems present a clear structure of source, network and load boundaries. In the future, a large number of energy storage technologies will be introduced into the energy Internet. At the same time, the boundaries between source, network and load are gradually blurred, and the coupling in different energy systems is gradually enhanced. The Internetization of source, network, load and storage has brought great challenges to the traditional operation and trading mechanisms. The characteristics of blockchain peer and decentralization can provide key technical support for the Internet development of sources, networks, loads and storage.
In the attribute dimension, blockchain is essentially a distributed database technology. The objects stored in the database can not only be "value" quantities such as Bitcoin, but also be able to store other quantities that need to be registered, authenticated, traced, traded or shared, such as ownership, production processes, control signals, copyrights and even health files. The energy Internet is a network that integrates energy, information and value. The information flow and physical flow are deeply integrated and flowing in two directions. The open and flat energy system will nurture a free and diversified energy and its derivatives market, thus bringing a complex and diverse "value flow". Blockchain can support the operation of the energy Internet in three aspects: energy, information and value.
3 Typical Application of Blockchain Technology in Energy Internet
Blockchain can provide an intelligent system platform for the certification of carbon emission rights and the measurement of carbon emissions, as shown in Figure 2.
Figure 2 Application of blockchain technology in carbon emission rights certification
The nature of blockchain decentralization helps solve some of the security problems faced in physical information systems, see Figure 3.
Figure 3 Application of blockchain technology in information physics system security
Blockchain can provide a low-cost, open and transparent system platform for transactions of virtual power generation resources, see Figure 4.
Figure 4 Application of blockchain technology in virtual power generation resource transaction
Blockchain can provide a decentralized system platform for multi-energy systems, see Figure 5.
Figure 5 Application of blockchain technology in the collaboration of multi-energy systems
4 Challenges of the application of blockchain technology in the energy Internet
There are still huge challenges in the application of blockchain technology in the energy Internet. These challenges come from the limitations of blockchain technology itself, and from the potential constraints of the combination of blockchain and the energy Internet. In the application of energy Internet, blockchain still has some endogenous shortcomings:
1) There are still bottlenecks in the computing power and response speed of blockchain;
2) Fault-tolerant challenges of asynchronous consensus networks;
3) The problem of the lack of responsible subjects in smart contracts. In addition to the endogenous shortcomings of blockchain, the characteristics of the energy Internet themselves also make blockchain technology use in the energy Internet face different challenges: ① Blockchain technology has less practical experience in energy Internet; ② The monopoly of energy Internet poses a threat to the security of blockchain information; ③ Challenges brought by the internal complexity and physical laws of the energy system; ④ Blockchain laws and supervision still need to be improved.