*6.4. Ecological Livability*

The key application scenarios of blockchain technology in the field of ecological livability include: smart energy, smart new retail, as shown in Figure 11.

**Figure 11.** Ecological livability structure diagram.

With the development of industrialization in China, energy, as the support of national life, has received more and more attention in terms of security, efficiency and trust in its development and transaction process. Combining blockchain technology with energy can optimize the traditional energy transaction mode, improve transaction efficiency, and promote the healthy development of energy [109]. Some scholars have elaborated the current situation and challenges faced by blockchain technology in the application of integrated energy system, analyzed the key issues to be solved in the construction of energy blockchain system, and made an outlook on the future development of integrated energy based on blockchain [110], and some scholars have also conducted research on the optimization of energy costs [111,112]. However, there are still many challenges when applying blockchain technology. Firstly, the energy interaction information of the energy system is dynamically changing, and the data throughput is significantly more than the blockchain application scenario of transaction settlement, which causes difficulties for the efficient operation of the system, and even the communication delay and information blockage. Secondly, the consensus mechanism is wasteful of resources for the high energy demand, and it is needed to reduce the energy consumption in the future. The data of the energy production chain is generated and stored locally by each energy vendor, and the data of each energy vendor is disconnected and unconnected. It can be combined with IoT devices to realize safe storage and sharing of production data by applying blockchain technology based on data collection, improving monitoring accuracy, mining data value, and creating an information basis for government supervision.

There are already a large number of use cases in real-world applications, for ex ample, the US energy company LO3 Energy partnered with Siemens Digital Grid in April 2016, and the Bitcoin development company Consensus Systems to create the Brooklyn Microgrid-an interactive grid platform based on the blockchain system the project is the world's first energy marketplace based on blockchain technology. This microgrid project enables peerto-peer electricity trading for residents between communities, allowing users to access data related to electricity generation and consumption in real time through smart meters and buy or sell electricity and energy to others through the blockchain; Power Ledger was founded in Perth, Australia, by Ledger Assets, an Australian blockchain software company. Power Ledger uses blockchain-based software to build a P2P system for trading surplus solar power to the grid. Unlike the PoW (proof of work) mechanism used by Bitcoin, Power Ledger uses a POS (proof of stake) mechanism, and the blockchain was developed by Ledger Assets and is called Ecochain [113]. The above cases are representative cases, where the Power Ledger platform has modular and scalable features, mainly through three aspects of sustainable energy aspects of business, and any individual module can be extended

on demand, namely energy trading and traceability, VVP model, and environmental commodity trading [114], as shown in Figure 12.

**Figure 12.** Power ledger module.

The energy trading and traceability product is called xGrid. xGrid allows trading renewable energy across the grid or behind the meter, improving the relationship between customers, retailers, and the distribution network to make it more efficient. Specifically, xGrid supports customers in selling energy from solar panels to other energy consumers connected to the same grid. From generation to consumption, it manages the settlement of energy transactions between the two parties, allowing dynamic price discovery at intervals as short as five minutes. Users can customize their profiles to sell power in their preferred way, and the VPP model software will detect when wholesale market prices are peaking. Managing stored power, helping customers maximize their return on investment while supporting the grid with clean solar energy. The environmental commodity trading product, called TraceX, is a digital marketplace for trading and settling environmental commodities, such as Renewable Energy Certificates (RECs) and Time-based Environmental Certificates (T-EACs).

With the increasing maturity of blockchain technology, this has brought new opportunities for the development of various fields in China. The main problems faced in China's new retail supply chain are also found, namely, transaction payment security, logistics information and commodity traceability. It was shown that the asymmetric encryption technology in blockchain technology achieves the upgrading and optimization of the retail supply chain, while blockchain technology makes it possible to realize the decentralization of transaction payments, thus improving the effectiveness of logistics information and the integrity of commodity traceability [115]. Using the distributed bookkeeping and non-tampering characteristics of blockchain, the supply chain data of commodities are stored in a distributed manner, access rights and encryption verification are set, the data exchange, and sharing in the supply chain process, and the business operation process simplified to realize the overall efficiency improvement and optimization of the supply chain. Using blockchain technology to build a digital supply chain, especially the supply chain management in cross-border trade, the distributed bookkeeping, and tamper-evident characteristics of blockchain are used to distribute the supply chain data of commodities for storage, authorized access and encryption verification, simplifying the data exchange and sharing in the supply chain process and the business operation process. Realizing the overall efficiency improvement and optimization of the supply chain.

The above four aspects do not cover all of the smart city, but can give a direction to the blockchain-based urban governance. It can be seen that when the industry is combined with blockchain it can bring security and efficiency improvement, moreover, it can reduce the cost of governance.
