# 1.1 Overview of Blockchain and Cryptocurrency Since the emergence of Bitcoin in 2009, blockchain technology has driven innovation across various industries, including finance, supply chain management, healthcare, and energy. Based on distributed ledger technology (DLT), blockchain enables direct peer-to-peer transactions without intermediaries, offering a high level of security, transparency, and immutability. These features make blockchain a promising alternative to traditional centralized systems, overcoming their limitations and enhancing trust and efficiency. However, despite advancements in blockchain technology, issues such as scalability, interoperability, and sustainability persist. Renowned public blockchains like Bitcoin and Ethereum have very limited transaction processing capabilities per second (TPS). Moreover, the lack of interoperability between various blockchain platforms, along with sustainability concerns associated with traditional Proof of Work (PoW) consensus algorithms, such as substantial energy consumption and environmental issues, pose ongoing challenges. To address these issues, the blockchain industry is exploring various technological innovations. Solutions like sharding, Layer-2, and Layer-3 aim to enhance scalability, while the development of cross-chain protocols seeks to improve interoperability. Additionally, there is a shift towards energy-efficient consensus algorithms like Proof of Stake (PoS) and Delegated Proof of Stake (DPoS) to achieve greater sustainability. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://pemcoin.gitbook.io/pem-project/1.-project-background/1.1-overview-of-blockchain-and-cryptocurrency.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.