depending on the network size and the number of blocks or nodes

involved in a blockchain.

Waste of computational power: Every node runs the blockchain

giving extreme levels of fault tolerance, ensuring zero downtime, and

making data stored on the blockchain forever unchangeable and

censorship-resistant in order to maintain consensus across the

blockchain. All this is wasteful as each node repeats a task to reach

consensus, burning electricity and time on the way. This makes

computation far slower and more expensive than on a traditional

single computer. There are many initiatives that seek to reduce this

cost focusing on alternative means of maintaining consensus, such as

proof-of-stake.

Large energy consumption: Bitcoin introduced the blockchain

technology, which uses the proof-of-work consensus algorithm and

relies on the miners to do the hard work in solving the complex

mathematical problems for which the miners are incentivized. What

makes these complex mathematical problems not so ideal for the real

world is the large energy consumption. The miners need to solve the

problem, which means spending a lot of energy every time the ledger

is updated with a new transaction; however, not all blockchain

solutions work in the same manner. The problem has been solved by

other consensus algorithms. As the number of nodes within the

network is limited, the permissioned or private networks do not have

these problems. They use efficient consensus methods to reach

consensus as there is no need for global consensus. The problem in

Bitcoin still persists, which needs to be solved. The public networks

consume a lot of energy to remain operational, whereas permissioned

networks are efficient when it comes to energy consumption.

Integration concerns: As blockchain implementations in large

corporations move from pilot experiments to larger adoptions, the real

challenge is the integration with existing and usually complex legacy

systems. As corporations figure out their blockchain strategy, it is no

wonder that most of the use cases so far have been limited to specific

parts of businesses. It is important for blockchain systems to develop

the capability to integrate with legacy systems as there is a

predominance of such legacy systems, which are national IDs,