Comparative Analysis of Layer-1 Blockchain Economies

Co-authored by Viktor Smirnov, Shahmeer Khan and David Kavazi

Validators are the guardians of the blockchain, ensuring the security, accuracy of, and consensus on transactions across a decentralized ledger. Their task is monumental – maintaining the pulse of blockchain operations through block creation, finalization and the enforcement of a consensus mechanism.

However, beyond the technicalities and the critical role they play, lies a complex system of economic rewards and incentives designed to sustain their operations and, by extension, the blockchain itself.

The blockchain ecosystem is diverse, with each network employing its consensus mechanisms – such as Proof of Work (PoW), Proof of Stake (PoS), and others – with unique methods for incentivizing validators. These incentives are crucial, as they ensure that validators are compensated for their efforts, resources, and the risks they undertake to keep the network secure and running. Yet, as the blockchain space evolves, it becomes increasingly apparent that not all incentive structures are created equal. Some are more sustainable and equitable than others, leading to varying degrees of decentralization, security, and economic viability.

The focus of our discussion revolves around the economics of validator incentives – how validators are subsidized through a combination of transaction fees, block rewards, and other mechanisms. We delve into the differences between these economic models across major Layer-1 networks, identifying the challenges they face, including the reliance on monetary inflation, the distribution of rewards, and the sustainability of these models in the long term.

This exploration is particularly timely, as the crypto community seeks to understand the implications of these economic structures, not just for validators, but for the entire ecosystem—investors, developers, and end-users alike. Let’s delve into it.

A. Role of Validators in Blockchain Networks

Validators in blockchain networks serve as the anchor of the system's integrity and efficiency. Their roles, though diverse across different types of blockchains, share a common goal: ensuring the network operates smoothly, securely, and without centralized control. Let's delve into the various responsibilities these guardians uphold.

Consensus Mechanism

Validators are key players in achieving network consensus, a state where all participants agree on the current state of the blockchain. Depending on the blockchain, validators may operate under different consensus mechanisms, such as PoW, PoS, and others. Each mechanism has its method for achieving consensus, but all rely on validators to enforce the agreed-upon rules and protocols, ensuring that the blockchain remains decentralized and secure.

Transaction Validation

At the heart of a validator's duties is the validation of transactions. Validators scrutinize each transaction for its legitimacy, verifying that all the necessary criteria are met before it can be added to the blockchain. This process is critical in preventing fraud and ensuring that each transaction is accurate, thus maintaining the trustworthiness of the entire network.

Block Creation and Finalization

Participation in block creation and finalization is another vital role of validators. They not only validate transactions but also bundle them into new blocks to be added to the blockchain. This process involves solving complex computational problems in PoW mechanisms or being selected to finalize block based on stake in PoS systems, among other methods in different consensus models. Successful block creation is rewarded, incentivizing validators to continually support the network's growth and security.

Security

By verifying transactions and participating in the consensus mechanism, validators contribute significantly to the blockchain's security. They help prevent attacks such as double spending or malicious transaction ordering and ensure the network's resilience against attempts to alter past transactions. Their role is fundamental in maintaining the blockchain as a tamper-resistant ledger.

Node Operation

Validators operate nodes—computers that hold a copy of the blockchain and hold fast to its protocol. Running a node is essential for participating in the network, as it allows validators to verify transactions, propose or vote on new blocks, and maintain the integrity and synchronization of the blockchain across all participants.

Decentralization

A key attribute of blockchain technology is its decentralized nature, and validators are instrumental in preserving this characteristic. By distributing the validation process across numerous participants, the network ensures no single entity has control over the entire system. This decentralization is crucial for reducing vulnerabilities and enhancing the network's security, and trustworthiness.

B. The Necessity of Validator Incentives

The vitality of blockchain networks hinges not just on the robustness of their technical infrastructure but equally on the incentives they offer to those who maintain and secure this infrastructure. Incentivization of validators, through various mechanisms, is not just a reward system but a fundamental aspect of maintaining network integrity, security, and longevity. This section explores the reasons behind these incentives and the balance they seek to achieve between network security, financial attractiveness, and sustainable economic model.

Why Incentivize Validators?

Validators invest time, energy, and financial resources to keep the network running, facing direct and opportunity costs.

To compensate for these investments and risks, blockchain networks pay them from reserved token supply, by issuing new tokens, distributing transaction fees, or using a combination of those. The incentives ensure that validators are economically motivated to act in the best interest of the network, maintaining its operation and securing it against attacks. Without such incentives, the network could struggle to attract and retain enough validators to remain decentralized and secure, jeopardizing its functionality and the value of its native cryptocurrency.

Balancing Act: Security, Incentives, and Economics

Achieving a harmonious balance between ensuring network security, providing sufficient incentives to validators, and maintaining the network's economic sustainability is a complex challenge. This balance is critical for the long-term viability of any blockchain network.

Network Security: The primary goal of subsidizing validators is to secure the network against various forms of cyber attacks, such as double-spending or 51%/33% attacks. A well-compensated validator pool is more likely to remain loyal and diligent, contributing to the network's overall resilience. However, overly generous rewards can lead to economic imbalances, especially when the amount of tokens entering the circulating supply exceeds demand.

Financial attractiveness: Incentives need to be structured in a way that aligns validators' interests with those of the network. This means not only rewarding validators for their current contributions but also incentivizing ongoing investment in the network's future—encouraging validators to upgrade their hardware, for instance, in a PoW system, or to increase their stake in a PoS system. The challenge lies in setting these incentives at a level that is attractive without being unsustainable.

Sustainable Economics: The economic model of a blockchain must account for the long-term implications of validator subsidies. This includes considering the rate of new tokens entering the circulating supply, the potential for transaction fees to replace block rewards over time, and the impact of these factors on the network's native currency value. A sustainable economic model ensures that the network can continue to operate and grow even as the initial subsidy mechanisms evolve or diminish.

Blockchain networks continuously experiment with and adjust their models to find the optimal balance that can accommodate these often competing priorities. The evolution of these models is a testament to the ongoing innovation within the blockchain sector, seeking to reconcile the need for robust security, fair and effective incentives for validators, and the overarching goal of long-term economic sustainability.

C. Comparative Analysis of Validator Incentive Structures Across Networks

The blockchain landscape is populated by diverse networks, each with its unique approach to consensus and validator subsidies. These models have evolved to address the varying needs and philosophical underpinnings of each network, from Bitcoin's pioneering PoW to Ethereum's recent transition to PoS, and innovative models introduced by newer entrants like Solana, BSC, Avalanche, Cardano, Mina, and Humanode. This section provides a comparative analysis of these cryptoeconomic models, highlighting their strengths and challenges.

1. Bitcoin: PoW and Disinflationary Model

• Network Overview: Bitcoin is the first and most renowned cryptocurrency, utilizing a Proof-of-Work consensus mechanism.

• Consensus Mechanism Explained: In PoW, validators (miners) solve complex mathematical puzzles to validate transactions and create new blocks. This process requires significant computational power.

• No of Mining rigs: 1,000,000+

• Validator Rewards: Bitcoin operates under a disinflationary mechanism known as the "halving," where the reward for mining a block is reduced by half approximately every four years. These blockrewards come from the reserved supply, and will stop when the number of coins in circulation reaches the total supply. Usually, the distribution between the block reward and transaction fees is between 90-99% for the former and 1-10% for the latter. However, there have been a few instances, driven by high demand, where the proportion of fees exceeded 20%.

• Costs to Validators: Major costs include electricity and hardware amortization due to the intense computational effort required for mining.

• Net Incentives: Currently Bitcoin rewards miners through Block rewards () + Transaction fees which accounted for = $1.33 Billion/month in Feb 2024.

2. Ethereum: PoS Consensus, Staking Rewards, and Fee Models

• Network Overview: Ethereum has transitioned to a PoS mechanism with its Ethereum 2.0 upgrade, moving away from PoW.

• Consensus Mechanism Explained: In Ethereum’s PoS, validators stake their ETH as collateral to be chosen to validate transactions and create new blocks. It's less resource-intensive than PoW.

• Total Active Validator Nodes: ~950000

• Validator Rewards: Ethereum adjusts its issuance rate based on the ETH staked, with its current inflation rate at 0.54%, down by 0.19% since the Merge. This adjustment, coupled with burning a portion of transaction fees, allows Ethereum to reduce monetary inflation, thanks to high demand from protocols, dapps, and L2s. However, this demand has also driven up transaction fees. Potentially, if the demand is even higher and stays stable, Ethereum's system will be able to offset monetary inflation through its burn mechanism.

• Costs to Validators: Costs are lower compared to PoW and include running a node (server costs, electricity) and Capital to stake ETH.

• Net Incentives: Block subsidy + partial fee revenue. For February 2024, Ethereum validator revenue accounted for 199.52 million USD in total including $157.39 million in issued tokens and $42.13 million in transaction fees. A large part of ETH minted on top of the total supply was offset by a burning mechanism.

3. Solana (Proof of History)

• Network Overview: Solana is a high-performance blockchain supporting decentralized apps and crypto-currencies, using an enhanced PoS consensus.

• Consensus Mechanism Explained: Solana's PoS is enhanced by Proof of History, creating a historical record proving an event occurred at a specific time.
  

• Validator Rewards: Rewards are based on the stake amount and the validator's effectiveness in processing transactions.

• Total Active Validator Nodes: 1877

• Costs to Validators: Similar to Ethereum, including operational costs of running nodes and Capital to stake SOL.

• Net Revenue for validators: Solana burns half of the transaction fees generated during each epoch and uses the other half to pay the validators. Block rewards from SOL issued on top of total supply ($211.17 million) + partial fee revenue ($6.61 million) = $217.78 million for February 2024.

4. Binance Smart Chain (Proof of Staked Authority)

• Network Overview: Binance Smart Chain is a blockchain that supports smart contracts and runs alongside Binance Chain, emphasizing speed and low costs.

• Consensus Mechanism Explained: BSC uses Proof of Staked Authority (PoSA), combining elements of staking and authority for fast, secure transactions.

• Total Validators: 41 active validators out of 63 registered validators

• Validator Rewards: Validators on BSC earn from transaction fees, distributing 90% while 10% of the fees are burnt to reduce BNB supply. The burning will stop once BNB total token supply drops down to 100M.

• Costs to Validators: Costs include hardware, electricity, node operation, and capital to stake BNB tokens, varying by the scale and location of the validator's operations.

• Net Rewards for Validators: Validators on BSC get rewarded from 90% of the transaction fees generated through the on-chain activities and in February 2024 the revenue for validators accounted for $14.59 million.

5. Avalanche (PoS)

• Network Overview: Avalanche is a highly scalable blockchain platform for decentralized applications and custom blockchain networks, noted for its low latency and high throughput.

• Consensus Mechanism Explained: Utilizes PoS consensus mechanism with a unique algorithm combining aspects of Classical and Nakamoto consensuses, allowing for rapid transaction finality while maintaining robust security and decentralization.

• Total Validator Nodes: 1759

• Validator Rewards: Avalanche operates on a disinflationary supply model, similar to Bitcoin. However, all the fees collected from the users are burned. Current maximum APR for staking AVAX is at ~8% and depends on how long the validator has been staking the tokens. Validators earn from AVAX distributions, as 50% of the total supply was initially reserved for them. The disinflationary schedule aims to decrease the token unlock rate by ~0.5% until 2030, after which the plan for validator compensation is unclear. Probably the burning of transaction fees will stop and fees will be redirected to reward validators. Validators may also earn from operating subnets, though detailed information on post-2030 operations and subnet revenue is sparse.

• Costs to Validators: Include the expenses of running validator nodes and capital to stake AVAX.

• Net Rewards for Validators: AVAX unlocked from total supply and distributed to validators in February 2024 accounted for $28.44 million.

6. Cardano (PoS)

• Network Overview: Cardano positions itself as an environmentally sustainable blockchain, using the Ouroboros algorithm and PoS consensus mechanism.

• Consensus Mechanism Explained: A delegated PoS mechanism with a novel algorithm, Ouroboros, which divides physical time into epochs and slots, where slots are specific periods during which a block can be created.

• Total Validator nodes: 2977

• Validator Rewards: Cardano just like Avalanche allocated a chunk of its initial token supply (30.9%) for staking rewards, with a slight difference of redistributing network fees to staking pools rather than burning them. The current monetary expansion rate is 0.3% per epoch, leading to an annual unlock rate of about 2.0%. This expansion decreases over time, with early years seeing more ADA released. Over time, transaction fees are expected to constitute the majority of rewards, driven by network usage and adoption.

• Costs to Validators: Includes the cost of running a staking pool and capital to stake ADA.

• Net Rewards for Validators: The total amount of validator reward was $14.02 million for February 2024. $393 thousand is coming from transaction fees and $13.63 million from the unlocked total supply.

7. Polkadot (NPoS)

• Network Overview: Polkadot is a multi-chain framework that supports interoperability among blockchains, allowing for cross-chain transfers of any data or asset type, not just tokens.

• Consensus Mechanism Explained: Polkadot uses Nominated Proof of Stake (NPoS), where validators secure the network, and nominators select trustworthy validators, enhancing network security and efficiency.

• Validator Rewards: Validators and nominators earn rewards from new tokens issued on top of the current total supply and transaction fees, distributed according to their stake.

• Validator Nodes: Active 297 and 701 waiting.

• Costs to Validators: Includes costs related to running secure and performant hardware, network connectivity, and staking capital.

• Net Rewards for Validators: Transaction fees ($13.21K) + tokens issued on top of the current total supply ($70.71 million) = $70.713 million for February 2024.

8. Mina Protocol (PoS)

• Network Overview: Mina Protocol is renowned for its lightweight blockchain design, enabling efficient data verification and high levels of privacy. Unlike traditional blockchains that grow with each transaction, Mina maintains a constant size through zk-SNARKs, facilitating quick and easy access from any device without compromising security or decentralization.

• Consensus Mechanism Explained: Mina utilizes Ouroboros Samasika, a variation of the Proof of Stake (PoS) consensus mechanism. This approach emphasizes long-term security, succinct blockchain size, and inclusive participation. Validators, known as block producers, are chosen based on their stake to create new blocks, while snarkers and provers contribute to data compression and verification processes, ensuring the blockchain remains lightweight.

• Validator Rewards: In Mina Protocol, rewards come from additional issuance on top of the current total supply and are distributed to block producers (validators), snarkers, and provers for their roles in maintaining network integrity, compressing data, and verifying transactions. The reward structure incentivizes participation and supports the network's unique lightweight architecture.

• Total Validator Nodes: 940 among which 388 are active.

• Costs to Validators: The operational costs for participants in the Mina Protocol are significantly lower compared to traditional blockchains. Since the blockchain maintains a constant size, the hardware and network connectivity requirements are minimal, making it easier and more cost-effective for individuals to contribute as block producers, snarkers, or provers. However, as the network uses PoS consensus the capital required to stake makes the cost to running a node a little higher.

• Net Rewards for Validators: newly issued tokens($13.55 million) + 100% Transaction Fees ($9.82 thousand) = $13.56 million in February

9. Humanode (Proof of Uniqueness and Existence)

• Network Overview: Humanode is a Layer 1 blockchain that focuses on creating a network secured by biometrically verified human nodes, emphasizing one person = one node to ensure decentralization, democratic and equal participation in the network's consensus and governance.

• Consensus Mechanism Explained: Humanode utilizes a novel approach to consensus that involves elements of Proof of Uniqueness and Existence to ensure that one person can launch only one validator node, aiming to prevent Sybil attacks, maximize Nakamoto coefficient and ensure that each participant in the network contributes equally to consensus decisions, hence achieving higher decentralization compared to Proof-of-Stake blockchains.

• Total Nodes: 712 among which 575 are active

• Validator Rewards: Rewards for participants or validators in Humanode's network stem from transaction fees and network participation incentives from unlocked total supply, designed to reward active and verified human participation.

• Costs to Validators: In contrast to many blockchains that demand significant initial investments for infrastructure setup or large amounts of capital for staking, the operational expenses on Humanode are notably low. Launching a node on the Humanode network is accessible to anyone who can verify their identity as a unique, living human and can establish a server with costs ranging merely between $10 to $50. However, in order to maintain a validator status, node runner should prove she’s still a unique and real human behind this node by going through a private face scan every week.

• Net Rewards for Validators: Humanode Treasury ($138) + Fee Transactions ($4928) = $5066 for February 2024.

Analysis of Validator Earnings

Analysis of Costs and Net Rewards for Validators

D. Economic Sustainability Problem in Major Blockchains

As blockchain technologies have matured, the economic models underpinning them have come under increasing scrutiny. Major Layer-1 blockchain like Bitcoin and Ethereum, pioneers in the space, have set precedents for how validators are compensated through a combination of transaction fees and block rewards. However, these mechanisms, particularly the reliance on pre-defined minting schedules, reveal sustainability challenges that could impact the long-term viability and security of these networks.

Pre-defined Minting and Reward Systems

Bitcoin introduced the concept of a disinflationary supply, where block rewards—compensation for miners validating transactions— halve approximately every four years. This system, designed to mimic the scarcity and value preservation of precious metals, ensures that new coins are introduced into the system at a decreasing rate and total supply is limited.

Ethereum, following its transition to PoS with the Merge, adopted a dynamically adjusting reward system, where the issuance rate is determined by the amount of ETH staked. While these models have distinct advantages, including incentivizing early network participation and ensuring security, they inherently depend on continued network growth and participation to remain sustainable.

Insufficient Transaction Fees for Incentivizing Validators

A critical assumption underlying the economic models of most blockchains is that transaction fees would eventually replace block rewards as the primary incentive for validators. This transition is crucial for the networks' long-term sustainability, especially as subsidies diminish.

However, the reality has been more complex. For Bitcoin, transaction fees have seldom accounted for a significant portion of miners' rewards, approximately 10% of the validator revenue, raising concerns about the network's economic viability as block rewards from unissued supply continue to decrease and will one day stop. If the block rewards decrease this much, mining  becomes unprofitable. As a result the hash rate will decrease as well, drastically reducing the costs of 51% attack on the leading cryptocurrency.

The Issue of Minting New Tokens

Ethereum and blockchains which reward validators with new issuance of tokens, on the other hand, do not face this issue, but they constantly dilute value of tokens held by the holders which lowers financial attractiveness, especially when the amount of tokens minted can be changed by a governance decision. This can devalue the native cryptocurrency over time if not properly managed or if the increase in supply is not matched by new demand.

Comparison of Validator Reward Structures

Disproportionate Subsidies

Another concern is the disproportionate nature of subsidies within most of the networks. In systems where rewards are significantly weighted towards validators or miners with more substantial resources (e.g., more significant stakes or more computational power), there's a risk of centralization.

This centralization can lead to a small number of participants having undue influence over the network, potentially compromising its security and the decentralized ethos of blockchain technology. This challenge is particularly pronounced in networks that rely heavily on block rewards, as the wealthiest participants can continually reinvest to maintain and grow their influence.

In summary, the risk of disproportionate reward distribution varies across networks, with traditional PoW systems like Bitcoin showing a high tendency for reward concentration among large mining pools. PoS networks offer mechanisms to mitigate this, though the risk remains for those with more significant stakes or better infrastructure, as seen in Solana, Avalanche and Cardano. Mina Protocol show lower risks due to their design and reward mechanisms, while Humanode's unique one human = one node consensus presents a very low risk of disproportionate rewards and centralization. BSC's limited validator set also poses a high risk of concentration, underscoring the importance of network design in ensuring fair and decentralized reward distribution.

Impact on Network Decentralization and Security

The sustainability challenges faced by major blockchains are not merely economic but also foundational to the networks' decentralization and security. A blockchain that becomes too centralized, whether through the accumulation of power by a few large validators or through reliance on a diminishing source of rewards, risks losing the trust of its users.

Furthermore, if the economic model fails to incentivize enough participants to secure the network sufficiently, it becomes vulnerable to attacks.

While the block subsidy for rewards of major Layer 1 blockchains has successfully bootstrapped these networks to widespread adoption and security, they present decentralization challenges that need to be addressed. Balancing the economic incentives for validators with the principles of decentralization and long-term viability is complex but necessary.

Conclusion - Lack of Self-Sufficiency a Major Hurdle

A fundamental sustainability issue for most of the blockchains in our analysis is their lack of self-sufficiency. Reliance on continuous subsidies, without a corresponding increase in transaction fees, creates an environment where networks are perpetually dependent on new coin issuance or paying out from the limited treasury for validator compensation.

Networks like Bitcoin, Avalanche and Cardano rely highly on subsidies for validator/miner rewards, indicative of a lack of self-sufficiency from network fees alone.

Ethereum, in its PoS iteration, is working towards reducing this dependence by enhancing fee-based incentives largely depending on the expansion of their ecosystem.

These models raise questions about what happens when these rewards dwindle or cease altogether. Can transaction fees alone sustain the network's security and operational needs? The current evidence suggests that most networks are not yet in a position where transaction fee revenue can fully replace block rewards, leading to potential long-term sustainability issues.

Networks like Solana, Mina and Polkadot chose constant dilution of token holders and increase of total token supply in order to subsidize validators indefinitely.

Humanode stands out for its minimal resources required to support a decentralized and relatively big validator set, and its blockchain economy has almost become self-sufficient even with comparatively low on-chain activity. It is possible thanks to its consensus mechanism and a cost-based fee system. However, Humanode relies on a novel consensus mechanism which needs more time to prove its long-term security and reliability.

Only Binance Smart Chain pays validators only from fees generated by the network but at the same time, the low number of active validators raises questions about the decentralization of the chain.

Disclaimer - The data provided above is an estimated data calculated based on data collected from various sources mentioned at the corresponding place. Actual value may vary a bit according to the fluctuation in price of each token. The authors of the article are currently working on Humanode, and are users and holders of small amounts of ETH, AVAX and BNB.