A blast from the past!

Algo-stables, as you mentioned, are making a comeback. In fact, some of these stablecoins have already gained popularity in recent years. For instance, DAI (DAI Stablecoin) has become one of the most widely used decentralized stablecoins.

Regarding your idea about a commodity-backed stablecoin and measuring energy via Proof-of-Work (PoW), that's an interesting concept!

In a commodity-backed stablecoin, the value of the coin is pegged to a specific asset or basket of assets. This can be done by collateralizing the stablecoin with said commodity, ensuring its value remains tied to the underlying asset.

The idea of measuring energy via PoW is also intriguing! Proof-of-Work is an energy-intensive consensus algorithm that has been used in various cryptocurrencies, including Bitcoin. By leveraging this concept, you could potentially create a stablecoin that's not only backed by a physical commodity but also incentivizes sustainable energy production and consumption.

Some potential advantages of a commodity-backed stablecoin with PoW-based energy measurement include:

1. **Environmental benefits**: By aligning the stablecoin with sustainable energy production, you're encouraging eco-friendly practices.
2. **Increased trust**: The use of a physical commodity as backing can provide an added layer of security and trust for users.
3. **Unique value proposition**: This concept could differentiate your stablecoin from others in the market.

However, it's essential to consider some potential challenges and limitations:

1. **Scalability issues**: PoW-based consensus algorithms can be energy-intensive and may not scale well, potentially leading to high transaction fees or network congestion.
2. **Energy consumption concerns**: While promoting sustainable energy practices, it's crucial to ensure that the energy required for the stablecoin's operation is indeed environmentally friendly and justifiable.
3. **Commodity market volatility**: The value of the commodity used as backing can fluctuate, which may affect the stablecoin's peg and overall stability.

To overcome these challenges, you could explore alternatives, such as:

1. **Hybrid consensus algorithms**: Combining different consensus mechanisms (e.g., PoW, Proof-of-Stake, or Delegated Proof-of-Stake) to achieve a better balance between energy efficiency and scalability.
2. **Renewable energy sources**: Focus on using only renewable energy sources for the stablecoin's operation to minimize environmental impact.
3. **Commodity diversification**: Use a diversified basket of commodities as backing, reducing reliance on any single asset and minimizing potential price volatility.

I hope this feedback helps you further develop your idea!