Grin coin is a private & lightweight open source project based on the mimblewimble blockchain implementation. MimbleWimble is a lightweight blockchain protocol proposed by anonymous author that goes by the name Tom Elvis Jedusor (inspired by Harry Potter) in July 2016. Since then, the proposal has gained a huge following among Bitcoin and privacy advocates. Unlike bitcoin or ethereum, there are no addresses in Grin. In order to transact using Grin, both wallets must communicate with each other online with the results broadcasted to the network. Another key different is that transaction history (sender, receiver, amount) will not be recorded on the blockchain. Due to the removal of these information from the transaction, the data size remains small and that keeps the blockchain lightweight. New nodes can easily join the network without having to download a large blockchain. Grin coin was launched without an ICO, fundraising, or pre-mine. Developers around the world contribute openly with the goal to ensure the coin distribution remains as fair as possible. There are 2 popular wallets widely available to interact with the Grin network. Grin core wallet: https://www.coingecko.com/buzz/how-to-use-grin-wallet-to-send-receive-grin-coins Wallet713: https://www.coingecko.com/buzz/how-to-use-grin-wallet713-to-send-and-receive-grin-coin-step-by-step-guide The consensus algorithm used by Grin is the Cuckoo Cycle proof-of-work based. There are 2 hashing algorithms involved with Grin. Cuckoo-29 is meant for GPU mining while Cuckoo-31 is meant fo ASIC mining. This is a deliberate design to encourage miners to eventually move into ASIC mining for efficiency while keeping it fair at the beginning of the launch. Grin coin has launched its mainnet on 15th January 2019 and is now available for mining and trading.
Solarcoin is a Scrypt based alternative digital currency and its innovation comes from the secondary proof of work reward: the Solar Proof of Work. Green solar energy producers are entitled to receive one SLR for every MWh electricity generated. In order to claim a Solar Proof of Work reward, solar plant owners must submit 3rd party verified energy generation certificates such as a Solar Renewable Energy Certificate (SREC) or equivalent country specific documentation. All Solar Proof Of Work rewards will be stored as transactions in the blockchain. The supply of SLR comprises of the following: - The Mining Pool: 105 million Solarcoins (0.1%) to be publicly mined over the next 40 years. All publicly mined Solarcoins represent historically generated and unclaimed solar electricity. - The Generator Pool: 97.5 billion SolarCoins (99.4%) are currently stored in the OCA non-circulating generation pool account. These will be exchanged for Solar Proof of Work claims of solar electricity generation submitted over the next 40 years at the rate of 1 SLR per MWh of solar energy. - The Genesis Pool: 500 million Solarcoins (0.5%) are stored in the genesis pool account for environmental charities, early volunteers, advisers, builders and maintainers of SolarCoin infrastructure. Genesis pool circulation is capped so that it will never represent more than 5% of total Solarcoin in circulation.