Hi,

I've had recently this idea for a more ecological and economical way of mining bitcoins and I'd like to contrast it with technical minded people.

I've written a small post at https://josefemenias.wordpress.com/2016/12/07/bitcoin-coopetition-mining/ with a little more detail, but I am presenting a brief description below.

The basic idea is to alternate bitcoin mining in two phases that use competition and cooperation (relative duration is just an example):

Tic Phase - Competition. 144 blocks long
During this phase (144 blocks long for instance) everything works as always. Mining pools compete to validate and add new blocks to the blockchain.
This phase is open to anyone. After the 144_th block has been mined, the network enters the Tac Phase.

Tac Phase - Cooperation. 1440 blocks long
This phase is restricted. Only those who have solved at least one block during the most recent Tic Phase can validate blocks during the Tac phase. No hashing is performed during this phase, only signing.

New blocks are added to the blockchain following these rules:

• The cooperation phase will last for 144 x 10 blocks = 1440 blocks.
• The rewards during this cooperation phase (fees and new coins) will be fairly distributed among the winners of the previous competition phase. Fairly should be interpreted as proportional.  That means that a mining pool that solved 7% of the blocks during the competition phase will get 7% of the total proceedings from every block mined during the competition phase.
• Every 10 minutes a new block is created and broadcasted to the network.
• The new block is considered valid if:
  
  • 1.- All of its transactions are valid.
    
  • 2.- It transmits the newly generated coins and any fees due in a fair manner, as described previously.
  • 3.- The block has been signed by the winners of the Tic phase. The signatures must represent more than 50% of the total network hashing power, as proven during the competition phase.

• No hashing at all will be performed during this phase; signing will be interpreted by the network as proof enough that the block is valid. (That is where the energy savings come from, obviously).
• In case of conflict, the block with more valid signatures is considered the valid one.
• After the 1440_th block has been mined this way, the network enters again the Tic phase.
  
  

As you can see, this system would preserve most of the current Proof Of Work characteristics of bitcoin mining but with a twist that allow the mining pools to put their system to rest for a significant period of time, thus saving energy and money. I've chosen the duration of the two phases in an arbitrary manner, so that, for every day of competition we'd 10 have days of minimal energy consumption.

While I can't see any major drawbacks to this system, I know how tricky game theory can be, so I'd love to hear your feedback on the idea.