RE: How to trade electricity using SolarCoin - yeah, really!
Another thing I think will be important in driving adoption of SolarCoin is to first make it what I'm calling a "discount" or "concession" currency. Meaning that the party accepting SolarCoin offers a discount/concession to the cash price for being paid in SolarCoin. This is similar to how fuel stations will sometimes offer discounts for cash payment over credit card payments.
The concession can be justified by the party accepting payment for a number of reasons. Perhaps the party giving the reduced price sees a currency backed by solar power generation as more valuable or having better global or social utility than one simply given out by a government or highly backed by the trade of oil or warfare.
Or perhaps they see the opportunity to earn interest by staking the coins being higher than that of earning interest on a cash deposit and would like to give a discount to encourage people to give them payment in the currency that will give them a higher return over time.
These are just some of the ways adoption could be driven by offering concessions on the price for the use of SolarCoin in the transaction.