powertac/powertac-server — Issue #412: Default broker trading does not generate good market records
Author: jecollins
Created: 2011-11-03 02:13:05+00:00
State: open

Currently, the default broker offers a high price for its power, and always gets what it asks for. But it pays way more than the minimum price, because the market surplus is split between seller and buyer. So if the entire quantity can be supplied by the lowest-price producer at 20/mwh, and the default broker offers 100, then if the surplus is split at 50%, the price is 60. Real brokers would never have to pay this much. But one of the purposes of the bootstrap period is to help brokers understand what the market prices should be.

So I can see two possible solutions that will give us more realistic market prices:

* during the bootstrap period, assign 100% of the surplus to the buyer.
* Have the default broker offer a low price in the furthest timeslot, and raise the offer price as the leadtime narrows.

I like the second approach better, because it is more realistic and could introduce at least a bit of randomness to the market records.