Hi,
this is related to the Power Sink discussion http://screeps.com/forum/topic/279/Power-Sink, but does not fit right in there.
The general concern of most players is, that with no power sink and huge income of the top players, they will become even stronger, having more and more of their normal creeps replaced by immortal power creeps, or form the ****ing 300 of the screeps world and crunch through every defense, not any more limited by range etc..
But first the numbers:
The cost p_n of one power level n is as follows (stand 2017_02_15):
(p_n = pow(1.15; n) * 1000
) or p_n = n^1.15 * 1000
the overall power cost P_n = 1/2.15 * n^2.15 * 1000
Considering a mean cost for a maxed out power creep (PC) = 18.33 lvl/PC
This means for Hernanduer (mean income 5million power/month):
starting now with lvl 239 (13 maxPCs),
lvl 300 (16 maxPCs) in 7.6 months,
lvl 400 (21 maxPCs) in 24.5 months,
lvl 500 (27 maxPCs) in 47.0 months
For e.g. AndrolGenhald (mean income 0.5 million power/month):
starting now with lvl 36 (2 maxPCs),
lvl 100 (5 maxPCs) in 16.5 months @ 0.5mio power/month
lvl 100 (5 maxPCs) in 1.6 months @ 5mio power/month
lvl 239 (13 maxPCs) in 11.9 months @ 5mio power/month
One may consider the income of ca. 5 million the maximum caused by the CPU limit of 300, then every player will eventually hit a soft wall, but at several 100 levels.
With modification of the base of 1.15 or the use of a exponential function instead, the soft wall can be set whereever one want it to be and the "softness" is adjustable (which will also affect the gap between middle and top players). In my humble opinion there is therefore no need for a power sink.
The question is, how much levels do we want at the upper end of the playerscale?
If it is left at 200-500 levels then there should probably a mechanic introduced to counter massive concentrations of power levels (many low level PC or less high levels).
Maybe something like a DISRUPT_POWER method. Which will render the .usePower method in this room useless. The amount of time could be higher the more power levels are present at trigger and with severe punishment for the triggering PC, ranging from not responding for several ticks up to sacrifice of the PC. That might counter a power army and force players to diverse tactics.