So Faustmouse has been pushing to add Electricity as a new property. So since he offered to help and I have put it off for quite some time I would like to work with him to implement it after the next release.
Cool. This would be a very good improvement if we do it right.
3. City Growth - We will have to decide how much electricity each pop size will add. This is just a single number set on the property.
and
6. Era Power Consumption - It has been discussed in the original Power Mod topic that as you progress through the eras that power consumption should increase as you tech up. Mainly because more people are consuming power than when electricity first was invented. This can be done by auto-build buildings that are triggered by new techs on the tree and consume a little bit more power.
It might be more important to see it as Electricity property is supply and population would therefore consume. Thus population REDUCES the property locally. As techs increase, sending more and more electrical appliance conveniences out to the public, the population would suck up more and more of the electricity property. Additionally, it would be appropriate that more population eats more electricity in general.
MOST buildings would consume electricity as well and the penalty for not running enough electricity generation would be that said buildings would cease to function if the electricity property goes too low. So you'd have buildings turning off and turning on as brownouts occur since buildings would suck up electricity unless deactivated by not having enough.
Might therefore be important to give additional power plant buildings with prereqs on the previous power plant buildings that would enable a player to build a second, third, fourth power plant of a given type etc...
Electricity property would need to bottom out at 0 I think, not being possible to have less than no power on hand.
Housing buildings that would emerge soon after electricity should be technologically available to the civ would replace and then almost immediately obsolete all predecessor buildings making it possible for a blackout to plunge the city into absolute homeless status - and all the unhappiness that would come with it. In fact, come to think of it, the homelessness 'building' should have an unhappiness/pop level tag implementation rather than a flat value to represent that larger cities would suffer even more greatly if the civ allows this to take place.
5. Building Power Consumption - We will need to add an electricity property any and all buildings that require electricity. This is where the most help and discussion need to be done. I have no idea how much each building should consume. This will be Faustmouse's biggest task if he wants this implemented.
Yup, this will be the bugbear of the system... balancing out supply and demand appropriately. I'd suggest starting with very small numbers. Like -1/pop soon after electricity should be available. -1 for a shop or standard building size then judge size of building and electrical consumption up very gradually from there. Some buildings would also have tech modifiers affect them here as they'd consume more as more techs enable various things. Perhaps they should also thus become more effective in what they 'do' as the power enables them to be. For example, an Intelligence Agency might consume -3 power when it can be first built but after x technologically developed resource is available, such as perhaps electric typewriters or phones, it now consumes -4 power but gains another +1 espionage.
7.
Electricity to Hammers - Right now each power plant produces a different number of hammers based on 100 MW = +1

So rather than putting it on the Power Plants directly anymore Auto-Build buildings with a +1

would need to be made every +100 Electricity. Note that with the property system +1 Electricity = +1 MW to keep it easy to convert.
Power itself doesn't do much unless there's a means to convert that power into useful action for industry. I'd have buildings improve with techs/resources/further power consumption as noted above rather than having power have any direct effect.
I also think we should eventually make the system more difficult for players by capping a maximum energy held (excess goes to waste as its harmlessly grounded out.) Some buildings opening up through further tech progress could increase the cap, which really just enables a larger margin to store the ever important energy property resource. The more time goes on, the more crushing the effect is on a city when the power goes out so it becomes a bigger and bigger concern for the advanced era players.
In short, we shouldn't need to shortcut and make energy directly become a mysterious source of production itself. Instead, make factories more valuable the more they develop ways to USE the electricity. This proposal will make all those seemingly superfluous 'goods' resources we're using in this game a lot more meaningful when access to them and power makes a building more valuable but also makes the building consume more.
8.
Electricity Loss - Counterintuitive to what we have had before, power plants will not trigger weather a city has power or not. The first 1MW auto-build +1

building will have a trigger to tell you city if it has power or not. If it goes above you should be fine and its present. If you go under then it will disappear and your city will be without power until you get it back up.
Excellent. Yes, you have power or no you don't. Make it a boolean on a greater than 0 or 0 on the property value level in the city.
9. Property Diffusion - Properties like Crime, Disease and Pollution defuse over the map however do we need it to do that for Electricity?
10. Improvements - Should improvements on the map such as solar panels, windmills and geothermal plants add to a cities power? If so how to get the property to they city? In addition should other improvements like Factories and Cottages be consuming power?
hmm... perhaps yes. #9 would be an initial answer as to how to go about #10 but the property would diffuse from one plot to another quickly rather than slowly as crime and disease do. The math would be a lot more fluid than it is for crime. For example, a solar panels improvement could increase power and then that diffuses across the tiles back to the city or to the improvements around it that are also reliant on and drawing power. (The reliance on a property for the functioning of an improvement is probably going to take more programming but would be a good reflection of reality... a Town is going to suck up quite a bit of electricity.)
Mind... I wish we could have a 'second route' type here - power lines - that would enable this diffusal of energy across tiles and as varying qualities of powerlines are developed and implemented could determine how quickly and seemlessly that power diffuses. We may well be able to do this somehow already but It would probably take use of the multi-feature 'feature' and some tricksy xml work. It doesn't need to be graphically displayed but the tile does need to note the 'second' feature... I might be able to assist with that if AIAndy can't be summoned for this small task.
However, though I know the property system CAN do all of this coolness, I'm not sure on HOW exactly to make it do it all so it'd take some serious consideration, research and planning to make it all work properly I think.
These are just my thoughts on the subject. This project would be easily as massive as any of the worst parts of the combat mod but may not need a whole lot of programming and be able to utilize existing methods. It's just going to take a thorough understanding of how to apply all the generic factors we can toggle in the property system... more thorough an understanding than I alone can offer.