Energy Bank (SMAC)

is a base facility in Sid Meier's Alpha Centauri. The Energy Bank adds +50% Economy at the base.
==Strategy==
As long as you're making good money anyway, it can't hurt to make a bit more. Energy Banks are always worth having, especially if you can get one in every base for free with The Planetary Energy Grid (Alien Crossfire only). However, there are two questions to ask yourself before building an Energy Bank: "Will it give me a profit?" and "What else could I be building?"
Firstly the profit question. An Energy Bank gives you +50% Economy, at a cost of 1ec/turn. So if you're producing 2 Economy (not total energy, just Economy) at that base, you will gain 1 energy/turn at a cost of 1 energy/turn — not such a great deal. With 4 Economy at that base you gain 2 energy/turn which means it will only take 160 turns to cover the value of the minerals involved in building the Energy Bank. Of course, the base will grow, and the returns will improve over time, so the sooner you build one, the quicker you'll make the money back. Energy Banks are like a stock exchange: you put some cash in now, and hope the company goes up, and stays up long enough for you to profit from it. So, as with all facilities that improve the base's mineral or Economy production, the sooner you build an Energy Bank, the more you will gain from it.
However, building too many facilities early on is going to kill your horizontal growth in favor of vertical growth. Which is better, 5 bases with Energy Banks now, or 15 bases with Energy Banks later? Instead of increasing the Economy of your bases by 50%, why not increase the number of your bases by 50%?
What else could we have built in the same time with those 8 rows? A Colony Pod, 2 Formers to develop the new base, and a 1-1(t)-1 unit to protect it? Recycling Tanks and a Crawler? Two Colony Pods and 1-1(t)-1 units to protect them? If every base did that instead of building an Energy Bank, you'd increase the number of bases by 200%.
So, we must decide between building early to get more cash for rush buying to speed a later but faster expansion, or building later, to expand faster in the first instance, but to get less efficient use from our Energy Banks. There really are a lot of factors to consider here, such as which faction, Social Engineering settings and map you are using, but with the exception of Morgan, it may be wiser to use those 8 rows in the early game to get more stuff on the map instead of more credits in your pockets. Morgan on the other hand has poor Support and high energy in the base square (easily gets 8+) so he can build Energy Banks as soon as he is running Free Market/Wealth and really rake in the cash. Morgan can easily get 16 energy at a size 3 base, which with the default 50/50 Economy/Labs split allows an Energy Bank to make a net profit of 3 energy/turn - only 53 turns at that rate to earn the value of the Bank back, and most probably less, and help to fuel a rush-buying frenzy that only Morgan can get away with.