Simulating Planetary Economics

Planetary Economics

This week I started writing the galactic economic simulation.  Each game year the universe evolves and each planet's economy grows or shrinks based on factors such as government type, stability, population size and natural resources.  Eventually you'll not just be limited to governing planets by controlling tax rates and setting government policy, but by waging intergalactic warfare you'll be able to influence the economy and populations of your enemies in more nefarious ways.  You'll be able to bomb their infrastructure and destroy large population centers such as cities.  You'll be able to pirate their freighters in order to interrupt supply chains.  But of course, if you don't defend you own empire with ground based lasers, missiles, air defences, space defence shields, orbital laser grids and battle fleets, enemy civilisations will be able to do exactly the same to you.

For now however, let's just start with the basic economic simulation.


To begin with, some simple rules.  I'll add more of these as I refine the simulation further :

  • Wealth attracts population - people like living on wealthy planets
  • Taxation deters population - people don't like paying taxes!
  • Tax revenue grows GDP - the government invests in infrastructure
  • Inflation reduces effective GFP - each year the inflation rate effectively devalues the currency, making each credit worth less.

Policy Making

The government applies policies to influence the economy.   When you own a planet, you get to set the policies.  If you don't, the government is simulated based on government type and its stability rating.  Right now I've only implemented one policy, but I'll add more and more of these as I go along : 

  • Tax change policy - adjust the taxation rate up or down by a certain amount over a period of N years

The Planet Iweho

random seed 1385353856
solar system id 16885
resources {'rocks': 813127, 'crystals': 2128, 'residential': 57, 'city': 348, 'timber': 328918}
num Moons 2
num Docks 2
num Shipyards 3
num Installations 39
economy $79.96 billion
population 4.60 billion
High Inflation (30.00) - The wage/price spiral means that businesses have low profits, workers are poor and exports are minimal due to the high local prices.
Very Stable (50.00) - Great politicians build a stable economy. Inspiring confidence in investors both local and off-world produces industries that are profitable and efficient. This drives inflation rates down.

As you can see, Iweho is an Industrial planet with high inflation but stable government. It is relatively rich in minerals and forests. 

Iweho's Economy, 2050 - 2100

Now running the economic simulation for Iweho over a period of 50 years gives the following results:

Iweho starts off as a fairly wealthy planet, however, GDP (red) drops substantially right from the start due to its very high inflation rate (50%).   With high wealth and low tax (yellow), the population (blue) grows steadily, until around the year  ...
... when the dropping wealth deters new arrivals.   As GDP bottoms out, the government implements a new tax policy that raises the tax rate to 50% over the course of 5 years.
This brings in new revenue, and GDP starts to increase.   As wealth increases, the population begins to grow gradually, despite the relatively high tax rate.
Now that GDP has stabilised, and population growth is locked in, the government reduces the tax rate to a more manageable 22%, attracting new and sustainable population growth.

Other Planets

Here are some other planets and how their economies went over the same period of time:

Fly Safe, Commanders!


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