OVERVIEW
Energy Choices is an agent-based simulation illustrating the interplay between social and scientific factors (in a global context) as people of the world strive to "grow" their economies. In this simulation, autonomous Country agents interact with a World agent, making choices about how to spend GDP. Starting with real data from the World Bank, Energy Choices can be run either as a simulation (i.e. choices made are pre-determined) or a game (i.e. individual players control choices of individual countries over time).
MODEL
Impact = Population x Affluence x Technology
CO2 = Population x GDP/Capita x Energy/GDP x FossilFuels/Energy x CO2/FossilFuels
In this variation of the IPAT model, impact on the world is measured in terms of CO2 emissions. Affluence is measured in terms of GDP/Capita. The model uses 3 terms for Technology: Energy Intensity (Energy/GDP), Fossil Percentage (FossilFuels/Energy), and Carbon Emissions (CO2/FossilFuels).
POPULATION
PGt = PGt-1 / (1 + 0.000064 x PGt-1 x (GDPperCapitat - GDPperCapitat-1))
where PG = population growth (annual)
As countries become more prosperous, their population growth rate tends to decrease. The simulation estimates that, for basic survival, at least $1 per person per day must be allocated to consumption (expenses).
GROSS DOMESTIC PRODUCT (GDP)
Prosperity is typically measured in terms of how much GDP is earned per person (GDP per Capita). Among the people, the amount of expendable income per person (Consumption per Capita) is also important. A country's current GDP may be invested 3 ways:
ENERGY INTENSITY
Energy Intensity represents how efficiently energy is used to generate GDP in the economy. This is based on the starting values in 2003, and currently does not change within the simulation.
COMBUSTIBLES, RENEWABLES, & WASTE (CRW)
In all places, some people get some of their energy from sources that are gathered rather than bought (e.g. wood, cow dung). This is particularly true in the poorer countries. In the current simulation, the amount of energy derived from CRW does not change.
RENEWABLE FUEL
P(ren) = 2P(initial oil) + P(initial ren) x exp(-7 x Epv(t)/E(t))
where Epv(t) is renewable energy use and E(t) is total energy use, both at time t
Renewable fuel includes nuclear as well as hydro-electric, solar, and wind energy sources. Although renewable energy is initially more expensive, costs decrease as use increases. In the simulation, renewable fuels have no impact on the environment.
FOSSIL FUEL
P(oil) = 2.9 x exp(Ei / Erem)
where P(oil) = the price of oil per MBTU, Ei = initial oil reserves, and Erem is remaining oil reserves
Fossil fuel has a major impact on the environment, because burning it produces CO2. Fossil fuel is currently cheaper and more readily available than renewable energy sources. However, fossil fuel reserves are finite, and therefore costs will increase as the size of those reserves decreases. In the simulation, only oil is being considered.
CARBON EMISSIONS
CO2 = k x Energy
Impact is expressed in terms of the carbon footprint, which comes from using fossil fuels. Carbon emissions (footprint) are calculated for fuel-grade oil, so 1 MBTU from oil produces 156 lb. CO2 (i.e. k = 0.00641).
GLOBAL WARMING
Temp Increase = 2.8 x (AC - 280) / 280
and 1.3E+10 tons CO2 = 1ppmv
where AC = atmospheric concentrations of CO2 = 370ppmv in 2003
and climate sensitivity => 2.8C for doubling CO2 concentration from preindustrial revolution (280ppmv)
As CO2 builds up in the atmosphere, average global temperatures increase. It is estimated that if these temperatures increase only 4C above pre-industrial levels, 40% of the world's species will be wiped out.
PLAYER SCORE
S(i) = (a x (GPC(i)t - GPC(i)t-1)) + (b x (CPC(i)t - CPC(i)t-1)) - (c x (CO2(i)t - CO2(i)t-1))
where GPC = GDP per Capita, CPC = Consumption per Capita, and CO2 = carbon emissions for the country
Score is based on balancing local needs (GPC and CPC) with global responsibility (CO2 emissions).
CAP & TRADE
With this strategy, the amount of CO2 that a country can produce is capped. This cap shrinks slowly with the goal of reducing all CO2 emissions to 80% of current use by some target year. The target year can be different for prosperous countries versus less prosperous countries. Countries must also pay a unit price for each ton of carbon emitted. The simulation currently does not support trading of cap credits.
Money generated from the sale of fossil fuels is used to subsidize the less prosperous countries. The size of the subsidy depends on the prosperity of the country, as well as the size of the population. So, the poorest countries get the largest subsidy per person, while countries with GDP/capita greater than the average get no subsidy.