How to play
In this game, you will balance power generation with the changing power demand to maintain the
grid frequency. Don't let the frequency (blue line) go beyond the limits (red lines) or the game will end!
Press the power button (space bar on a keyboard) to increase power generated (blue bar) to match the load (red
bar) to keep the frequency steady. The goal of the game is to generate as much energy as you can without
letting the frequency go beyond the limits!
As the game progresses you will unlock more resources and the grid conditions will change:
- Level 2: The inertia of the grid begins to decrease.
- Level 5: Storage is unlocked. Use the charge (down arrow) and discharge (up arrow) buttons to dispatch the storage!
- Level 10: Generation limits are introduced.
- Level 15: A proportional-integral-derivative (PID) controller for the generator is introduced and can be tuned.
Background information
What is an AC electrical power grid?
An electrical power system is a network of components that generate, transmit, and consume electric power. We commonly refer to the large-scale power system that supplies power to our homes as the grid. The grid is an alternating current (AC) system in which the voltage and currents within that system oscillate between negative and positive values. The rate at which these signals oscillate is referred to as their frequency.
What does it mean to balance the powers in the system?
In the power grid the electrical power that we are consuming is being produced at nearly the exact same time that we are consuming it. The electrical power being used to illuminate the lights above you was generated at some power plant and traveled through the transmission lines at nearly the speed of light to get there. Typically, in large scale power systems we do not store any significant amount of energy within the system. Because of this the amount of power that we put into the system must be equal to the amount of power that we take out of the system. When the input and output power are equal, we say that the powers are balanced.
How is frequency related to power balance?
In a conventional power system, large mechanical synchronous generators are used to produce electrical power. These generators convert potential energy from resources such as coal, natural gas and hydropower into electrical power. This conversion is done by first converting the energy into mechanical energy that can push against turbine blades which are connected to and spin a rotor shaft. As the generator's rotor spins, it produces a magnetic field which induces an electrical current in wires which surround the rotor. This electrical current oscillates at a frequency that is proportional to the rate that the rotor spins at. This coupling between the mechanical rotation and electrical oscillations can be used to help us determine if the power input and power output is balanced. If the mechanical power input is greater than the electrical power output, then the rotational frequency of the rotor will increase as more energy is stored as rotational energy. If the mechanical power input is less than the electrical power output, then the rate at which the rotor spins will decrease as energy is taken from it. Since the electrical frequency is proportional to the rotational frequency, we know that our system is balanced if the electrical frequency does not change.
Why do we need to manage the frequency?
In a power grid we want to maintain this frequency near to the nominal value. Everything in the grid, from the generators to the loads, is designed to operate at the nominal frequency and if the frequency deviates too far from this value the system can become unstable and the components within the system can become damaged. If the frequency deviates too far from the nominal value we have to shut the system down resulting in a complete interruption of power to consumers, typically referred to as a blackout.
How do we control the frequency?
When the supplied power and the consumed power are not equal this means that the amount of energy stored within the system must be changing to balance out this difference. In a conventional power system this energy is stored in the form of the rotational energy of the generators rotors. We can control the frequency by increasing or decreasing the power supplied to the generator. If the power supplied by the generator is greater than the power being consumed on the electrical side, then the frequency will increase. If the power supplied by the generator is less than the electrical power consumed, then the frequency will decrease.
What is the difference between power and energy?
Energy is the ability to do work. Power is how much energy is being transferred at any one time. An object that has energy can transfer that energy to another object, and the rate of this transfer of energy is power. In this game the score is the total amount of energy that was delivered to the load. This energy score is calculated by continuously adding up the amount of power the load is consuming over time.