Resources that players use in games but which may be replenished by regaining the original resources or receiving replacements are Renewable Resources. Renewable Resources can exist in several levels in the same game: A kind of resource that from the players' point of view feels renewable might not be renewable from the game system point of view, i. e. there is a may be a hidden limit on the availability of the resources in the game system.
Example: the players can renew their health by picking up health packs in Quake. In deathmatch versions these health packs are also regenerated in specific points after a certain time.
Example: in most arcade games the players receive new lives when they reach certain scores.
Example: the basic resources in Age of Empires are renewable from the players' point of view, at least in the start of the scenario, but there is only a certain amount of these resources available during the whole scenario.
Renewable Resources are created through use of Chargers, Converters and Closed Economies and can be modulated by the placement of Resource Generators, and Time Limits between when Resources can be renewed. In the case of Converters the resources may not be renewable from a game system perspective but may be so through the players' perspectives, since Closed Economies and Resource Generators can guarantee Renewable Resources even if players may not be aware of the possibility to replenish used Resources. Similarly, the number of Pick-Ups and the effect of Chargers may be limited in the game but can appear to provide Renewable Resources from the players' perspective.
Renewable Resources are always associated with a renewal rate, which dictates, as the name implies, how fast the Resource is generated. This rate can, as the Resource itself, be considered from the game system or the players' point of view. It is usually easier to calculate, modify, and balance the renewal rate from the game system point of view but it is as important to try to calculate the renewal rate from the players' perspective also. For example, the renewal rate of health packs in a deathmatch arena of a first-person shooter from the game system point of view is easy to modify by changing the number and location of the Resource Generators of the health packs, and modifying the Time Limit of health pack creation of each of the generators. These factors, together with the number of players, the tactics of the players, the estimated Damage dealt within a certain time (the main Consumer of health in these games), and so on determine the perceived renewal rate of health packs for the player.
Renewable Resources are always associated with Producers that govern the direct renewal rate of the Resources. This renewal rate can be static during the whole game, can be controlled by the players, or can change according to the game state. When the Renewable Resources are produced by Controllers, Units, or Characters under players' control the rate of renewal is usually limited by requiring another form of Resource (making the Units or Avatars into Converters), having Time Limits on how often the actions can be used, or using Budgeted Action Points. The ability of Units or Characters to produce Resource is often Privileged Abilities.
One interesting way to use changes in the renewal rate is to allow the players to overuse the Resources without direct Penalties, but where the overuse decreases the renewal rate steadily and permanently. This form of Diminishing Returns of the Renewable Resources is the basis for one of the Social Dilemmas called The Tragedy of the Commons when used together with Shared Resources.
Renewable Resources usually have a certain upper limit of the Container of these Resources. This is intuitive in the case of, for example, health of the players' Characters or Units. A slightly more unintuitive use of a Container with Renewable Resources is the use of Budgeted Action Points where the Container, together with the renewal rate, dictates how many action points are available to a player.
Renewable Resources can be used to give the players meaningful subgoals within a Hierarchy of Goals in the game as the players also have to struggle to Gain Ownership of the Resources during the game. This is the case in, for example, most of the first-person shooters and computer roleplaying games where the players have minor subgoals of replenishing ammunition, health, armor, and so on in order to reach the higher level goals in the game. Players may have Reconnaissance goals when the Resources are renewed but players do not know where or when they are renewed.
The second common case of Renewable Resources is with Resource Management when players have Ownership of Producers generating the Resources and the players' task is maximize the benefit of these basic Resources. For example, in Civilization the cities can produce Units and the players have to make Tradeoff choices when deciding which Units to produce. In these cases the renewal rate of the Renewable Resource is, in fact, the Limited Resource the players have to manage.
Instantiates: Hierarchy of Goals, Resource Management, Reconnaissance, Privileged Abilities, Tradeoffs
Modulates: Damage, Pick-Ups, Units, Resources, Social Dilemmas, Limited Resources, Transfer of Control, Gain Ownership, Lives, Characters
Instantiated by: Resource Generators, Closed Economies, Chargers, Producers, Budgeted Action Points
Modulated by: Pick-Ups, Time Limits, Chargers, Converters, Diminishing Returns, Ownership, Controllers, Asymmetric Resource Distribution
Potentially conflicting with: Non-Renewable Resources