Lightning rod

Lightning rod

Edit

Recipe
5 + 12 + 8 + 4 → 1
Total raw
8 + 6 + 8 + 4
Map color
Health	100 130 160 190 250
Resistances	Electric: 0/100% Fire: 0/90%
Stack size	50
Rocket capacity	50
Range	15 19.5 24 28.5 37.5 + Lightning reach
Efficiency	20% 26% 32% 38% 50%
Dimensions	1×1
Drain	150 MW (electric)
Energy capacity	500.0 MJ (electric)
Mining time	0.1
Buildable only on
Crafted only on
Prototype type	lightning-attractor
Internal name	lightning-rod
Required technologies
Produced by
Consumed by

Object description

	This article is a stub, and not comprehensive.
	You can help this wiki by expanding it.

Space Age expansion exclusive feature.

The lightning rod is a building from Fulgora that protects an area from getting struck by lightning from the nightly storms. When struck, they generate power for a limited time. The peak power production is limited only by the demands of the connected electric system, but the internal storage is subject to a 150 MW drain in addition to the load from the electric system. It is unlocked by researching the Planet discovery Fulgora technology.

The lightning rod cannot be crafted on any planet other than Fulgora, as other planets lack the same strong magnetic field.

Normal-quality lightning rods in a square pattern can be at most 34 tiles apart, or every 35 tiles, while completely protecting the area between them. This is a density of 1 lightning rod per 35x35=1225 tiles. More tile efficient is a triangular pattern with an outside 42x76 rectangle with one rod in its center. This is a density of 2 lightning rods per 42x76=3192 tiles, or one per 1596 tiles.

To align with a 50x50 grid of roboports the quality needed is epic, as epic-quality lightning rods in a square pattern can be placed 54 tiles apart.

Net Efficiency

Lightning rods are ultimately energy storage devices which are recharged with lightning strikes and have unlimited power output potential. However the 150MW drain-to-ground means that they are very lossy storage devices which will rapidly dissipate their stored energy even if unconnected. The actual usable energy we get out of a lightning rod per lightning strike is thus less than strike energy times efficiency. This section provides an overview of this relationship.

Definition of Net Efficiency

Energy stored in a lightning rod will inevitably go to one of two sources: base power or drain. With P representing power and d representing the drain-to-ground, it can be readily seen that the fraction of total energy that goes to each is simply P/(P+d) or d/(P+d) respectively. To see this note that energy-to-source = power-to-source x time and taking the ratio of energy-to-source over total energy will lead to cancelation leaving one with the desired result.

This means we can define a "net efficiency" (which depends on power) of the lightning rod that takes into account the drain by simply multiplying efficiency by the fraction of power we can actually use:

Net Efficiency(power) = Efficiency x power/(drain + power)

Note that here power is the power output by a single lightning rod. If one has N active lightning rods then power per rod will be power / N.

For example a 100 MW base with 100 common lightning rods will have (roughly, on average) 10 active common-quality lightning rods at a time. This will mean each active lightning rod outputs 10 MW and thus each has a net efficiency of only 1.25% (again, on average). Thus each strike will be converted into 12.5MJ of energy output over 1.25 seconds to meet the 10 MW power demand.

Implications

Because of the above dynamics, fewer lightning rods per unit area are better for capturing lightning energy as it increases the power draw per lightning rod. One can only achieve this with better packing (hexagonal placement is most efficient) or quality. This consideration can be important when one is dealing with beacons and modules that dramatically increase the power-density of the base or on small islands. It is also important for ensuring accumulators charge as soon as possible upon night falling and keep charging into the early morning as the lightning ends.

History

• 2.0.7:
  • Introduced in Space Age expansion.

See also

• Fulgora
• Lightning collector
• Electric system