Electricity

_{Focus Areas · Design document §3}

Available from: O06 (Natural Philosophy) + CH04 (Distillation — acids)

11 breakthroughs — CORE 4 · STANDARD 4 · UNCOMMON 1 · RARE 2 — Classical – Atomic

Builds on: Observation (1) · Social Organization (1) · Metallurgy (2) · Construction (1) · Mathematics (2) · Mechanics (1) · Thermodynamics (2) · Chemistry (3) · Materials Science (1)

Leads into: Metallurgy (1) · Warfare (1) · Water Management (1) · Thermodynamics (1) · Electronics (3) · Computing (2) · Nuclear Physics (5) · Quintessic Physics (3) · Quantum Physics (3) · Relativity & Cosmology (2) · Rocketry (2) · Aeronautics (3) · Energy Systems (4)

_{The numbers count prerequisite links between this focus and the other. How to read the tables.}

Theory-agnostic: electricity is a phenomenon — amber sparks, piles produce current, coils turn shafts — so the whole EL chain works identically in every world. What differs is the account: an atomic world explains current as electron flow; an elemental world treats it as a manifestation of a fundamental element or phase (a "fluid" or an aspect of the fire/metal phases), and unifies it with the rest of physics through Aetheric/Great-Harmony Field Theory (QM-E04) rather than atomic electromagnetism. No EL breakthrough requires atomic theory; EL03 (Electromagnetism) is the empirical field theory and stands in both kinds of world. Downstream nodes that need the deep unification read the HIGH_ENERGY_PHYSICS token.

Overview

ID	Breakthrough	Tier	Era	Prerequisites
EL02	Voltaic Pile (Battery)	CORE	Early Modern	O06 (Natural Philosophy) + CH04 (Distillation — acids) + ME01
EL03	Electromagnetism	CORE	Early Modern	EL02 + MA05 (Calculus)
EL04	Telegraph	STANDARD	Early Modern	EL02 + SO04 (Writing)
EL06	Electric Generator	CORE	Modern	EL03 + TH03 (Turbine)
EL07	Power Grid	CORE	Modern	EL06 + CO10 (Iron-Frame Construction)
EL08	Baghdad Battery	RARE	Classical	CH01 (Alchemy) + ME01
EL09	Wireless Transmission	STANDARD	Modern	EL03 + MA05 (Calculus) + MC10 (Precision Machining)
EL10	Piezoelectricity	UNCOMMON	Modern	EL03 + CH06 (Periodic Table — crystallography)
EL11	Superconductivity	STANDARD	Atomic	TH02 (Refrigeration — cryogenics) + EL03
EL12	Room Temperature Superconductor	RARE	Atomic	EL11 + MS02 (Nanotechnology)
EL14	Direct-Current Stations	STANDARD	Modern	EL06 (Electric Generator) + EL02 (Voltaic Pile)

Prerequisite map

flowchart LR
  n_EL02["EL02 Voltaic Pile (Battery)"]:::CORE
  n_EL03["EL03 Electromagnetism"]:::CORE
  n_EL06["EL06 Electric Generator"]:::CORE
  n_EL07["EL07 Power Grid"]:::CORE
  n_EL14["EL14 Direct-Current Stations"]:::STANDARD
  n_EL09["EL09 Wireless Transmission"]:::STANDARD
  n_EL10["EL10 Piezoelectricity"]:::UNCOMMON
  n_EL11["EL11 Superconductivity"]:::STANDARD
  n_EL12["EL12 Room Temperature Superconductor"]:::RARE
  n_EL04["EL04 Telegraph"]:::STANDARD
  n_EL08["EL08 Baghdad Battery"]:::RARE
  n_EL02 --> n_EL03
  n_EL02 --> n_EL04
  n_EL03 --> n_EL06
  n_EL06 --> n_EL07
  n_EL03 --> n_EL09
  n_EL03 --> n_EL10
  n_EL03 --> n_EL11
  n_EL11 --> n_EL12
  n_EL06 --> n_EL14
  n_EL02 --> n_EL14
  classDef CORE fill:#dbeafe,stroke:#1d4ed8,color:#0b1b3b
  classDef STANDARD fill:#f1f5f9,stroke:#64748b,color:#0f172a
  classDef UNCOMMON fill:#dcfce7,stroke:#15803d,color:#052e16
  classDef RARE fill:#fef3c7,stroke:#b45309,color:#3b2005
  classDef UNIQUE fill:#fae8ff,stroke:#a21caf,color:#3b0a3f

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_{Prerequisites within this focus. Box colour is the tier (blue CORE, grey STANDARD, green UNCOMMON, amber RARE, purple UNIQUE); dotted arrows are alternatives (“or”); a line can pass behind another box, so follow it from its start. 10 of these 11 breakthroughs also need breakthroughs from other foci, which the overview above lists.}

Breakthroughs

EL02 · Voltaic Pile (Battery)

• Tier: CORE · Era: Early Modern
• Prerequisites: O06 (Natural Philosophy) + CH04 (Distillation — acids) + ME01
• Unlocks: ⟨[+1 Gold] from [Silver] tiles [in all cities]⟩; ⟨[+1 Gold] from [Gold Ore] tiles [in all cities]⟩ — electroplating makes precious metal go further; ⟨[+1 Gold] from [Luxury resource] tiles [in all cities]⟩ — every luxury dressed in gold (Electrochemistry, merged here in v3.99: Davy's electrolysis was the pile put to work). Prerequisite for the Telegraph (EL04), Cold Fusion (NP10) and Electric Aviation (AE11). ⟨[+1 Culture] from all [Museum] buildings⟩ — galvanic demonstrations draw the crowds: Galvani's frogs and Volta's pile were one line of experiment (Static Electricity, merged here in v3.105). Foundation of electrical science.
• Leads to: EL03 Electromagnetism, EL04 Telegraph, EL14 Direct-Current Stations, NP10 Cold Fusion, AE11 Electric Aviation

EL03 · Electromagnetism

• Tier: CORE · Era: Early Modern
• Prerequisites: EL02 + MA05 (Calculus)
• Unlocks: ⟨[Great Scientist] is earned [+10]% faster⟩ — two forces found to be one. Foundation of all electrical technology — motors, generators, radio. Theory-agnostic: stands in every world.
• Leads to: ME13 Aluminium Extraction, WA19 Railgun Concept, EL06 Electric Generator, EL09 Wireless Transmission, EL10 Piezoelectricity, EL11 Superconductivity, EN01 Vacuum Tube, NP02 Atomic Model, QM-E04 Unified Field Theory (Elemental), QP04 Particle Accelerator, QP05 Quantum Field Theory, RC01 Relativity

EL04 · Telegraph

• Tier: STANDARD · Era: Early Modern
• Prerequisites: EL02 + SO04 (Writing)
• Unlocks: Telegraph Officeⁿ [160/1; +1 Gold; cityStrength +3; ⟨[+1 Gold] from each Trade Route⟩].
• Leads to: CP04 Internet

EL06 · Electric Generator

• Tier: CORE · Era: Modern
• Prerequisites: EL03 + TH03 (Turbine)
• Unlocks: Unlocks Electronics focus — generators on every turbine. Power plants become possible (Energy Systems). ⟨[-25]% construction time for [Railroad] improvements⟩ — electric traction: the motor is the generator run backwards (Electric Motor, merged here in v3.103).
• Leads to: WM06 Dam Construction, EL07 Power Grid, EL14 Direct-Current Stations, RK09 Ion Drive, AE02 Dirigible/Airship

EL07 · Power Grid

• Tier: CORE · Era: Modern
• Prerequisites: EL06 + CO10 (Iron-Frame Construction)
• Unlocks: ⟨[+2 Production] [in all cities connected to capital]⟩ and ⟨[+1 Happiness] [in all cities connected to capital]⟩ — the grid, and electric light. ⟨[+3 Production] [in all cities connected to capital] <in cities without a [Power Plant]>⟩ — transmission: a town on the network draws on the great stations and needs no plant of its own. The primary of the electrification Competing Solution; Direct-Current Stations (EL14) are its alternative. AC is central generation and therefore fragile: cut a road or railway, or blockade a harbour, and every city behind the break drops off the grid and loses its grid power.
• Notes: CORE since v3.112: both great instruments — QP04 Particle Accelerator and QM-E08 Boundary Furnace, CORE so that a CORE unified theory never waits on an idea that can be lost — need it.
• Leads to: QM-E08 Boundary Furnace / Cycle-Limit Observatory, QP04 Particle Accelerator, ES22 Smart Grid, ES18 Superconducting Energy Storage

EL08 · Baghdad Battery

• Tier: RARE · Era: Classical
• Prerequisites: CH01 (Alchemy) + ME01
• Unlocks: ⟨[+1 Gold] from [Gold Ore] tiles [in all cities]⟩; ⟨[+1 Gold] from [Silver] tiles [in all cities]⟩ (plating); reveals the Voltaic Pile (EL02) as a concept a millennium early.
• Notes: What if the Baghdad Battery led somewhere?

EL09 · Wireless Transmission

• Tier: STANDARD · Era: Modern
• Prerequisites: EL03 + MA05 (Calculus) + MC10 (Precision Machining)
• Unlocks: Radio Transmitterⁿ [250/1; ⟨New [Military] units start with [15] XP [in this city]⟩; ⟨[+25]% spy effectiveness [in this city]⟩ (<when espionage is enabled>)]. Prerequisite for Radio (EN11) and the Internet (CP04). Telephone Exchangeⁿ [375/2; +2 Gold; ⟨[+1 Gold] from each Trade Route⟩] — Bell and Marconi: telecommunication by wire and without (Telephone, merged here in v3.103). ⟨[+1 Gold] from all [Harbor] buildings⟩ — storm warnings reach ships by wireless (from Atmospheric Science, cut in v3.124).
• Leads to: EN04 Radar, EN11 Radio, CP04 Internet, QM-E18 Aether Telegraphy (Flow Signalling)

EL10 · Piezoelectricity

• Tier: UNCOMMON · Era: Modern
• Prerequisites: EL03 + CH06 (Periodic Table — crystallography)
• Unlocks: All Water units gain the Sonarⁿ promotion (⟨Can see invisible [Submarine] units⟩) — the pressure-sensing crystal.

EL11 · Superconductivity

• Tier: STANDARD · Era: Atomic
• Prerequisites: TH02 (Refrigeration — cryogenics) + EL03
• Unlocks: ⟨[+1 Production] [in all cities connected to capital]⟩ (a lossless grid); ⟨[+1 Happiness] [in all cities] <in cities with a [Hospital]>⟩ (imaging). Prerequisite for Fusion (NP04) and some FTL paths.
• Leads to: TH20 Boundary Ring / Cycle-Limit Ring, EL12 Room Temperature Superconductor, NP04 Nuclear Fusion, NP15 Superconducting Storage Rings, RC10 Gravitic Lift, RK15 Mass Driver, ES08 Fusion Reactor, ES18 Superconducting Energy Storage

EL12 · Room Temperature Superconductor

• Tier: RARE · Era: Atomic
• Prerequisites: EL11 + MS02 (Nanotechnology)
• Unlocks: ⟨[+2 Production] [in all cities connected to capital]⟩; ⟨[+1] Movement <for [Civilian] units>⟩ (maglev). Frontier Question FQ3 validates here. Also reachable through Electronics or Materials Science.
• Leads to: NP09 Compact Fusion, AE11 Electric Aviation

EL14 · Direct-Current Stations

• Tier: STANDARD · Era: Modern
• Prerequisites: EL06 (Electric Generator) + EL02 (Voltaic Pile)
• Unlocks: Generating Stationⁿ [a grid plant: ⟨Power Plant⟩ (tag); 310/2; requires a Factory in this city; +2 Production; ⟨[+5]% [Production] [in this city]⟩; ⟨Remove [{Power Plant} {non-[Generating Station]}] [in this city]⟩ — a neighbourhood station, built in any city, connected or not]; ⟨[+2 Production] from all [Generating Station] buildings <after discovering [Aluminium Extraction]>⟩ (direct current is what aluminium smelting runs on — the Hall–Héroult cell is electrolysis). Competing Solution (§1.2): the alternative to the Power Grid (EL07), detour margin ×1.5; if the grid is discovered first this is never developed, and if it arrives later this persists — it works where the network does not reach. The trade: a Generating Station is a cheap, weak plant in the city's plant slot, so a connected city that builds one gives up AC's free grid power; a disconnected city has nothing to give up. The War of the Currents (an easter egg). Thomas Edison and Nikola Tesla are already in Unciv's canonical Engineer name group (UnitNameGroups.json), so the egg needs no new data: it turns on which civilisation's Great Engineers they become. Unciv never reuses a Great Person's name within a game (gameInfo.unitNamesTaken), so at most one civilisation ever receives each — the war can be fought between two rivals. The fork records the Great Person names each civilisation receives (one line where Unciv assigns the name, UniqueTriggerActivation), and while the race is still open the discovery roll reads that record: a civilisation that has had Edison, DC's champion, finds Direct-Current Stations first — the Power Grid cannot fire until they have, and their detour margin is dropped; one that has had Tesla, whose induction motor was the heart of the AC system, never develops DC at all — Direct-Current Stations are locked out, a Path Not Taken. The effects are not mirror images because lock-out runs one way: a primary is never locked out, so Edison's AC still arrives in time, and DC persists beside it.
• Notes: Edison's Pearl Street station, 1882: power had to be made within a mile or two of where it was used.