An independent concept rebuild of apparent.com, unaffiliated with Apparent Inc. Built by Daniel Ramirez as an application for the Software Engineer role.

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Technology

REMI

Your on-site copilot.

The Realtime Energy Management Interface is the hardware and software that lives in the electrical room. It connects solar, battery storage, generators, EV charging and facility loads, and it talks to igOS in real time.

The interface, literally

What REMI looks like from the other end of the wire.

An interface is only real if something can talk to it. Below is the live simulation from the home page, exposed the way this equipment is actually exposed on a site: as Modbus/TCP holding registers, laid out to the SunSpec model 103 convention.

SunSpec model 103 holding registers, live from the running simulation
AddrPointRawDecodedSFAccess
40000ID SunSpec model identifier. 103 = three-phase inverter.0x0067103.00R
40001L Model payload length in registers, excluding ID and L.0x001218.0 reg0R
40002W Real power at the point of common coupling. Positive is export.0x0000300.0 W+2R
40004VAr Reactive power. Positive injects vars and raises local voltage.0xFFFF-40200 var+2R
40006VA Apparent power magnitude. This is what the switchgear is sized for.0x000040200 VA+2R
40008PF Power factor. Negative indicates a lagging, inductive condition.0x00080.008 cos()-3R
40009PPVphAB Line-to-line voltage, phase A to B, at the PCC.0x12B1478.5 V-1R
40010Hz Line frequency.0x177060.0 Hz-2R
40011DCW DC power from the PV array, after any commanded curtailment.0x00001762800 W+2R
40013ChaState Battery state of charge.0x020952.1 %-1R
40014St Operating state. Mirrors the dispatch state machine.0x0005CHARGE_SURPLUS0R
40015VArPct_Ena Volt-var mode enable. 0 disables reactive support entirely.0x0001ENABLED0
40016VRef Voltage setpoint for the regulation loop, per unit.0x03E81.000 pu-3
40017WMaxLimPct Export ceiling as a percentage of nameplate. The interconnection limit.0x02EE75.0 %-1
40018OutPFSet Commanded power factor target, when operating in fixed-PF mode.0x00080.008 cos()-3
40019StorCtl_Mod Storage control mode. 0 auto, 1 hold, 2 forced charge, 3 forced discharge.0x0000DISABLED0
Master
Wire

No transactions yet. Poll the device.

Scale factors, not floats

Modbus has no data types. A register is sixteen bits and nothing more, so physical quantities travel as integers paired with a signed base-ten scale factor: actual = raw × 10sf. Reactive power at −634 kvar goes on the wire as −6340 with a scale factor of +2. Getting the sign of that exponent backwards is the most common integration bug against these devices, and it fails quietly — everything is off by a factor of ten thousand and nothing throws.

Exceptions are the interface too

Try Read past end, or a write to a read-only point. A real device answers with an exception code, not a crash: 0x02 for an illegal data address, 0x03 for an illegal value. A client that only handles the happy path will hang the first time a technician mistypes a register offset at three in the morning.

The writes are live

VRef, VArPct_Ena and WMaxLimPct are writable, and they take effect on the running plant immediately — the same way a utility changes a voltage setpoint or an aggregator curtails an export limit in the field. Everything else refuses the write, as it should.

What it does on site.

24/7 active monitoring

Continuous watch on the quality of power in and out. REMI sees, aggregates and orchestrates every dimension of facility power, protecting against disruption while optimising usage.

Adaptive response

Power distribution adjusts on forecast data and live conditions. Micro-fluctuations are detected instantly and modulation is signalled before they propagate.

Coordinated reactive power

Injection and absorption of vars, sequenced against what the grid needs at that moment rather than against a fixed schedule.

Seamless islanding

Transition to on-site generation during an outage, with no manual switching and no spin-up gap.

Plug-and-play integration

Solar and battery storage connect without bespoke engineering. REMI also coordinates with existing building management systems.

Automatic cycling

Charge and discharge cycles managed against pricing and grid conditions, continuously, without an operator in the loop.

Where it goes

Built for places that cannot go dark.

  • Data centres and AI facilities
  • Advanced manufacturing
  • Commercial and campus buildings
  • Healthcare
  • Critical infrastructure requiring zero-downtime operations

REMI is the hands. igOS is the brain →