Industrial energy glossary

aFRR

Automatic frequency restoration reserve — a MAVIR system service in which participation is mandatory for solar generators above 50 kVA.

Aggregator

The market participant that pools the aFRR obligations of generators below 5 MW and manages them toward MAVIR.

BTM (Behind-the-Meter)

An on-site system “behind” the consumption meter that generates for self-consumption and may not feed back into the grid.

C-rate

The charge/discharge speed relative to capacity: 0.5C = a full cycle in 2 hours, 1C = in 1 hour.

Clipping (inverter clipping)

The part of a solar array’s DC output that the inverter cannot convert above its rated AC power and is therefore lost — unless battery storage absorbs it.

DAM (Day-Ahead Market)

The HUPX day-ahead market, where hourly/15-minute prices for the next day are set; the settlement basis for spot contracts.

DC/AC ratio

The quotient of a solar array’s DC peak power (kWp) and the inverter’s AC power (kW); the industrial standard is 1.2–1.3.

GBER

The EU General Block Exemption Regulation, which sets the maximum intensity of state aid — for battery storage, 50% for small enterprises.

HMKE

Household-scale small power plant — the connection category below 50 kVA, with a simplified notification to the distribution system operator.

HUPX

The Hungarian organized power exchange; day-ahead (DAM) prices change every 15 minutes and provide the settlement basis for spot-price industrial contracts.

Time-series settlement

Settlement for industrial consumers based on 15-minute metering; structured as basic charge + capacity charge + volumetric charge + reactive charge.

KÁT levy

The cost of the mandatory feed-in support for renewable generators, borne by every consumer in proportion to the kWh drawn, as a charge that changes monthly.

Contracted capacity

The maximum power (kW) contracted at the grid connection, on which a fixed annual capacity charge is payable — reducing it with a BESS is a saving.

Self-consumption rate

The share of solar generation used locally at the site; typically 80–95% for industrial plants.

Peak shaving

Battery storage smooths the peak load, reducing the peak power drawn from the grid — and with it the contracted capacity charge.

Profile-based settlement

Settlement for smaller consumers based on standard load profiles, with no capacity charge and higher volumetric tariff rates.

RTE (Round-Trip Efficiency)

The round-trip efficiency of battery storage: the share of the charged energy that can be discharged, typically 86–92% for modern industrial systems.

SCTE

A small power plant in the 50 kVA – 0.5 MW band; requires a MEKH notification and a grid connection agreement.

SOC (State of Charge)

The current charge level of battery storage in percent; daily cycles typically use a 10–90% range.

Spread (price difference)

The difference between the highest and lowest electricity price within a day; the source of battery storage arbitrage profit.

TAO tax allowance (22/H. §)

The energy efficiency allowance of the corporate tax, which makes a significant part of a BESS/PV investment deductible over 6 years.

Reverse power

Power flowing back toward the grid, which occurs when solar generates more than the site’s instantaneous consumption.