What is the Day-Ahead Market (DAM)?

What is the Day-Ahead Market?

The Day-Ahead Market (DAM) is a spot market for electricity where prices are set for each hour of the next day through a day-ahead auction. AiBEX (B2B energy management platform, aibex.bg) uses these prices as the basis for its daily optimization plan.

How does the mechanic work?

Hour	What happens
12:00	Bid acceptance closes for the next day
12:00-14:00	The algorithm computes a clearing price for each of the 24 hours
~14:00	Prices are published by the operator (БНЕБ for BG, OPCOM for RO, HEnEx for GR)
23:50	Deadline for submitting a ToU plan to the inverter
00:00 (next day)	Prices are active — realization begins

Why do prices change hourly?

Electricity supply and demand are not constant. For example:

• Midday, sunny day: PV generation is high → supply exceeds demand → low price.
• Winter evening, 18:00-20:00: people return home, heating runs full → peak consumption → high price.
• Night: low consumption, baseload plants sell cheaply → low price.

In a typical day, the spread between the cheapest and most expensive hour can reach 50-200 EUR/MWh.

Why does this matter for your business?

If you have a battery and charge/discharge against dynamic prices, you effectively buy cheap energy and use (or sell) it when it’s expensive. This is arbitrage — the core value mechanism that AiBEX automates.

AiBEX vs Excel-based planning

Method	AiBEX	Manual in Excel
Computation time	5-10 seconds	30-60 minutes per day
Can it handle 96 intervals?	Yes	In theory
Accuracy	LP optimization	Heuristic / mental
Reaction to price changes	Automatic	Only if someone notices
ToU deploy to inverter	Automatic before 23:50	Manual

Which markets do we support?

Market	Operator	Currency	Number of intervals
Bulgaria	БНЕБ	EUR/MWh	24 hours × 4 = 96
Romania	OPCOM	EUR/MWh	24 hours × 4 = 96
Greece	HEnEx	EUR/MWh	24 hours × 4 = 96