Press · ERR, Aktuaalne kaamera, 11 May 2026
Why one home battery cannot reach the power exchange
Estonia’s public broadcaster looked at the batteries going into Estonian homes since the Baltics left the Russian grid, and at whether they pay for themselves. Fusebox was asked about the part an owner cannot do alone.
Desynchronisation changed what a battery in a house is for. Frequency has to be held inside the Baltic system itself now, and prices move more sharply across the day, so a battery that was bought for backup turns out to have something to sell. Enough households noticed that the reporter, Toomas Pott, went to find out whether the arithmetic actually works.
The programme’s answer was cautious, and fairly so: payback depends on the hardware, the tariff and how the battery is used, and it is still worth working out carefully before buying. That is the consumer’s question. There is a second one underneath it, which is the one we were there for.
A megawatt is the smallest thing the market will trade
An owner cannot sell stored electricity to the exchange directly. The smallest volume traded there is one megawatt, and a home battery is orders of magnitude short of it. Left alone, the electricity is worth only what it saves the household.
Aggregation is what closes that gap. Fusebox pools the volumes of many owners into a single portfolio and trades that portfolio on the exchange, so each battery participates through a position large enough for the market to accept. The control and the forecasting sit with the aggregator; what the owner sees is a share of what the portfolio earns.
Aleksandr Sepp, who runs strategic partnerships at Fusebox, told the programme that the portfolio’s growth had come specifically from home batteries and small batteries — not from the large industrial assets that flexibility has historically meant.
Why this matters beyond Estonia
The same shape repeats wherever distributed storage arrives faster than the market rules adapt to it: thousands of assets that are individually too small to trade and collectively significant. The software problem is not the battery. It is forecasting what a heterogeneous fleet will do, bidding it, following the dispatch, and settling what each owner is owed — which is the system Fusebox sells to utilities and aggregators running that fleet in their own market.
The original segment is in Estonian: Koduakude soetamise tasuvust tuleb endiselt hoolikat kaaluda (ERR). ERR’s Russian service covered the same report: В Эстонии наблюдается рост популярности домашних накопителей электроэнергии.