Most companies think of electricity purely as a cost. On the reserve markets it can also be a source of income: Fingrid pays for a load or battery storage being on standby to flex when the power system needs it – often without the flexibility ever being used.
Why flexibility is needed
In the grid, production and consumption must balance at every moment. As the share of wind and solar grows, production varies more, and balance is maintained with reserves: power plants, storage and loads that can raise or lower power quickly. Fingrid buys this readiness from the market, and an ever larger share comes from the consumption side – industry, properties and batteries.
The reserve products in brief
Reserves differ in how fast and how long they must respond. The fastest activate automatically based on frequency, the slowest manually at Fingrid’s request.
| Product | Full activation | Duration |
|---|---|---|
| FFR | ≈ 1 s | 5–30 s |
| FCR-D up and down | 50% in 5 s, 100% in 30 s | at least 20 min |
| FCR-N | 3 min | continuous regulation |
| aFRR | 5 min | per control signal |
| mFRR | 12.5–15 min (transition to MARI) | per request |
Activation times: Fingrid, reserves.
- FFR – fast frequency reserve. Responds in about a second to large frequency disturbances and holds power for 5–30 seconds. In practice a product for batteries and precisely controllable loads.
- FCR-D up and down – disturbance reserve. Half of the power within five seconds and full power within 30 seconds when frequency deviates clearly from normal; power must be held for at least 20 minutes. The most common product for company loads and battery storage.
- FCR-N – frequency containment reserve for normal operation. Adjusts power continuously to small frequency variations, full activation within three minutes; requires both up and down regulation.
- aFRR – automatic frequency restoration reserve. Activates within five minutes from Fingrid’s signal.
- mFRR – manual frequency restoration reserve, i.e. the balancing energy market and its capacity market. Activates in 12.5–15 minutes (transition to the European MARI platform), suits large loads that can be run down on request.
The products’ technical requirements and compensation levels change, so the choice should be made on current information and the characteristics of your own load – not on which product sounds best.
What the compensation consists of
The reserve markets mainly pay for readiness, not activation. The capacity fee is paid for the offered power for every hour the site is on the market, regardless of whether it is activated. Prices vary by hour and season, and for some products an energy fee is paid for activation as well.
This makes flexibility a different kind of savings target from energy efficiency: the income does not depend on reducing consumption but on the site being available to offer for as many hours a year as possible.
Which loads suit flexibility
A good flexible load meets three conditions: it can be controlled automatically, a brief interruption does not harm operations, and it is large enough or can be combined with others. Typical ones:
- Heating and cooling: electric boilers, heat pumps, cold stores – thermal mass allows minutes of interruption unnoticed.
- Storage tanks and charging: hot-water tanks, forklift and EV charging.
- Ventilation and pumps whose momentary power drop does not show in conditions.
- Battery storage, the best possible flexibility resource: it can regulate in both directions, responds in milliseconds and saves on demand charges at the same time.
The production process is rarely offered – the interruption costs more than the compensation yields.
The aggregator combines small sites
Reserve products have a minimum bid size that a single property or medium-sized factory usually does not meet alone. That is why companies take part through an aggregator: a service provider that combines several sites into one bid, handles control, metering and Fingrid reporting, and shares the income at an agreed rate.
Aggregators differ in revenue share, contract length, control technology and the products offered. Comparison pays off: the same load can yield significantly different sums with different partners.
How to get started
- Survey – which loads are controllable, how large, and how many hours a year they can be offered.
- Product selection – speed and regulation direction according to the load’s characteristics.
- Revenue potential calculation – with realised market prices, not brochure figures.
- Aggregator comparison and contract.
- Implementing the control in the automation and commissioning.
When battery storage is being planned, flexibility is included already at the sizing stage. The battery’s profitability often consists of three sources together: demand charge shaving, spot price arbitrage and reserve income.
We calculate the flexibility potential and compare aggregators for you. Read about demand response and reserve markets or about battery storage.