Is your PV exporting energy at negative prices?
We turn it into free hot water for your workforce.
Polish PV farms wasted 1 TWh of energy. SolarShower is Poland's first EMS that diverts that surplus to heating DHW for your workforce. Instead of paying negative prices, you save on gas.
Your supplier settles PV surplus at prices you don't know in advance.
You buy energy from the grid at a fixed tariff. Surplus you send back is settled at balancing market prices published by PSE with a delay. Every 15-minute sunny window is a blind lottery. You learn the result a week later on your invoice.
−30,000
PLN/MWh, 2025 record
That's how low the balancing market price dropped in extreme 15-minute windows in 2025. Every kWh exported in such a window is 30 PLN of cost, not revenue. And by the next quarter-hour it's history.
After the fact
You learn the price a week later
Your supplier won't tell you how much you earned (or lost) on export. They'll tell you when nothing can be changed. Planning production around the market? Impossible.
Zero export
The default defence, and the trap
Most industrial PV farms have switched to zero export. Safe, but every sunny hour is wasted production. Panels stand idle, inverters wait, the sun shines for nothing.
In 2025 Polish companies wasted 1 TWh of PV energy (×2 vs 2024). Enough to heat DHW for hundreds of thousands of workers.
⚠️ The other side of the same problem
Meanwhile you pay a fortune for hot water for your workforce.
The same showers your workers use every day are heated by expensive gas or even more expensive district heating. Every day is a bill for energy your PV could supply for free.
300–400
PLN/MWh for business gas
Natural gas for businesses (Poland's W-5/B-1 tariff) in 2026: 250–400 PLN/MWh net. Add boiler efficiency (~90%) and service, and the real cost of 1 MWh of heat from gas starts at 330 PLN. It rises every year with TTF.
486+
PLN/MWh for district heating
Polish national average per URE in 2025: 135 PLN/GJ ≈ 486 PLN/MWh. Higher in larger cities. Veolia Poznań from November 2025: 559 PLN/MWh. You don't negotiate this tariff. You pay what the regulator approves.
+55%
B23 capacity charge in 2026
The capacity charge rose 55.4% year over year, from 141 to 219 PLN/MWh. Every kWh drawn from the grid costs more and more. And your PV surplus, meanwhile, vanishes into zero export.
A 500-employee company (80 showers a day) = 55 MWh DHW/year. On gas 17–20 k PLN, on grid heaters up to 52 k PLN a year. Paid today. Can be zeroed.
⚡ Solution
Two problems. One solution.
SolarShower makes sure no kilowatt-hour leaves your farm to be settled at a price out of nowhere. At the same time it diverts that energy to electric heaters in DHW tanks, killing the gas or district-heating bill. One action closes two expensive streams at once. The decision is taken four times a second.
📊
1. Real-time measurement
Every second we measure how much your PV produces, how much the plant uses, and how much surplus is left. No guessing.
🚪
2. Hard zero export
Nothing leaves to the grid. Ever. The supplier has nothing to settle at balancing market prices.
🚿
3. Energy into DHW tanks
Every surplus kW lands on a heater inside a hot water tank. We react in 250 ms.
🏭
4. External heating disabled
We tell your heating system: "stand down, we're heating". Gas and the district heating grid don't duplicate the sun's work.
🔧 How it's built
A system for industry, not a home gadget.
Four elements, one logic. Scales from 200 kW to 5 MW PV. Works with any inverter on the market. Full integration with your plant automation.
1
Brain in the cloud
A central application that ties everything into one system: your PV farm, heaters, tanks, electricity prices, weather, and the production plan. Runs on our infrastructure or yours. Supports all common inverters: SolarEdge, Fronius, SMA, Huawei, Sungrow, Apator. No vendor lock-in.
2
Controller in the cabinet next to the tanks
A small industrial computer. It measures temperatures with multiple sensors. If one fails, another takes over. Every 250 ms it decides which heater to switch on. Safety: hard cutoff at 80°C, SMS alarm on fault, automatic restart on lost communication.
3
Heaters and tanks
Electric heaters sized to your PV, typically 10–50 kW per tank, scalable to 100+ kW. Three-phase control. Optionally we tie into the existing heating controller (e.g. Danfoss) so neither gas nor district heating duplicates what the sun is already doing.
4
Data and reports
Every decision recorded in a database. Live dashboard from any device, monthly savings reports in PDF and Excel. Integration with your SCADA, Grafana, or Power BI. Full auditability, ready for ESG and inspections.
SOLARSHOWER · LIVE VIEW
System statusACTIVE · heating DHW
PV production412 kW
Plant consumption403 kW
Surplus available+9 kW
Grid export0 kW (zero export)
Balancing market price−42 PLN/MWh
Heaters on2 of 3 (20 kW)
Tank 1 · temperature47.2 °C
Tank 2 · temperature52.8 °C
District heating · DHWdisabled
DHW produced today142 kWh
💰 Benefits
Concrete numbers. Concrete money.
Every company is different, but the pattern is the same: PV produces when nobody wants to buy, and hot water for staff is heated with expensive gas or grid electricity. SolarShower closes both problems with one solution.
🛑
End of the balancing market lottery
Nothing leaves to the grid, so the supplier has nothing to settle at prices you only see a week later. All the surplus stays with you and becomes hot water.
0 export risk
🚿
Free hot water for staff
A 500-employee company, 80 showering after work ≈ 55 MWh of hot water per year. On gas that's 17–20 k PLN; on grid heaters about 52 k PLN. From PV: 0 PLN.
17–52 k PLN/year
💸
Recovered energy that was lost
Energy that used to go to the grid or get curtailed now goes into the tanks. In a typical plant that's 30–60 MWh per year of recovered production without adding any new panels.
up to 60 MWh/year
⚖️
Lower capacity charge
The system helps shift peak consumption out of the most expensive grid hours (B23/C23 tariff, +55% y/y in 2026). A few extra thousand PLN per year on the capacity charge alone.
+5–15 k PLN/year
🏦
FEnIKS 1.1 EU funding
Converting electricity into heat is a qualifying activity under FEnIKS 1.1. Medium-sized companies: up to 49% of costs covered. Large: up to 30%. We do the energy audit together.
up to 49% of CAPEX
📊
Full reports, ESG-ready
Every decision logged in the database. Monthly savings summaries in PDF and Excel, ready for CFO, auditor, and sustainability reporting. Nothing left in the dark.
100% auditable
📍 Reference case
Industrial manufacturer with a 750 kW PV farm
Manufacturing plant on Poland's B23 tariff with 450 kW contracted demand. Two DHW tanks for workers after manual labour. We commissioned the full installation: three 10 kW heaters, a controller in the switchboard cabinet, integration with the existing heating controller (Danfoss / Belimo / any automation).
The system runs continuously. It makes a decision every second, measures temperature four times more often, logs everything to a database. Push notifications on any anomaly: overheating, sensor fault, lost connection. Nobody has to babysit it.
Plug-in to infrastructurePV inverter + heating controller
DHW produced (peak day)142 kWh
Cost of that energy~0 PLN
📸 Live from production
This is what it looks like at our first client.
Screenshots from our dashboard, captured today. 750 kW PV farm, B23 tariff, two DHW tanks. Status: 100% time at zero export over the last week, over 13 MWh of self-consumption, over 10,000 PLN saved in 7 days.
⚡ Smart Export · live
Real-time export control
Zero-export status, PV generation, current 15-min TGE prices, self-consumption, heating stages. A decision every second.
💰 Smart Analyzer · 7 days
Real money saved
Total benefit +10,084 PLN in 7 days. Self-consumption 13 MWh, export 0.1 MWh. Zero-export time 170 hours (100%).
📊 History · 1h
Full historical charts
PV generation vs grid exchange, 15-min TGE prices, grid frequency, phase-to-phase voltages. Full auditability.
🌡️ Danfoss · DHW
Integration with the existing heating system
Danfoss ECL310 controller integrated over Modbus TCP. DHW temperatures, sensors, relays, alarms in one place.
The data shown in the screenshots comes from our production installation at an industrial client. After NDA we can arrange a reference visit or grant remote access to the live dashboard.
🆚 Comparison
The competition offers 9 kW for a single home. We: a system for the plant.
Most products on the market are gadgets for residential prosumers: tied to one inverter brand, up to 9 kW of heaters, no integration with plant automation. For a 750 kW farm with 50 kW of heaters that's not enough.
Feature
Fronius Ohmpilot
my-PV AC•THOR
SolarEdge Hot Water
SolarShower
For whom
Single-family homes
Homes / agriculture
Single-family homes
Plants 200 kW – 5 MW
Max heater capacity
9 kW
9 kW
3 kW
100+ kW
Inverter choice
Fronius only
Any
SolarEdge only
Any
Hard zero export
No
No
No
Yes, nothing leaves
Plant automation integration
None
Modbus only
None
Modbus, BACnet, OPC-UA
Control of existing heating
No
No
No
Yes (e.g. Danfoss)
Full historical data
Vendor cloud only
CSV
Vendor cloud only
Own database, full history
Energy audit + EU funding
No
No
No
Included
❓ FAQ
Frequently asked questions
Do I need to replace my PV installation?
No. SolarShower works with existing PV installations and inverters (SPV SM Apator, AISWEI, SolarEdge, SMA, Fronius, Huawei). We don't replace panels, inverters, or meters. We just add the ESP32 controller, heaters, and cloud integration.
What's the minimum PV installation size?
The sweet spot is PV from 200 kW to 5 MW with documented export surplus or curtailment experience. For smaller companies, cheaper residential products exist (Fronius Ohmpilot, my-PV); we'll happily tell you when SolarShower is NOT the right fit.
How much does a deployment cost?
CAPEX depends on heater capacity, number of tanks, and integration scope. Typically 80–250 k PLN net for a medium-sized company (30–60 kW of heaters + 2–4 tanks + SCADA). With FEnIKS 1.1 EU funding (up to 49% reimbursement) the real cost is 40–130 k PLN. The free benefit analysis gives you a concrete payback figure for your specific company.
What's the payback period?
Without funding: 5–7 years for a typical company with clear PV surplus. With FEnIKS 1.1 funding: 2–3 years. Operational value (eliminating the cost of DHW from gas/district heating) + option value of curtailment hedging = a solid economic case.
Do I need to hire my own programmer?
No. Grid Experts delivers the full service: energy audit → design → deployment → maintenance. After commissioning you have a SCADA dashboard and monthly savings reports. 24/7 support + SLA available.
What if I don't have DHW tanks?
We supply tanks as part of the project. Typically 1–3 tanks of 500–1500 L, with DS18B20 sensors, three-phase heaters, and RC snubbers on contactor coils. Full electrical and hydraulic installation by our subcontractor.
How does it integrate with my SCADA?
SolarShower exposes a REST API (JSON) and a Modbus TCP server. All metrics (Pexp, stage, temperatures, decisions) are available in your SCADA as standard Modbus points. We also have ready-made connectors for Grafana, Power BI, and Wonderware.
What about safety? I don't want to scald workers with the 80°C sensor.
The system has 11 independent watchdogs: temperature cutoff (≥80°C → all OFF), sensor loss (15 s), Ethernet loss (30 s), lost VPS comms (5 s), hardware restart on hang, real-time Pushover alarms. RC snubbers on contactor coils eliminate EMI. Every state change is logged to PostgreSQL, fully auditable.
Can I see a working system?
Yes. We've commissioned the first deployment at an industrial manufacturer with a 750 kW PV farm (the reference case described above). After NDA we can arrange a reference visit or grant remote access to the live production dashboard. Write to kontakt@gridexperts.pl.
🎯 Next step
See how much your company will save. Free. Zero commitment.
Fill in a short form: PV capacity, load profile, headcount, current DHW source. Within 5 business days you get a concrete calculation of annual savings, payback, and a map of available EU funding for your company.
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