For a modern enterprise, a solar power plant (SPP) is a full-fledged investment asset. Own generation helps control costs, increases energy independence and creates a projected cost of production for decades to come. However, the main question that every business owner asks before investing in renewable energy is the same: how to calculate a solar power plant and how long will it take to pay for itself?
What does the payback of a solar power plant depend on?
There is no single payback period. Each project is calculated individually, since its economics are influenced by a number of factors. The main ones are:
- annual electricity consumption by the enterprise;
- installed capacity of the SPP;
- load profile (day or night consumption);
- electricity tariff;
- region of the facility's location;
- level of solar insolation;
- equipment efficiency;
- possibility of using energy storage systems (ESS, UZE);
- participation in Net Billing mechanisms or electricity markets.
That is why professional calculation of a solar power plant always begins with an analysis of the energy consumption of the enterprise, and not with the selection of equipment.
How is the calculation of a solar power plant performed?
During the design, ETL Group engineers analyze:
- hourly consumption schedule;
- maximum loads;
- seasonality of production;
- roof or land area;
- orientation of the future station;
- shading;
- possibilities of connection to the network.
After this, a technical and economic model of the future project is formed.
How to calculate the annual generation of a solar power plant?
For a preliminary estimate, the basic formula is used:
Annual generation = Solar power plant capacity x Specific output of the region**
For Ukraine, the average specific output is:
- central regions — 1100–1250 kWh/kW per year;
- southern regions — 1250–1450 kWh/kW per year;
- western regions - 1050–1200 kWh/kWh per year.
Example: 500 kW solar power plant. Average output: 500 × 1200 = 600,000 kWh per year - this indicator becomes the basis for further financial analysis.
How are savings calculated?
The main effect is achieved due to the fact that the enterprise consumes its own electricity instead of purchasing it from the network.
Savings = Own consumption x Current tariff
Example. The enterprise uses 85% of the generated electricity: 600,000 x 85% = 510,000 kWh If the average cost of electricity for the enterprise is 8 UAH/kWh, the savings will be: 510,000 x 8 = 4.08 million UAH per year.
The higher the electricity tariffs, the faster the project pays off.
How is the payback of a solar power plant calculated?
The simplest formula:
Payback = Project cost / Annual financial effect
For example.
Cost of a solar power plant: UAH 18 million. Calculated annual savings: UAH 4.08 million. Payback period: 18 / 4.08 = 4.41 years.
After reaching payback, the company actually receives its own electricity with minimal operating costs for another 20–25 years.
What is the ROI of a solar power plant?
For a business, it is important to evaluate not only payback, but also ROI (Return on Investment) - the profitability of the investment.
ROI = (Net profit / Investment) x 100%.
For modern industrial solar power plants in Ukraine, the average ROI is:
- 18–30% per annum — for projects with high self-consumption;
- 20–35% — when integrating solar power plants + ESS;
- even higher potential is possible due to energy arbitrage and participation in the ancillary services market.
That is why many enterprises today consider a solar power plant as an alternative to traditional financial investment instruments.
Why does an energy storage system accelerate payback?
More and more businesses are integrating an ESS (Energy Storage System) together with a solar power plant, because it allows
- to use electricity generated during the day in the evening;
- to minimize the purchase of expensive electricity;
- to work during emergency outages;
- to optimize peak load;
- to implement energy arbitrage.
As a result, the share of own use of solar generation can increase from 60–70% to 90–95%, which directly improves the economics of the project.
What factors most affect payback?
The fastest payback is achieved by enterprises that:
- operate mainly during daylight hours;
- have stable electricity consumption;
- use refrigeration, compressor or production equipment;
- have large roof areas;
- integrate energy storage systems;
- planning to scale up production.
It's time more precisely:
- manufacturing enterprises;
- agricultural complexes;
- logistics centers;
- shopping and entertainment complexes;
- warehouse complexes;
- municipal enterprises.
Why won't a standard online calculator show the real payback?
On the Internet, you can find dozens of services for quick calculation of a solar power plant, but they only take into account general parameters.
Instead, a professional calculation must analyze many factors, such as hourly consumption schedule, real enterprise tariffs, load profile, seasonality, generation losses, module degradation, prospects for tariff changes, business scaling scenarios.
That is why a feasibility study (FEA) is a mandatory stage before starting a project. ETL Group has been implementing industrial solar power plants and energy storage systems for Ukrainian enterprises for over 15 years.
During the project preparation, our specialists perform:
- energy audit;
- feasibility analysis;
- generation modeling;
- calculation of the payback of the solar power plant;
- ROI assessment;
- financial model of the project;
- selection of the optimal configuration of the solar power plant + ESS;
- support for financing and implementation of the project on a turnkey basis.
We form not just a solar power plant, but an energy strategy for the business that ensures economic efficiency, cost predictability and long-term competitive advantage.
Correct calculation of a solar power plant is the basis of a successful investment. It allows you to assess the real potential of generation, future savings, payback period and profitability of the project. With professional design, a modern solar power plant for business pays for itself in an average of 3 years, after which it provides the enterprise with its own electricity for more than two decades and protects against tariff increases.
