BESS and solar power plants: how to increase your own consumption and accelerate your project’s payback

Solar power plants have become a familiar part of the Ukrainian energy landscape. Factories, agricultural complexes, and logistics centers are increasingly turning to their own power generation. But there’s a catch: not all of the energy generated is used efficiently. Some of it goes to the grid at a low rate, and in the evening the company is forced to buy electricity again at a high price.

This is where energy storage systems come into play.

Why solar generation isn’t always utilized at 100%

Imagine: during the day, a solar power plant produces peak output. The office empties out for lunch, and the workshops don’t operate at full capacity. As a result, a significant portion of the energy goes to the grid. You sell it below market price, essentially giving the resource away.

But in the evening, everything changes. The station is no longer operating, but the load increases: power lines, server rooms, and lighting are turned on. What does the company do? Correct—it again takes electricity from the grid, but at a higher rate.

It’s a paradox: the station exists, but savings aren’t maximal.

BESS changes the picture. During the day, it collects the surplus and returns it to the company in the evening. The share of internal consumption rises to 80–90% instead of 50–60%. The project is starting to generate tangible benefits faster than planned.

The Economic Logic of BESS Integration

The average payback period for a solar power plant without a storage system is 5–7 years. However, with a BESS, the payback period becomes shorter, especially for companies with an evening load profile.

Scenario One: A logistics center operates until midnight. During the day, half the energy is sent to the grid, and in the evening, the company spends money on expensive electricity. With a storage system, the same energy is used on-site—savings amount to tens of thousands of hryvnias annually.

Scenario Two: A factory with 24/7 production. Each line downtime costs thousands of hryvnias. BESS not only saves money but also provides insurance: if the grid goes down, the enterprise continues to operate at least partially.

Another important factor is peak smoothing. For grids, this means less overload, and for businesses, fewer fines and equipment stability. As a result, the company achieves not only savings but also cost predictability.

Farmers use BESS to ensure uninterrupted irrigation and storage of crops, shopping centers use it to keep tenants working in the evening, and the food industry uses it for nighttime processing cycles. What was once considered a "just-in-case" backup has become a daily optimization tool.

Why an experienced partner is important

Some people think, "Well, what’s so difficult? Just buy a battery and connect it." In practice, things are quite different. It’s necessary to calculate the capacity, understand the consumption profile, and consider growth prospects. A design error can result in a system that’s either too expensive or insufficiently efficient.

Therefore, an experienced integrator is not a luxury, but a necessity. Unisolar offers energy storage systems that are tailored to a specific business. This isn’t just equipment, but a full cycle: from analysis to commissioning and support.

A solar power plant is a step toward independence. But only when paired with a BESS does the project unlock its full potential. Energy that was previously sold for pennies stays with the company and works for it. Return on investment accelerates, risks are reduced, and business resilience increases.

And in today’s environment, it’s no longer a question of "should" or "wouldn’t"—it’s a question of "when."