Does an Office Need Battery Storage, or Is a Grid-Tied Inverter Enough?

We’re Hybrid Energy — we sell both grid-tied inverters and hybrid inverters
with battery storage, so we have no reason to push the more expensive option
if you don’t need it. For an office, salon, clinic, or studio, the answer is
often simple: a grid-tied inverter without battery storage, because you
consume electricity exactly when it’s generated. This article shows when
that’s true, and when it isn’t.

The short version

• Office working hours (roughly 8 a.m.–6 p.m.) overlap with solar
  generation hours. This is the only segment in this series where battery
  storage’s main selling point — shifting consumption to the evening — is
  largely irrelevant.
• A business property pays not just for kilowatt-hours but also for agreed
  capacity — €3.00/kW per month excluding VAT — every month,
  whether you have battery storage or not.
• Exceed your agreed capacity and that same capacity charge becomes
  three times higher. For an office running air conditioners on
  a summer afternoon, that’s just as relevant as for any other business.
• A Deye grid-tied inverter starts at €309 (3 kW, single-phase), while a
  similarly sized hybrid inverter that can take a battery starts at €949
  (Solis S6-EH1P5K-L-PLUS, 5 kW, single-phase). The price gap shows up before
  you even buy the battery itself.
• Server rooms and medical equipment need uninterruptible power, not a
  generator. That’s a separate question from whether an office should buy
  battery storage for the rest of its load at all.

What you’re choosing between

A grid-tied (string) inverter. Converts the direct
current from solar modules into alternating current and feeds it straight
into the property’s switchboard or the grid. You can’t connect a battery to
it. In our catalogue, Deye grid-tied inverters range from €309
(SUN-3K-G04, 3 kW) to €3,149 (SUN-100K-G03, 100 kW).

A hybrid inverter. Differs from a grid-tied inverter in
one way: you can connect a battery to it, either right away or later. In our
catalogue, hybrid Solis inverters range from €899 (3.6 kW, single-phase) to
€9,299 (125 kW, three-phase), and hybrid Deye inverters from €899 (3.6 kW) to
€7,899 (60 kW, three-phase). Without an actual battery attached, a hybrid
inverter works exactly like a grid-tied one — the difference is an option, not
an obligation.

A battery. A separate unit that can be connected to a
hybrid inverter at any time. ESO defines a battery’s purpose this way:

„Dalis gaminamos elektros energijos pertekliaus gali būti kaupiama elektros
energijos kaupiklyje (EEK) ir sunaudojama vakare.“ (in English: Part of the
surplus generated electricity can be stored in a battery storage unit and
used in the evening.)

ESO — Elektros energijos kaupikliai

The axis this choice turns on: a battery pays off when
you need to shift consumption to the part of the day with no sun. An office
whose working hours overlap with sunlight hours often doesn’t have that
need — but “often” doesn’t mean “always,” and the next section shows where
the line is.

Comparison at a glance

When a grid-tied inverter without battery storage is the right answer

The obvious case: an office, salon, or clinic runs from morning to
evening, and the lighting, computers, air conditioners, and equipment all
operate during exactly the hours when solar generation is highest. In that
case, generated electricity is used almost immediately, and a battery’s main
function — shifting consumption to the evening — simply doesn’t apply to the
property.

A less obvious case: a company rents its premises and doesn’t plan a
long-term investment in them, or the roof area only allows a small plant
whose entire output already fits within daytime consumption. In that case, a
battery only adds to the investment, with no place to put the benefit it
would otherwise provide.

The mechanism is simple: a battery pays for itself to the extent it shifts
consumption from a more expensive time to a cheaper one, or shaves an
exceeded peak. If consumption already happens during the day, when the plant
is generating, there’s nothing left to shift.

What that costs. A grid-tied inverter offers no
protection during a power cut — it’s required to shut off along with the
grid, a safety requirement that protects grid workers. It also doesn’t lower
the monthly capacity charge if the property briefly draws more power than
its contract allows — the only saving is that part of the daytime consumption
never travels through the grid at all.

When a hybrid inverter with battery storage is the right answer

A battery wins where an office’s working hours aren’t limited to daylight,
or where consumption isn’t steady. A clinic running shifts, a salon seeing
clients in the evening, a studio with evening classes — their consumption
schedule no longer matches the solar generation schedule, and a battery then
works exactly as it would for any other business.

A second case is short but large power spikes: a compressor in clinical
equipment, air conditioners switching on at the same time, a forklift
charger in a small warehouse next to the office. Such spikes can push the
property close to its agreed capacity limit, and a battery shaves them before
they turn into a line item on the monthly bill.

The mechanism is the same ESO rate that applies to every business
property:

„Atkreipiame dėmesį, kad viršijus objekto leistiną naudoti galią, vartotojas
privalo sumokėti trigubą vartotojo objektui taikomo tarifo plano galios
dedamosios kainą.“ (in English: Please note that if a property exceeds its
agreed capacity, the customer must pay triple the capacity charge under
their tariff plan.)

ESO — Elektros energijos persiuntimo paslaugų kainos verslui

With a capacity charge of €3.00/kW/month, exceeding it costs
€9.00/kW/month. A battery that shaves a short peak reduces exactly this line
item, not overall consumption.

What that costs. A hybrid inverter with battery storage
is a bigger investment: a 5 kW hybrid inverter alone (Solis
S6-EH1P5K-L-PLUS) costs from €949, and every extra 5.12 kWh battery module
(Deye BOS-G Pro) adds another €1,049. If the property’s consumption already
happens during the day, that investment pays back more slowly than in a case
where the battery genuinely shifts evening consumption.

What the property itself decides for you

A few circumstances typical of offices, salons, and clinics decide the
choice before you’ve even had a chance to form an opinion.

Summer cooling strengthens the case for a grid-tied inverter, not
a battery. Cooling demand peaks on a hot day — exactly when the
solar plant generates the most. That’s the same load that already overlaps
with generation. Our catalogue includes solar AC/DC air conditioners that
can draw part of their power straight from the modules: from €999
(9,000 BTU) up to €1,899 (Deye cassette unit, 24,000 BTU). The risk is
different: if the air conditioner also runs after hours or during evening
peaks (ESO’s peak-load windows run 6–8 p.m. from October to March, 7–9 p.m.
in April and September, and there’s no evening peak window at all from May
to August), that portion of the load falls outside the solar generation
window — and that’s exactly the part a battery could shave.

Server rooms and medical equipment need uninterruptible power, not
a generator. A diesel generator with an ATS doesn’t switch over
instantly: that brief gap is fine for lighting or air conditioning, but a
server, network equipment, or a medical device reboots or aborts a running
process during it. That kind of load needs to be fed by a battery through a
hybrid inverter, and that’s a separate decision from whether it’s worth
adding battery storage for the rest of the office’s load. We don’t quote
exact switchover times here — for your specific property, check the
inverter manufacturer’s documentation.

Your agreed capacity limits how much power you can draw at
once. If the property is allowed, say, 15 kW, and several air
conditioners, the server room, and lighting all run at once on a summer
afternoon, exceeding that limit costs triple the capacity charge —
regardless of whether the office has a solar plant or not.

Roof space or your lease can limit the plant’s size before
battery storage even becomes relevant. An office in a business
centre often has no right to the roof, or only to part of it. That’s a
technical constraint that determines the plant’s size before the battery
question is even on the table.

What changes in day-to-day operation

A grid-tied inverter needs no extra maintenance — it simply runs as long
as there’s sun and grid. A hybrid inverter with battery storage needs one
upfront decision: which panel circuits (server room, refrigerators,
essential lighting) stay powered when the grid is down. That’s decided at
installation, and redoing it later costs more than planning it up front.

What doesn’t change: in both cases the property remains
the same ESO customer with the same agreed capacity and the same supplier
contract. A solar plant doesn’t change the meter or the contract form.

Do you really have to pick just one?

Usually yes, but offices often also fit an intermediate option.

Grid-tied inverter now, hybrid system later. You can
install a grid-tied inverter today and switch to a hybrid one later if an
evening work schedule or a server room shows up. That means double
installation work, so it’s worth mentioning such a plan up front — some
projects are designed from the start to leave room for a battery, even if
it’s not bought in the first phase.

Grid-tied inverter for the whole office load, small storage system
just for the server room. When the critical load is small (server,
network equipment, alarm system), it gets its own small hybrid inverter with
battery, while the rest of the office stays on the grid-tied inverter. That
way you don’t pay for storage capacity the bulk of the office load doesn’t
need.

Frequently asked questions

Does a grid-tied inverter actually lower the electricity bill?

Yes — to the extent the office consumes the electricity it generates
immediately, during the day: that portion no longer needs to be bought from
the supplier. A grid-tied inverter doesn’t reduce the monthly capacity
charge (€3.00/kW excluding VAT), since it’s calculated from agreed capacity,
not actual consumption.

Can you add a battery to an already-installed grid-tied inverter later?

Not to the grid-tied inverter itself — it’s not designed for that.
Instead, you install a separate hybrid inverter or a parallel storage
system. So if you’re considering a battery as a future option, it’s worth
mentioning before buying your first inverter.

Do summer air conditioners change the answer on whether you need battery storage?

Usually not — peak cooling demand overlaps with peak solar generation.
The answer changes if the air conditioners also run in the evening, within
ESO’s peak-load windows (6–8 p.m. October–March, 7–9 p.m. in April and
September; no evening window May–August): a battery can shave that portion
of the load, a grid-tied inverter can’t.

Does a generator protect a server room as well as a battery does?

No. A generator with ATS switches over after a brief but noticeable gap,
during which a computer or network equipment has time to reboot.
Uninterruptible power for a server or medical device is provided by a
hybrid inverter with battery storage, not a diesel generator.

What does the cheapest option for an office without battery storage cost?

The inverter alone starts at €309 for a 3 kW single-phase Deye grid-tied
model (SUN-3K-G04). The final price depends on the number of solar modules
and installation, which we calculate based on your property’s roof and
consumption.

What we suggest you do

Send us three things: your property’s agreed capacity (stated in your ESO
contract), your working hours (daytime only, or evenings too), and whether
you have a server room, network equipment, or medical equipment that needs
uninterruptible power. That’s enough for us to tell you whether a grid-tied
inverter is enough, or whether you need a hybrid one with battery storage.
We deliver across Lithuania.

Sources

• ESO, Electricity distribution service prices for business customers — capacity charge, capacity overrun, peak-load windows:
  eso.lt (reviewed 2026-09-18)
• ESO, Electricity storage units — storing surplus and using it in the evening:
  eso.lt (reviewed 2026-09-15)
• Hybrid Energy, grid-tied (string) inverter catalogue — models and prices:
  hybridenergy.lt (reviewed 2026-09-18)
• Hybrid Energy, Deye hybrid inverter catalogue — models and prices:
  hybridenergy.lt (reviewed 2026-09-18)
• Hybrid Energy, air conditioner catalogue:
  hybridenergy.lt (reviewed 2026-09-18)