Does a Farm Need a Generator or Solar with Storage? An Honest Comparison

We are Hybrid Energy: we sell diesel generators, hybrid inverters with
battery storage, solar modules, and systems that combine them. We sell all
three options, so we have no reason to favor any one of them. This article
won’t tell you which option is better. It shows what each one actually costs a
farm, and which one the situation itself rules out, before you form an
opinion.

The short version

• A business or farm site pays for more than kilowatt-hours. ESO charges a
  capacity charge of €3.00/kW per month excluding VAT on the
  permitted capacity, every month, even if you use that capacity only a few
  times a year.
• Exceed the permitted capacity, and that same capacity charge becomes
  triple. That’s why a new compressor, dryer, or forklift
  charger sometimes ends up costing more on the bill than it did in the shop.
• A generator solves the problem of a power outage, but it doesn’t lower
  either of these charges. Storage lowers both, but only as much as it actually
  shaves your peak; and during a long outage, it doesn’t replace a generator.
• The gap between the maximum-load and minimum-load transmission rates is
  €0.0116/kWh. That’s not the whole electricity price, only the
  transmission part, and it’s exactly what shifting consumption to nighttime
  reduces.
• Most farms end up with both units eventually, but buying them at the same
  time is almost never necessary, and that’s exactly what we cover here: which
  one to buy first.

What you’re choosing between

You’re choosing between three technically different things that solve
different problems. The confusion starts because all three get sold under the
same label: “power for the farm.”

Diesel generator with ATS. A three-phase unit with an
automatic transfer switch (ATS). Our range runs from 18 kW (Marsun MHD20000,
€5,999) up to 90 kW (Marsun MHD100, €16,499). The ATS unit is bought
separately and sized to the generator’s output: our catalog offers units for
6-15 kW and 20 kW machines (€199 and €269), and we size larger ones to the
site. All are three-phase, with an AVR, a voltage regulator, without which
machinery and pumps take voltage surges. The generator starts when power goes
down and runs as long as fuel remains in the tank.

Solar plant with a hybrid inverter and battery storage.
A hybrid inverter differs from a grid-tied one in one thing: you can connect a
battery to it. ESO describes it 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 system and
used in the evening.)

ESO — Electricity Battery Storage

Storage works every day, not just during an outage. It shifts consumption
to a different time of day and shaves short capacity peaks.

The combination. A hybrid inverter with storage for daily
use, and a generator for a long outage. Technically, this isn’t two separate
systems: some hybrid inverters have a generator input and can start it
themselves.

The pivot this whole choice turns on: a generator solves a
rare and long event, storage solves a daily and short one.
Until you know which of the two actually costs you more, any comparison of
price tables is pointless.

Comparison at a glance

When the right answer is a generator

A generator wins where a power outage instantly turns into spoiled product
or a risk to livestock. A milking parlor, a milk cooler, ventilation in a pig
or poultry barn, a water pump for the herd, these are sites where the question
isn’t “how much would I save,” it’s “what does one day without power cost.”

A second, less obvious case: the grain-drying season. A dryer runs for days
at a stretch, and you can’t stop it mid-cycle without a loss. Storage that
carries a household through an outage can’t handle that load for even an
hour.

The mechanism is simple: a generator is the only one of the three options
whose run time depends not on the sun, but only on the fuel tank. That’s why
it’s the only one that covers a long winter outage, exactly the case that
prompts farms to consider this in the first place.

What that costs. The equipment sits idle for most of the
year and earns nothing during that time. A 40 kW Marsun MHD40000 costs
€10,699; on top of that, add an ATS unit, fuel storage, and regular test
runs, without them a generator you’ve never started won’t start on the day it
fails. And most importantly, it won’t lower your bill by a single euro.

When the right answer is solar with storage

Storage wins where the electricity bill is large and supply disruptions are
rare and short. That covers most crop farms, workshops, warehouses, and farms
with an office, sites that consume a lot but whose operations don’t stop over
two hours.

A second case, and the one that most often brings people to us: a farm
wants to connect a new, powerful piece of equipment and finds out it will need
to raise its permitted capacity. Storage can sometimes eliminate that need
entirely, since the peak only lasts minutes.

The mechanism is the ESO tariff. Permitted capacity is billed every
month:

„Galios dedamoji — 3,00 Eur/kW/mėn.“ (in English: Capacity charge: €3.00/kW
per month.)

ESO — Electricity Transmission Service Prices for Business Customers

60 kW of permitted capacity is €180 a month, €2,160 a year excluding VAT,
just for the right to use that capacity, regardless of how much you actually
consume. And on exceeding that capacity, ESO states:

„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 customer exceeds the
site’s permitted capacity, they must pay triple the capacity-charge rate under
their tariff plan.)

ESO — Electricity Transmission Service Prices for Business Customers

Triple the €3.00/kW rate is €9.00/kW per month. That’s exactly the figure
storage lowers, because it shaves the peak itself, not overall consumption.

What that costs. During a long outage, storage won’t
carry a farm. On a December afternoon there’s almost no sun, and at full farm
load storage drains within a few hours. On top of that, storage’s payback
depends directly on when you actually consume electricity: if your
consumption already happens during the day, the investment pays off far more
slowly than any advertisement promises.

What the farm itself decides for you

Some choices disappear before you even form an opinion. These constraints
matter more than price.

Permitted capacity sets an upper limit. If the site is
allowed 30 kW, no system will let you draw 50 kW from the grid at once.
Anything above that limit has to be covered by a generator or storage, or you
have to raise the permitted capacity and start paying more every month.

The nature of the load rules out storage or a generator.
A constant, day-long load (refrigeration, ventilation, drying) is a
generator’s job. Short, powerful surges (motor starts, compressors, forklift
chargers) are storage’s job. Equipment whose starting current is several times
its rated output determines the minimum generator size, and rated kilowatts
alone tell you nothing here.

Working hours decide whether shifting to nighttime is worth
it. ESO applies a maximum-load transmission rate of €0.0313/kWh and a
minimum-load rate of €0.0197/kWh to third-tier customers. The gap is
€0.0116/kWh; that’s not the whole electricity price, only the transmission
part. Maximum-load hours run from 8 to 11 and 18 to 20 in October-March, from
9 to 12 and 19 to 21 in April and September, and from 9 to 12 in May-August;
minimum-load hours run from 23 to 7. If your work already happens at night,
there’s nothing to shift.

The reliability category adds a fee that’s rarely
discussed. For second- and third-tier sites, ESO applies a
reliability-category charge: €1.00/kW per month for the first category and
€0.50/kW per month for the second. That’s another line item to factor in
alongside the capacity charge, not calculate separately.

The roof and location decide whether solar is even possible.
A north-facing slope, trees, an old slate roof, or a roof you’ll be replacing
in two years: that’s a technical “no,” not a question of price.

What changes in day-to-day operation

A generator requires routine: test runs, fuel stock and its aging, oil, and
battery charge. A unit no one has touched in two years becomes a decoration on
the day it fails, the most common reason a farm ends up without power despite
owning a generator.

Storage and the inverter need almost no daily maintenance, but they need a
decision made in advance: which switchboard groups stay powered when the grid
is down. That’s decided at installation, and redoing it later costs more than
getting it right the first time.

What doesn’t change: none of the options changes your
supplier, contract, or meter. After connecting storage, the site remains the
same ESO customer with the same permitted capacity; what changes is only how
much of it you actually draw.

Do you really have to choose just one?

Usually not, and three combinations come up repeatedly.

Generator first, solar later. Fits livestock farms and
anyone for whom one day without power costs more than a year’s electricity
bill. First you buy a generator with ATS, and add solar later once you have
the funds; a hybrid inverter allows for that.

Storage first, generator later or never. Fits crop
farming, workshops, and warehouses, where an outage doesn’t spoil anything.
Usually, a generator never gets bought here at all.

Both at once. Makes sense when the site is new or being
rebuilt: the switchboard is being redone anyway, so wiring out separate backup
circuits costs nothing extra.

Frequently asked questions

Will a generator lower my electricity bill?

No. A generator only runs when the grid is down, so it lowers neither the
price of the kilowatt-hours you consume nor the monthly capacity charge,
which in ESO’s tariffs is €3.00/kW excluding VAT. Storage and a solar plant
lower the bill; a generator is insurance against downtime.

What generator output does a farm need?

That’s determined not by the total equipment output, but by starting
currents. Motors, compressors, and pumps draw several times their rated power
at start-up, so the generator is sized to the heaviest piece of equipment
started at any one time. Send us your equipment list and we’ll calculate it.

What happens if I exceed my permitted capacity?

ESO states that exceeding a site’s permitted capacity triggers triple the
tariff plan’s capacity-charge rate. At €3.00/kW per month, that’s €9.00/kW per
month. That’s exactly why short peaks sometimes cost more than steady
consumption.

Will storage replace a generator in winter?

Not fully. In December and January there’s almost no sun in Lithuania, so
storage drains and stops recharging. Storage covers short supply disruptions
and daily peaks, while a long winter outage is reliably covered only by a
generator, or by a generator-and-storage combination.

Can a generator be connected to an already-installed solar system?

It depends on the inverter. Some hybrid inverters have a separate generator
input and can start it automatically; grid-tied inverters can’t do this. We
check this against the specific inverter manufacturer’s documentation before
you buy, not against a general rule.

What we suggest you do

Send us three things: your site’s permitted capacity (stated in your ESO
contract), a list of your equipment with its outputs, and the answer to one
question, what one day without power costs you. That’s enough for us to tell
you whether you need a generator, storage, or neither. We deliver across
Lithuania.

Sources

• ESO, Electricity Transmission Service Prices for Business Customers:
  capacity charge, reliability categories, time bands, exceeding capacity:
  eso.lt (reviewed 2026-09-18)
• ESO, Electricity Battery Storage: storing and using surplus in the
  evening: eso.lt (reviewed 2026-09-15)
• Hybrid Energy, generator catalog: models, outputs, and prices:
  hybridenergy.lt (reviewed 2026-09-18)