30kW solar system can be a useful scale for an Irish farm, warehouse, workshop, office, retail premises or other property with significant electricity demand. It may also suit a large home with several electric vehicles, a heat pump and high daytime consumption. For remote properties, a carefully designed battery-backed or off-grid system may be considered, although that requires much more than simply installing 30kW of panels.
The cost and design depend on the property. Panel wattage, roof condition, mounting equipment, inverter type, electrical works, grid connection requirements, battery storage and backup arrangements all affect the final result. A 30kW system for a grid-connected business is a different project from a 30kw off grid solar system designed to operate independently through periods of low winter generation.
This guide covers the 30kW solar system price in Ireland, panel quantities, roof space, expected output, off-grid requirements, grants and the main stages of a professional installation.
What is a 30kW solar system?
A solar PV array is usually described by its rated capacity in kilowatts peak, or kWp. A 30kWp array has panels whose combined nominal rating is at least approximately 30,000 watts under standard test conditions.
Capacity is not the same as energy generation:
•kW or kWp describes the power rating of the system at a point in time.
•kWh describes the amount of energy generated or used over a period.
A 30kW solar panel system does not produce 30kW continuously. Output varies with daylight, cloud, temperature, panel direction, shading and system losses. In Ireland, solar PV generation is seasonal. SEAI states that around 75% of annual solar electricity is produced between May and September.
A system of this size may be suitable for:
•Farms and agricultural buildings.
•Workshops, factories and manufacturing sites.
•Warehouses, distribution centres and cold stores.
•Offices, retail premises and hospitality properties.
•Schools, community buildings and non-profit organisations.
•Large homes with heat pumps, EV charging or unusually high demand.
•Remote properties considering battery-backed or off-grid operation.
The correct size should be based on electricity consumption and the intended use of the energy, not just the roof area available.
30kW solar system price in Ireland
Commercial solar pricing varies considerably by project. An Irish commercial solar pricing guide reports a broad installed range of approximately €600–€1,700 per kWp, depending on system size and roof complexity. On that basis, a simple calculation for 30kWp would be roughly €18,000–€51,000 before grants, although a real 30kW quotation may fall outside that range where there are difficult access, structural, electrical or grid requirements.
This is an indicative planning range, not an official tariff or guaranteed market price. A large, uncomplicated commercial roof may achieve a lower cost per kWp than a fragmented roof. A 30kW project with structural reinforcement, long cable runs, specialist switchgear or battery storage can cost considerably more.
The 30kW solar installation cost may include:
•Solar panels and mounting equipment.
•One or more inverters and monitoring hardware.
•System design, engineering and performance modelling.
•Scaffolding, access equipment and installation labour.
•Roof repairs or structural reinforcement.
•Cables, protection, switchgear and distribution-board work.
•Grid connection or export-limitation equipment.
•Commissioning, certification and handover documentation.
•Battery storage, backup inverters or a generator, if required.
•Ongoing service, maintenance and warranty support.
Ask installers to show the gross price, any grant assumption, VAT treatment, battery cost and exclusions separately. A low headline figure may not include scaffolding, electrical upgrades or the connection work needed for a commercial property.
How many solar panels are needed for a 30kW system?
The calculation is:
30,000 watts ÷ individual panel wattage = panel quantity
The result is rounded up where necessary so that the array reaches at least 30kWp.
•400W panels: 30,000 ÷ 400 = 75, so approximately 75 panels are required, resulting in a 30.00kWp system.
•450W panels: 30,000 ÷ 450 = 66.67, so approximately 67 panels are required, resulting in a 30.15kWp system.
•500W panels: 30,000 ÷ 500 = 60, so approximately 60 panels are required, resulting in a 30.00kWp system.
•550W panels: 30,000 ÷ 550 = 54.55, so approximately 55 panels are required, resulting in a 30.25kWp system.
The final array may be slightly above the target because panels are installed as whole units. The installer must also consider panel dimensions, string voltage, inverter limits, roof faces, shading and access routes. The quotation should state the total panel capacity in kWp, the inverter’s AC rating and the expected annual generation.
30kW solar system roof space requirements
Many modern solar panels are approximately 1.7–2.0 metres long and around 1.1 metres wide. Using an illustrative panel surface area of 1.9m², the configurations above would require roughly:
•400W panels: 75 panels, covering about 143m² of panel surface.
•450W panels: 67 panels, covering about 127m² of panel surface.
•500W panels: 60 panels, covering about 114m² of panel surface.
•550W panels: 55 panels, covering about 105m² of panel surface.
The combined panel surface is not the same as the total roof area required. The design must allow for roof edges, maintenance access, walkways, mounting clearances, rooflights, skylights, vents, valleys, chimneys and shaded areas.
As an early planning allowance, a 30kW rooftop array may require approximately 125–200m² of suitable usable roof area. A clean commercial roof may use space efficiently, while a complicated roof may require more space or may not accommodate the full array. SEAI gives a commercial example of a typical 30kWp system using around 125m², but actual panel dimensions and layouts vary.
The survey should also examine roof structure and condition. Installing panels on an ageing roof can create additional cost if repairs or replacement are likely. Orientation, pitch and shading affect annual production, while an east-west layout may spread production across more of the working day. Ground-mounted panels may be considered where the roof is unsuitable, but they add foundations, civil works, cable trenches, access and sometimes planning considerations.
How much electricity does a 30kW solar system produce?
The 30kW solar system output depends on the exact location and design. The rated capacity is approximately 30kWp, but the array does not operate at that output for every hour of the year.
SEAI states that a well-located 3kW Irish home system can generate around 2,600kWh per year. That is approximately 867kWh per kWp. Applying a similar benchmark to 30kWp gives roughly 26,000kWh per year.
For early planning, a broad range of approximately 24,000–28,000kWh per year may be reasonable for many well-designed Irish sites. This is an estimate, not a guarantee. It is equivalent to approximately:
•Daily average: 66–77kWh across the year.
•Monthly average: 2,000–2,330kWh across the year.
•Annual generation: 24,000–28,000kWh.
Actual output may be lower or higher depending on:
•Location and local weather.
•Roof direction and pitch.
•Shading from trees, buildings or roof structures.
•Panel, inverter and mounting-system performance.
•Dirt, snow, downtime and electrical losses.
•The amount of usable roof area and the final layout.
Summer production can be much higher than the annual daily average. Winter production is lower because of shorter days and more overcast conditions. SEAI notes that solar PV still works on overcast days in Ireland, but not at its maximum rated capacity.
30kw off grid solar system: how does it work?
A 30kw off grid solar system is designed to operate without relying on the public electricity network. It is not simply a grid-connected array with the grid cable removed. It needs enough storage, control equipment and backup capacity to supply the property when solar generation is low or absent.
A typical off-grid solar system in Ireland may include:
•Solar PV panels producing DC electricity.
•An off-grid or hybrid inverter that supplies AC electricity.
•Battery storage measured in usable kWh.
•MPPT charge controllers where the architecture requires them.
•Energy-management controls and monitoring.
•A backup generator or another firm source of power.
•Protection, isolation and suitable distribution equipment.
The system must be designed around actual electricity use, including peak loads such as pumps, compressors, refrigeration, heating elements and machinery. It must also account for several days when winter solar production is poor. A 30kWp array may produce useful energy over the year but still require substantial battery and generator support during a dark, overcast period.
An off-grid solar system Ireland project should therefore begin with a detailed load profile and a decision about the required level of resilience. Critical loads may be placed on a separate backup board so that the system does not need to support every appliance during a prolonged low-generation period.
Off-grid system cost and battery requirements
An off-grid project normally costs more than a grid-connected project of the same panel capacity. It needs storage and controls that a standard grid-connected installation may not require. It may also need a generator, larger inverter capacity, additional protection and more detailed energy management.
Battery capacity is measured in kWh, while battery power is measured in kW. These are different requirements:
•Battery kWh: how much energy can be stored and delivered over time.
•Battery kW: how much power can be supplied at once.
For example, a property may need a high battery power rating to start a motor even if its total daily energy use is moderate. Conversely, a property with modest peak loads but long overnight demand may need more kWh of storage.
Battery sizing should consider:
•Average daily consumption.
•Maximum simultaneous demand.
•Critical and non-critical loads.
•Desired autonomy in hours or days.
•Winter solar generation.
•Minimum state of charge and usable depth of discharge.
•Battery efficiency, warranty and expected degradation.
•Generator capacity and fuel availability.
There is no single battery size that is suitable for every 30kW off-grid property. A battery that works for a lightly used remote building could be entirely inadequate for a busy farm or workshop. The installer should show the assumed load profile, winter scenario, battery usable capacity and backup strategy.
Grid-connected versus off-grid solar
Upfront cost
A grid-connected 30kW system usually has a lower upfront cost because it may operate without a large battery bank or generator. An off-grid 30kW system is generally more expensive because it requires batteries, controls and backup equipment.
Battery requirement
Battery storage is optional for a grid-connected system and depends on self-consumption goals. It is usually essential for an off-grid system to provide electricity outside daylight hours.
Grid dependence
A grid-connected system uses the public electricity network when solar generation is insufficient. An off-grid system is designed to operate without the network, subject to the limits of its panels, batteries, inverter and backup equipment.
Backup power
A grid-connected system needs special backup functionality to operate during a grid outage. An off-grid system often includes a generator or another reliable backup source for extended periods of low solar generation.
Export
A grid-connected system may export surplus electricity, subject to the connection agreement and electricity supplier arrangements. An off-grid system normally stores surplus electricity or reduces generation unless it also has a grid connection.
Suitable applications
Grid-connected systems suit businesses and properties with an available electricity connection. Off-grid systems may suit remote sites or properties that prioritise energy independence.
Key design issue
For a grid-connected system, the main design considerations are self-consumption, export and connection capacity. For an off-grid system, the key issues are load management, battery autonomy and resilience during periods of low solar generation.
A 30kW solar array does not automatically allow a property to operate independently during a grid outage. Ordinary grid-connected inverters generally shut down when the grid fails unless the system has been specifically designed with suitable backup or islanding capability.
Commercial applications for a 30kW system
A 30kW solar system may suit a farm with daytime pumping, refrigeration or milking loads. It can also support workshops, warehouses, offices, retail units, schools and small manufacturing sites.
The strongest financial case often occurs where the property can use a large share of generation as it is produced. A business operating during daylight may offset imported electricity directly. A property that is closed during the day may export more or require battery storage to move electricity into the evening.
Solar should be sized using at least 12 months of electricity bills or interval data. Future loads such as EV charging, heat pumps, cold storage or machinery should be included, but should not be assumed without a realistic installation plan.
Battery storage and energy management
A battery can charge from surplus PV during the day and discharge when the building needs electricity later. This can improve self-consumption and reduce grid imports. It may also support selected backup circuits when the inverter, switchgear and controls are designed for that purpose.
Energy management can prioritise flexible loads such as hot-water heating, EV charging or scheduled machinery. It can also limit export where the connection agreement requires it. Monitoring is important because the owner can compare actual production, battery state of charge, self-consumption and exports with the original design.
SEAI explains that batteries can increase the percentage of solar electricity used on site, but add cost and involve energy losses during charging and discharging.
SEAI grants and support in Ireland
Grant support depends on the property type, applicant and scheme rules. Domestic support should not be assumed to apply to a 30kW commercial or off-grid system.
Domestic installations
SEAI’s current domestic solar PV grant provides up to €1,800 for eligible homes, with a separate €600 battery grant potentially available. The scheme page states that the home must have an MPRN, must have been built and occupied before 2025 and must not have previously received solar PV funding at that MPRN. The domestic PV support is capped at 4kWp, so it does not fund the full cost of a 30kW array.
Applicants must receive the grant offer before work starts and use the applicable registered company. An off-grid property without the required connection and eligibility conditions should not assume that domestic support is available.
Commercial, agricultural and non-domestic installations
Businesses, farms, public-sector bodies, schools, community centres and non-profit societies may be eligible for the SEAI Non-Domestic Microgen Grant. The scheme supports systems up to 1,000kWp.
The current SEAI scheme page states that new applications made from 6 October 2026 to 6 July 2027 receive support at an effective 45% rate, subject to the scheme conditions. Its published grant table lists €400 per kWp for systems from 21kWp to 200kWp. On that published rate, a 30kWp system has a calculated grant value of €12,000 before the lower-of-cost and other scheme limits are applied. The payment is the lower of the amount shown on the application summary and 45% of the invoiced cost.
Grant rates and application windows can change. The applicant should check the current SEAI page, appoint the appropriate registered company, obtain the letter of offer and avoid starting work before approval. The grant does not automatically cover batteries, generators, off-grid controls or every associated project cost.
Savings and payback period
A grid-connected 30kW system can reduce imported electricity when the property is using solar generation. Financial returns depend on the amount consumed on site, the import tariff, exported electricity value, system price, grant support, maintenance and future energy use.
For a transparent hypothetical example, assume:
•Annual generation: 26,000kWh.
•Direct on-site use: 70%, or 18,200kWh.
•Avoided electricity cost: €0.30/kWh.
•Exported electricity: 7,800kWh.
•Hypothetical export value: €0.10/kWh.
•Net installation cost after an assumed grant: €30,000.
The illustrative annual benefit would be:
•Direct-use saving: 18,200 × €0.30 = €5,460.
•Export income: 7,800 × €0.10 = €780.
•Total annual benefit: €6,240.
•Simple payback: €30,000 ÷ €6,240 = approximately 4.8 years.
This is not a promised result. The assumptions must be replaced with the property’s actual load profile, quotation, grant offer and supplier export rate. It also excludes finance costs, maintenance, inverter replacement and battery costs.
For an off-grid project, the comparison is different. The owner should compare the total PV, battery, generator and maintenance cost with the cost and reliability of the alternative supply being replaced. Fuel, generator servicing and eventual battery replacement need to be included.
Installation process and technical requirements
A professional solar panel installation Ireland project should normally include:
1.Review of electricity bills, interval data and future demand.
2.Site survey covering the roof, ground area, structure, shading and access.
3.Design of the panel array, strings, inverters and battery.
4.Assessment of planning, fire safety, electrical and grid requirements.
5.Written quotation with generation and financial assumptions.
6.Grant check and application before work begins where relevant.
7.Grid connection application where the system is connected to the network.
8.Installation, testing, commissioning and certification.
9.Handover of warranties, manuals, safety documentation and monitoring access.
10.Ongoing performance checks and maintenance.
ESB Networks states that micro-generation is limited to approximately 6kVA on single phase or 11kVA on three phase under its micro-generation route. A 30kW system may therefore need a different connection route or assessment. ESB Networks also says that the inverter must comply with IS EN50549-1 with the current Irish settings and that the installation must be completed by a registered electrical contractor following the applicable process.
Off-grid systems still require safe electrical design, isolation, protection and appropriate installation standards even when there is no public-grid export.
How to choose the right solar installer
Compare written quotations rather than headline prices. Each proposal should state:
•Panel and inverter models.
•Total capacity in kWp and inverter AC rating.
•Expected annual generation and modelling assumptions.
•Roof loading, mounting method and access requirements.
•Battery usable capacity, power rating and warranty.
•Backup circuits and generator integration, if applicable.
•Grid connection or export-limitation responsibilities.
•Product, workmanship and installation warranties.
•Monitoring, maintenance and after-sales support.
•Grant eligibility, timing and exclusions.
For supported work, use the appropriate SEAI-registered company. SEAI advises applicants to compare quotes, check references and obtain a written contract covering the works, price, payment terms and warranties.
Conclusion
The 30kW solar system price in Ireland depends on equipment, roof complexity, electrical work, grid requirements and battery storage. Broad commercial pricing information suggests an indicative range of approximately €18,000–€51,000 before grants, but a proper site survey and quotation are essential.
Depending on the chosen panel rating, a 30kW array may use around 55–75 panels and require approximately 125–200m² of usable roof area. A reasonable early planning estimate for 30kW solar system output is around 24,000–28,000kWh per year, although orientation, shading, location and weather will affect the result.
A 30kw off grid solar system needs much more careful planning than a grid-connected array. Battery kWh, inverter power, winter autonomy, critical loads and generator backup must all be designed around the property’s actual use. Domestic and non-domestic SEAI grant rules are also different, and no grant should be assumed until eligibility is confirmed.
Visit LVP Renewables to enquire about a tailored solar quotation for your business, farm or property.
FAQs
How much does a 30kW solar system cost in Ireland?
A broad commercial planning range is approximately €18,000–€51,000 before grants, based on an indicative €600–€1,700 per kWp installed range. Roof complexity, electrical work, grid connection requirements, batteries and backup equipment can change the final price substantially.
How many solar panels are needed for a 30kW system?
The answer depends on panel wattage. A 30kW array may use approximately 75 panels at 400W, 67 panels at 450W, 60 panels at 500W or 55 panels at 550W. The final capacity may be slightly above 30kWp because panels are whole units.
Can a 30kW off-grid solar system power a business?
It can power some businesses, but only if the panel, inverter, battery and backup system are designed around the business’s actual loads. Peak demand, overnight use and periods of low winter generation are particularly important. A generator or other backup source may be required.
How much battery storage is needed for a 30kW off-grid solar system?
There is no universal battery size. The required usable kWh depends on daily consumption, peak loads, critical circuits, desired autonomy, winter generation and generator support. A professional design should model the property’s load profile and show the battery’s usable capacity and power rating.
