Planning a Phased Solar Rollout for Your Factory

This guide is for factory owners and plant managers who want solar but prefer not to commit the whole budget at once. There is no fixed timetable for each phase. It depends on your cash flow, your data and equipment availability.

Why factories phase their solar

• Cash flow. One large payment is hard for many SMEs. Phasing matches spending to what the business can fund, through its own funds or a bank facility. See our industrial solar financing guide.
• Better decisions with real data. A battery is expensive. After a phase 1 plant has run for a while, its monitoring shows how much solar you use, how much you export and when the generator runs. That data sizes phase 2 far better than estimates.
• Lower risk of oversizing. Under net billing, oversized plants export surplus at a low rate. Starting at the daytime base load avoids that.
• Factory changes. New machines, a new shed or an extra shift may change your load. Phasing lets the design follow the business.

Diagram

Phased industrial solar

Phase 1

Largest day loads

Phase 2

More roof, more kW

Phase 3

Battery storage

Before phase 1: measure

The most common mistake is sizing phase 1 from the monthly bill alone. A bill shows total units, not when they were used. Before design:

1. Log the load for at least a week of normal production, including a holiday.
2. Note shift times, machine start-up patterns and MDI peaks.
3. Record generator running hours and fuel use.
4. Check your sanctioned load, connection voltage and transformer.

Our energy audit before solar guide explains each measurement.

Phase 1: daytime solar sized to self-use

Phase 1 is usually an on-grid plant sized to the load your factory draws every working day between morning and afternoon. Nearly every unit it produces is used on site, which is where solar earns the full tariff.

For example, if logging shows a factory never draws less than about 200 kW between 9 AM and 4 PM on working days, a phase 1 plant sized near that daytime floor would export very little. Holidays, cloudy days and winter shift that picture, so the engineer checks those too. These are round illustrative numbers only.

Build phase 1 ready for phase 2

This is where good phasing is won or lost. Ask for these in the phase 1 design and BOQ:

Our in-house design guide explains how an AutoCAD layout with future phases marked prevents costly rework.

Phase 2: the options

Once phase 1 has run long enough to give useful data, phase 2 usually takes one or more of these forms.

Battery storage (BESS)

A BESS added in phase 2 is usually AC-coupled: it connects on the AC side beside the existing on-grid inverters, so the phase 1 equipment stays in place. The battery is sized from the monitoring data, for a specific job:

• storing midday surplus that would otherwise be exported cheaply;
• covering outages that stop production;
• cutting generator running hours;
• shaving demand peaks where the tariff rewards it.

Our guide Battery storage (BESS) for factories: when does it pay? explains how to test each job. For larger factory batteries we work with Luminey and current Huawei and Sungrow options, chosen per project. The home-scale logic of adding a battery to an existing system is in adding batteries or panels to an existing system.

Generator integration

If outages are frequent, a controller that lets solar share the load with your generator can be added in phase 2. See hybrid systems with generators: our engineering approach.

More capacity

New sheds, a carport or spare land can carry more panels later. See ground-mounted solar and solar carports and canopies. Adding panels to existing inverters is limited by their input ratings; our guide to the inverter DC/AC ratio explains how far that can go. New panels may differ from the phase 1 model, so they usually go on their own strings or inverters.

Net billing limits to check before you phase

Phasing does not get around the rules. Check these at the start, because they cap the final size of all phases together. From NEPRA's net billing regulations, notified on 9 February 2026:

• Total system size cannot exceed your sanctioned load, with an overall cap of 1 MW.
• A load flow study is required for systems of 250 kW and above.
• Transformer limit: no new applications once connected generation on a transformer reaches 80% of its rating.
• Exported units are credited at a much lower rate than imported units cost.

Adding capacity in a later phase changes your installed size, which may mean a fresh or revised application with your DISCO. If you have an older net metering agreement, changing system capacity may affect it; ask your DISCO in writing before you expand. Full details are in our net metering and net billing guide.

If your planned final size is above your sanctioned load, apply to raise it early. See how to increase your sanctioned load.

A battery used only for self-use and backup does not export, but it still changes your electrical installation, so include it in the phase 1 single-line diagram.

Phasing across several buildings

Factories with several sheds, or campuses with several meters, can phase building by building. Standardise equipment and monitoring so all phases look the same to your maintenance team. Our guide to solar for universities and large campuses covers multi-building phasing in more detail.

Risks to manage

• Equipment changes. The exact inverter or panel model in phase 1 may not be available later. Choose platforms and manufacturers likely to support future additions, and record model details in the BOQ.
• Warranty boundaries. Each phase has its own manufacturer warranties per product. Keep the documents for each phase together.
• Costs move. Phase 2 is priced when you order it, not when phase 1 is signed. Prices change with the dollar rate, import costs and stock.
• Maintenance across phases. One O&M plan should cover the whole plant. See O&M for commercial solar plants.

Phased plant price

How Solar Works Pakistan plans phased projects

Solar Works Pakistan is a Faisalabad-headquartered solar EPC, engineering and trading company founded in 2021, with a branch in Lahore. We have served 300+ customers, including 50+ industrial clients, and we build projects from about 6 kW to megawatt scale. Industrial EPC, hybrid systems and BESS are our specialist areas.

• In-house load analysis, feasibility and AutoCAD design, with future phases drawn from day one.
• Detailed BOQ for each phase, naming brand, model, quantity and warranty.
• Structures designed in-house and assembled by our own teams, with a 3-year structure warranty.
• Installation, testing and safe commissioning by our own teams. Small projects can normally be completed in about a week, subject to payment, stock and site readiness; larger phases follow a project-specific schedule.
• Remote monitoring subject to equipment capability, and a 48-hour target to send service personnel after a complaint is registered.

See our industrial and commercial solar page and our Faisalabad page.

Get today's price or a free site survey

Send us 12 months of bills, your sanctioned load, shift pattern and generator details. We will propose phase 1 and show where phase 2 fits.

• WhatsApp or call: 0336 666 4321
• Email: info@solarworks.pk
• Head office: Main Boulevard, Sargodha Rd, Block F FDA City, Faisalabad
• Lahore branch: 2nd Floor, Jeff Heights, Gulberg, Lahore
• Hours: 9:00 AM to 6:00 PM, daily

We serve all of Punjab, and site surveys are normally free. You can also contact us online.

Frequently asked questions

Is it better to install factory solar all at once or in phases?

All at once can cost less per kW and avoids a second round of work. Phasing spreads the cost and lets real data size the battery or extra capacity. The right answer depends on your cash flow and how settled your load is.

What should phase 1 of a factory solar plant include?

A plant sized to your daytime working load, plus expansion-ready panels, cable routes, earthing, inverter room space and monitoring. Those items cost little in phase 1 and save rework later.

Can I add a battery to my on-grid factory plant later?

Usually yes, by AC coupling a BESS beside the existing inverters. Plan the space and panel connections for it in phase 1.

How long should I wait between phases?

There is no fixed period. Phase 2 is best decided once phase 1 monitoring has covered enough seasons and production patterns to show what a battery or more capacity would do.

Does a phased plant still have to stay within my sanctioned load?

Yes. All phases together must stay within your sanctioned load under net billing, with an overall cap of 1 MW. Raise your sanctioned load first if your final plan needs it.

Will my DISCO need a new application for phase 2?

It may, if phase 2 increases installed capacity. Ask your DISCO in writing before you expand.

Sources

1. Net billing limits (sanctioned-load cap, 1 MW cap, 250 kW load flow study, 80% transformer rule) are carried over from our net metering and net billing guide, which lists its own sources, including the NEPRA (Prosumer) Regulations, 2026, SRO 251(I)/2026: https://ke.com.pk/wp-content/uploads/2026/04/8.-NEPRA-Prosumer-Regulations-SRO-251I2026-09-02-26.pdf