Hi,

We're potato farmers in the Western Cape looking to install solar to reduce our costs for irrigation. We have about four 200KVA supply points distributed across our farms which we're planning to add solar. We've gotten a few quotes from installers and all of them seems to have different opinions regarding a question we had for one or two of our supply points. As we're expanding our operations, some of the 200KVA points are being utilised to their limit, so what we wanted to do is to cover the additional demand via solar by installing for instance a 300kw system instead of only 200kw. However, this is where the installers differ, some say due to the Eskom SSEG regulations it is not allowed, while others say it is possible with the correct protection and motivation in the application. Does anyone have any experience in this regard?

Thank you!

Hi Aartappel,

Thanks for the details on your potato farm setup in the Western Cape. Irrigation is excellent for solar self-consumption during the day.

On oversizing beyond your 200 kVA supply points:

You're right that many farms push larger PV arrays, but the inverter AC export capacity is normally limited to or below the supply transformer rating to avoid network issues. When the local transformer is at or near maximum capacity, the common compliant solution used by Western Cape farmers is.

Oversize the PV array add Battery Energy Storage System (BESS) with strict export limitation and zero-export control.

This allows you to.

Generate more solar higher DC:AC ratio, e.g. 1.2–1.5 for better yield.

Store excess daytime production in batteries.

Discharge batteries to loads pumps, etc. without exceeding the transformer’s export and import limits.

Keep net export at or below the allowed value (often 0 kW or a small % of NMD).

Modern hybrid inverters (e.g.Solis Sunsynk, Victron, Deye, GoodWe, etc.) support dynamic export limiting via CT sensors or zero export mode. The system throttles PV/battery output so the net flow back to the grid stays within Eskom’s approved limit.

Important rules & realities Eskom SSEG:

The generator size inverter AC rating is generally capped around your supply rating 200 kVA or 75% of transformer capacity on LV supplies. Significant oversizing usually requires a network impact study.

Batteries do not bypass the limit Eskom assesses the total possible export. However, with proper export control plus anti-islanding, many farms get approval for larger PV and BESS setups because net export is controlled.

Systems >100 kW total need NERSA registration plus a Pr Eng sign-off.

Battery charging from the grid is usually limited e.g. 25% of breaker size in some guidelines to prevent cold load pickup issues.

Practical recommendations for your 4 × 200 kVA points:

Do a proper load & export study Measure actual daytime irrigation demand vs proposed solar. Batteries shine here for shifting energy.

Contact Eskom Western Cape early [email protected] with your account numbers and proposed setup PV kW and BESS kWh plus export limit. Ask for a pre application network assessment.

Choose installers experienced with farm BESS us export limited SSEG in the Western Cape. Ask for references of similar approvals.

Key documents needed:

Eskom SSEG application.

Detailed single line diagram showing export control.

Inverter and Battery datasheets (NRS 097-2-1 compliant).

Export limitation settings & test procedure.

CoC and Pr Eng sign off where required.

This approach larger PV + batteries + export limit is indeed what many farmers are successfully using when transformers are constrained it maximises self-consumption, reduces diesel and generator runtime, and stays compliant.

If you share more info current peak loads, quotes received, exact transformer details, or whether you want zero export or limited expor ), the forum can give even more specific feedback.

Solar with storage should significantly cut your pumping costs. Good luck!

Hi, thank you for your reply. Okay so I left out quite a few details.

• The supplies are all Ruraflex points

• Currently not interested in feeding back into the grid

• We'd like to keep the supplies at 200kVA to keep Eskom's costs down

• To keep costs down we're looking to implement a battery system to "bridge" the peak tariff hours (3 hours at night and 2 hours during the morning)

• The full load of one of our farms is around 340 amps, which is over the 200kVA supply's 300A capacity

So, for instance, our projected future load is around 450A during daylight hours (pumps feed a dam up a hill during the day with gravity feed at night) is it allowed within Eskom's regulations to install a 300/350kW hybrid inverter system while keeping the supply at 200kVA?

Eskom will then only be used during the day to maybe charge batteries, supplement the solar on cloudy days and used at night to run reduced loads.

Hi Aartappel,

Thanks for the extra details on your 4 × Ruraflex points, the 450A projected daytime load, and your preference for zero export while keeping the NMD at 200 kVA.

On inverter options

Several hybrid inverters can handle high inductive loads like irrigation pumps, offer generator integration, fast response times, and good zero-export blending. Solis is one of the brands that performs well in these areas for farm applications, but there are others too the best choice depends on the specific quotes, support, and installer experience.

Regulatory reality & frustrations

Many people feel that Eskom and NERSA are overreaching with their registration requirements, even for strict zero-export systems. The OUTA challenges highlight that a proper CoC + compliant installation should often be sufficient, especially when no power is exported. However, for a large 300–350 kW commercial setup on Eskom supplies, they still classify it as SSEG and want involvement.

Best recommendation: Consider going fully off-grid

If your goal is to minimise Eskom involvement and avoid all the red tape, the cleanest solution is a true off-grid system completely disconnected from the Eskom supply.

No parallel connection = no SSEG registration or NERSA requirements.

You run entirely on solar + battery with generator backup if needed.

Eskom infrastructure is only used as a completely separate backup feed if you keep one of the supplies live for emergencies.

Pros for your farm:

Full independence during the day for the 450A pumping loads.

Batteries handle the peak tariff periods and excess load.

No risk of future Eskom disconnection notices or compliance issues.

Cons to be realistic.

Significantly higher upfront cost much larger battery bank needed for reliability during cloudy periods or winter.

No automatic Eskom fallback on very bad weather or battery depletion unless you keep a separate grid connection.

Requires careful design for your gravity feed night loads.

Many farms in similar situations are moving toward full off-grid on at least some of their supply points to escape the bureaucracy.

If you still prefer a hybrid/parallel setup cheaper and uses Eskom as backup, then

Get a detailed CoC from a qualified installer.

Engage Eskom Western Cape anyway for peace of mind on a system this size.

Document everything thoroughly.

This kind of setup should still deliver major savings on your pumping electricity let us know how you want to proceed.

You are welcome to contact us directly to assist you with a system that can provide for your requirement and a suitable EPC to facilitate the installation.

@Aartappel I would recommend that you contact @Steve87 he has experience with commercial systems of that scale, another option would be @TaliaB.

7 hours ago, Aartappel said:

is it allowed within Eskom's regulations to install a 300/350kW hybrid inverter system while keeping the supply at 200kVA?

No you cannot just install a 300–350 kW hybrid inverter system behind a 200 kVA Eskom supply without formal approval and likely network upgrades.

You mentioned: Supply: 200 kVA

Proposed inverter: 300–350 kW (~300–350 kVA) Immediate problem: You are proposing generation larger than your point of supply that triggers Nersa registration required and Eskom connection study.

Not a simple SSEG anymore moves into embedded generation project territory.

In real projects like yours (irrigation / farms)

Option A What most guys do (legal route) is upgrade supply to 500 kVA or MV then install 300–500 kW solar.

Option B Hybrid workaround (semi-legal if approved) Keep 200 kVA supply and install large PV. Use zero export + strict control, but still requires Eskom approval.

The second option if you don’t want to upgrade to 500 kVA Eskom supply you can go off grid(remove point of supply) and install what you want(need) with backed up supply in mind.

12 hours ago, TaliaB said:

Option B Hybrid workaround (semi-legal if approved) Keep 200 kVA supply and install large PV. Use zero export + strict control, but still requires Eskom approval.

Yes, this exactly what we're trying to achieve. Some of the installers we had here (who does inhouse financing) said they can do it; however, their quotes don't make sense financially. Any pointers or ideas where I could get more information regarding this option?

19 hours ago, TaliaB said:

Option B

Option C. Build an off grid system as large as you want. You can use change over switches or chargers from the existing supply and it should still be seen as off grid.

@Aartappel your problem is quite a generic one and I have seen a few different solutions that the farming community is deploying...Direct Solar panels on VFDs, some farmers creating micro Grids large in size and then installing their own MV transmission lines and then disconnecting the various Eskom incomer points. I have at least 3 users completed these projects & have done it in a staged approach but the savings and the benefits are there to witness. Those unreliable expensive Eskom points are worth shutting down & pocketing the ongoing costs into your own infrastructure.

I have been involved with especially ATESS and more recently over the last 2 yrs Megarevo Transformer based Hybrids and AC coupled Grid ties and DC coupled ATESS topology. The largest plant at 1.5MW carrying a base load of 700kW is in a factory with massive HVAC and high inductive loads. The Atess equipment is really robust and honestly can take a heavy punch with large motors starting and stopping...

Its just my personal opinion that the High frequency non transformer based inverters won't last long for the irrigation environment or SAs farming environment because we have harsh conditions and we require equipment that will last the next decade that is serviceable in the field.

If you need basic advice and user cases please PM me. I can definitely point you in the right direction as well as share plants with you that have proven themselves in the field. The farming community are ripe to reap the rewards of solar power & with Diesel pricing very volatile id imagine it's going to accelerate...