{"id":4123,"date":"2026-07-28T13:40:23","date_gmt":"2026-07-28T05:40:23","guid":{"rendered":"https:\/\/www.solidess.com\/?p=4123"},"modified":"2026-07-28T15:06:44","modified_gmt":"2026-07-28T07:06:44","slug":"%d8%af%d9%84%d9%8a%d9%84-%d8%a7%d9%84%d9%85%d9%82%d8%a7%d8%b3%d8%a7%d8%aa-%d9%84%d9%85%d8%b3%d8%aa%d8%b4%d9%81%d9%89-%d8%a8%d9%8a%d8%b3-%d9%81%d9%8a-%d8%ac%d9%86%d9%88%d8%a8-%d8%a3%d9%81%d8%b1%d9%8a","status":"publish","type":"post","link":"https:\/\/www.solidess.com\/ar\/hospital-bess-south-africa-sizing-guide\/","title":{"rendered":"\u0643\u064a\u0641\u064a\u0629 \u062a\u062d\u062f\u064a\u062f \u0633\u0639\u0629 \u0623\u0646\u0638\u0645\u0629 \u0627\u0644\u0637\u0627\u0642\u0629 \u0627\u0644\u0634\u0645\u0633\u064a\u0629 \u0648\u0646\u0638\u0627\u0645 \u062a\u062e\u0632\u064a\u0646 \u0627\u0644\u0637\u0627\u0642\u0629 (BESS) \u0644\u0644\u0645\u0633\u062a\u0634\u0641\u064a\u0627\u062a \u0641\u064a \u062c\u0646\u0648\u0628 \u0623\u0641\u0631\u064a\u0642\u064a\u0627: \u062f\u0631\u0648\u0633 \u0645\u0633\u062a\u0641\u0627\u062f\u0629 \u0645\u0646 \u0627\u0644\u0634\u0628\u0643\u0629 \u0627\u0644\u0635\u063a\u064a\u0631\u0629 \u0641\u064a \u0645\u0627\u0641\u064a\u0643\u064a\u0646\u063a \u0628\u0642\u062f\u0631\u0629 200 \u0643\u064a\u0644\u0648\u0648\u0627\u0637\/400 \u0643\u064a\u0644\u0648\u0648\u0627\u0637 \u0633\u0627\u0639\u0629"},"content":{"rendered":"\t\t
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MegSolid\u2019s first recommendation for a hospital BESS in South Africa is to separate critical medical loads from the hospital\u2019s total demand before selecting a battery.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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A hospital does not need every circuit to receive the same backup duration. It does need a documented power-continuity plan for the ICU, operating theatres, emergency department, medical gases, communications, controls and other loads identified by the hospital\u2019s clinical risk assessment.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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The Mafikeng Provincial Hospital project provides a current South African reference. According to SAnews, Eskom delivered a 200kW ground-mounted solar PV system and a 400kWh battery energy storage system integrated through a Central Microgrid Controller.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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The system supports critical hospital departments and is intended to improve resilience in an area affected by cable theft while reducing reliance on diesel backup.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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MegSolid did not supply the Mafikeng project. This article uses its public configuration only to explain how hospital owners and EPC contractors should prepare a BESS sizing study and RFQ.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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What the 200kW\/400kWh Configuration Does\u2014and Does Not\u2014Tell Buyers<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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The public project figures define the scale of the solar and storage installation, but they are not a complete hospital BESS specification.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Public information<\/th>What it confirms<\/th>What remains undisclosed<\/th><\/tr><\/thead>
200kW solar PV<\/td>Installed PV power<\/td>Interval yield, clipping and island-mode availability<\/td><\/tr>
400kWh battery<\/td>Stated stored-energy capacity<\/td>Usable AC energy, SOC window and EOL guarantee<\/td><\/tr>
Central Microgrid Controller<\/td>Coordinated system control<\/td>Dispatch hierarchy, fallback logic and communications<\/td><\/tr>
ICU, theatres and emergency department<\/td>Critical clinical areas are supported<\/td>Actual circuit list and measured critical-load profile<\/td><\/tr>
Reduced diesel requirement<\/td>BESS and PV can reduce generator operation<\/td>Generator capacity, start sequence and fuel savings<\/td><\/tr><\/tbody><\/table><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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A common mistake would be to calculate:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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400kWh \u00f7 200kW = 2 hours<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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That conclusion is not supported by the public data. The 200kW figure is the PV rating, not a published battery PCS rating or hospital critical load.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Actual battery duration depends on usable energy, critical-load demand, conversion losses, auxiliary consumption, minimum SOC, battery state of health and the contribution available from solar or generators during an outage.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Request a Preliminary Hospital BESS Sizing Review<\/h3>\t\t\t\t<\/div>\n\t\t\t\t
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Send MegSolid the hospital\u2019s interval load data, critical-circuit schedule, existing UPS and generator ratings, required backup duration and site single-line diagram.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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The initial review can identify the required power range, delivered-energy requirement, missing engineering data and suitable product families before a firm quotation.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

\n\t\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\tSubmit a South Africa Hospital BESS Project<\/span>\n\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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Separate Hospital Loads into Three Continuity Tiers<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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Hospital BESS sizing should start at the protected distribution boards, not at the monthly electricity bill.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Load tier<\/th>Typical function<\/th>BESS design implication<\/th><\/tr><\/thead>
Tier 1: No-break loads<\/td>Selected medical equipment, life-safety controls, communications and systems designated by the hospital risk assessment<\/td>Retain equipment-level or medical-grade UPS protection; the BESS supports the upstream microgrid<\/td><\/tr>
Tier 2: Rapid-restoration loads<\/td>Selected ventilation, pumps, cooling, medical-gas support and clinical services permitted a short interruption<\/td>Include steady power, motor starting and restart sequence<\/td><\/tr>
Tier 3: Deferrable loads<\/td>Offices, laundry, non-essential HVAC and other shed-capable circuits<\/td>Exclude during an outage unless sufficient reserve is available<\/td><\/tr><\/tbody><\/table><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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The exact classification must be approved by the hospital, electrical consultant and relevant authority. Generic equipment lists cannot replace a circuit-level clinical risk assessment.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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A BESS should not automatically be described as a replacement for the hospital\u2019s existing UPS. UPS equipment protects loads that cannot tolerate an interruption, while the BESS and microgrid controller manage longer-duration energy, solar, generators and protected buses.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Size BESS Power from the Critical-Load Profile<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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Battery power must cover the highest verified demand on the protected bus and the largest permitted load step.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Use both checks:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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P_steady \u2265 Tier 1 load + selected Tier 2 load + BESS auxiliaries<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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P_dynamic \u2265 running protected load + largest simultaneous starting or restart step<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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The EPC should obtain at least several weeks of interval data from the proposed protected bus. One-minute or sub-minute records may be required where chillers, pumps, compressors or imaging equipment create short peaks that 15-minute billing data cannot show.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Illustrative 170kW Critical-Load Example<\/h3>\t\t\t\t<\/div>\n\t\t\t\t
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Assume a hospital study identifies 170kW of coincident critical load. This is an illustration, not a published Mafikeng load.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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If the consulting engineer applies a provisional 15% design margin:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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170kW \u00d7 1.15 = 195.5kW<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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The preliminary study would therefore investigate approximately 200kW of continuous AC capability before checking power factor, motor starting, overload duration, redundancy and future load growth.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Solar generation should not be subtracted from the guaranteed outage power unless the microgrid can keep the PV plant operating in island mode. That capability must be demonstrated through the selected PCS, PV inverter, protection and controller architecture.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Review the MegSolid PCS engineering guide<\/a><\/strong> before selecting the protected-bus and islanding arrangement.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Calculate Required Energy from Backup Duration<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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The delivered-energy requirement is:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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E_delivered = critical load \u00d7 required backup duration<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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For the same illustrative 170kW load and a two-hour requirement:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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170kW \u00d7 2 hours = 340kWh delivered to the protected load<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Installed nameplate energy must then account for the approved SOC window, conversion efficiency, end-of-life retention and configuration availability:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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E_nameplate \u2265 E_delivered \u00f7 (usable SOC \u00d7 discharge efficiency \u00d7 EOL retention \u00d7 availability)<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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An illustrative calculation using 90% usable SOC, 92% discharge-path efficiency, 80% EOL retention and 97% availability gives:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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340 \u00f7 (0.90 \u00d7 0.92 \u00d7 0.80 \u00d7 0.97) \u2248 529kWh<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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These factors are modelling assumptions, not MegSolid product guarantees. The final values must come from the ordered configuration, warranty, PCS data and agreed test method.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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The calculation shows why 400kWh of stated battery capacity cannot automatically be treated as two hours of guaranteed support for a 170kW hospital load at end of life.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Coordinate the UPS, BESS, Solar PV and Diesel Generator<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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A hospital microgrid should define the operating sequence before equipment selection.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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System state<\/th>Required control action<\/th><\/tr><\/thead>
Grid healthy<\/td>Supply hospital loads, charge the battery and manage solar production<\/td><\/tr>
Grid disturbance<\/td>Existing UPS protects designated no-break loads while the microgrid changes operating state<\/td><\/tr>
Island established<\/td>BESS supports the protected bus; solar remains available only if the approved architecture permits<\/td><\/tr>
Extended outage<\/td>Start the generator at a defined SOC, load or forecast threshold<\/td><\/tr>
Generator online<\/td>Keep the generator inside its approved operating range and limit battery charging power<\/td><\/tr>
Grid restored<\/td>Resynchronise, transfer safely and rebuild the required reserve SOC<\/td><\/tr><\/tbody><\/table><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t
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The Central Microgrid Controller or EMS must know the status and limits of the grid connection, protected bus, UPS, BESS, PV inverter and generator.<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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Required fallback rules include:<\/p>\t\t\t\t<\/div>\n\t\t\t\t

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