Separate the bill-saving goal from the backup goal
Whether solar keeps supplying power during an outage has to be answered from the design and the capability of the system actually installed. Panels on the roof do not by themselves guarantee that the building will stay powered, or that every appliance will run as it does normally. So state your backup requirement from the first conversation with the designer.
The U.S. Department of Energy explains that a typical grid-tied solar system is designed to shut down when the grid fails, for safety, and that operating during an outage requires the right components and configuration. That explains the principle; it is not confirmation that any given system in Thailand is ready to provide backup power.
List the work that cannot stop, before choosing equipment
Start from the impact on the business: orders have to be received over the network, work in progress has to be saved, certain areas have to stay lit. Then convert each task into a list of appliances and locations. Separate what is needed immediately, what can pause, and what needs a dedicated system.
A hypothetical example: an office wants the router and one computer to keep running so work can be saved, but is willing to switch off the air conditioning during an incident. That scope is very different from asking for whole-building backup. Where there is medical equipment, a security system, or a process that becomes dangerous if it stops, the responsible specialist must set the standard for it.
State both the power and the duration you need
Give the designer the number of units, models, power figures from the equipment documentation, and how each is used. Say which items start up at the same time or contain motors, because handling start-up surge and delivering continuous energy are two different questions. Do not choose on battery capacity alone.
State the backup duration you need and why — time for an orderly shutdown, or continued work over a particular window — and separate daytime from night-time needs. The designer has to assess the real constraints and the energy actually usable; a single "hours of runtime" number from an advertisement cannot be applied to every load.
Ask exactly which circuits get power, and how it switches over
Have the bidder point out which equipment is on the backup circuit, which is not, and what the limits are on running things simultaneously. If boards or circuits have to be separated, include that work in the scope and the price. The building owner should get an explanation they can follow, without having to open a switchboard to check.
The other question is whether equipment blips when the grid fails, whether someone has to operate anything, and how it returns to the normal supply. Do not assume that "battery", "hybrid solar" and "backup power" all mean the same kind of uninterrupted supply. Check suitability for equipment sensitive to brief interruptions against the manufacturer's information and the system design.
Agree how acceptance will be tested, against the scenario you settled on
Before buying, ask how the backup capability will be demonstrated against your chosen load list, who carries out the test, and what the starting conditions are — state of charge, or how many items are switched on. Test results should be recorded as they actually occurred, not extrapolated from a short demonstration into a guarantee under all conditions.
Simulating an outage and verifying islanding from the grid is work for a responsible person with the knowledge and the safety procedures. The building owner should not disconnect cables, modify protective devices or back-feed power themselves. Agree instead on how to report problems and on the operating instructions given to the assigned building manager.
Send the design team a single, consistent brief
Summarise the critical tasks, the equipment list, the backup duration required and what you are willing to let stop, all in one document, together with space constraints and any expansion plans. When the proposals come back, check that everyone answered the same brief before comparing prices.
Preparing the brief this way makes a solar design discussion with Kintury Energy clearer — both the bill-saving side and the part that needs continuity of operations. System size, installation method and expected results still have to go through a site-specific survey and assessment.
