Reliable electricity is essential as Internet services reach more remote locations and support activities such as telephony, messaging, banking and telemedicine. solar photovoltaics paired with battery storage are increasingly presented as an alternative to vulnerable grid connections and diesel generators, but choosing a system that fits local requirements can be challenging.
The first step is to identify every device the system must power, including routers, servers, switches, transmitters, cooling equipment and on-site tools. The article recommends recording each device’s wattage, checking manufacturer labels or using a power meter when figures are unavailable, and accounting for less obvious loads such as hot water equipment. Adding the expected loads helps establish the system’s peak power requirement and reduces the risk of buying an undersized installation.
Designers also need to decide whether the system should operate independently or connect to a local grid. An off-grid system is simpler and may be the only option where no grid is available, but it must be sized to cover demand through extended periods of poor weather. A grid-connected system can send excess electricity to the network, potentially reducing generator use in small grids, though its design and operation are more complex. Equipment that cannot tolerate interruptions may need a UPS to bridge brief power gaps when the system switches between grid-connected and island operation.
The article advises against installing solar solely as a backup system, arguing that this leaves the panels idle while users continue paying for grid electricity. Instead, system design should account for regular use and, where possible, the role of excess generation.
The next stage is modelling expected generation using a tool that takes location, panel orientation and tilt, available area, and shading into account. Standard panels may have peak ratings of around 430 to 460 watts, but actual output varies with conditions. For smaller systems, the article suggests considering a hybrid inverter with capacity well above average load, while battery storage should be assessed against the amount of time the network must run without incoming charge. It gives five days of autonomy as a design reference and notes that greater panel and inverter capacity can allow for less storage by enabling faster recharging.
Modelling can help determine whether the proposed panels, inverter and batteries can meet demand in island mode. Designers can adjust capacity or identify loads that could be switched off during an outage. The article also notes a trade-off between generation and storage capacity, says installations beyond a few kilowatts should generally use three-phase AC, and describes adding panels as relatively inexpensive.
The piece is the first instalment of a series by Dr Ulrich Speidel, a senior lecturer in computer science at the University of Auckland. A forthcoming part will cover suppliers and components, quote evaluation, cybersecurity, support and long-term reliability.
Sources: APNIC Blog.