Connecting one remote solar plant over cellular is easy. Connecting 50 or 100 sites is a different problem.
At that scale, the real question is no longer, “Can this router get online?” It becomes:
Can every site use the same network design, recover from link failures, stay within its SIM data plan, and be maintained without sending an IT engineer on site?
That is the problem an industrial cellular router should solve.
A useful real-world reference comes from an IT manager responsible for more than 50 PV plants, more than 10 energy storage sites and around 10 hydro plants. Most locations rely on LTE because they are remote. A typical site includes a cellular router, switches, an NVR/DVR, 7–15 IP cameras and other field equipment. The team also plans to connect PLC and datalogger data to a second-level SCADA system. One recurring problem is SIM data unexpectedly running out, while IT staff cannot easily identify which device caused the traffic spike.
This is a very typical multi-site energy networking problem.
For 50+ sites, avoid designing every network separately.
A better approach is to define one repeatable site architecture:
PLC / Datalogger / Energy Meter
↓
Managed Ethernet Switch
↓
Industrial Cellular Router
↓
4G/5G Network + VPN
↓
Central SCADA / Monitoring Center
Cameras, NVRs and maintenance laptops can connect to the same physical infrastructure, but they should not necessarily share the same logical network.
For example, divide the site into three VLANs:
VLAN 10 — SCADA, PLCs and dataloggers
VLAN 20 — CCTV and NVR
VLAN 30 — engineering and maintenance access
This keeps video traffic away from control equipment and makes troubleshooting much easier.
It also avoids a common mistake: expecting the cellular router to replace the switch, firewall, protocol gateway and SCADA gateway at the same time.
For a small site, let the industrial cellular router handle WAN access, VPN, failover and remote access, while a managed industrial switch handles most local VLAN segmentation.
Once dozens of sites are connected, inconsistent addressing becomes a maintenance problem.
Create a predictable subnet for every plant.
For example:
Site 001: 10.10.1.0/24
Site 002: 10.10.2.0/24
Site 003: 10.10.3.0/24
Site 050: 10.10.50.0/24
Then reserve address ranges inside each subnet:
.1 — router
.10–.19 — switches
.20–.49 — PLCs and dataloggers
.50–.99 — cameras
.100–.120 — NVR/HMI
.200+ — maintenance devices
The exact numbers are not important.
Consistency is.
When someone reports that the inverter gateway at Site 37 is offline, your IT team should already know where to look before logging into the network.
Remote solar and hydro sites often have only LTE or 5G available.
That makes theindustrial cellular routerthe WAN edge of the plant.
For this role, PUSR USR-G816 is designed with 5G SA/NSA support with fallback to 4G, Gigabit Ethernet interfaces, VPN functions and an RS232/RS485 serial interface. It also supports switching between cellular, Ethernet and Wi-Fi network paths when different uplinks are available.
For an isolated hydro station, cellular may be the only WAN connection.
For a larger solar or storage site, Ethernet or fiber may be the primary connection, with cellular used as backup.
The site network design can remain almost identical in both situations.
That consistency matters more than having a different router architecture for every plant.
Remote sites often fail because of coverage, not because the router lacks throughput.
Carrier A may work well at one solar farm and poorly at a hydro station 200 km away.
For remote deployments, use SIM cards from different operators where possible.
USR-G816 supports dual SIM operation and cellular network fallback, which gives the site another recovery path when one carrier connection becomes unavailable.
But do not install two SIM cards and assume the problem is solved.
Before commissioning each site, record:
carrier
signal strength
antenna position
normal daily traffic
expected monthly data consumption
fallback SIM
VPN status
This turns cellular connectivity into something measurable instead of something technicians troubleshoot only after the site goes offline.
This is especially important in renewable-energy sites.
A PLC usually sends relatively small amounts of telemetry.
An IP camera does not.
The reference multi-site operator specifically reported SIM packages running out while the team could not determine which device was consuming the data. The same discussion pointed out that cameras or NVR cloud synchronization can become a major source of unexpected cellular traffic.
So do not simply connect the whole site LAN to the SIM connection without traffic rules.
At minimum:
Put CCTV on a separate VLAN.
Disable unnecessary cloud services on NVRs and cameras.
Avoid continuous remote video upload unless required.
Restrict camera remote access to authorized destinations.
Set cellular traffic thresholds and alarms.
USR-G816's remote management functions can report network conditions and generate alarms for conditions including device offline events, weak signal and traffic overrun.
This is much more useful than discovering the problem when the SIM stops working.
If a second-level SCADA system is planned, design the secure remote path before connecting PLC networks to the public cellular network.
A simple architecture is:
Energy Site → Industrial Cellular Router → VPN Tunnel → Control Center Firewall → SCADA Server
The router should not expose PLC web interfaces or engineering ports directly to the Internet.
USR-G816 supports VPN technologies including IPSec and OpenVPN, together with firewall, NAT and access-control functions for remote networking.
For dozens of sites, use a consistent VPN naming scheme as well:
SITE001-SOLARSITE002-HYDROSITE003-BESS
If there is a VPN problem six months later, nobody should need an Excel sheet just to understand which tunnel belongs to which plant.
This becomes important once SCADA is introduced.
MQTT, Modbus TCP and OPC UA are application protocols. A router can transport their IP packets without necessarily understanding or converting them.
If a site only needs to send Modbus TCP traffic through a VPN, the router mainly provides secure IP connectivity.
If an old energy meter outputs Modbus RTU over RS485, however, protocol conversion may be required.
USR-G816 provides an RS232/RS485 interface and supports functions such as Modbus RTU-to-TCP conversion, which can be useful for relatively simple serial equipment.
But if the project requires complex OPC UA aggregation, protocol mapping, edge logic or data preprocessing, use an industrial gateway or edge computer instead of trying to push every function into the router.
Keeping these roles separate makes the system easier to maintain.
When there are five sites, driving to a plant may still be inconvenient.
When there are 70, it becomes part of your operating cost.
A multi-siteindustrial cellular routerdeployment should therefore allow engineers to check remotely:
whether the router is online
cellular signal condition
traffic usage
VPN status
network configuration
fault alarms
USR-G816 supports remote device management, allowing authorized engineers to remotely view and modify router parameters instead of configuring every unit locally.
This should be part of the architecture from day one, not added after dozens of routers are already installed.
Do not order routers for all sites immediately after a successful desk test.
Start with three different locations:
Site A: strong cellular coverage
Site B: weak or unstable cellular coverage
Site C: representative site with PLC, SCADA and CCTV traffic
Run them long enough to understand:
failover behavior
VPN recovery
monthly SIM consumption
remote configuration
camera bandwidth
modem reconnect behavior
power-cycle recovery
Then freeze the configuration as the standard template for the remaining sites.
When Site 51 is commissioned, it should not be a new network project. It should be another copy of a design that has already been tested.
For multi-site solar, hydro and energy storage systems, selecting an industrial cellular routeris only part of the job.
The bigger gains come from standardizing the entire site:
one IP plan, one VLAN strategy, one VPN architecture, one router configuration template and one remote maintenance process.
For sites requiring 4G/5G connectivity, VPN access, cellular failover, remote monitoring and occasional RS485/RS232 integration, an industrial router such as the USR-G816 can serve as the WAN edge of that standardized architecture.
Once that architecture is repeatable, expanding from 10 sites to 50—or from 50 to 100—becomes much easier.
The goal is not to build 50 individual networks.
It is to buildone reliable network design and deploy it 50 times.
