4G Cellular Connectivity for BESS, Solar Farms, and Energy Infrastructure
Utility-scale battery energy storage systems (BESS), solar farms, and remote substations are increasingly dependent on reliable, secure communications for SCADA monitoring, EMS control, grid compliance reporting, and remote diagnostics. These sites are frequently in rural locations without fixed broadband, and the communications infrastructure must meet both availability and security requirements that consumer 4G cannot satisfy.
SimWise supplies industrial 4G routers, private IP SIM cards, and external antennas for energy asset operators, EPC contractors, and BESS developers. Our connectivity solutions are specified with the protocol requirements of energy monitoring in mind – DNP3 over TCP, Modbus TCP/IP, IEC 61850, and ICCP are all routable over our private IP SIM infrastructure.
Why Standard 4G SIMs Are Unsuitable for SCADA
SCADA systems communicate over TCP/IP. The control centre opens a connection to the RTU or BESS EMS at the remote site. This means the remote site must have an IP address that is reachable from the control centre network – either via a private circuit, a VPN, or a private IP SIM card.
Standard consumer SIM cards place the device behind carrier-grade NAT (CGNAT). The device can initiate outbound connections but cannot be reached by an inbound connection from the control centre. This makes standard SIMs fundamentally unsuitable for SCADA without additional tunnelling infrastructure.
Private IP SIMs for SCADA: How They Work
SimWise private IP SIM cards provide a static, routable IP address on a private APN (Access Point Name). Traffic from the control centre to the remote site travels over a private IP path that does not transit the public internet. This meets the security requirements of NIS/CSRB-regulated energy operators and eliminates the CGNAT problem entirely. The IP address is fixed, known in advance, and can be whitelisted at the control centre firewall.
Resilient Communications for BESS: The Right Architecture
ENA Technical Solution 2 (controllable BESS assets) and NIS Directive requirements for critical national infrastructure create specific availability requirements for BESS communications. A single-SIM router on one network does not provide the resilience these requirements demand.
SimWise recommends a layered resilience architecture for BESS and grid-connected energy assets:
- Primary router – dual-SIM, with SIMs from two verified different MNOs (site-tested, not assumed from coverage maps). Both SIMs active simultaneously for load balancing. MWAN3-based failover configured to switch within 30 seconds of a primary path failure.
- Secondary router – a second physical router on a third MNO, connected to the WAN port of the primary router. Provides a third independent path if the primary router itself fails.
- UPS – four to six hours of battery backup protects against brief power outages and generator transfer switching that might otherwise interrupt communications at a critical moment.
- Private IP SIM cards on all paths – all three SIMs on private APNs with static IP addresses, ensuring SCADA connectivity is maintained regardless of which path is active.
Protocol Compatibility
SimWise private IP SIMs are protocol-agnostic at layer 3. Common energy sector protocols that operate correctly over our SIM infrastructure include:
- DNP3 over TCP (port 20000) – used by most BESS and substation RTUs
- Modbus TCP/IP – used by inverters, meters, and ancillary plant
- IEC 61850 (MMS, GOOSE over IP) – used in modern digital substations
- ICCP / TASE.2 – used for inter-control centre communications
- HTTPS / REST APIs – used by cloud-connected BESS EMS platforms
Other Energy and Remote Monitoring Applications
Solar Farm Monitoring
Solar farms in rural locations use 4G routers to backhaul inverter data, weather station readings, and security camera feeds. A multi-network SIM ensures connectivity in locations with variable coverage, and an external antenna on the monitoring kiosk maximises signal.
Wind Farm Communications
Wind turbine SCADA systems use 4G as a primary or backup communications path. Each turbine may have its own router, or a site-wide network may aggregate traffic to a single point before backhauling over 4G.
Remote Substation RTUs
Distribution network operators (DNOs) and transmission system operators use 4G as a backup communications path for substations where fibre or leased line failure would otherwise leave the site unmonitored. A dual-SIM router with private IP SIMs on diverse networks provides a credible secondary path.
External Antennas: Do You Need One?
Every 4G and 5G router ships with stub antennas attached to the ports on the casing. In many installations these are perfectly adequate. In others – particularly inside metal-framed buildings, below ground level, or in rural areas far from the nearest mast – an external antenna can make a significant and measurable difference to both signal quality and sustained throughput.
Before purchasing an external antenna, we recommend working through a structured test process:
- Baseline test with supplied antennas in the intended location. Install the router where it will live in normal operation. Note the RSRP value from the router diagnostic page – this is a more reliable indicator than signal bars. Run a speed test and record the results.
- Try different positions within the same space. Cellular signal varies considerably within a single room. A window-mounted location can outperform a cabinet in the centre of the same space by 10-15 dB. Try several positions before concluding signal is poor.
- Test outdoors on a dry day. Take the router outside – clear of the building envelope – and run the same tests. Building fabric, particularly reinforced concrete, metal cladding, and low-emissivity glass, can attenuate signal by 20 dB or more. If outdoor results are substantially better, an externally-mounted antenna is the right solution.
- Test each network in turn. If you have a multi-network IoT SIM, lock the router to each available network and test each one. Coverage and performance vary significantly by network at any given location. EE frequently outperforms in rural areas; Three tends to be strongest in urban environments.
- Consider a directional antenna if signal is marginal. An omni-directional antenna captures signal from all directions but lacks gain. If you know the direction of the nearest mast, a directional or panel antenna aimed at the mast can provide 5-9 dBi additional gain over a standard stub – the equivalent of moving the router significantly closer to the mast.
Antenna Connection Note
Most 4G and 5G routers use SMA or TS9 connectors. Check your router specification before ordering an antenna and cable. For cable runs over five metres, use low-loss coaxial cable – standard RG58 introduces approximately 1.5 dB of loss per metre at LTE frequencies, which can negate the benefit of the antenna. Speak to SimWise before specifying a long cable run. Browse our antenna range.
Get a Quote for Energy Site Connectivity
Tell us about your asset – BESS, solar farm, substation, or other energy infrastructure. Include the SCADA protocol in use, whether you need private IP addressing, and whether this is a primary or backup communications path. We will specify the right solution.