Running power and signal cables to a remote tank farm is not an instrumentation problem — it is a civil engineering problem. Trenching across 300 meters of access road,laying conduit through a tank dike,and pulling shielded twisted-pair cable from each level transmitter back to a central RTU carries an installed cost of $80–150 per linear meter once you factor in permitting,excavation,conduit,cable tray,junction boxes,terminations,and site restoration. For a tank located 500 meters from the nearest power drop,the installed cost of the cable run can exceed the cost of the level transmitter by a factor of five. Solar-powered wireless level monitoring eliminates this cost entirely — but it substitutes a different set of operating expenses that need to be understood before committing to a fleet-wide deployment.
The Trenching vs. Solar Trade-Off: Five-Year TCO Model
The wired approach front-loads cost into installation. A 4–20 mA loop-powered level transmitter connected by buried cable and conduit carries essentially zero ongoing operating cost beyond sensor calibration — no batteries,no SIM cards,no cloud subscriptions. The solar-wireless approach eliminates civil works but incurs recurring costs: battery replacement every 2–5 years (depending on measurement interval and sun exposure),cellular or LoRaWAN data plan fees,and typically a cloud or on-premise data aggregation platform subscription.
At the 10-tank scale,the wired approach usually wins over a five-year horizon because the trenching cost per tank is manageable when tanks are clustered within a 100-meter radius. At the 50-tank scale,particularly when tanks are spread across a 2–5 km site,the solar-wireless TCO becomes compelling — the incremental cost of adding a wireless transmitter to a distant tank is just the sensor plus mounting hardware,whereas each additional wired tank drives a new cable run whose cost scales linearly with distance. At the 100-tank scale with tanks distributed across multiple remote sites,solar-wireless is almost always the lower-cost option unless the site already has existing conduit infrastructure from a previous wired instrumentation installation.
LoRaWAN vs Cellular: Choosing the Right Wireless Backhaul
The wireless physical layer decision shapes the entire system architecture. LoRaWAN operates in the unlicensed ISM band (868 MHz in Europe,915 MHz in North America) with a range of 2–15 km depending on terrain and antenna height. It requires deploying at least one LoRaWAN gateway on site — a single gateway typically covers 50–200 end devices across a 5 km radius in flat terrain. There is no per-device data plan cost,which makes LoRaWAN the default choice for dense tank farms where the gateway cost can be amortized across many transmitters.
Cellular (LTE-M or NB-IoT) eliminates the gateway entirely — each transmitter talks directly to the nearest cell tower. The per-device data plan typically costs $1–5 per month depending on message frequency and carrier. Cellular is the better choice for geographically isolated tanks — one tank on a hilltop 20 km from the nearest other instrumentation — where a dedicated LoRaWAN gateway cannot be justified. Cellular also offers higher data throughput,which matters if you need 1-minute update intervals instead of the 15-minute intervals typical of LoRaWAN deployments.
The Ellenex PLS2-L is a LoRaWAN wireless level transmitter designed for this exact application: low-power operation from a small solar panel or long-life battery,with sub-1-second measurement and a configurable transmit interval from 1 minute to 24 hours. Its IP67 rated body and ATEX Zone 0 certification cover the majority of remote tank monitoring scenarios including fuel and chemical storage.
Power Budgeting: Solar Panel Sizing and Battery Life
A wireless level transmitter running on a solar panel and rechargeable battery must survive the worst-case winter week — overcast skies,short daylight hours,and sub-zero temperatures that reduce battery capacity by 20–40%. The power budget starts with the transmitter's energy per measurement cycle: a typical LoRaWAN level transmitter consumes 40–80 µJ per measurement (ultrasonic pulse + microcontroller processing) and 100–200 mJ per LoRaWAN transmission (sensor reading + battery voltage + diagnostic flags). At a 15-minute transmit interval,that is 96 transmissions per day,or roughly 10–20 J per day for radio alone.
A 5-watt solar panel in a temperate climate produces roughly 10–25 Wh per day on average,but only 2–5 Wh on a dark December day. A 5 Ah lithium battery at 3.7 V stores about 66 kJ (18 Wh) — enough to run the transmitter for 20–30 days with zero solar input. The rule of thumb: size the battery for 21 days of autonomy and the solar panel for 3× the average daily consumption. Sites above 50° latitude need roughly double the panel area of sites below 30° latitude for the same reliability.
Which level sensing technology works best in a solar-powered deployment?
Ultrasonic and radar are the two practical options for non-contact measurement in remote tanks. Ultrasonic is lower cost and lower power — a typical ultrasonic transducer draws 5–15 mA during a 50 ms measurement burst — but it struggles with foam,vapor layers,and condensation on the transducer face. Radar (FMCW or guided wave) handles foam and vapor far better but draws more power per measurement due to the faster electronics. For clean water,diesel,and light chemicals in vented tanks,ultrasonic is usually the right starting point. For tanks with agitators,steam,or heavy foam,consider radar — but verify that the solar panel and battery can supply the higher average power before committing to a design. For more options,browse our wireless telemetry and level transmitter ranges.
How reliable is LoRaWAN in an industrial tank farm with metal structures?
LoRaWAN's sub-GHz frequency and chirp spread spectrum modulation give it excellent penetration through non-metallic obstacles and reasonable performance around metal structures — but it is not immune to multipath fading. A gateway antenna mounted at 10–15 meters above ground with a clear line of sight to the tank top typically achieves 3–5 km range even in a tank farm with steel tanks. Transmitters mounted at grade level behind a steel tank skirt can lose 10–15 dB of link budget. The fix is simple: mount the transmitter antenna above the tank rim or on an extension mast that clears the tank roof by at least 0.5 meters. Site surveys with a portable spectrum analyzer are essential before committing to gateway and antenna locations.
For additional level sensing technologies,see our level sensors category covering ultrasonic,radar,and hydrostatic options for tank inventory management.
