Why is offshore wind production relatively expensive?
A chunky 38% of the operating costs of offshore wind farms is allocated to maintenance. What’s contributing to that cost?
- Equipment failure: on average, each turbine will experience 8.3 failures every year, comprising 6.2 minor repairs, 1.1 major repairs, and 0.3 major replacements
- Manpower: on average, it takes 116 days and 9 technicians to undertake a major replacement, and 7 days and 3 technicians for a minor repair. Delays are frequent, due to ‘no access days’ caused by bad weather
- Ageing equipment: some analysts project that opex costs increase from £184,000 per MegaWatt per year when the turbine is new, to £426,000 per MW/Year when the turbine is 15 years old.
Wireless connectivity options for transmitting IoT data from offshore wind farms
LoRaWAN coupled with satellite connectivity is getting an increasing amount of attention for this application. LoRa networks are very easy to set up, and have a wireless range of approximately 16km. They’re specifically designed for IoT data so LoRa-enabled sensors have very long battery lives, but very small data-throughput.
Aggregate each turbine’s sensor data in a LoRaWAN gateway, and then use a single satellite transceiver to transmit the data into the cloud. This is easily achieved with technology that’s widely available today. For example, a device like the RockREMOTE Rugged can be placed almost anywhere on a turbine, as its omni-directional antenna connects with the Iridium satellite network: if the turbine moves, there’s no loss of connection.
This combination of a Wide Area Network and satellite means that most turbines don’t need a specific piece of hardware to communicate to the satellite network: only one, the ‘master’ turbine, needs this, along with the gateway. The gateway can help to lower the cost of data transmission by providing edge computing capabilities: reporting on exception, for example, ensures that only data points falling out of agreed parameters is transmitted.
Recommended OSV satellite IoT hardware
While OSVs usually have a heavyweight VSAT system for crew communication, we’d recommend a separate, lighter-weight system for the transmission of IoT and tracking data, both as a failsafe and to use the bandwidth more efficiently.
The Thales VesseLINK is an ideal for solution for this purpose. It utilises the Iridium satellite network which has 100% global coverage, and the antennas are omni-directional, meaning there’s no need to re-point the device when the OSV moves. Because the network is in Low Earth Orbit (LEO), the latency is low – less than one second. Coupled with the fact that it uses the L-band frequency to transmit data, which is unaffected by weather conditions, Iridium-enabled devices are ideal for mission-critical data.
The Thales VesseLINK is available in two versions: the VesseLINK 200 and VesseLINK 700. The difference between them is the data speeds: the former is designed for IoT data and basic voice / internet access, with data speeds of 176 Kbps. The latter delivers high-speed internet with speeds of 700 Kbps, and creates a WiFi hotspot for any device within a 300 metre range. So it’s capable of far more than transmitting IoT data, but will do so under any conditions.
Talk to the experts
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