When people hear “wind farm,” most imagine tall turbines spinning in an open field. But today, wind power exists in two very different environments: onshore (land) and offshore (sea).
And the difference between the two is not just geography, it determines cost, output, maintenance, and even how nations plan their energy future.
Here’s a practical guide to help you know instantly whether a wind farm is offshore or onshore, and why the distinction matters.
1. The Easiest Indicators: How to Tell Them Apart
1. Location and Foundation Type
- Onshore wind farms sit on solid ground, mounted on concrete foundations. You can usually access them by road.
- Offshore wind turbines are installed in the sea, often several kilometres from land, mounted on monopiles, jackets, or floating platforms.
If the base structure is surrounded by water that’s offshore, no question.
2. Turbine Size
- Offshore turbines are massive, typically 12–18 MW today.
- Onshore turbines range from 2–6 MW.
If the blades are the size of football fields, likely offshore.
3. Proximity to Transmission Lines
- Onshore wind is usually connected directly to nearby grid lines.
- Offshore wind requires subsea cables, then a landing point, then an onshore substation.
A map showing a subsea transmission route = offshore.
4. Noise & Access Patterns
- Onshore wind farms are often accessible to technicians by car.
- Offshore wind farms require boats or helicopters.
2. Why Location Matters: Output, Cost & Reliability
Understanding the difference is more than trivia, it helps explain why governments make certain energy decisions.
A. Output & Wind Speed
Offshore wind farms produce more power because they benefit from:
- Stronger, steadier winds
- Fewer physical obstructions
Offshore wind capacity factors typically range 40–55%, while onshore averages 25–35%.
B. Cost Differences
Offshore wind is far more expensive to build and maintain:
- Foundations in water
- Installation vessels
- Subsea cables
- Harsh marine conditions
IRENA estimates offshore wind capex at $2.5–4 million per MW, versus $1–1.5 million per MW for onshore.
C. Maintenance Challenges
Onshore turbines can be serviced daily. Offshore turbines require:
- Weather windows
- Marine vessels
- Higher safety protocols
This increases operating costs significantly.
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3. Why Some Countries Prefer Offshore and Others Prefer Onshore
Offshore is ideal for:
- Countries with limited land (UK, Japan, Netherlands)
- Nations seeking massive utility-scale power
- Coastal regions with deep-water ports
Onshore is ideal for:
- Countries with abundant land (USA, China, Kenya, South Africa)
- Lower-cost rural electrification
- Faster installation timelines
GWEC 2024 report shows over 80% of global wind capacity is still onshore.
4. A Quick Checklist: Onshore vs Offshore
| Feature | Onshore | Offshore |
| Terrain | Land | Sea |
| Typical Capacity | 2–6 MW | 12–18 MW |
| Costs | Cheaper | Higher |
| Capacity Factor | Lower | Higher |
| Maintenance | Easy | Difficult |
| Grid Connection | Overhead lines | Subsea cables |
If it stands on land, uses concrete foundations, and sits near transmission lines, it’s onshore.
If it’s planted in the sea, supported by steel structures, accessed by vessels, and linked via subsea cables, it’s offshore.
And the location determines everything from power output to government policy to investment trends.
