When talking about solar power, you’ll often hear terms like megawatts (MW) and megawatt-hours (MWh) — but many people use them interchangeably without realizing they mean very different things.
What is the Difference Between MW and MWh?
| Term | Definition | Example |
| Megawatt (MW) | A unit of power, representing the rate at which energy is produced or consumed. | A solar farm with a capacity of 10 MW can produce 10 million watts at full output. |
| Megawatt-Hour (MWh) | A unit of energy, representing the amount of power produced or consumed over time (1 MW for 1 hour). | If that 10 MW solar farm runs at full power for 1 hour, it generates 10 MWh of energy. |
👉 In short:
• MW = power capacity
• MWh = energy produced
How This Applies to Solar Power:
When we talk about solar projects, both MW and MWh come into play at different stages:
1. During Installation – Capacity (MW)
Developers and government agencies describe solar plants in megawatts (MW).
For example:
• A 5 MW solar plant in Rajasthan can power roughly 2,000 homes.
• A 500 kW (0.5 MW) rooftop solar project might be installed on an industrial building.
This tells you the maximum potential output, not how much electricity it actually generates.
2. During Operation – Generation (MWh)
Once the plant is running, the focus shifts to energy generation — measured in megawatt-hours (MWh).
For instance:
• A 1 MW solar plant typically generates 1,400–1,600 MWh per year in India, depending on sunlight and location.
• That’s the actual usable electricity fed into the grid or consumed onsite.
How Do You Convert MW to MWh?
Formula:
Energy (MWh) = Power (MW) × Time (hours)
Let’s assume:
• You have a 10 MW solar farm.
• It operates at an average capacity factor of 20% (typical for solar).
Annual energy output = 10 MW × 24 hours × 365 days × 0.20 = 17,520 MWh/year
So, this project produces 17,520 megawatt-hours per year, enough to power ~7,000 homes!
Why It Matters for Solar Stakeholders?
🔹 For Homeowners
If you install rooftop solar, your installer might tell you your system is 5 kW. But your electricity savings depend on how many kWh (kilowatt-hours) you generate — that’s the real energy you consume or export.
🔹 For Solar Developers
Project bids, tenders, and Power Purchase Agreements (PPAs) use both units:
• MW defines project size.
• MWh defines delivery obligations and revenue.
For instance, a 50 MW solar farm selling power at ₹3.00 per kWh (₹3,000 per MWh) will earn ₹52.5 crore/year if it produces 175,000 MWh annually.
🔹 For Policymakers & Utilities
When states announce targets — like “10 GW of solar capacity by 2030” — they refer to installed MW.
But when reporting generation or grid contribution, they talk in MWh.
Global Perspective:
Countries measure their renewable achievements differently:
• China and India focus on total installed MW.
• Europe and the U.S. often highlight annual MWh generation to track carbon reduction.
Both are important — one represents potential, the other performance.
Conclusion:
In the world of solar energy, knowing the difference between MW and MWh is more than just technical — it’s financial, strategic, and environmental.
When you hear that a solar farm has a capacity of “100 MW,” think of it as its engine size. When you see that it generated “200,000 MWh last year,” that’s how much distance it traveled — the real impact of solar power.
