Megawatts to Gigawatts

Rolling Turbines and Projects Up into Gigawatts

Wind development happens in megawatts and gets reported in gigawatts. A turbine has an MW nameplate, a project consent is written in MW, an export agreement is in MW — but the board pack, the investor deck and the press release all want the portfolio expressed as a single GW number. Anyone maintaining that spreadsheet does this division several times a week.

Conversion factor: 1 MW = 0.001 GW, so divide megawatts by 1,000. An offshore array of 62 machines rated 15 MW is 930 MW of nameplate capacity, which reads as 0.93 GW — near enough to a gigawatt that the announcement will probably round it up and say so.

What Gets Added Together

Onshore clusters

Land-based projects run from a handful of machines to a few hundred megawatts, so an onshore portfolio is usually a long list of modest numbers rather than a few large ones.

Offshore arrays

A single offshore lease can carry more capacity than an entire onshore region, and it is bid, financed and built in phases that each carry their own MW figure.

Repowering uplift

Replacing 1990s machines on an existing site can multiply its megawatts several times over on the same footprint, so the fleet total moves without a new consent.

Stages of the pipeline

Early-stage, consented, under construction and operating are four different totals. Adding them into one gigawatt headline is common — and is exactly where readers get misled.

Building a Portfolio Figure from Project Megawatts

The arithmetic is trivial; the discipline is in keeping the stages apart so the gigawatt headline still means something when someone checks it.

Total one stage at a time

Sum the nameplate megawatts of everything in a single stage — operating, say — and type it in the left field. 102, 930, 3500: the gigawatt value appears as you type, and a comma or an extra space in the number is handled without complaint.

Check the count against the turbine rating

Divide the project megawatts by the machine rating to sanity-check the layout: 930 MW at 15 MW a machine is 62 positions, while the same 930 MW built onshore at 3.4 MW would need 274. If the turbine count in the drawing does not match, one of the two numbers is stale.

Reverse to unpack a gigawatt target

Announcements and government targets come in GW. The swap button (↔) runs GW → MW so a 3.5 GW programme becomes 3500 MW, which you can then split across phases the way the construction schedule actually works.

Take the number into the tracker

Copy puts the plain value on the clipboard with no unit attached, ready to drop into a capacity tracker or a slide. Ctrl + C inside either field behaves the same way.

Nameplate is a ceiling, not a yield: gigawatts of installed capacity say what the fleet can do in a good wind, and nothing about annual energy. Two portfolios of identical GW can differ by a third in output if one sits offshore in a steady resource and the other inland behind hills.

Turbine Ratings and Machines per Gigawatt

Nameplate ratings across four decades of turbine design, with what each one contributes in gigawatts and how many positions a full gigawatt would need.

Turbine class	Nameplate	Per machine	Machines per 1 GW
Legacy onshore, 1990s–2000s	1.5 MW	0.0015 GW	667
Mid-size onshore	2.5 MW	0.0025 GW	400
Recent onshore average	3.4 MW	0.0034 GW	294
Large onshore / low wind	6 MW	0.006 GW	167
Early offshore fixed-bottom	8 MW	0.008 GW	125
Current offshore workhorse	15 MW	0.015 GW	67
Next-generation offshore	18 MW	0.018 GW	56
Announced offshore prototypes	22 MW	0.022 GW	46

The right-hand column is the story of the industry in one line: a gigawatt that once meant 667 machines and 667 foundations now takes 67, or fewer. Fewer positions means fewer sea-bed surveys, fewer cable runs and fewer installation days — which is why nameplate ratings kept climbing even after the rotors became awkward to transport.

Handy When the Capacity Sheet Is Open

Project megawatts to portfolio gigawatts as you type

Paste each stage total in turn and read the GW figure straight off, without clearing the field between projects.

Unpack a gigawatt target back into phases

Swapping direction gives GW → MW, the way round you need when a published target has to be reconciled with a build programme.

Kilowatts too, for the small legacy sites

The searchable dropdowns carry every power unit, so a 600 kW machine from an old wind cluster drops into the same calculation as a 22 MW prototype.

Values that paste into the pipeline sheet

Up to eight decimals are kept, so 3.4 MW does not collapse to 0.00 GW, and copy hands over the number alone.

Wind Portfolio Questions

Does a 1 GW wind farm actually deliver 1 GW?

Only in the wind band where every machine is at rated output, which is a minority of the year. The gigawatt is the sum of the nameplates. Averaged over a year an onshore fleet typically settles around a third of that and a modern offshore one around half, so 1 GW installed is closer to 350 MW or 500 MW of average delivery.

What capacity factor should I assume for onshore versus offshore?

As a planning rule of thumb, 30–40 % onshore depending on the site and the rotor-to-generator ratio, and 45–55 % for recent fixed-bottom offshore, with the best sites and largest machines quoted higher still. Modern low-wind onshore turbines lift the factor by fitting a big rotor to a modest generator, so a lower nameplate can post a better percentage.

Why did offshore turbines grow from 8 MW to over 20 MW?

Because the expensive parts offshore are per position, not per megawatt. Foundation, cable, vessel time and consenting cost roughly the same whether the machine on top is 8 or 18 MW, so halving the number of positions in a gigawatt halves a large slice of the capital cost. Swept area rises with the square of the rotor radius, which is where the extra megawatts come from.

What does a developer mean by a 5 GW pipeline?

Everything the company is working on, from sites with turbines already turning to leases with nothing but a boundary on a map. Read the split before the headline: operating capacity earns revenue now, consented capacity has planning permission, and early-stage capacity is an option that may never be built. Two developers claiming the same gigawatts can be in very different businesses.

How many machines sit behind a gigawatt of capacity today?

Offshore, about 67 at the 15 MW rating now going into the water, dropping toward 46 as 22 MW machines arrive. Onshore it is several hundred: at the 3.4 MW class that is 294 positions, which is why land-based gigawatts are assembled from many separate projects rather than one array.