Acres to Square Meters

Sizing a Ground-Mount Array on an Acre-Measured Parcel

Land comes to a solar developer in acres — the option agreement, the lease, the tax map and the interconnection application all say acres. Everything downstream of that is metric. Module datasheets give millimetres, ground coverage ratio is an area fraction, irradiance is kilowatt-hours per square metre, and the layout software works in metres. The first thing a land budget has to do is cross that line.

Conversion factor: 1 acre = 4 046.8564224 m², so multiply acres by 4 046.86. A 10-acre buildable envelope is 40 468.56 m²; at a ground coverage ratio of 0.40 that leaves 16 187.4 m² of module surface to fill.

Where the Metric Numbers Come From

Modules are dimensioned in millimetres

A current utility-scale panel measures about 2 278 × 1 134 mm, which is 2.583 m² of aperture. At 550 W that is 213 W per square metre of glass, or roughly 21.3 % efficiency at standard test conditions.

Ground coverage ratio splits the land

GCR is module area divided by the ground it sits over. Fixed-tilt blocks usually run 0.40–0.50; single-axis trackers sit lower, near 0.28–0.40, because they need clearance to rotate without shading the next row.

Resource data is per square metre

Plane-of-array irradiance arrives as kWh/m² per year. Multiplying it by module area and efficiency only works once the site is in square metres, which is why a yield estimate cannot start from the acre figure.

Gross acres are not buildable acres

Fence offsets, property-line setbacks, wetland buffers, access roads, inverter pads and drainage swales come off the top. Convert the buildable envelope, not the deed acreage, or the module count overstates the site.

From Deed Acreage to the Metric Layout Sheet

A land budget is short arithmetic done in the right order: convert, apply coverage, divide by module area, multiply by module wattage.

Enter the buildable acreage

Put the net developable acres in the left field — 12.5, 38, 240 — and the square-metre value appears as you type. Spaces are ignored and a comma is accepted as a decimal point, so a figure pasted from a European site plan still reads correctly.

Multiply by your ground coverage ratio

Take the square metres and scale by the GCR the racking vendor assumes. At 0.40, one acre gives 1 618.7 m² of module area; at 0.50 it gives 2 023.4 m². That single choice moves the capacity of a site by a quarter.

Copy the metric figure into the layout tool

The copy button gives the bare number with no unit and no digit spacing, which is what a PVsyst project field, a CAD area prompt or a capacity spreadsheet expects. Ctrl + C in a field does the same.

Reverse it when capacity comes first

If the offtake contract fixes the megawatts, press the swap button (↔) and run square metres back to acres to see how much land the deal actually needs before you approach a landowner.

Module area is not array area: the square metres of glass you calculate here are the aperture total, not the footprint of the racking blocks or the fenced envelope. Both matter, and confusing them is the fastest way to promise a landowner more capacity than the parcel can carry.

Land Budget for a Fixed-Tilt Array, Acre by Acre

Worked at a ground coverage ratio of 0.40 with 550 W modules of 2.583 m² each, so every row can be checked by hand.

Buildable land	Area (m²)	Module area at GCR 0.40	Modules	DC capacity
1 acre	4 046.86 m²	1 618.7 m²	626	344 kW
2 acres	8 093.71 m²	3 237.5 m²	1 253	689 kW
5 acres	20 234.28 m²	8 093.7 m²	3 133	1.72 MW
10 acres	40 468.56 m²	16 187.4 m²	6 266	3.45 MW
20 acres	80 937.13 m²	32 374.9 m²	12 532	6.89 MW
40 acres	161 874.26 m²	64 749.7 m²	25 065	13.79 MW

The ratio holds all the way down the table: about 344 kW of glass per buildable acre, or 2.9 acres per megawatt of aperture. Real projects report 4–6 acres per MW because roads, setbacks, substations and unusable ground never appear in this arithmetic — the table is the ceiling, not the promise.

What Earns Its Place in a Land Budget

Redraw the envelope, reread the metres

Both fields are live, so when a wetland delineation takes 3.4 acres out of the site you retype the new acreage and the square-metre budget follows immediately.

Work backwards from a target megawatt

Swapping the direction answers the landowner's question instead of the engineer's: how many acres does a 5 MW block need before setbacks are added?

Hectares for the grid application

The searchable dropdowns carry hectares and square kilometres too, which is what utility and permitting forms outside the United States ask a site area to be stated in.

Decimals fine enough for a string count

Up to eight decimal places are shown, so dividing a site area by a 2.583 m² module still lands on a whole-string number rather than a rounding argument.

Land, Modules and Ground Coverage Questions

How much DC capacity fits on one acre of fixed-tilt ground mount?

Around 344 kW with today's hardware. One acre is 4 046.86 m²; at GCR 0.40 that is 1 618.7 m² of module area, which holds 626 panels of 2.583 m², and 626 × 550 W is 344.3 kW. A decade ago the same acre carried closer to 200 kW, purely because panels were less efficient.

What does changing the ground coverage ratio do to the square metres I can fill?

It scales the answer directly. On one acre: GCR 0.30 gives 1 214.1 m² and 469 modules (258 kW), GCR 0.40 gives 1 618.7 m² and 626 modules (344 kW), GCR 0.50 gives 2 023.4 m² and 783 modules (431 kW). Tighter rows buy capacity and pay for it in winter row-to-row shading.

Why do developers quote 4 to 6 acres per megawatt when this maths says under three?

Because the parcel carries more than panels. Perimeter fence offsets, 20–50 ft internal access roads, inverter and transformer pads, a collection substation, stormwater basins, vegetated buffers and any awkward geometry all consume land that never appears in a GCR calculation. The 2.9 acres per MW figure is the aperture limit; the site limit is always larger.

How do I get from a kWh/m² resource figure to annual output on my parcel?

Multiply module area by efficiency by irradiance, then by a performance ratio. On one acre at GCR 0.40: 1 618.7 m² × 21.3 % × 1 800 kWh/m² per year ≈ 620 MWh at the glass, and about 496 MWh delivered at a performance ratio of 0.80 — roughly half a gigawatt-hour a year from a single acre.

How is row pitch related to the acre figure I converted?

Pitch is the metric expression of the same ratio: GCR equals table width divided by row pitch. A two-up portrait table about 4.56 m wide at GCR 0.40 sits on an 11.4 m pitch, so each row occupies 11.4 m of the site's north-south depth. Convert the parcel to metres and the number of rows that fit is a division you can do on paper.