If photovoltaics were a primary energy source, what would

the world look like? Would PV collectors cover every square

inch of available land? Contrary to popular opinion, a world

relying on PV would offer a landscape almost indistinguishable

from the landscape we know today.

The impact of PV on the landscape would be low for three

reasons. First, PV systems have siting advantages over other

technologies; for example, PV can be put on roofs. Second,

even ground-mounted PV collectors are efficient from the

perspective of land use. Third, adequate sunlight is ubiquitous and present in predictable amounts almost everywhere.

As we move away from fossil-fuel energy, PV use will be 

crucial because of its land-use advantages.

PV’s Low-Impact Siting for Flat-Plate Systems

In the United States, cities and residences cover about 140

million acres of land. We could supply every kilowatt-hour

of our nation’s current electricity requirements simply by

applying PV to 7% of this area—on roofs, on parking lots,

along highway walls, on the sides of buildings, and in other

dual-use scenarios. We wouldn’t have to appropriate a single

acre of new land to make PV our primary energy source!

PV’s Efficient Ratio of Produced Energy to Land Use

Even if it isn’t installed on rooftops, flat-plate PV technology

is the most land-efficient means to produce renewable energy.

As the table to the right shows, 

PV has a competitive converter

efficiency, a high capacity 

factor, and can be “packed”

densely in a given area.

We still wouldn’t have a landuse issue, even if we didn’t 

use roofs for PV. We would 

need only 10 million acres 

of land—or only 0.4% of the

area of the United States—to

supply all of our nation’s electricity using PV. Is 0.4% a lot 

of land? Not for something as

important as producing electricity, and not in comparison

to some of the other ways we

use land.

One way to understand land-use issues for different energy

sources is to realize that the federal government idles 

30 million acres of farmland every year—or three times 

the area needed to generate all our electricity from sunlight. We also set aside 23 million acres of land for the 

Arctic National Wildlife Refuge, which is more than twice

the acreage needed to generate all our electricity with PV. 

Furthermore, we set aside hundreds of millions of acres for

rangeland, military bases, airports, and rights-of-way for 

fossil fuel pipelines, drilling, and reserves every year—

How much land will PV need to supply our electricity?

U.S. Department of Energy

Energy Efficiency and Renewable Energy

Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable

Rooftop PV is practical in urban areas with high land costs. 

PV graces a rooftop in Brisbane, Australia.

Uni-Solar/PIX12961

PV: The Land-Area Advantage

Converter Capacity Land per year for:

Technology Efficiency (%) Factor (%) Maximum Packing GW GWh

Flat-Plate PV 10%–20% 20% 25%–75%d 10–50 km2/GW 5000–25,000 m2/GWhk

Wind Low to 20%a 20%c 2%–5%e 100 km2/GWg 140,000 m2/GWhi

Biomass 0.1% totalb High—plants compete 1000 km2/GWh 500,000 m2/GWhi

for sunlight

Solar Thermal 15%–25% 25% 10%–20%f 20–50 km2/GWh,i 10,000–20,000 m2/GWh

or PV Concen- 20 km2/GWj

trators

awww.windpower.org

b0.5% or less light-to-biomass; then 33% to electricity; 0.1% total 

cSite dependent

dTilted arrays at high latitudes versus flat ones at the Equator; 

room between for maintenance

ePimentel 2002; Dohn Riley et al.

f

Tracking arrays need wider separation to avoid shadowing

gHansen 2003

hHughes 2002

i

Pimentel 2002

j

Cohen 2003

kAt 15% module efficiency, 12% module-to-system 

operating efficiency losses
and most of us barely notice this land use. Thus,

even if we didn’t put PV on a single existing

structure, rooftop, or building, we’d still use

only a tiny fraction of our available land to

produce clean energy from PV.

A second way to compare energy sources is to

see how much the cost of land contributes to

overall electricity costs. Which technologies

produce enough energy so that land cost is 

not relevant to the total cost of the

energy produced? For PV, even if land

were to cost more than $80,000 per

acre, this cost would contribute less 

than one cent per kilowatt-hour to the 

cost of PV energy. Concentrator systems, or other solar systems that aren’t

flat-plate, offer 

similar landefficient energy

production. In

contrast, wind

and biomass 

are only able to

“afford” land at

less than $5,000

per acre to keep

the land’s contribution below one cent per kilowatt-hour. PV

can convert sunlight efficiently into energy,

with converters packed together densely. In

cities and affluent suburbs, where land costs

exceed $80,000 per acre, PV can be installed 

on roofs and structures. In other places, where

land costs are lower, PV can be installed almost

anywhere.

PV’s Ubiquitous Energy Source

The sun’s intensity doesn’t vary by region as

much as we might think. Looking at the

extremes, the U.S. Desert Southwest gets only

about 25% more sunlight annually than Kansas City. And Buffalo receives only 25% less

sunlight than Kansas City. Because PV energy 

output is proportional to sunlight, its cost

varies proportionally with local sunlight. If 

PV is cost effective in a location with average

sunlight, such as Kansas City, it will be 25%

more expensive in the cloudiest place, Buffalo. 

It will be 25% less expensive in the sunniest

place, Arizona. Also consider that conventional

energy prices vary by more than this range

across the nation because of locally used

hydropower, nuclear, natural gas, coal, or oil.

Once PV costs fall to competitive levels in an

average solar location in the United States,

more than 95% of the nation would have

enough sunlight to produce economical energy

with flat-plate PV. Compare this estimate to

other technologies: 15% or less for wind,

because wind speeds vary so much, and wind

generation relates to the cube of wind speed;

20% for concentrator solar collectors, because

they track the sun and use only direct sunlight,

which limits them to less-cloudy climates; and

50% for the best-case biomass scenario, because

crops must be

grown on arable

land with good

water resources.

Non-PV sources

may be confined 

to locations that 

are far from 

markets or even 

off limits to energy

development.

Advantage PV!

The use of PV

affords numerous

land-use advantages. PV has flexible siting, with

rooftops and other urban settings being ideal

locations for PV collectors. Even groundmounted PV produces the most energy per 

unit of land area. And PV uses a natural

resource available across the United States 

and the world.

We started by asking: What would our world

look like if we used PV to produce significant

amounts of electricity? The answer is that

instead of our sun’s energy falling on shingles,

concrete, and under-used land, it would fall 

on PV—providing us with clean energy while

leaving our landscape largely untouched.

References

G. Cohen, Solargenix Energy, Solar Energy Technologies Systems Symposium CD. Albuquerque, 2003.

T. Hansen, Chief Engineer. Springerville PV System,

Tucson Electric Power, 2003.

E. Hughes, Greenhouse Gas Reduction with Renewables. EPRI, TR-113785, 2000.

M. McLaughlin and D. Riley, Alternative Energy

Institute, Turning the Corner: Energy Solutions for 

the 21st Century, 2001. 

D. Pimentel et al., Bioscience, Volume 44, #8, 

Sept. 1994.

Wind Power, http://www.windpower.org/en/tour/

index.htm.

S O L A R E N E R G Y T E C H N O L O G I E S P R O G R A M

For more information

on PV, please read the

other PV FAQs in this

series. You can order

hard copies of the

FAQs from the

National Center for

Photovoltaics, or 

visit our Web site at

www.nrel.gov/ncpv.

A Strong Energy Portfolio

for a Strong America 

Energy efficiency and

clean, renewable energy

will mean a stronger

economy, cleaner 

environment, and greater 

energy independence for 

America. Working with 

a wide array of state, 

community, industry, 

and university partners,

the U.S. Department of

Energy’s Office of Energy

Efficiency and Renewable

Energy invests in a

diverse portfolio of 

energy technologies.

The National Renewable

Energy Laboratory, a DOE

national laboratory,

produced PV FAQs for:

U.S. Department of Energy

Office of Energy Efficiency

and Renewable Energy

1000 Independence Ave., S.W.

Washington, D.C. 20585

DOE/GO-102004-1835

Revised February 2004

Printed with a renewable-source

ink on paper containing at least

50% wastepaper, including 10%

postconsumer waste

Uni-Solar/PIX12965

Shell Solar/PIX12960

PV installations often

do not require land.

Above, an 84 kW

installation on a

Quonset in North

Wales; left, PV atop 

a carport in Santa

Monica, California.