Producing solar panels does require energy,
which produces pollution and carbon dioxide emissions. The good news is that as
creating solar panels has become more efficient, and the energy payback time
(EPBT) has decreased significantly. In 1970, the EPBT for solar was 40 years,
but as of 2010 it’s only 6 months! This means that after 6 months, the green
energy produced by your solar panels will offset the emissions produced during
Most solar cells and modules are made of crystalline silicon,
which use wafers of purified silicon. Purifying and crystallizing silicon are
the most energy-intensive parts of the manufacturing process, but other parts
of the process that consume energy include cutting the silicon into wafers,
processing the wafers into cells, assembling the cells into modules,
encapsulating them in glass and frames, and the overhead energy used by
manufacturing facilities. The PV industry generally uses “off-grade”
silicon from the microelectronics industry that is then recrystallized. While
producing energy with photovoltaic (PV) cells does not emit pollution or use
energy resources, producing the panels themselves does consume energy, which,
depending on the energy source, produces pollution and CO2 emissions.
According to a 2012 report issued by Columbia University, the
average energy payback time (EPBT) for US solar is 6 months.
According to a 2004 National Renewable Energy Laboratory
study that analyzes several different panel technologies, it takes 1 – 4 years
for the energy savings accumulated by producing electricity from solar to equal
the energy cost of producing the panel. Solar panels generally have life
expectancies of 30 years, so 87% – 97% of the energy produced by the panels is
clean energy (i.e. no pollution and/or greenhouse gas emissions).
NREL: What is the energy payback for PV?
Mother Earth News: Dispelling the Myths of Solar Electricity: Energy Payback
Columbia: How Long Does it Take for Photovoltaics to Produce the Energy Used?