Question

Solar electricity cost.

Despite all the advantages of using solar cells to harvest solar energy, solar electricity still has an insignificant share (~1%) in the world’s overall energy supply picture. This is mostly due to the economic consideration. While there’s virtually no fuel (sunlight) cost and maintenance cost once the solar panels are installed, the initial cost of solar electricity systems is still the obstacle for wide-spread adoption of solar photovoltaic technologies.

a. Use the single-crystalline Si solar panels as an example. Typical module fabrication cost is $150/m2, and typical efficiency is 15% (the commercial panel efficiency is significantly lower than the efficiency of champion laboratory cell; why?). Calculate the cost of the solar panels in terms of $ per peak power output ($/WP). [Hint: what is the optical power intensity for AM1.5 global spectrum?]

b. Assume all the other cost items (transportation, installation, and other Balance of Systems such as inverters, meters, etc.) is about 150% of the panel cost. A typical panel lifetime is 25 years. In Gainesville, we get about 2000 hours per year sunlight at standard AM1.5G power (1 kW/m2). Calculate, over the lifespan of the solar panels, how much is the cost of the solar electricity in terms of cents per kWh.

Answer 1

a.> The global formula to estimate the electricity generated in output of a photovoltaic system is :
E = A * r * H * PR E = Energy (kWh)

A = Total solar panel Area (m2)
r = solar panel yield or efficiency(%)
H = Annual average solar radiation
PR = Performance ratio, coefficient for losses (range between 0.5 and 0.9, default value = 0.75)

Assuming A=1m² , H=1000, PR=0.75 & given r=0.15

E=112.5 kWh

Solar Modules are rated in Watt Peak. Watt peak (sometimes Kilowatt peak is used for PV plants) stands for peak power. This value specifies the output power achieved by a Solar module under full solar radiation (under set Standard Test Conditions). Solar radiation of 1,000 watts per square meter is used to define standard conditions.

A PV system with a kWp of 3kW which is working at its maximum capacity (kWp) for one hour will produce 3kWh.

So cost=150$/37.5kWP=4$/kWP

b.> 150% of panel cost + panel cost= 375$

E=225kWh

And for 25 yrs E=5625kWh

So cost of  the solar electricity=375*100cents/5625kWh=6.67cents/kWh