Compare the costs of generating electricity using solar energy in different parts of the united states. a. (5 points) let us consider a simple 25.m2 rooftop installation of crystalline-silicon (c-si) pv modules. now remember that pv modules are rated to receive 1kw/m2 of solar radiation. assuming peak solar irradiation of 1 kw/m22, what would the peak output of this system be (in kw) if the modules are 16% efficient? b. (10 points) compute the annualized cost for this type of pv module (in $/year), assuming for simplicity that operating costs can be ignored. assume a 6.0% discount rate and 25-year lifetime. initial cost unit value ($) module cost $/watt 2.20 permitting and inspection cost $/watt 0.25 installation labor cost $/watt 0.90 inverter cost $/watt 0.50 c. (10 points) now, consider how much electricity our pv system from part (a) will actually be able to generate in different cities based on variation in insolation levels. calculate the annual electricity generated by our pv system and the levelized cost of solar energy in san francisco, ca (2,500 kwh/m2-year); new york city, ny (1,600 kwh/m2-year); detroit, mi(1,500 kwh/m2-year); and flagstaff, az(3,200 kwh/m2-year). d. (5 points) calculate the simple payback period for your solar system in san francisco. assume that your household consumes 15,000kwh/year.

carbon is found in all living things. carbon atoms move constantly through

living organisms, the oceans, the atmosphere, and the earth’s crust in what is

known as the carbon cycle. the directions taken by carbon atoms through this

cycle are very complicated and can take millions of years to make a full circle.

all animals, from humans to the dinosaurs are part of the carbon cycle. when

animals eat food, they get carbon in the form of carbohydrates and proteins.

in animals, oxygen combines with food in the cells to produce energy for daily

activity and then gives off carbon. the carbon combines with oxygen to form

carbon dioxide (co2) and is released back into the atmosphere as a waste

product when animals breathe and exhale.

from 145-65 million years ago, earth was much

hotter than today and covered with dense,

tropical swamp forests. the trees and other

plants were immense and

provided an endless supply of

food for the giant animals that

roamed the land. somewhere in

the air above one of these

forests, a lone carbon atom has joined

up with two oxygen atoms to form a molecule of co2.

the co2 molecule was sucked into the tiny holes (stomata) on the leaf of a

fern plant and joined with sunlight, chlorophyll and water to make food and

energy in the plant’s cells through photosynthesis. the oxygen (o2) from the

co2 molecule was sent back into the atmosphere; the carbon atom (c) was

detached and used to make a molecule of sugar.

if that carbon atom had been eaten instead, a totally

different situation would have developed. let’s say

that a giant plant-eating dinosaur (herbivore) ate the

fern for breakfast, and swallowed the carbon in the

fern in the form of carbohydrates and proteins. in

the process of respiration, oxygen combined with

the carbohydrates and proteins in the dinosaur’s cells

to provide energy for its daily activity.  

well clustered together.

points close on a scatter diagram