Currently, residents of Chapel Hill who are “on the grid” get their power by buying it from Duke Power Company, where approximately 48% of the energy is derived from nuclear power.  The rest originates in coal-fired power plants.  Based on data obtained from Duke Power, their plant delivers 30% of their electricity generated to Chapel Hill.  Based on annual data from 2002, 2003, and 2004, an average of 30,504,880 KWH end up on the grid within Chapel Hill's borders annually.  An efficiency of 30% accompanies the energy derived from coal at Duke Power.  The University of North Carolina at Chapel Hill obtains 60% of its energy from the Duke Power grid, and the other 40% from its UNC Cogeneration facility.  This facility utilizes the byproduct steam created from the production of their electricity in a manner that allows them to generate even more electricity.  The excess steam is used to power turbines, effectually creating extra electricity from the byproduct of the original electricity.  UNC's Cogen facility operates at approximately 60% efficiency, since less coal actually produces more energy.

Transportation - 1.25e^-9 BMT
The transportation sector, though it is a significant source in the entire United States, only contributes about a quarter of the total carbon emissions of Chapel Hill.  Within this category, the primary sources of carbon dioxide emissions are automobiles and trucks, but Chapel Hill's extensive Transit system maintains a fleet of approximately 200 buses.

Residential – 1.8e^-9 BMT
The majority of the carbon dioxide emissions within the residential sector are a result of generating the electricity for domestic uses such as air conditioning, lights and appliances. The second largest source of residential carbon dioxide emissions is from the combustion of natural gas, primarily for heating.

Commercial – 1.53e^-9 BMT
Maintaining a suitable indoor environment in structures such as office buildings or stores via lighting, heating, ventilation and cooling accounts for the majority of commercial carbon dioxide emissions.

*Data obtained from our STELLA model.

    Most of the energy that is used to power residential and commercial units in Chapel Hill is derived from Duke Power and the UNC Cogen facility.  Based on data we collected, propane counts for less than 1% of the energy usage of residential units in Chapel Hill.  With this in mind, we decided to disregard the negligible amount of emissions that result from propane for our model.  Since little of Chapel Hill is wooded or available for cutting, traditional fuel sources (wood) are also negligible enough so as not to contribute enough to our model for consideration.

    Alternatives for energy include building on-site power sources, which can be a centralized power plant, or decentralized, including fuel cells, solar panels, and other alternative energies that might be located at each building. Examining all the alternatives, and irrespective of price, to lower CO2 emissions the most, it seems likely that some combination of decentralized fuel cells and solar panels, as well as buying some energy from NC Green Power may be the best combination. However, with an eye to future technologies, the option of a super-efficient power plant that either uses hydrogen or a fossil fuel may be viable.

Coal is the dominant source of energy in North  Carolina.  Sixty-three percent of North Carolina's  electricity comes from coal-fired power plants.  Currently, the state has 14 coal-fired power plants  that contribute 72 million tons of Carbon Dioxide  to the atmosphere each year.  As a result, North  Carolina ranks 38th in the world, ahead of Venezuela, Belgium and the Czech Republic in terms of its contribution to global warming.