Carbon emissions and how they are determined
May 24, 2011
by Lime Energy
These days, whether or not you believe that adding certain gasses to the air will heat up planet earth and lead to catastrophic changes does not matter. You need to listen to what customers and consumers demand in the way of reporting these emissions and make sure you appear to be working hard to reduce, rather than increase your carbon footprint. Carbon footprint is the amount of carbon dioxide or CO2 equivalent (CO2e) that is required to maintain a business or produce and deliver a product. The media is full of messages reinforcing that lower is better when it comes to carbon footprint.
Whenever fossil fuel is burned, carbon dioxide is released to the atmosphere as a byproduct of combustion. An operation that is consuming fuel directly will be creating emissions according to the table below.
||Carbon Dioxide (CO2) Emissions per million BTU of fuel burned |
| Natural gas
|| 117 lb |
|| 139 lb |
|| 205 lb |
|| 19.4 lb |
| Diesel fuel
|| 22.2 lb |
Any reduction in these fuels through more efficient processes will reduce CO2 emissions and save production costs — savings that flow to the bottom line.
Other gasses trap heat and contribute to warming the atmosphere, and these are measured by comparing their heat-trapping potential relative to carbon dioxide. In addition to carbon dioxide, small amounts of methane and nitrous oxide are released when burning natural gas. Methane can also be released from wastewater processes and industrial landfills. This is why food processing facilities that burn natural gas, have co-generation and/or their own wastewater systems, and landfill sites are under scrutiny to provide additional reporting for these gasses. The table below shows that methane and nitrous oxide have a much higher impact on global warming potential than carbon dioxide.
|| CO2 Equivalent (CO2e) |
| Carbon Dioxide
|| 1 |
|| 21 |
| Nitrous Oxide
|| 310 |
Electricity consumed in food processing plants produces carbon dioxide emissions because well over half of the electricity produced in the US comes from burning coal or natural gas in a utility power plant to make steam that drives a generator. The electricity is then delivered to homes and businesses along the transmission and distribution electricity grid. Each kilowatt-hour of electricity (kWh) requires a certain amount of fuel to produce, and the amount of CO2 per kWh depends on the fuel. The Environmental Protection Agency (EPA) has developed statewide averages for electricity generation that are based on the mix of the type of power plants used to produce electricity in each state.
The table below gives some of these greenhouse gas emission factors for a few states in the US in terms of pounds of CO2 per kWh. Although CO2 from a utility power plant is presently not included in the proposed EPA reporting requirements, it is impossible to predict where future regulations may take us. What is clear, however is that reducing electricity consumption does save money and also reduces CO2 emissions. Producers should document and publicize their steps to save electricity and reduce their carbon footprint.
Read more about Sustainability
||Emission Rate (CO2 per kWh)
|| Electricity Generation Sources |
|| 2.1 lb
|| High percentage of electricity comes from coal |
|| 1.3 lb
|| Mixture of coal and natural gas |
|| 1.1 lb
|| High percentage of zero-emission nuclear power |
|| 0.8 lb
|| Natural gas, hydroelectric, coal, oil, and nuclear |
|| 0.5 lb
|| Natural gas, hydro, nuclear, geothermal, wind |