Green Wiki

An overview of carbon offset projects


Biomass is fuel made from recently dead or living material. Biomass doesn’t necessary refer to hardwood from trees, it can also also come from several other sources such as miscanthus, switchgrass, hemp, corn, poplar, willow and sugarcane. Biomass is part of the carbon cycle. Carbon from the atmosphere is converted into biological matter by photosynthesis. On decay or combustion the carbon goes back into the atmosphere or soil. This happens over a relatively short timescale and plant matter used as a fuel can be constantly replaced by planting for new growth. Therefore a reasonably stable level of atmospheric carbon results from its use as a fuel.

Compact Fluorescent Light Bulbs

Compact Fluorescent Light Bulbs (CFLs) use 13 or 14 watts to produce the same amount of light (lumens) that a traditional 60 watt incandescent bulb would use. A by product of power generation are N, Hg, S and C. There are varying formulas to calculate how much carbon is saved from the CFLs anywhere from 80 to 100 tons per year. Currently, LiveCooler is the only offset provider involved in this program.

There are some detractors from this as a carbon offset project. The main reason why this is not viewed as a good carbon offset project because their is a chance that the carbon reduction could be double counted. Power companies have to report how much carbon they produce in the generation of power. If you replace your incandescent bulbs with CFLs the power company will report the energy reduction as part of their daily operation. This will create a situation that the power company is reporting the energy reduction and you are reporting the energy reduction. This situation will lead to double counting of the carbon reduction!

Geothermal energy

Geothermal energy literally uses the Earth’s heat to generate power. There are three types of power plants that use geothermal energy; dry steam, flash, and binary. Dry steam plants take steam out of fractures in the ground and use it to drive a turbine that spins a generator. Flash plants take hot water, usually at temperatures over 200 °C, out of the ground, and allows it to boil as it rises to the surface then uses steam to drive a turbine that spins a generator. In binary plants, the hot water flows through heat exchangers, boiling an organic fluid that spins the turbine.


Methane is a greenhouse gas which is approximately 10 times more harmful to the environment then carbon dioxide. Methane is produced from a number of sources; such as in digestion in farm animals, sewage treatment, and landfills. The waste is collected then funneled to an anaerobic digester, the anaerobes are bacteria that digest and release methane as a byproduct. Methane is a valuable resource because it burns more cleanly than coal, and produces more energy with less emissions of CO2.

No till farming

Farm soil is full of carbon from dead and rotting plants that have grown there years before. Soil is black in color from all the carbon that is contains. When you till the soil you expose it to the sun. Once exposed to the sun microbes start to digest the carbon and breath out carbon dioxide.

To plant without tilling a farmer needs to use a no-till planter. A no-till has sharp steel wheels that cuts through the debris from the last crop, opening up a narrow slit in the soil; seeds drop through a tube into the opening, then a wheel comes along and closes it up again. It doesn’t stir up the soil, it lets the soil keep its stored carbon and adds some, because plants on the surface gradually become part of the soil.

Planting trees

Planting trees is the most common way to offset carbon production and is the most controversial. The theory is that one tree over the life time of that tree destroy one ton of carbon dioxide. Here are just a few problems with that theory. What is the life time of a tree? Will it take 75 years to remove a ton of carbon? Will it take 100 years to remove a ton of carbon?

A 2005 Lawrence Livermore National Laboratory(LLNL) study using climate models examined the effectiveness of planting trees in different areas as a way to offset carbon production. What they found was nothing less shocking, snow is white and reflects heat. Trees are not white and absorb more heat then snow, hence heating the earth up. As the earth gets hotter more snow melts, more trees grow making the earth even hotter. You can see were this is going. LLNL ran simulation models comparing trees versus shrubs/grassland. Trees were shown to make the earth 1.6 C warmer when planted and grasslands were shown to make the earth cooler by 0.38C. So why would anyone plant trees as a carbon offset project?

There are some exceptions to this idea. The first exception is planting trees in the Amazon rain forest. The idea is that the rainforest works in a synergy and adding more trees to this synergy is beneficial. The other exception is planting trees in an urban area. Trees are cooler then pavement, and will provide a cooling effect to the pavement.

The Austrilia Institute also took a look at tree planting as an offset project. They found some rather interesting results. The first issue is that forestry projects can not perminanetly store carbon. At some point the forest will be cut down or burned, when that happens the stored carbon is released into the environment. The forest soil can hold a vast sums of carbon from decaying leaves, trees, and branches. When the forest is cut down or burned the soil can release that carbon into the environment.

Tree planting can lead to carbon leakage. When trees are planted on land, the land use changes. If the land was being used for farms, houses, or recreational activities people may just clear new land and continue those activities. Where this happens, the apparent emission reductions from a forestry projects could ‘leak’ out of another forest area.

Climate change will have an impact of forestry offsets. With the current environmental change caused by global warming rain fall levels are not the same. Many tree planting offset projects are happening in areas that might not have enough rain to support a forest.

Renewable Energy Certificates

Renewable Energy Certificates (REC) also know as Green Tags or Renewable Energy Credits. In a state that has an REC program a green energy producer can get REC for every Megawatt of power they put on the grid. Companies can buy, sell and trade these certificates. There are several organizations that verify the creation of RECs and insure they are not double counted; Green-e, Environmental Resources Trust’s EcoPower Program, and The Climate Neutral Network. Currently only certain types of power generation can qualify as an REC; Wind, Biomass, Solar, Fuel Cells, Geothermal, Biodiesel, Low Impact Hydropower (not from dams).

Traffic Light Optimization

A relatively new offset project, a city will examine pattern flows in a given area then adjust the traffic lights for the most optimal for traffic. When the traffic lights are optimized this will decrease car idling and accelerations at traffic lights, resulting in less gas used. The less gas you use the less carbon you produce.

The largest traffic light optimization happened in Portland. Portland did a major study of seventeen major arteries in the city. The city estimates with traffic light optimization that over five years they have prevented 189,000 tons of carbon from being created.


For more information about carbon offset projects, turn to the original article at Carbon Neutral Digest

List with Carbon offset projects