Once your Subpod is fully up and running and you are adding 15 kg of organic waste per week, after 1 year (52 weeks), you have composted 780 kg of food waste! In a landfill, that food would have generated a lot of methane which is at least 25X more potent a greenhouse gas than CO2 Using the conversion factor used by the United States Environmental Protection Agency to estimate the waste carbon emissions in CO2 equivalents when waste is diverted from landfill, this gives a value of approximately 2.24 metric tonne equivalents of CO2.
Considering the average car passenger driven 11,500 miles/ 18,500 km per year produces 4.7 metric tonnes of carbon dioxide equivalents, you are keeping almost ½ a years worth of a car’s carbon emissions out of the air for every Subpod composting food waste!
Our pilot project at Habitat Byron Bay has 10 active Subpods in 2 raised garden beds. When fully utilized, these are composting 15 kg of organic waste per Supod x 10 Subpods x 52 weeks in a year = 7800 kg of waste composted. This accounts for the higher potency of methane as a GHG, and expresses the total amount as 26.6 metric tonnes of carbon dioxide ( CO2 ) equivalents kept out of the atmosphere. This is equivalent to the CO2 emissions from more than 5 passenger cars each with an average annual driving distance of 11,500 miles/ 18,500 km.
With our aspirational vision of 20,000 people using Subpods, diverting this much organic waste from landfill will reduce toxic greenhouse gas emissions by 53,300 metric tonnes of CO2 equivalents per year1. This is equivalent to a year's worth of carbon emissions from 11,340 cars.
Harvesting this compost and adding it to the soil to feed your plants, you are both increasing soil carbon and providing plants with the nutrients and microbes that support photosynthesis to pull additional CO2 from the air as the plants grow.
When plants grown in this soil are themselves eventually composted, this cycle continues to add to soil carbon. Because most of our soils have become depleted of carbon, there is a lot of capacity for soil to absorb more carbon.
1. 20,000 composters x 15 kg waste x 52 weeks = 15,600,000 kg . Using a landfill waste spreadsheet developed by the U. of Texas, Austin which adjusts for the additional GHG potency of methane, this quantity of waste prevents 53,308 metric tonnes of CO2 equivalents from reaching the atmosphere.
2. Based on US EPA estimates of average passenger cars each driven 11,500 miles (approximately 18,500 km)