Behind the numbers: Social Impacts
The numbers we present within the site are an “order of magnitude” of what is taking place in the developing world. There are literally hundreds of published studies showing the key social metrics we cite. Where possible, we use exact data, but when none is available, we use conservative averages from various secondary sources. Stove benefit numbers cited throughout this website reflect social assumptions (such as average wage per day) taken from primary research conducted by The Paradigm Project and baseline studies conducted by our qualified partners in Kenya as these represent the most conservative view.
We define stoves as improved cooking devices that are based on the “rocket” technology that maximize efficiency, heat transfer, combustion, safety and usability. Each stove that is distributed can be traced from the manufacturer to the distributor to the retailer and finally, to the individual. Our whole program depends on our ability to accurately track when and where our Rocket Stoves go, so we are extremely committed to making sure we know who is using our stoves where. The life or durability of a stove is important as well. We distribute a variety of Rocket Stoves that meet our benchmarks, but which also have varying durability and life. Some of our stoves will last 3 years and some 5 or more years. The numbers you see illustrated in our “What one stove can do” graphic are based on a 5-year Rocket Stove.
1 stove = 5 lives impacted
People Impacted can be a nebulous and sometimes vague phrase. We define this in relation to the benefits that our Rocket Stoves deliver to each individual in a family. Our conservative assumption is that the average family size is 5 in the countries where we work so each stove equals 5 lives impacted. Why? Well, the mother is certainly impacted the most directly by reduction of work and health risks. However, her children are also very directly impacted as mothers inadvertently expose children to indoor air pollution pre-natally and as they carry and cook around infants and toddlers. Finally, older siblings, spouses and extended family who live in the home are impacted because of the elimination of smoke in the home. Often the houses or huts are single or 2-room dwellings where indoor air quality is dramatically affected by the presence of an open fire. “Changed” in our context means that the burdens related to cooking are drastically reduced and in some cases eliminated. If you observe the “What one stove can do” section, watch our videos and read our blog, you will see the change that can really take place.
1 stove = $282 in income saved
Believe it or not, most people in this world are living on less than $2 a day. Up to 35% of that income can be spent on fuel for cooking over open fires, which is incredibly taxing on a family’s ability to pay school fees, purchase food or seeds for planting crops or even just every day necessities. "Income saved” refers to the money that the family will save from purchasing 40%-60% less cooking fuel through the use of our Rocket Stoves. Here's how we get there:
- $ 0.31: typical amount spent on daily fuel wood for those who purchase it
- $ 0.31 * 365 = $113.15 in annual fuel costs
- 50%: typical fuel savings of fuel efficient cook-stove
- $113.15 * 50% = $56.58 in annual fuel cost savings
- $56.58 in annual fuel cost savings = $282.90 in income saved per stove over 5 years
1 stove = 1300 hours saved
When we say “productive hours” we are talking about the time that women could use to work in their fields, to spend time with and take care of their families, to generate income or to use for other productive tasks during the working hours of each day. Time saved refers to the reduced time that women spend collecting wood through the use of our Rocket Stoves. With women spending up to 30 hours a week collecting wood and then realizing an improved fuel efficiency of 40%-60%, the savings really start to add up. Here's how we get there:
- 8 – 10 km: average round trip distance for wood collecting
- 10 km @ 5 kph (typical walking speed) + 1 hour gathering = ~3 hrs per trip
- 3 hours per trip * 3.5 (average trips per week) = ~10 hours per week
- 10 hours per week * 52 weeks = 520 hours spent annually collecting wood
- 520 hours * 50% (typical fuel savings) = 260 hours saved annually
- 260 hours saved annually = 1300 total hours per stove over 5 years
1 stove = 33 trees saved
Trees saved can also be a difficult number to quantify since there are so many types and species of trees, but in looking at Kenya as our baseline, the average weight of a tree across the three most prevalent species, is 195.5 kilograms or 430.1 pounds. Based on our baseline studies we are able to determine how many kilograms or pounds of wood are used in open fire cooking and compare that to the amount saved per efficient stove each year. Many women are using up to 10 kilograms of wood to cook each day over inefficient open fires and are then using only 5 kilograms of wood on an efficient stove. Using these recorded differences we are able to quantify the weight in wood that is saved each year and convert that into the number of trees based on the 195.5 average kilogram weight of a tree. Here's how we get there:
- 1.2 kg: average amount fuel wood consumed per capita in rural Kenya
- 6 persons: average household size in rural Kenya
- 1.2 kg * 6 persons = 7.2 kg of fuel wood consumed per household, per day
- 7.2 kg * 365 days = 2628 kg of fuel wood consumed annually per household
- 195.5 kg: approximate weight of an average Kenyan tree
- 2628 kg ÷ 195 kg = 13.44 trees consumed annually
- 50%: typical fuel savings of fuel efficient cook-stove
- 13.44 * 50% = 6.72 trees saved annually or 33.6 trees saved over 5 years.
“Emissions” or greenhouse gases are byproducts that are released from a certain activity. Greenhouse gases include carbon dioxide, methane and nitrous oxide and an activity that creates it could be driving a car, firing and running a coal plant or, in this case, burning wood to cook. Open fires are incredibly inefficient in both how cleanly and completely they burn fuel, but also in how much fuel they require to cook a meal. This inefficiency creates an incredible amount of carbon dioxide, methane and other greenhouse gases that are both harmful to the women cooking and to the atmosphere and planet. It is estimated that 25% of all global CO2 emissions are generated from the rural poor. That’s more than all global transportation emissions combined—every car, truck, train, plane and bus together! This is largely because the rural poor have no access to better, more efficient technologies. On average Rocket Stoves reduce emissions by 1 to 2 metric tonnes per year. How do we know? Because in order to certify our projects through UN-sanctioned auditors, we have to do extensive annual testing and monitoring on the ground to measure the reductions and prove the validity of the savings. You can learn more about the carbon markets and offsets here.
Behind the numbers: Carbon Offsets
We've given you two ways to offset your carbon emissions: Quick & Easy, and Deep & Detailed. For the Quick & Easy calculations, we use the same robust emissions factors and data as we would doing a very customized estimation of your carbon footprint. The only difference is in that we are giving you general category reduction equivalents instead of numbers based on your particular car or home or skinny no foam half caff latte. In each case we provide the parameters for the estimation so that you can determine if your house size, for instance, is closer to "Small" (1000 sq. ft.) or Medium (2250 sq. ft.). Of course you can always customize from there by choosing the "A La Carte" option and just selecting the specific number of tonnes you want to purchase based on estimating your own levels if they land between our basic categories.
If you choose the Deep & Detailed option, we'll have a specialist contact you directly to estimate your specific carbon footprint and provide the exact number of offsets needed to make your lifestyle carbon neutral. Either way, we greatly appreciate your support.
Below you will find the methodologies and emissions factors used to calculate our Quick and Easy selections.
The amount of carbon dioxide a car emits every year is factor of mileage driven and the type of vehicle. Our Quick & Easy categories simplifies things by offering offset packages based on your car or truck's estimated fuel economy performance (miles per gallon, or MPG). Per the name, it's pretty simple, but here's how we get there:
The average American drives 12,000 miles per year, so this is what we use as a basic for driving carbon footprint calculations. At each level of fuel economy offered, multiplying the average number of miles driven by the average fuel economy rating gives us the approximate quantity of fuel used in a year, in gallons.
We then take that number and multiply it by a greenhouse gas emission factor. A greenhouse gas emission factor is the number of pounds of carbon dioxide which will be emitted when your car combusts a gallon of fuel. We use a regular gasoline emission factor (again to simplify) equal to 19.42 pounds of carbon dioxide per gallon. As a final step, we then divide that number by 2,204.6 (the number of pounds in a metric tonne) since all carbon offsets are sold in metric tonnes. That gives us the Quick & Easy estimate of offsets required to neutralize your driving.
Our estimates may be quite different than estimates you find on other websites or published elsewhere. Some sources include other greenhouse gases that your car emits in addition to carbon dioxide. Others factor in the emissions from the processing of your gasoline, including its extraction, transportation, and dispensing. Our calculation is comparatively simple, using only carbon dioxide emissions, and only from fuel combustion inside your car (we did say it would be Quick & Easy).
If you don't know the average fuel efficiency of your car or truck, you can reference the U.S. Environmental Protection Agency (EPA)'s ratings atn their website at fueleconomy.gov. These ratings are expressed as miles per gallon, or mpg. The EPA provides one fuel economy rating for highway driving, a second for city driving, and a third which combines the two at a ratio of 55% city - 45% highway. This third figure is likely the most accurate for determining real-world use.
Our air travel calculations are based on average flights from multiple sources and we use a number of assumptions to come up with these estimates, so the final amount should be regarded as a general guide based on industry averages rather than a precise figure. The actual amount of fuel burned per passenger per mile depends on the type of plane, the number of people flying, the weight of the cargo, and other factors. Our assumptions are based on the greenhouse gas emissions protocols developed by the World Resource Institute (WRI). Here's how we get there:
Because planes burn more fuel at takeoff and landing than at cruising altitude, short-haul trips are less fuel-efficient per mile flown. Thus you will find that longer flights are actually more efficient per mile traveled than shorter ones. We use a different emission factor index based on the length of the flight that indicates the amount of fuel burned, on average, per mile of the journey. By multiplying this index by the distance of the trip, we determine how much fuel was burned per passenger for that particular flight:
- Short (500 miles or less): 0.64 lbs/mile
- Medium (1000 miles): 0.45 lbs/mile
- Long (1500 or more miles): 0.39 lbs/mile
On average, the resulting flight emissions profiles provide a good approximation of the global warming impact of your flying.
To estimate your home energy usage we use a combination of consumption, price and emissions statistics that are made publicly available by various government agencies. Consumption and price information for electricity, natural gas, heating oil and propane all come from the Energy Information Administration at the Department of Energy. Electricity emissions data comes from the EPA's eGRID program. Some of the emissions factors we use to generate numbers for our Quick & Easy estimates include:
- Natural Gas: 12.0593 lbs/CCF (100 cubic feet)
- Propane: 12.669 lbs/gallon
- Heating Oil: 22.384 lbs/gallon
As with our automobile emissions estimates, the home energy calculations are greatly simplified for ease of use. Emissions rates for electricity varies by area due to regional differences in fuel sources for power plants. You can check your electricity's emissions rate using the EPA's Power Profiler. Fuel use can also vary widely by location and by number of individuals in a household. Therefore our home energy offset offerings use a national average for consumption based on home size and number of people in the household.
As always, if you have any questions or trouble with these calculations, please contact us.