Grilling and picnic season is back. Your choice of a new grill can minimize the greenhouse gas emissions created by summer parties. Before buying a new grill, take a few minutes to understand the impact of charcoal, wood pellets, propane, natural gas and solar grilling. And if you buy a new grill as a replacement, don’t forget to recycle your old grill.
Making food from scratch is better for the planet and your body than choosing processed foods, according to a 2014 study published in the Journal of Cleaner Production, reducing global warming and human toxicity potential of a meal by up to 35%. But that doesn’t mean your backyard barbecue is carbon-free. Researchers at University of Sheffield Institute for Sustainable Food found that grilling meat and vegetables for four people on a charcoal grill in the backyard can produce as much CO2 as driving 80 miles.
Before heading to the store, consider the carbon impact of the fuels used to power different barbecues. Charcoal is the worst choice for the planet, followed by natural gas, propane and solar grills. But if you cherish the scorched lines of a grill, you’ll likely choose an option that involves burning fuel.
The Burning Truth
Grilling is a science, as grill masters know. Cooking a meal for four will take between 30 minutes and an hour, and different fuels require different heat-up times to be ready to cook. Our estimates assume one hour of cooking time is needed to cook dinner – your actual results will vary depending on the grill and fuel you use.
A dinner for four requires about 300 square inches of cooking space for meat, vegetables and warming buns. When using charcoal, which requires about 30 briquettes per 100 square inches, you will need about 90 pieces. The average briquette weighs about 0.8 ounces, so cooking for four will use 4.7 pounds of charcoal.
When choosing charcoal, there are two carbon impacts to understand: the embodied carbon generated by the manufacture of the briquettes and the emissions associated with their combustion.
Making charcoal uses a lot of heat to burn off organic material and leave essentially pure carbon burning in your grill. Charcoal production can emit between 3.5 and 7.05 pounds of CO2 per pound of charcoal produced, according to various reports. It’s just the impact before you light your grill. Burning all 90 briquettes for one hour will emit approximately 21 pounds of CO2, 0.79 pounds of carbon monoxide, and 1.6 pounds of particulate matter.
Charcoal is by far the dirtiest way to grill a meal for four with a total carbon footprint of over 28 pounds of CO2, plus other pollutants.
Wood pellets, a popular alternative to charcoal, are considered by some to be a low-carbon, renewable energy source. Cooking on a 300 inch grill requires about two pounds of pellets.
The embodied carbon of wood pellets can vary greatly depending on the type of wood used, the manufacturing process, the distance and the mode of transport. Typically, a pound of pellets contains about 0.09 pounds of embodied carbon and produces 1.8 pounds of CO2 when burned – our dinner of four has a total carbon footprint of 3.78 pounds. Because pellets burn cleaner than charcoal, flour produces only a few grams of carbon monoxide, particulates, nitrogen, and sulfur compounds.
Wood pellets are the second worst but far less impactful grilling option, with a carbon footprint of 3.78 pounds for a meal for four.
The environmental price of gas cooking
Propane and natural gas grills are popular options. Overall, they have a lower environmental impact than burning charcoal and wood pellets because these grills heat up faster and can be turned off after cooking. The additional heating time control makes a big difference.
A propane grill uses about half a pound of propane for 30 minutes of cooking, which is what our meal for four people needed. Including the embodied carbon emitted during manufacturing, propane used for dinner has a total carbon footprint of 1.99 pounds.
Natural gas usually requires a gas line to be installed in the house, so propane is more convenient for many grills. Our 30-minute cooking session will require approximately 1.2 pounds of natural gas, which has a carbon footprint of 1.73 pounds.
Going solar is the cleanest
Solar ovens use the energy of the sun to prepare your meal with no carbon footprint. They use reflectors that collect and focus the sun’s heat on the cooking space.
Ideal for cooking, solar ovens prepare a moist, flavorful meal by heating food in a sealed container. It takes a very sunny day to reach the temperatures needed for broiling or broiling using solar power. These systems do not produce the signature grill lines on meat and vegetables prized by cooks.
The carbon impact of grilling
A cooking season of 45 meals using each of the options we looked at will produce the following emissions:
- Coal: 1,260 pounds. of CO2, plus other pollutants
- Pellets : 170 pounds. of CO2, plus some other pollutants
- Propane: 90 pounds. of CO2
- Natural gas: 78 pounds. of CO2
- Solar: No CO2
The grilling choices you make today will have a long-term climate impact that will make life more difficult for future generations. So choose wisely when you grill and choose to eliminate other emissions from your life to offset the impacts of cooking.