Backyard and picnic grilling season is back. Your choice of a new grill can minimize the greenhouse gas emissions created by summer parties. Before you buy a new grill, take a few minutes to understand the impact of charcoal, wood pellets, propane, natural gas, and solar grilling. And if you’re buying 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 food, according to a 2014 study published in the Journal of Cleaner Production, lowering global warming and human toxicity potential from a meal by up to 35%. But that doesn’t mean your backyard barbecue is carbon-free. Researchers at the University of Sheffield Institute for Sustainable Food found that grilling meat and veggies for four people on a backyard charcoal grill can produce as much CO2 as an 80-mile drive.
Before you head to the store, consider the carbon impacts of the fuels used to power different barbecue grills. Charcoal is the worst choice for the planet, followed by natural gas, propane, and solar grilling. But if you treasure the seared lines of a grill, you’re likely to select 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 the different fuels require different lengths of time to heat up to be ready for cooking. Our estimates assume that one hour of cooking is necessary to make dinner — your actual results will vary based on the grill and fuel you use.
Dinner for four requires about 300 square inches of grill space for meat, veggies, and warming buns. When using charcoal, which needs about 30 briquettes per 100 square inches, you’ll 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 making the briquettes and the emissions from burning them.
Making charcoal uses a lot of heat to burn off the organic material and leave the mostly pure carbon that burns in your grill. The production of charcoal can emit between 3.5 to 7.05 pounds of CO2 per pound of charcoal produced, based on various reports. That’s just the impact before you light your grill. Burning the 90 briquettes for an hour will emit about 21 pounds of CO2, 0.79 pounds of carbon monoxide, and 1.6 pounds of particulate materials.
Charcoal is by far the most polluting way to grill a meal for four at a total carbon footprint of more than 28 pounds of CO2, along with other pollutants.
Wood pellets, a popular alternative to charcoal, are considered by some to be a low-carbon, renewable source of energy. Cooking on a 300-inch grill takes about two pounds of pellets.
The embodied carbon of wood pellets can vary greatly depending on the type of wood used, the manufacturing process, and the distance and method of transportation. In general, 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 the pellets burn cleaner than charcoal, the meal produces only a few grams of carbon monoxide, particulate matter, nitrogen, and sulfur compounds.
Wood pellets are the second worst but far less impactful grilling option, with a 3.78-pound carbon footprint for a meal for four.
The Environmental Price of Cooking With Gas
Propane and natural gas grills are popular options. Overall, carry a lower environmental impact than burning charcoal and wood pellets because these grills heat faster and can be turned off after cooking. The extra control over heating time makes a big difference.
A propane grill uses about a half pound of propane for 30 minutes of cooking, which is needed for our four-person meal. Including the embodied carbon emitted in manufacturing, the propane used for dinner has a total carbon footprint of 1.99 pounds.
Natural gas typically requires the installation of a gas line in the home, so propane is more convenient for many grillers. Our 30-minute cooking session will require approximately 1.2 pounds of natural gas, which carries a carbon footprint of 1.73 pounds.
Going Solar Is Cleanest
Solar ovens use the sun’s energy to make your meal with no carbon footprint. They use reflectors that collect and concentrate the sun’s heat on the cooking space.
Great for baking, solar ovens make a moist, flavorful meal by heating the food in a sealed container. It takes a very sunny day to reach the temperatures needed to broil or grill using solar. These systems do not produce the signature grill lines on meat and veggies prized by cooks.
The Carbon Impact of Grilling
A season of cooking 45 meals using each of the options we’ve reviewed will produce the following emissions:
- Charcoal: 1,260 lbs. of CO2, plus other pollutants
- Wood Pellets: 170 lbs. of CO2, plus some other pollutants
- Propane: 90 lbs. of CO2
- Natural Gas: 78 lbs. of CO2
- Solar: No CO2
The grilling choice you make today will have a long-term climate impact that makes life harder for future generations. So, pick wisely when you grill and choose to eliminate other emissions from your life to make up for cooking impacts.