From Envirowiki

cooking is a requirement for making a number of foodstuffs edible. it also uses a fair slab of household energy - in a typical australian home for example, cooking uses around 12% of household energy^[1]. that said, it is important to try to reduce greenhouse gas emissions from cooking.

[edit] 1 methods

cooking can be done by a great variety of methods, but household cooking is currently done on a stove top, or in an oven. stoves and ovens are usually run on either electrical resistance heating (using a filament to change electricity into energy), or via the direct burning of liquified petoleum gas, or natural gas (methane).

stoves can also be run on various other fuels, including other petrochemicals, such as kerosene, or paraffin, as well as more recently organic chemicals, such as alcohol. stoves can also run on wood.

cooking can also be done on an open fire, and this is certainly the oldest method.

solar ovens take heat directly from the sun, and focus or condense it into temperatures high enough to cook food or boil water.

[edit] 2 energy efficiency

technically speaking, electrical resistance heating can have an efficiency of almost 100%^[2], but in practice this is not necessarily true. a solar oven is the only method of cooking that requires no major infrastructure, and creates no greenhouse gasses. it is perhaps also the most efficient method, assuming the device is well constructed and insulated.

Cooking fires are probably fairly inefficient, and are not suitable to in-doors. They emit GHG, but the carbon is arguably in the cycle already, so may be discounted.

Gas burners are relatively efficient in creating heat^{[reference needed]}, some energy escapes as light. but require drilling and transportation (lpg), or massive pipeline infrastructure and pumping (natural gas). efficiency is also lost on the stove top, as a lot of heat escape around the sides of pots etc.

electric stoves range from dismal to extremely good efficiency. Old style coil filaments are relatively inefficient - 50-65%^[1], due to heat loss. the more contact the pot/pan has with the coil, the better the efficiency (conductive heat vs. convective heat). electrical heat induction coils are much more efficient, at around 80-85%^[1]. electrical systems generally suffer from similar supply system inefficiencies, in that the coal or gas must be mined or drilled, and transported to a power station. coal powerstations are extremely inefficient, at a maximum of about 40%^{[reference needed]}. further efficiency is lost through the high-voltage AC electrical grid (around 12%), bringing even the best induction cooker down to under 30% efficiency, without counting mining.

of course, electrical systems can run on pure renewable energy, removing their running greenhouse gas emissions, but this is often the case currently, and electrical heating is a large load to put on a renewables system.

another possibility is bio-gas: using a methane digester to trap the methane from compost and manure, and using that for cooking.

[edit] 3 Sources

1. ↑ ^{1.0 1.1 1.2} "Cooking", Energy Smart, Sustainable Energy Development Office, Western Australia http://www1.sedo.energy.wa.gov.au/uploads/cooking_52.pdf
2. ↑ "Electrical Resistance Heating", Energy Efficiency and Renewable energy, US deptartment of Energy, http://www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/mytopic=12520