Thursday, October 02, 2008

cooking with gas

A further thought on that home electrolyser.

I dissed its stupidity for turning electricity into hydrogen into electricity. However, they tell us some of it can be used directly for cooking.

At present, when we cook with gas we are actually cooking with hydrogen. Natural gas is essentially methane; CH4, carbon and hydrogen. In burning it we combust the hydrogen and the carbon reacts with atmospheric oxygen to form CO2.

Manufacturing hydrogen from natural gas emits 9.1kg CO2 per kilo of hydrogen(1). So if cooking with gas is a way of splitting hydrogen from carbon, it seems reasonable to presume that we emit about the same when we cook with gas.

It takes 39kWh of electricity to make 1kg of hydrogen(2).

UK grid emissions are 480g of carbon dioxide per kWh(3).

480gx39 = 18,720g.

By this calculation, if the cooking hydrogen is made from grid electricity, it releases 18.72kg of carbon dioxide per kilo of hydrogen - more than twice the amount of someone cooking with gas.

= = = = = = = =

1. IPCC, Special Report on Carbon Dioxide Capture and Storage, Cambridge University Press, 2005, p131.

2. J. Levene, B. Kroposki, and G. Sverdrup, Wind Energy and Production of Hydrogen and Electricity — Opportunities for Renewable Hydrogen, US National Renewable Energy Laboratory, March 2006, p2.

3. Table 3, Fuel Mix Disclosure Data Table, DBERR 2006-07,

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