Creating CH4 from H2 + CO2 This was a topic raised before. However a point that should have been made and wasn't is as follows. The problem with electricity is that it cannot be stored. Wind energy often has to be dumped at times of low demand (night, holiday periods, weekends). The amount and frequency of excess energy availability will increase as more and more wind generation is installed. The "storage" of electricity in one form or another is the key issue. Batteries and Fuel cells are other options, but both are still basically chemical reactions. If excess green energy is the source for the CH4 reaction then the question is:- 1) What is the cycle efficiency of a CH4 reaction. The cycle being a) create CH4 using CO2 + H2, b) store CH4 c) Use CH4 burning Gas Turbine Electricity Generator at high demand times 2)What would the capital cost of the CH4 plant. 3)Storage might not be an issue, if the gas can be pumped into an already existing gas network. Cost may be too high now, but the break even point is a function of the cost of Oil/Gas or Coal. All the above questions could be asked of batteries and fuel cells and there are associated capital costs. The Gas Turbine will already be built so there is no captital cost associated with it.