How do we think they are doing now?

whjohnson:

On the subject of renewebles, I read today that there is talk of going for 'Green Steelmaking' by running electric arc furnaces from windmill output!

These so-called 'Scientific Journalists' really have no idea do they?

All currently used bulk steel making proceses use coke as both the heat source AND as the chemical feedstock that reduces iron oxide to liquid iron, and then adds carbon to molten iron to make steel..

An electric arc could be used instead of burning coke for the heat, I am not aware of this being done to make "new" steel, though it is widely used for steel recycling.

Carbon would still be needed to reduce iron oxide to liquid iron, and then form steel which contains a mixture of iron and carbon. The amount needed would be very much smaller than when it is burnt as the fuel supply. Biochar made from waste wood would be suitable.


Another way to reduce iron oxide to metallic iron is to produce hydrogen and oxygen by electrolysis of water. Burn these gases in a furnace, with hydrogen being present in excess of that required for perfect combustion. This will produce a reducing atmosphere and turn iron oxide into iron. No carbon needed at this stage. Carbon would still needed to add to the iron to make steel, but the small amount needed could be from biochar as above.


Either process needs a great deal of electricity, but there is no reason why this can not be produced from wind turbines.


Neither process is used on a significant scale at present, therefore I reluctantly support the proposed coal mine for coking coal.

lyledunn:

Their efficiency is one thing but are they being used to best individual benefit? Feeding back into the supply network isn’t really worth the effort, perhaps the EV roll out might find a better purpose for them. 

If you've got an installation that's a few years old, then by far the most important thing is "farming" subsidies.  The government went a bit mad on subsidies in the early years.  As a result, my overall energy bills every year are strongly negative - I get paid more every year for generation than I spend on gas and electricity combined.  Given that, what I do with the electricity I generate is largely lost in the noise.


When my original inverter failed after only 6 years (some early ones were very poorly designed), I got a new one with a battery attached.  I can be smug posting from my computer at 9.30pm, running entirely on battery power.  But actually the economics don't make much sense.  Batteries are still expensive, and I actually lose a bit in subsidies.  Charging a battery and then discharging it is never 100% efficient.  On the plus side, I actually got to use "islanded" mode for the first time during a power cut last Monday.  I switched the house to solar-only and ran off-grid for a few hours.


The economics for new installs are totally different, and it only makes sense if you use electricity continuously during the day.