About 1 kW of solar radiation falls on every square meter of earth , when it ' s sunny . Assume 40 % photovoltaic efficiency , take the square root , and perhaps a square that ' s around 1 km by 1 km could supply the power . I assume you normally run the steel mill during daylight hours anyway , but this doesn ' t really account for winter or weather . Batteries or other types of offpeak power storage will be crucial . <| sep |> The empty OEM cartridges I have go in and the printer registers them as all empty . Not sure if the printer checks the cartridges levels before or after it checks for the printheadcarriage error though . So no sure way for me to know until I buy new OEM ink . <| sep |> One tit is very clearly bigger than the other .