Ask HN: What can I do with extra electricity?
I&#x27;m in Washington state and I&#x27;m not sure what latitude you live at, but for my house, my low, without snow on the panels, is about 8 kWh for an overcast day in December or January and my high is 107 kWh for a day in the middle of summer.  For me to average out my needs I need a dam... like on the Columbia.  In WA state, you don&#x27;t sell the power, your extra power is future credit to your power needs.  I&#x27;m on a heat pump and my highest demand is in the winter where lows dip to 15F or 25F.  For me to save up enough energy on my own land would require more of a pond pumping scheme and it would be a massive undertaking.  On the order of being able to store huge portions of energy for a quarter to a third of the year to get through winter.  FYI, my system is Goldilocks&#x27;s just right. I pay about $25&#x2F; year for extra power once my credits run out at the end of winter.<p>I&#x27;ve bought two different solar systems in two different states and the devil is in the details for your hypothetical situation.   You need to understand average overcast days, ~90 percentile run of overcast days in your lowest intensity  sun month, intensity of sun, angle of the sun, et c.  Also, if you optimize for the worst days of the year, you could be reducing total energy output because your panels would be optimized for a lower sun angle.