Off-Grid Energy Strategy

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All loads can run during the day if one devises a smart energy system for a home and has access to low cost photovoltaic power such as from Sunelec.

Further, one can run most loads on solar: cooking with high efficiency induction cooktop; hot water with minitank heaters; AC and heat with heat pump. Fridge as a Freezer to Fridge Conversion. Then the only loads left for the night are lights and computers if one is a late night information worker.

Thus, there is a low level of power that is required during the night. This power can be produced with a small battery bank, or with a house generator. It seems that a sensible way to achieve this would be via nickel iron batteries - a small backup system that lasts for a long time. For a household that runs 3 hours of 200W - that would be under 1 kWhr of power.

The most energy-saving route is the nickel-iron. If you examine [1] from Nickel-Iron Battery Quotes - a 2kWhr system would cost $1100 in nickel-iron batteries. If this is true - ie, if the batteries can really be discharged down to near full - then this is a promising way to solve the storage issue. The key is superefficiency by blowing out of proportion the available solar photovoltaic power during the day - and coasting at night with a small load. A backup house generator can complete the whole package - a small remote control or auto transfer switch generator converted from a portable generator. This is possible because PV panels now cost about 34 cents per watt.

The ramifications for the Seed Eco-Home are true zero energy operation option, with minimal lifestyle adjustment. For those who would like to have no lifestyle adjustment, they can still use a transfer switch option, and not pay their energy bill. It makes no sense to run coal and nukes when free electricity from the sun is available.

Cost Savings

Average household utility bills total $2k per year [2] or $3k per year [3]. Thus, over a lifetime, one can save $140-210k in utility bills alone! Think about what could be done with this money if the costs didn't exist.

In practice, electricity ($110) and gas ($70) add up to $180 per month - $2160 per year. So this is the real savings of going solar. Solar pays for itself in 4 years - say with a 15kW system that costs $8k.

This is definitely worth optimizing for the Seed Eco-Home.