Published Friday September 4, 2015: Updated September 5, 2015


Tesla Power Wall

A few months ago, Tesla announced that they are getting into the energy storage business. Soon they will be selling 7 kilowatt-hour battery packs for daily residential use, 10 kWh packs for occasional backup power use and 100 kWh battery racks for industrial and utility scale energy storage. All of these are scalable with the 100 kWh unit being infinitely scalable.


This technology makes 100% renewable energy for the entire planet not only plausible someday in the not too far distant future but affordable and doable TODAY!!
Solar power is capable of providing thousands of times more energy than what all of humanity currently requires. The only limitation is solar energy is intermittent. Having a way to store energy in high-density, reliable batteries until it is needed solves this problem. 
Even without solar panels, a power wall can level load the existing power grid, making it more reliable and cheaper to operate. 
 
So does this mean I can buy one of these power walls, put up some solar panels and go totally off-grid right now?
 
Making your home net-zero is no longer difficult or expensive.
Being grid-tied with battery backup is no longer difficult or expensive.
But going totally off-grid while still maintaining your same lifestyle and standard of living is still very difficult, impractical and very expensive.
I would love to do the same but here in Northern Utah, the differences in solar illumination between summer time and winter time create difficult engineering problems to solve. Also because of home heating needs, wintertime energy usage is higher than AC usage in the summer time.

Engineering Challenges in Going Totally Off Grid:
  • How do you collect and store sufficient solar energy for use during the dark winter months? 
  • Where do you store the enormous overabundance of energy during the rest of the year, (not just tens of kilowatt-hours but hundreds and perhaps even thousands of kilowatt-hours)? For my house and cars, they would require around 140 Tesla Power walls worth of storage. Yikes!
For my house and cars, a few Tesla power walls would make it possible to go off-grid 9 months out of the year but during December-February it becomes nearly impossible to go totally off-grid without either increasing battery storage requirements by 20x or way over-sizing the solar array. Over-sizing the array is extremely wasteful in an off-grid configuration and if grid-tied, it greatly complicates the grid's job of managing power, especially if more than 1/3rd of the population were to do it.
 
Until these challenges can be solved, (and I guarantee you they will be), I think the immediate answer lies in working with government leaders and power companies to stop praising, subsidizing and coming to the aide of dirty, immoral fossil fuels, to quit vilifying grid-tied solar power and just allow it to happen for everyone.