Monday, May 4, 2015

Have Solar Systems Finally Reached Financial Viability For The Masses?

With the release of Tesla's PowerWall last week at an incredibly reasonable price, I got really excited about the prospect of solar energy becoming financially viable again.  So, I started looking into a modern Solar system for our house.  My interest was motivated not so much to go off the grid as much as to lock in more stable and reasonable electricity costs through the next 20 years and to be a good steward of natural resources.  The bottom line was that it was going to cost around $50,000 after the 30% tax credit for my house to meet our energy demands.

The estimated energy cost with the solar system including use of PowerWall to store solar energy collected during the day would be reduced to about 7.9 cents per kWh.  And the electricity usage  offset by solar production for my household as you can see below would only be around 58% with existing solar system technology:

My current rate in the DFW area of Texas is only 8.4 cents per kWh.  And the energy rate over the last year has seen a downward trend as you can see from the screen shot from  The current rate for new annual contracts is around 7 cents per kWh.

The estimated lifespan of a solar system with a good maintenance program (a.k.a. additional cost) is only about 20 years.  If the current electricity rates persisted at around 7 cents per kWh over the next 20 years, I would loose money from the investment.  Given these data points, it was a no brainer to put the brakes that project for now.

On the up side, if researcher's claims about graphene increasing solar cell power production 1,000 fold materializes in the next 5 to 10 years, then solar will finally become a financially viable option for the masses.  And this would only be amplified further if the advancements by graphene also improve AC to DC and DC to AC conversion efficiency, battery charging efficiency and power density of batteries.

On a related but separate topic, the biggest concern that I have with Tesla's PowerWall is the risk it poses on making a house fire much worse since Lithium Ion batteries are well known for their explosive potential if charging is not properly regulated and retention guidelines observed or if the batteries catch fire from external factors.  But even that risk may be mitigated over time as aluminium-ion batteries improve and make their way into main stream.

Time will tell.  Here's hoping that Solar finally becomes economically viable for the masses in the next 5-10 years.