New CA Home Construction Mandate: Offsets?

[Cosmacelf]

Thought there are enough really knowledgeable people here to answer this question:

My understanding is starting in 2020, CA will mandate that all new home construction must be net zero energy (first, is this true?). My question is can a homeowner purchase offsets, for instance, part ownership in a desert solar farm, to reach this mandate? Or must the home stand alone in net zero energy usage?

 

[Tam]

...net zero energy...

I am not sure about new home net zero energy mandate but I do hear about solar photovoltaic mandate for single and multi-family residential building up to 3 stories high.

I think, for now, net zero is the goal but not the law. However, solar photovoltaic is the law starting in 2020.

 

[Cosmacelf]

I am not sure about new home net zero energy mandate but I do hear about solar photovoltaic mandate for single and multi-family residential building up to 3 stories high.

I think, for now, net zero is the goal but not the law. However, solar photovoltaic is the law starting in 2020.

OK, does the mandate address how big the PV array must be? Does it need to offset a certain amount of energy?

 

[bkp_duke]

Here is a summary I found:
The California Solar Mandate Rolls Out In 2020. Here's How to Comply.

• New homes built in CA after Jan 1, 2020 must be equipped with a solar electric system
• Solar systems must be sized to offset 100% of the home’s electricity usage – but homes can still use energy from other sources, like gas
• The size of the solar array can be reduced if other energy efficiency improvements are made elsewhere, like the inclusion of energy storage or green building materials
• The CEC expects the mandate to add roughly $9,500 to up-front development costs, but save the homeowner $19,500 over the life of the system
• Housing developers can save money on solar installation by sourcing wholesale materials and employing their own contractors to build the systems

 

[Tam]

OK, does the mandate address how big the PV array must be? Does it need to offset a certain amount of energy?

As @bkp_duke said above:

The solar system must be sized to offset 100% of the electricity used with the exception that you can use a smaller size with the compensation of others such as energy storage, non-electricity power such as natural gas.

The keyword here is "electricity". If you avoid using electricity in your home then there's no need for a solar system even your house might use lots of energy like natural gas, gasoline...

 

[bkp_duke]

The site I linked also has a calculator for this, since it is not apparently a straightforward calculation (climate zones, etc.).

California Solar Mandate Efficiency Standards Calculator - Wholesale Solar


EDIT - Apparently the requirements are REALLY low. I just used the map and plugged in things for our house . . . . 4.33 kW system required for a 4500+ SF house (3.24 kW with storage). By comparison we have a 12 kW system in reality.

Builders are not going to have to drop a lot of coin into these systems it seems.

 

[woferry]

I could have sworn I heard on the news several weeks ago that some towns were implementing bans/restrictions on future hookups to natural gas. Not sure if that was related to this (i.e. prevent the 'out' of moving away from electricity), or more just trying to eliminate fossil fuel sources independent of this state mandate. But intentional or not it sure seems like these two will interact, at least in some towns.

 

[bkp_duke]

I could have sworn I heard on the news several weeks ago that some towns were implementing bans/restrictions on future hookups to natural gas. Not sure if that was related to this (i.e. prevent the 'out' of moving away from electricity), or more just trying to eliminate fossil fuel sources independent of this state mandate. But intentional or not it sure seems like these two will interact, at least in some towns.

Yes, Berkeley and a few others have done this. They are all local restrictions, nothing implemented on the state level.

 

[mspohr]

I'm going to build a small retirement cottage on my property. Just put the 1200 sq.ft. into the calculator and came up with a minimum size of 1.93 kW. I plan on putting in about 5 kW solar so no problem.

 

[jboy210]

Just ran this for my house and came out with 3.9KW. I assume a Tesla Roof V3 on a 3100 sq foot house should put out what more than that.

 

[bkp_duke]

Just ran this for my house and came out with 3.9KW. I assume a Tesla Roof V3 on a 3100 sq foot house should put out what more than that.

Probably 3-3.5X that, depending upon the cuts of your roof (more lines/cuts, less active panels and more decorative ones).

 

[jboy210]

Probably 3-3.5X that, depending upon the cuts of your roof (more lines/cuts, less active panels and more decorative ones).

The roof is 2 side by side A frames. Both face due south on one side and due north on the other. On a normal summer's day all of the roof is in sun from 9 AM to 6PM. And the South side gets sun by 7 AM.

Still waiting on Tesla for the Solar Roof V3 quote and size. Hoping it is capable of producing a lot.

32 Panasonic panels on the South facing roofs were in the design we got in another company's proposal.