The current "ZEV" mandate includes partial credits for plug-in hybrids and the manufactures are having no problems meeting the requirements.
In fact they can meet the requirements for the next four years with bankrolled credits. Without selling anymore ZEVs.
Currently, CA has 1.7% market share for BEVs and 1.1% for PHEVs.
For the "large manufactures" right now the requirement for BEV is only 1.25% of the fleet. That is for GM, Ford,Fiat Chrysler,Toyota,Nissan,Honda,Hyudai,VW,BMW and MB.
The mid-size OEMs that have global revenues less than $40B but sell more than 10k cars worldwide don't have a requirement til 2018. These are Subaru,Mazda, Land Rover-Jaguar, Volvo and Mitsubishi. Then they can meet all their requirement with PHEVs. For a while they don't actually need to sell a single BEV or FCEV.
They can easily meet 22%. This is 22% of CA not the USA. BMW is planning to switch all cars to plug-ins. Most to PHEV and a few to BEV.
All they need is to sign contracts with either Tesla,LG, Samsung or one of the second tier Japanese or Chinese firms to have 5-10 kWh battery packs for enough PHEVs. OEMs will not be required to sell 22% of the fleet with 70+ kWh packs.
There is one poster here who believes Tesla will not sell battery packs for PHEVs only BEVs. This is a belief as Tesla has said no such thing to my knowledge plus there are plenty of battery/automotive supplier firms that can handle the business they just need a few years lead time to have the capacity. There is plenty of time between now and 2022.
BTW It does look like by 2030 all cars and light duty trucks sold in CA will be required to be either BEV or FCEV. The heavy duty half ton and 3/4 ton trucks and SUVs might be allowed to be PHEV. Again, 2030 is a long way off.