However, it appears this will be restricted to PlayStation Plus Premium subscribers.
According to a leak from the PS App, PlayStation Portal is likely to gain the ability to stream games from the PlayStation Plus library soon — but that functionality seems limited to Premium plan members.
On the official PlayStation Portal subreddit, user GetTheWetsOn posted a screenshot of the Deliver at All Costs page in the PS App showing confirmation of cloud streaming via Portal. The user also said that similar information (which was later removed) had appeared on the PS App page for the Dead Space remake.
Although Sony has not made an official announcement, the appearance of this option on the store pages for two different titles is unlikely to be an accidental oversight.
Source: iXBT.games