By not being specific, its not really an easy answer to come out with as even with as low as 1 Steem Power you are able to earn some sort of income.
However, lets explore what would contribute to a better flow of income which could be automated without much intervention. How much can be made would be fully dependent on how much Steem power you have.
1. Minnowbooster or Delegationhub - Delegation ( Recommended min SP 150 )
By the time you reach 150 Steempower , you are able to start delegating using minnowbooster as you would need at least 50 sp balance after the delegation. As you can see below, there are individuals requesting to lease steempower as low as below 100 SP with about > 15% APR ( annual percentage rate )
2. Minnowbooster - Selling Votes ( Recommended min SP 500 )
You can start selling votes as soon as you have some decent steem power. I do not recommend you start when your steempower is below this as it would take a long time to gain any significant profit. At this rate you would be able to get a few SBD a week without wasting your Voting Power. Be sure to set it up so it does not drain up all your Voting Power and perhaps set it to 70% would be ideal.
3. Steemauto / Steemvoter - Following Trails ( Recommended min SP 100 )
By following other people's trails you are able to not only support authors however you are also able to receive curation rewards which you may already know. But how much in curation rewards would you be able to receive ? That really depends if you are able to upvote these accounts before they get the whale upvotes.
You would be surprise that up-voting on comments can also receive lucrative curation rewards. Curation rewards really depends on how much % you vote and most importantly when you voted.
With HF20 just happened to the steem blockchain, the recommendation now is to upvote posts just after the 15th minutes mark. Anything earlier, the curation rewards would be returned to the reward pool.
This are just a few tools which you can automate your income on steem. So coming back to your question, how much Steempower you need to have a sustainable flow of income. You may want to invest significantly into steem first before you are able to start seeing a really sustainable flow of income towards your expectation.
Cheers and have an amazing weekend.
It depends on how much you are willing to earn. But I saw a Steemian who is earn a good chunk of curation rewards and he is only having 500 Steem Power. It's a small amount that even has almost zero in value (though it will depend on the price of Steem). He is doing a great thing in maximizing his stake in the platform.
What he does is amazing. He upvotes the comments from the Musers who are very active in the platform. He upvotes it at 10% (even me, I am upvoted) and with that he is earning curation rewards almost 1 Steem Power per day. Imagine, 1 Steem power in just 1 day? It's purely amazing!
Now, allow me to do the math.
See in just 500 SP, that account earned more than 1 SP per day. Let's make it an average of 1 Steem Power per day with his 500 SP investment.
every day, he is earning 1/500 of his current investment. If you'll calculate that in a year (which we have 364 days), he will be earning 364 Steem Power from his investment. If you'll calculate his earnings :
364 / 500 x 100 = 72.80% of increase in his investment in a year.
That's only a rough estimation. It could increase because the SP earned per day could generate another SP curation rewards too. It might go more than that increase of investment.
With the current fork of the platform, it allows curators maximize the curation rewards of a post. That alone can boost your investment in the platform if you just continue to upvote contents at a desired minute.
I am only focusing on the curation rewards here because for me, it's the best behavior in the platform - voting on other people's post. You just need to play the game how to maximize the curation rewards allocated to curators. I'm liking how this @green-heron is doing. He's absolutely a great tactician with his investment.
So my advice to us Steemians, let's work our way to maximize our potential in the platform by voting on other's posts and get the curation rewards. We have helped the user itself and at the same time helping ourselves.
Question is too vague. However, inorder to have "steady income" one just need to make sure a self upvote that worth 0.02, which at the current Steem price can be done at 100%Voting power at about 400sp. So, from here you can work your way up to find out what is your desired output.
Note that I answer this because you asked for steady flow, which is something you can control. Which is self upvote. And you haven't define what is your minimum income desired. But you can always multiply the SP to with the current payout to ensure what is your targeted payout.
There are 2 major factors to be considered here:
As someone who actually considered going full time here on Steem, one thing that made me backed out was the fluctuating price of Steem in the market. I've joined this platform at $8 and now it's only around $0.8.
One might feel that he is earning enough at the moment, but what happens when the price drastically drops once again? Which is why I think there is just no way one could earn "steady" income here even if one has a decent amount of Steem Power.
One could earn some "extra" pocket money especially those living in countries where a dollar is traded at a high valie compared to their local currency. But that's it! Only extra but is never steady.