But when so many turn down leasing one and one-half acre for one Wind Turbine for each 80 acres, that lease certainly does not materially affect the rest of the Farm or Ranch grazing pasture and the lease pays much more than the farm crow or grazing pasture lease, just because some lawyer said the lease was too long: 30 years plus 30 year option = 60 years, and the wind turbine company has selling production/electricity contracts for the next 150 years – which is needed to obtain financing!
The term “residual income” refers to the income that someone makes after their work has already been completed. An example of residual income is the earnings an author continues to make on a book after it has been published, when fans continue to purchase copies years later. Residual income is ideal because it is money that is being earned while doing nothing in the present moment to earn that money.

During that time I’ve met many top earners who you would think had achieved the mythical walk away income, but guess what…? They are still working today, some in their 2nd or 3rd company since I’ve known them! So where is the walk away income? I say it doesn’t exist. I have known reps who have had 100’s of thousands of distributors on their teams at one time and now they are rebuilding and doing it all over again still promoting walk away income. It makes me want to scream! They can’t see that 99.9% of the people can’t do what they do and they can’t even achieve the mythical income. – Source Ezinearticles.com
The main advantage of the residual income metric is that it measures excess return earned by a department in absolute terms. A positive residual income means that the department has met the minimum return requirement while a negative residual income means that the department has failed to meet it. Return on investment (ROI) is another metric which measures return in relative terms.
Investing in real estate: Investing in real estate offers more passive income cash potential - but more risk - than investing in stocks or bonds. You'll need substantial amounts of cash to invest in buying a home -- it usually takes 20% down to land a good home mortgage loan. But history shows that home prices usually rise over time, so buying home a for $200,000 and selling it for $250,000 over a five-year time period, for example, is a reasonable expectation when investing in real estate.
Investing in rental properties: Another form of real estate investment, rental investments (i.e. becoming a landlord) could steer you down the passive income path of steady monthly rent checks that you can use to pay off a mortgage loan on the rental property. After the mortgage is paid off, those monthly checks go right into your bank account -- potentially for years to come. 
In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.