Cramer's 'Mad Money' Recap for July 31

Finally, Cramer reiterated his buy on Mastec, a company whose stock is up 18.9% since it was added to his "Windex" index of wind power stocks.

In the solar industry, Cramer reiterated his buy on First Solar (FSLR Quote), a company he called the best of breed in the solar industry. The company recently posted earnings of 85 cents a share, blowing away estimates of 58 cents a share, a 47% upside surprise.

He said First Solar is not a maker of residential rooftop solar panels, but a provider of large-scale industrial solar facilities. The company manufactures solar cells at a price of just $1.42 per watt, compared to traditional cells which average $2.50 per watt.

Cramer did warn that Congress' eighth delay in passing a bill to provide investment tax credits for wind and solar may hurt both industries to the tune of $11 billion in lost investments. However he remains confident that the measure will eventually pass.

Taking the Long View

Cramer talked with Peter Miller, National Oilwell Varco (NOV Quote) chairman, president and CEO, about the company's outlook amidst falling oil prices.

Miller said the demand for new oil rigs is not declining with oil prices. He said the company's backlog extends well into 2011.

Even with oil prices as low as $110 or even $100 a barrel, Miller said National Oilwell Varco would not be affected. He explained that many of the orders in the company's backlog were placed over two years ago when prices first hit those levels.