No energy play is currently hotter than energy efficiency, in all its forms. Think about it...

For several years running now, the hottest cars at the Detroit Auto Show — and most auto shows, for that matter — have been cars that use less gas: the Tesla, Volt, new versions of the Prius, etc.

And this year was no exception. In fact, the show added an all-electric wing called Electric Avenue that hosted popular attractions like the Nissan Leaf, Volvo C30, and the Ford Fusion Hybrid, which won Car of the Year.

There wasn't a Hummer to be found. Ironically, GM is halting production of all Hummers this week as the brand continues its stay in auto purgatory.

Efficiency is all the rage in home appliances, too. I just bought a new Energy Star dishwasher made by Maytag, thanks to a $300 million rebate program made possible through the stimulus — the equivalent of Cash for Clunkers for water heaters, air conditioners, clothes washers, and more.

Surely you haven't heard anyone asking for appliances that use more energy or cars that use more gas...

And the reason for that is simple: using more energy costs more money.

The Fifth Fuel

It's not as sexy as erecting a massive wind farm or commissioning a new nuclear reactor — and it certainly offers far fewer photo ops — but businesses and decision-makers the world over are quickly starting to realize the power of energy efficiency.

Wal-Mart is adding billions to its bottom line by making its stores and supply chain more efficient. Boeing has outdone Airbus with its 20% more efficient Dreamliner. Forbes recently reported that "BP made over $2 billion substituting efficiency for fuel; DuPont and Dow Chemical, $3 billion apiece."

That's what's so exciting about energy efficiency... A small investment on the front-end leads to huge savings on the back-end. And it applies to every business...

Retail chains can save money by retrofitting stores with energy efficient lights and HVAC systems. Grocers can improve the electricity use of their massive coolers and freezers. Companies producing goods can optimize their factories and distribution chains.

It's like a brand-new, earth-shattering discovery has been made. Only it's not a new product — it's a concept. The idea is to do more with the energy we already have access to. And the net savings have been dubbed "The Fifth Fuel."

And there are two best parts here...

First, there are incentives available for many of these upgrades. I already mentioned the $300 million available to upgrade your appliances. The Cash for Clunkers budget came in at $3 billion. And just this month, the Department of Energy announced $187 million to improve efficiency for heavy-duty trucks and passenger vehicles, $47 million to improve efficiency in the information technology and communication sectors, and $37 million for next generation lighting.

Second, there's more than a handful of publicly-traded companies on the receiving end of not only billions of gov't cheese, but also billions in sales from the private sector as the financial benefits of efficiency are realized.

They Spend, You Profit

As these billions are spent on energy efficiency upgrades, a few companies (and their shareholders) are making a lot of money.

For example, Ford, Cummins, GE, IBM, BAE, HP, Yahoo!, and many others have all been declared recipients of energy efficiency dollars from the federal government.

And look how companies that provide energy efficiency solutions have been performing:

Veeco Instruments (NASDAQ: VECO), a smart lighting company — and the best performing stock in the chart above — has gone from about $3.00 to over $32.00... since March.

Many companies have made runs like that. And more are about to.

I actually have my eye on one company — currently trading for less than $1.00 — that's about to make a similar run.

They make a device called a "Negawatt Box" that can drastically reduce energy consumption in both residential and commercial buildings. And a tax credit is being offered to all who install it.

Our electrician recently installed one at our Baltimore headquarters... and we quickly realized 44% savings on our utility bill.

The device is so unique — and the investment opportunity so large — that I've compiled a full report about the company.

It describes not only how to take advantage of the product for yourself, but also how you can profit by owning shares of the company that makes it.

Call it like you see it,

Nick