Late last month, a Wall Street Journal article discussed the impact of putting plans on hold for a large number of new conventional-coal plants. Concerns over global climate change and the rising cost of building cleaner plants are causing many of the delays. The article specifically cited TXU's (NYSE:TXU) decision to cut back on its number of new plants from 11 to three earlier this year as part of its equity deal, and it pointed to the recent problems FPL Group (NYSE:FPL) and Xcel Energy have encountered in their attempts to gain regulatory approval to build new coal-fired plants.

The takeaway from the article would seem to be that this is bad news for coal-mining plants and good news for zero-emission energy sources such as nuclear, solar, and wind power. Surprisingly, however, the article didn't mention perhaps the most obvious winner, and I think Fools could benefit from the oversight by better understanding this hidden opportunity.

A nega-what?
The hidden opportunity is the negawatt. The idea behind the negawatt is that the easiest, fastest, cheapest, and ultimately cleanest way to meet new power demand is to keep that demand from ever occurring in the first place. After all, the greenest and cheapest type of energy is that which never has to be produced.

And therein lies the opportunity. If consumers' demand for electricity is increasing -- and it is, to the tune of 2.7% a year -- but new coal plants aren't being built, and nuclear and wind plants cannot scale up quickly enough to meet demand, one of the lesser-known alternatives for addressing the problem is to find innovative ways to reduce consumer demand.

Demand management to the rescue
In just the past few months, two companies working in this field -- Comverge (NASDAQ:COMV) and EnerNoc (NASDAQ:ENOC) -- have filed for IPOs and are now trading on the public markets. These two "demand management" companies, along with Itron (NASDAQ:ITRI) and Echelon (NASDAQ:ELON), specialize in providing negawatt resources to utility companies.

The companies achieve their goal by installing in residences and businesses the technology and systems, such as "smart meters," that allow them to remotely manage electricity consumption. In essence, the companies can regulate usage by controlling air conditioners, refrigeration units, and other large electricity-consumption sources via a sophisticated network of computers, sensors, and wireless technology.

Without negawatt technology, utilities are frequently left with unattractive alternatives to reduce consumer demand: Either they need to buy additional capacity on the spot market, often at high prices, or they need to impose rolling blackouts.

A win-win situation
The negawatt approach is a classic win-win situation. Consumers and businesses that agree to install the smart meters benefit from a healthy discount -- often between 15% and 25% -- on their monthly utility bills, while the utility companies avoid the hassle and cost of needing to juice up older power plants or, worse yet, having to incur large capital expenditures by building new plants.

And even if utility companies want to, and can afford to, build new coal plants to meet greater demand, they might not be able to, because of environmental or regulatory concerns. Therefore, they might have little choice but to begin pursuing the types of solutions that demand-management companies are offering.

Foolish final word
One smart way to play this opportunity is to consider an investment in the PowerShares WilderHill Clean Energy (AMEX:PBW) exchange-traded fund, which has small holdings in Comverge, EnerNoc, Itron, and Echelon. However, for investors who have a higher tolerance for risk and are looking for more of a pure play, I would encourage considering a direct investment in either EnerNoc or Comverge. They are both young companies, and although they possess limited financial track records and have only between 1,000 and 1,400 megawatts under management -- which, in the energy world, is chump change -- I see a very promising future for the type of technology and services they are providing. As the old saying goes, sometimes less really is more.

Interested in clean-tech-related foolishness? Check out:

PowerShares WilderHill Clean Energy is a Motley Fool Rule Breakers recommendation. To find which stocks the market-beating service pegs as power generators for your portfolio, check out a 30-day free trial.

TXU is a former Income Investor pick.

Fool contributor Jack Uldrich does not own stock in any of the companies mentioned in this article. The Fool has a strict disclosure policy.