With the global lighting market representing a $75 billion opportunity – and lighting consuming about a fifth of all the power generated in the United States – it's little wonder that investments into lighting efficiency are taking off.

At Greentech Media's Greentech Innovations: End-to-End Electricity conference in New York on Monday, three companies – HID Laboratories Inc., BridgeLux and Eden Park Illumination – laid out how they're looking to capture different parts of that market by offering ways to cut down on that power use.

Venture capital investments in lighting technology companies surpassed investment in biofuel companies for the first time in the third quarter of 2008, according to Greentech Media figures. VCs have put $174.2 million in lighting through the third quarter of 2008, up from $85.6 million in 2007.

At the same time, major lighting companies are snapping up startups at a rapid pace. Philips spent $5.4 billion from 2005 to 2007 on promising startups, and Cree, which makes LED components, spent $303 million from 2007 to the most recent quarter for acquisitions, including LED Lighting Fixtures for about $77 million in cash and stock in February (see Cree to Buy Firm Founded by Its Former Execs).

Since its invention more than a hundred years ago, the incandescent light bulb has dominated indoor lighting, although it converts only about 15 percent of the electricity running through it into light. Compact fluorescent light bulbs are a more efficient alternative, but not only do they provide a light that's less pleasing to the eye, they also contain mercury, a toxin that makes their disposal and recycling problematic.

So many companies have turned to light-emitting diodes, or LEDs, to try to find an alternative that combines incandescent light's pleasant qualities with fluorescents' energy efficiency.

LED technology is already well developed for uses like traffic lights and billboards, but a U.S. Department of Energy study last month projected using them in other applications, including indoor light, could lead to power savings equal to 27 1-gigawatt coal-fired power plants (see DOE Says LEDs Can Shine in 12 Markets).

Keith Scott, Vice President of Business Development for Sunnyvale, Calif.-based LED maker BridgeLux, said Monday that LED technology has improved to the point where it can compete on light quality and efficiency for indoor purposes.

The problem for LEDS in this market comes down to price, he said.

"You can easily pay $100 for an LED light bulb that looks good," he said. "It's the competitive cost that we at Bridgelux see as the barrier."

Bridgelux intends to beat this problem by focusing on a more streamlined and cost-effective manufacturing process, he said, likening the current production methods to "hand-making LED light bulbs."

Bridgelux raised $40 million in an April round of funding led by VentureTech Alliance, bringing the company's total funding to $71 million. But it isn't the only LED company seeking to break that price barrier.

One is Westhapton, N.J.-based Lamina Lighting, which in July was acquired by Dallas-based Lighting Science Group for $4.5 million in cash, as well as up to $10.5 million in the second quarter of 2010, depending on Lamina's 2009 sales. Lamina raised $37.5 million in venture capital by 2005 and an additional $7 million in 2007.

And Luminus Devices in Billerica, Mass. has raised a total of $139 million, including a $72 million round in March that could be the largest single funding ever for an LED company (see Luminus Closes $72M to Light Up New Applications).

While LED companies compete for the indoor lighting market, a University of Illinois spin-off says it has created a new type of light that's more flexible – literally.

Eden Park Illumination has created what it calls microplasma lights that will produce 40 lumens of light or more per watt and contain no mercury, making them recyclable.

Clara Powell, Vice President of Marketing and Business Development, showed off one of Eden Park's microplasma lights at Monday's conference. The tabletop portrait-sized light consists of two glass panels sandwiching an aluminum mesh with tiny cavities filled with phosphors, which illuminate when a current is passed through them.

Eden Park, which has raised $1.9 million in a funding round led by Illinois Ventures, can make the panel lights with plastic and other flexible materials as well, Powell said. The company's plans focus on the commercial market, and early plans call for a one foot-by one foot light to be embedded in office ceiling panels, she said.

While Eden Park looks to illuminate the office space, HID Laboratories Inc. is targeting bigger spaces and brighter lights. developing systems that can control and dim commercial lights to save energy.

The Menlo Park, Calif.-based startup has said it can cut up to 40 percent of the power consumption from some high-intensity discharge lights – bright lights that use capsules of gas instead of filaments and are often used in stadiums, parking lots and warehouses.

"The only thing you can do with those light is essentially dumb – you can turn them on and off, that's it," said CEO Antonio Espinosa. That is, that was all you could do before HID Labs came out with its digital ballast systems, which can control voltage and current to dim HID lights at levels that the human eye can't notice.

HID Labs' digital ballasts are meant to replace the magnetic ballasts now standard in HID lights. Ballasts deliver power to the bulb, exciting their internal gases to create light.

HID lights cost their owners around $34 billion a year in the United States to power, making the savings HID Labs can offer well worth their while, Espinosa said. HID Labs received two investments from the California Clean Energy Fund's Clean Energy Angel Fund last month, as well as two investments from American River Ventures in August, though no dollar amounts were disclosed.

Other companies in the HID lighting technology field include Metrolight, which last year received funds from Virgin Fuels and Gemini Israel Funds, and Nedap Light Controls, Espinosa said.