LED Lighting Technology
LEDs have many advantages over conventional incandescent light sources, including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching.
Light-emitting diodes, or LED’s, are now used in applications ranging from aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, and camera flashes. However, LEDs powerful enough for room lighting are now very commonplace, and they have many advantages over traditional halogen lights.
• Solid-state devices such as LEDs are subject to very limited wear and tear if operated at low currents and at low temperatures.
• LEDs emit more lumens per watt than incandescent light bulbs.
• LEDs light up very quickly.
• LEDs can be dimmed very easily.
In contrast to most light sources, LEDs radiate very little heat in the form of IR that can cause damage to sensitive objects or fabrics.
LEDs mostly fail by dimming over time, rather than the abrupt failure of incandescent bulbs.
LEDs can have a relatively long usage life. One report estimates 35,000 to 50,000 hours of usage, though it may even be longer. Fluorescent tubes typically are rated at about 10,000 to 15,000 hours, depending partly on the conditions of use, and incandescent light bulbs at 1,000 to 2,000 hours.
LEDs, being solid-state components, are difficult to damage with external shock, unlike fluorescent and incandescent bulbs, which are fragile.
With the development of high-efficiency and high-power LEDs, it has become possible to use LEDs in lighting and illumination. Replacement light bulbs have been made, as well as dedicated fixtures and LED lamps.
LEDs are small, durable, and need little power.
Efficient lighting is needed for sustainable architecture. In 2009, a typical 13-watt LED lamp emitted 450 to 650 lumens, which is equivalent to a standard 40-watt incandescent bulb. In 2011, LEDs have become more efficient, so that a 6-watt LED can easily achieve the same results. A standard 40-watt incandescent bulb has an expected lifespan of 1,000 hours, whereas an LED can continue to operate with reduced efficiency for more than 50,000 hours, 50 times longer than the incandescent bulb.
One kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO2 emission per year. The 6-watt LED equivalent will only cause 30 pounds (14 kg) of CO2 over the same time span. A building’s carbon footprint from lighting can be reduced by 85% by switching out all incandescent bulbs for new LEDs.
LED light bulbs are a cost-effective option for lighting a home or office space because of their very long lifespans.
Efficient LED lights are appearing more and more in homes and businesses. Today, LEDs (Light Emitting Diodes) use about 85% less electricity than a conventional lighting source such as an incandescent bulb. They may soon use even less.
This is a significant reduction. Around 19% of the world’s electricity demand is used for lighting, compared to just 3% going to smelting aluminium. In Australia we only use about 12% of our electricity for lighting and 8% for smelting aluminium.
A simple measure for lighting efficiency is the number of lumens (a measure of light intensity) that a lighting source produces per watt.
A conventional incandescent bulb gets 13 lumens per watt to light your room, while a replacement LED bulb from Philips that can be bought at Coles or Woolworths achieves 80 lumens per watt. (A compact fluorescent globe gets about 60 lumens per watt – see technical note at the end)
So, where is LED lighting going?
CREE, the industry leader who it is speculated may purchase the next best, Philips’ Lumileds division, has successfully demonstrated Light Emitting Diodes running at 300 Lumens per watt in the lab. CREE currently sell a $10, 9.5W bulb (available in the US), which produces 85 Lumens per watt and can directly replace an old style 60W globe.
Other breakthroughs and innovations are contributing to achieving higher efficiency in LED lighting, including a breakthrough by German researchers http://www.ciol.com/ciol/news/217344/german-researchers-cut-energy-loss-half which will not only effect LED lights, but laptop and mobile phone chargers, cutting losses in today’s most efficient power supplies by half from 10% to just 5%.
Taking all of this into consideration, according to the US Department of Energy SSL (Solid State Lighting) program http://energy.gov/eere/ssl/solid-state-lighting we should be able to achieve wall plug efficiencies of 250 Lumens per watt by 2020. That means that a conventional bulb replacement in 2020 would be available using only a third of the electricity of today’s LED bulbs.
3 Watts to light a room
At that staggering rate of 250 lumens per watt, it will only take 3 watts to light a room, when it used to be done with 60 Watts of power. This represents a 95% reduction in energy required for lighting.
This will have a profound effect on the world’s requirement for lighting energy. We can expect that 19% of the world’s electricity which is currently used for lighting will dramatically drop by at least 75%. By today’s numbers, the reduction is the equivalent of the entire electricity consumption of the European Union.
In developed nations these huge efficiency gains from LEDs in the lighting sector will contribute to the continuing restructure of the electricity supply industry, which is currently facing a crisis, unless it can electrify the automotive industry and other fossil-fuel dependent industries.
In developing countries, rooms can be lit with 3W, and task lights with even lower electricity consumption. This means that almost all of the remaining 1.5 billion of the world’s population without an electricity supply will be able to access one at very minimal cost in the next 5 years.
While energy requirements and costs for lighting go down, photovoltaic and battery efficiency are going up, and their costs are coming down, as well. This nexus means that turnkey solar photovoltaic panels, with batteries and high performance lighting, will be the mobile phone of the all-electric renewable revolution.
In order to focus capital on achieving the lowest cost and highest efficiency lighting, wealthy countries like Australia should be specifically focussing on research and development efforts.
This can be done through institutional and non-institutional research grants (equivalent to the US DoE and EU programs), and agencies such as the Clean Energy Finance Corporation. To be effective, it must make inroads into financing wholesale changeovers of the nation’s lighting infrastructure, and to use the most efficient technology as an incentive for suppliers to retool, upscale and mass produce the newest and highest performance LEDs.
In addition, halogen and fluorescent lighting should be phased out the same way incandescent lighting has been phased out to create even greater incentive to researchers and developers and manufacturers.
The future is looking bright for LEDs, and the applications are unlimited. LEDs have had a strong impact on the automotive industry, street lighting, appliance back lighting, bicycle lighting, and are now even being used in greenhouses, saving significant energy when growing food in controlled environments.