LEDs could slash street light energy usage by 97%

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LED streetlights could achieve efficiencies of 97% by 2020 – much higher than domestic or commercial lamps. But are our governments enlightened enough?

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There are almost 300 million streetlights installed around the world today and this is expected to grow to over 330 million by 2025. Generally, conventional street lights use technology that is more efficient than for lights we use in our homes, so you’d expect that the switch to LED street lights would not achieve the energy saving results that LED’s will give us in our homes. But this assumption is incorrect, because of the different requirements for illuminating our streets for driving and nighttime safety.

Today, most of the streetlights in Australia use mercury vapour bulbs; these consume about 80 watts and have an efficiency of about 30 lumens per watt. As reported in Reneweconomy recently Warrnambool, in Victoria’s south west, will trial LED street lights in a project funded by the CEFC, while other councils pursue projects to replace their conventional bulbs with soon to be out-dated fluorescent tubes.

With its simple approach to LED street lighting, Warrnambool will achieve energy savings of 50 per cent compared with their existing lights. If, however, they were to use new technology, developed by lighting company CREE and set to be available in 2015, which achieves 150 lumens per watt, Warrnambool would achieve savings of 66 per cent.

Savings like this should be particularly appealing to local councils in NSW, where the state government-owned network operator, Essential Energy, has proposed to hike up the costs of public lighting maintenance starting July 2015, claiming it has been under-recovering for the service in the past.

The proposed changes, submitted to the Australian Energy Regulator last week, would reportedly lead to huge increases in public lighting costs for some NSW cities, such as 102 per cent ($34,303) for Liverpool Plains between this financial year and next, and 65 per cent ($62,202) for Narrabri.

Cree LED street light E27 bulb
An earlier model Cree LED street light

But what is really interesting, in the world of LED streetlights, is if we fast forward to 2020, where much bigger savings will be achieved. In the Argentinian capital of Buenos Aires, for example, the entire city is getting retrofitted with LED lights a world first that will be repeated time and time again until over 95 per cent of street light sales will be LEDs by 2023.

97% reductions in street lighting by 2020

Streetlights will achieve higher efficiency than domestic or commercial lamps, emitting high quality light at 400 lumens per watt, in commercially available units, by the end of the decade. This will occur using a combination of Red, Blue and Green LEDs, whereas the approach for domestic and commercial lights has been to work solely with blue LEDs and make them appear very close to white by adding a layer of phosphorous.

The Red Blue, Green approach is very suited to street lighting as the colour rendering requirements for street lighting (quality of light) are not the same as what we’d expect to live and work under for lighting our houses and commercial spaces. At 400 lumens per watt, a future LED Street light will use one-thirteenth the electricity (6.15W) of a conventional mercury vapour (80W) fixture.

OLYMPUS DIGITAL CAMERAIn addition to this intrinsic energy saving future streetlight’s will have inbuilt ambient light sensors which will reduce lighting output in the early evening and early morning as well as when there is a lot of background light such as on clear nights when the moon is out, avoiding over illumination and the costs associated with providing light when it’s not required.

In addition street lights will have predictive forward illumination with auto-dimming which detects when a person or vehicle is present causing multiple lights in front and behind the person/vehicle to come on full power and stay on for a short period after the person or vehicle has passed.

The lights then auto-dim and the fixtures are ready for the next person or vehicle that comes into the coverage area of the lighting array. This “smart lighting” feature saves a further 50% on energy requirements. An entire road system can run at a low level dimmed point (when no one is present) and automatically ramp up to full output several lighting poles in advance of oncoming traffic, lighting up entire roundabouts or intersections as vehicles approach, without any human intervention, quietly dimming back to the low standby ready level after the traffic has moved on.

The combination of the most efficient LED street lights with ambient light sensors and smart lighting will achieve greater than 97% reduction in electricity requirements for new LED streetlighting by 2020. If all the world’s lights were replaced it would be the equivalent of 25,000MW saved (including grid losses and PowerStation internal consumption) or about the same as Australia’s entire overnight electricity demand being completely shut down every night of the year.

LED street lighting already delivers far superior colour rendering compared with traditional street lights and improves safety by making it much easier for drivers to recognise hazards and pedestrians. And although they suffer some degradation, LED lights don’t progressively degrade to the poor performance levels of mercury vapour lights, either.

Furthermore, with LED lighting the public can maintain a sense of security while reducing light pollution, which affects some people’s ability to sleep – not to mention the efforts of stargazers, who are currently hindered in practicing their hobby in and around cities.

Developers in the US are already choosing Solar powered LED street lights (Solar + LiOn Battery + Photovoltaic) because it is cheaper than trenching and cabling up conventional light poles in new developments with underground power.

The future is bright, with more opportunities to light dark spaces brought about by rapid LED research development and commercialisation, giving a higher sense of security as well as lighting the way for those in developing countries who have not yet had the opportunity to experience illuminated roads and streets.

There is a serious opportunity for Australia to play a part in these developments, and a forward looking “bright” government would be fostering research opportunities in our public, private and academic institutions.

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23 Comments
  1. Bob_Wallace 5 years ago

    Did I miss directionality?

    LED street lamps are going to put their lumens down on the street and sidewalk rather than letting half of them drift off into space as happens with non-directional bulbs.

    Less light pollution from urban areas. City kids might start understanding what “Twinkle, twinkle little star” is about….

    • Chris Fraser 5 years ago

      They could help this issue with clever lenses. Just one up front cost, too

    • Matthew Wright 5 years ago

      Thanks Bob, I think I covered it (indirectly though) in the paragraph where I wrote about stargazers:

      “Furthermore, with LED lighting the public can maintain a sense of
      security while reducing light pollution, which affects some people’s
      ability to sleep – not to mention the efforts of stargazers, who are
      currently hindered in practicing their hobby in and around cities.”

      • Bob_Wallace 5 years ago

        Yep, I missed that.

        Good write up. You might want to follow up with some of the cities that have already switched to LEDs. I think Los Angeles and, perhaps, San Diego are a couple. And report a 50% drop in city government electricity use.
        LA is looking at an annual $10 million saving in electricity and maintenance. (Interesting picture in the article.)
        http://cleantechnica.com/2013/09/12/worlds-largest-led-streetlight-retrofit-completed-in-los-angeles/

      • RobS 5 years ago

        The amateur astronomer in me is particularly excited about the potential to be able to travel far shorter distances from cities to be able to do meaningful astrophotography.

  2. Craig Allen 5 years ago

    So when councils start reducing their electricity usage by installing solar+storage+LED lighting, will the utilities squeal about them being cross-subsidized by other electricity users and start demanding that penalties be applied?

    • Matthew Wright 5 years ago

      Point well made. We should be charging Alcoa and Hydro for the electricity they’re not consuming on their shuttered smelters as well. Same goes for Mitsubishi, Toyota, Holden and Ford who are all free riding the energy supply system by moving their production off shore and not buying energy here.

  3. P_Curley 5 years ago

    Why do articles like this present the statistics in the most extreme case – and imply with the headline that it will the norm ! Appalling presentation of stats and drawing of conclusions. The 97% claim occurs when the lights are off !!!! most of the time and which only turn on when someone walks past. This would not be acceptable in any major city centre or residential area or highway. Energy savings with LEDs can be great – but examples of 40%, 50%, and with dimming okay 60-70%. Report those stats – not the 97% for the tiny percentage of bespoke situations where the lights can be turned off completely.

    • Matthew Wright 5 years ago

      Thanks Curley, You’re misunderstanding the assumptions.
      First up, with more R&D & Commercialisation (which is happening in a big way as LEDs have serious momentum when LEDs max out at about 350 / 400 Lumens per watt rather than the 150W Lumens per watt they are at now then there will be a 13times saving on current mercury vapour lights.

      Secondly, the predictive forward illumination has lights communicating with each other and multiple redundant sensors across a street lighting array which means that dimmed lights (dimmed to 30-40% of regular output) wake up instantly and wake up in advance and behind both people and vehicular traffic. This is a significant saving.

      Thirdly the lights include sensors to detect ambient lighting conditions so they do not provide excess illumination when there is a lot of other background light such as when the moon is significantly showing and bright and during the early evening and early morning.

      This all adds up to around a 96/97% reduction. Most street lights are on smaller minor “private” roads and are not installed on freeways. Though freeway lighting will significantly benefit as well.

      • P_Curley 5 years ago

        Oh for heavens sake – you use THAT HEADLINE and then qualify it with Well if this happens, and this happens, LEDs jump up to 400lm/W and if they perfect the light guidance, and antireflection coat all the optical surfaces, and if we dim here, and trim there, we can possibly eek out 97% savings. Industry and energy efficiency experts does not need headlines like that – which get repeated and we spend ever meeting bringing adopters back to reality. In case you had been following the trends laser driven phosphors will be coming soon – long way off, but long before LEDs hit 400lm/W in a street light. Please stop ‘helping’ the adoption of LEDs for street lighting applicaitons. You’re NOT helping !

        • Matthew Wright 5 years ago

          Did you know that headlines are more often than not done by sub editors than authors. And secondly the headline is 100% accurate. LED’s with smart controls, (they go hand in hand) and mesh networking, sensors (ambient light, motion) etc could achieve 97% savings – and I’ll go so far as to say will achieve 97% savings. As for your laser driven phosphors – way more over the horizon blue sky than ongoing incremental development of LEDs

          • Peter Curley 5 years ago

            Street lights operate in circumstances for public safety and security.
            City managers look to make the correct procurement decisions as they
            utilise public funds, and headlines and claims like yours only create
            confusion as they are duty bound to investigate the 97% solutions, and
            the future trends to make sure what they procure is future-proofed. But
            your claims only apply in the most extreme ideal conditions. Your
            articles only serve to create delays and confusion of adoption of much
            needed energy saving technologies. Engineers and policy makers who are
            working to accelerate the adoption have to then bring decision makers
            back to reality, and explain why the potential savings of the technology
            they can procure for most residential and road lighting (ie 95% ! of
            most street lights) are actually only 50-60% savings and NOT the 97%
            claims you seem intent on mindlessly repeating. The high % claims are
            for the uncommon applications like parks and paths where smart
            technologies can add real savings. So ‘No’ cities should not wait years
            and wait for these ‘dreamful’ 97% ones they read about in articles like
            yours….. I’ve no doubt your intentions are well meaning, but utterly
            misguided. I see articles claiming 95% savings, now its 97% savings.
            By Christmas, do you expect to be claiming 98% or 99% ?

          • Matthew Wright 5 years ago

            This is not an article about delay. This is an article about how much energy will be required in the future. It is reasonable to state what is available now, make short term forecasts and medium and longer term forecasts. This is a medium term forecast and these figures are correct for all lighting applications within a decade. This does not mean we should delay installing now as 5-10 years of savings in existing lighting systems will pay for themselves and the new technology can incrementally replace luminaires that fail. The only thing considerable we’re waiting on in terms of these numbers is the high efficiency LEDs. The rest is available now or very soon. (ie sensor and networking technology).
            The 95% savings were for domestic lights and the 97% savings were for street lighting. Maybe if you actually read the articles and were informed before commenting then you’d understand the considerable differences.

          • Peter Curley 5 years ago

            This is an appalling article about someone taking numbers and playing around with a calculator – making sweeping headline claims, and adding caveats and indicating it will be the norm. I hope to goodness this is not repeated in other media. You are damaging the uptake through misguided optimism and kindness. The careless way you play with numbers and draw conclusions is equivalent to someone saying they saw a car go over a speed bump and it was airborne – and printing a headline claiming that we’ve finally invented flying cars. Don’t worry you are not alone, other headlines include claims of millions of LEDs rolled out in one location…….but actually it was thousands of street lights with many LEDs in each one. Headline technically correct, but unfortunately ‘slightly’ misleading. Keep up the good work !

          • Peter Curley 5 years ago

            Fyi – take a look at the latest high end article on the ”BMW i8 with laser lights arrives early”. Good to be up to speed on the very latest developments, and they claim these use 30% less energy than energy saving LEDs. Basically a laser diode, clever optics and phosphor that generates white light ie the basic Stokes shift; high energy photon energy excitation of phosphor that reemits across a broad spectrum at lower photon energy. Far too early for large scale roll out, but about where LEDs were 10 yrs ago. The inventor of the blue LED (the key breakthrough to solving white light generation with phosphors) predicted at the LUX live LED conference in 2013 that Laser lighting will be the next innovation in future lighting – but LEDs and OLEDs will play a key role in the interim. Will leave it to you to see how you factor another 30% energy saving into your already fantastic 97% less energy claim. Playing with numbers, percentages and statistics can lead to very misleading thought processes, and you have to be cautious and responsible when drawing conclusions. ”97% reductions in street lighting by 2020” – it sounds too good to be true for an extremely good reason.

  4. Macabre 5 years ago

    I looked into all of this a few years ago, and realised that the biggest barrier to change is that street lighting is linked to baseload power – in part it justifies it, and at the same time it is very cheap to run. The cheapness of the night-time power has been a barrier to investing in new lighting options.

    In a world powered largely by solar it will become much more beneficial to reduce night-time electricity consumption.

    • patb2009 5 years ago

      this is part of the tech trend that will de-stabilize the electrical market.

      i would guess in a lot of cities, street lighting can be a big chunk of baseload.

      if street lighting goes to LED, there will be less demand for baseload.

      daytime they make money at night they lose money, this could just easily increase the suckage.

      • Bob_Wallace 5 years ago

        “daytime they make money at night they lose money, this could just easily increase the suckage”

        Let me finish that for you…

        “and suckage means less fossil fuels harming us and our planet”

  5. Ben Courtice 5 years ago

    I’m sold. The reduction in light pollution is the icing on the cake of course. I had to move outside the city to be able to see the stars, Melbourne’s light pollution has gone over the top in the last 20 years.

    But on the more important matters, that kind of reduction in night-time energy demand isn’t going to be popular with the big coal power generators, is it? The next twist in the death spiral? Bring it on!

  6. Platypus 5 years ago

    Many Victorian Councils are already installing LED streetlights and efficient T5’s. At the moment there is only one LED approved for usage and costs more than the T5 fluro. While LED is the future you have to drag energy distributors kicking and screaming to the table to make this change over. Old inefficient globes need to be changed more often = more money. New long lasting efficient globes less change over = less money.
    LED’s still remain a risk, trust me I have had plenty of emails and calls regarding T5 LED tube problems

  7. Adam Carey 5 years ago

    One has to be careful to make the assumption that the energy efficiency for streetlighting is the disincentive as to why there are not more LED because its not in the best interest of the energy company. The main reason is the sunk capital on other assets and ensuring the DNSP’s get a return on that capital, whether letting them run out to 20 years or getting compensated by the customer for early retirement. If energy companies invest in LED long term and because of the higher input capital, their maintenance prices will easily exceed the savings the customer would have made by the energy savings in the first place. Public Lighting services in Australia are generally classified as a service separate to that of the poles and wires and its more to do with the provision of the service. The problem is that its calculated the same way, so DNSP’s take little risk with the asset and they get a guaranteed rate of return on capital. Simply put, if councils want the benefit of maintenance savings and energy savings, they should take ownership of the asset.

    • Bob_Wallace 5 years ago

      After reading your comment four times I still have no idea what you’re saying.

      Is it the case that whomever owns street lights in Australia is not the public but a private company with a long term contract?
      And that in order to change to LEDs the contract would have to be bought out?

      If so, is it a ‘cost plus’ contract or a fixed price contract?

      If a cost plus, then negotiate a replacement contract in which the private company makes an equal profit to what they would have made.

      If a fixed price, I would think the contract owner would be replacing lamps at a blistering pace in order to greatly increase their profits.

      (Of course we realize that there are forces in Australia that are very opposed to efficiency as less demand would hasten the collapse of the coal industry.)

      • Adam Carey 5 years ago

        Hi Bob_Wallace. There are no contracts between Road Authorities/Councils and Energy Utilities for public lighting maintenance in Australia for the streetlights that are maintained by the energy utilities. Their maintenance prices covers basic lamps and the switches that turn the street light on and off. Tax payers/ Ratepayers fund the new cost of new streetlights ie LED, CFL, T5 and then they “gift” these new lights to power companies. Over time, due to vandalism and equipment failure, the energy utilities then replace those faulty or damaged light fittings. The energy companies do not invoice the customer. Instead what they do, is they invest that capital replacement into their regulatory asset bases (RAB) because they get a return on their capital that is approximately 10% interest over 20 years. Over time the valuations of these asset bases are worth significant sums. In NSW, Ausgrid’s RAB is valued at about $140M. For councils in Ausgrid’s area, they will only get LED over time as old light fittings reach the end of their economic life. If they want to hasten the roll-out, they have to compensate Ausgrid for the $140M. The energy usage for street lighting for councils and road authorities is high but for an energy distributor is the return on capital that is more important.

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