Circular Economy Lightbulbs

An InnovateUK funded research project that reimagined lightbulbs as a lighting service. By selling light as a service we created a business model that makes LED lighting more desirable for consumers, ensures a circular flow of the bulb’s critical materials and reduces the lifetime energy consumption of lighting.

17% of all energy generated internationally is used for lighting, provided through a mix of different lighting technologies, the most recent of which is the Light Emitting Diode (LED). They switch on instantly, create good quality light and offer dramatic improvements in energy consumption.

To deliver these energy savings, lightbulbs have become high technology products, containing a complex mix of materials, including a variety of critical materials. When they stop working LED bulbs should go into the electronic products recycling system, requiring a householder to go to a civic amenity site or lightbulb recycling point. In reality this simply doesn’t happen, either people aren’t aware of the regulations or it’s too much effort to get the bulb to the correct place for disposal. Instead they end up in the household bin, as a result the consumer recycling rates for lightbulbs in the UK are around 1%. Even for the bulbs that do make it into the recycling system, our current recycling technology isn’t able to recover their critical materials.

As a result these high-tech lightbulbs end up in landfill or a recycling system that can’t capture their value, losing the critical materials that they contain. This was the starting point for our research project; Can we make a lightbulb that will never be lost to landfill?

Our Process

Through a combination of existing literature, product teardowns and talking to experts we built our own picture of todays LED technology, including a detailed Life Cycle Analysis model (LCA). Our LCA highlighted how important energy in use was, accounting for 95% of the lifecycle energy. While the focus of the project was on material flows, this showed that any design solutions would have to tackle energy in use. Forecasts of future LED production also show how fast the technology is changing, with efficiencies set to double in the next 5 years and keep progressing. This poses an interesting obsolescence challenge for a product that has the potential to last such a long time.

Functionally, we found that power supplies can be the achilles heel of LED bulbs with the heat generated by the LEDs putting the capacitors under thermal stress that can reduce their life to only 5000 hours - much less than the commonly quoted 20-25,000 hours life for LED bulbs. We were surprised by how hard it was to isolate power supplies from the rest of the bulb, they were often embedded in potting compound, making disassembly near impossible.

We paid particular attention to the material composition of the bulbs. We looked at LEDs at a micro scale to understand their critical material content. Learning about the magic of n-doping and p-doping and how the ratio of Gallium Nitride to Indium Nitride leads to the emission of different light spectrums. The amount of these materials per LED is extremely small, to the point where they seem insignificant. Yet it is enough to make another LED bulb if we can capture it effectively. Unfortunately todays recycling technologies cannot recover these materials from end of life products. To find a future solution we talked to emerging recycling technology research groups (Imperial College, GeMMe, Atmi). While each employed different technologies, all said that recycling these materials would be possible in the near future. However the feedback was the same, they all needed a clean feedstock of just the LEDs or the LEDS on their circuit board. Something the current recycling system will never deliver.

While the recovery and recycling of critical materials is a challenging task it seems vital to find a model where recovery is as close to 100% as possible. The elements used in these lightbulbs have existed since the beginning of the universe and have the potential to solve all kinds of problems. LED production is set to boom in the coming years, if we don’t find a way to capture their materials we have no idea what sort of future technologies we will be inhibiting by losing track of these materials.

A lighting service

To solve the material challenge and fast paced technology change of LEDs, we developed a lighting service where consumers don’t own lightbulbs, instead they pay for their use. For an annual fee consumers get lightbulbs delivered to their door, if anything goes wrong with the product, it is replaced as part of the service.

Shifting the business model creates a very different consumer proposition. We remove the high upfront cost of LED technology, the major barrier to consumer adoption. We enable consumers to make the most of rapid technology improvements with efficiency upgrades as part of the service. We also give people the freedom to change and adapt their lighting as their needs change, if you change your fittings, redecorate or even move house, your lighting can change with you.

While the idea of a lighting service isn’t new for business to business sales, there is nothing that tackles this approach for consumers. This is in part because current products don’t fit the business model. The fast pace of LED technology is problematic for a service; if you are paying for light bulbs that are inefficient compared to the latest models, the service quickly becomes unappealing. Instead we created a modular bulb that decouples the fast changing LED technologies from more mature power supply technologies. This helps to avoid obsolescence, something that can be problematic and unprofitable when offering a product as service.

A modular approach also means we can post out product updates so the technology can get better over time and users get a continually improving service. By creating an ongoing interaction with the customer we make it easy for the old LED cores to be returned by post in the same packaging that the updates are sent out in. This crucial step can jump us from todays recycling rates of 1%, to recapturing 100% of the products, ensuring we have a continuous flow of materials.

By delivering a continuously improving product to the customer we can generate a 35% energy saving across the product lifetime when compared to a typical LED lightbulb.

Smarter services

To make a service like this work well we need as much information as possible about usage, performance and location. This is made possible by using low cost connected technologies that allow you to communicate with the bulb through the internet.

While connected technologies can deliver a host of functionality for the consumer (safety features, adaptive lighting, interconnectivity), it also enables a better service experience and better environmental performance. By measuring temperature information over time we can accurately predict when a bulb will fail, allowing us to pre-emptively replace it. Information on usage allows us to optimise when to send out updates, if a bulb is used a lot, energy in use dominates the lifecycle and upgrades should happen as soon as more efficient LEDs are available. Having accurate information about usage and performance also means you can make design decisions based on real data for the next generation of hardware.

More fundamentally, having live product information means we can transition away from the idea of products being sold and never seeing the materials again, to the idea of a live inventory of materials. One where you know how much is in use, where it is and when it’s coming back.

Where next

What started as project focused on critical materials grew into a business model that delivers benefit for consumers and manufacturers alike. The project is now being developed into a full service demonstrator, if you’d like to know more about the project, get in touch here;