What if Power could be controlled like Data?
Power Devices Over Data Cables
I've been playing with camera based security and monitoring systems for over a decade. The first system I created (probably in 2003) used a cheap webcam hooked up to an old laptop, and a programme I wrote to monitor for pixel-level changes.
It would then send me emails when motion occurred.
I was a little ahead of the game with the concept, and it took a while for hardware and connectivity to catchup. Now pretty much anyone can deploy a motion sensing smart camera in virtually any room in the house.
My CCTV systems evolve, too. The latest system I built was focused on keeping my sensitive images on-prem (e.g. in the house), while still giving me secure, remote access. The cameras I used were much more capable than the cheap webcam of my first system, and were connected to my home network using ethernet cables.
Even though I could have used these cameras over wifi, I chose to run wires to the cameras for two reasons. 1) Ethernet is harder to interfere with than wifi, and 2) the cameras needed a wire anyway, for power.
These cameras, like many on the market today, have the option of being powered over the ethernet cable. This means that one cable is both the connectivity and power. The term for this is power-over-ethernet (POE).
The Power of POE
In my set up, the power is 'injected' into the ethernet cable using a simple plug-in device like this one.
But there are routers and switches that you can buy that also can power devices over ethernet, using the POE standard.
With that in mind, POE could effectively be controlled like any other data port. Switched on, switched off and even monitored like data.
So I decided to speak with an ex-colleague and friend of mine, Angelo Fienga.
Networking & Sustainability
In addition to being an accomplished, certified drone pilot, Angelo has spent the last few years leading some of Cisco's sustainability activities.
Cisco has been developing POE capabilities for decades with the first desk phones powered over ethernet cables in 2003. Now, as Angelo explained to me, the potential of POE is significantly greater, and that they are supporting a new standard called universal POE, or UPOE and UPOE+ (which supports up to 90W per port).
Angelo described how Cisco's solutions are being deployed across smart budding to provide power to a multitude of devices, including lighting, displays, laptops, biometric door readers, sensors and of course cameras and network appliances.
Efficiency and Control
Angelo mentioned that replacing traditional lighting with LED lighting already gives an efficiency gain of at least 15%, however, when you can run multiple devices from one highly efficient POE switch, you can realise further incremental improvements, too.
Power efficient LED lighting requires direct-current (DC), while most buildings are supplied with alternating-current (AC). In order to run LED lighting AC needs to be converted into DC. This conversion is not 100% efficient, so energy is wasted each time it is converted.
Cisco's UPOE switches are certified against a standard known as "80 plus". This means that they are at least 80% efficient. Angelo said, some of them are even 80 Plus Platinum and some even Titanium (which is the top rating in the standard), taking them into the 90-96% efficiency ratings.
Angelo suggested that by opting for a highly efficient AC-to-DC converter such as those found in the Cisco switches, and powering a multitude of devices from that, you could gain additional energy savings when compared to using multiple, less efficient conversions.
Beyond the efficiency gains, the switches provide control and measurement capabilities for the attached devices. With this, it is possible to both develop a greater understanding of how much power is being consumed, and to be able to programmatically switch loads on and off - as if it were data.
Other cost savings.
Moreover, the cost savings from running devices over PoE vs traditional power sources goes beyond energy savings. It’s also about saving money (and carbon!) on copper conduits, steel, labor and materials for installation and reductions in CO2. For example, just consider the cost of cabling – much cheaper for a network engineer to run network cable than an electrician to run standard copper wire lighting cable.
I'm a little sceptical of the actual energy savings that could be achieved through this argument, as the line voltage of POE (44 volts to 57 volts) is not directly compatible with the equipment it is aiming to power (mostly 12 volts), so another level of conversion will be need. Plus, there will be voltage drop across the length of the cable too.
However, I can see energy saving potential that comes from the ability to more accurately measure consumption and intelligently control devices through centralised automation.
Tell me what you think
What do you think? Share your thoughts with me, and leave a comment below.