Metrics for decarbonization. Lighting projects in existing buildings have been limited to 2-3 year paybacks for decades. Standard practice has been limited to reduced wattage over duration of the energy services contract. When or if controls have been installed, the standard is 0-10V analog drivers and room area controls. Now that projects will be driven by a higher-level goal of reduced emissions, there are additional metrics that will come into play. Projects geared towards decarbonization and emissions reduction will use Life Cycle Analysis (LCA) as a primary decision tool. In fact, different methods of LCA are currently a hot topic in the world of BPS and decarbonization. Return on investment will be viewed at the building level along with things like GHG emissions and source energy, rather than the lighting payback by itself, so factors such as installation and maintenance savings will be more relevant. Increased stringency over time. BPS typically have several thresholds of compliance over many years. How do you get to the next level of savings with lighting? Sure, you can monitor energy at the circuit level, but circuits provide power for different fixture types, across different space types, which have different lighting needs. Michael Myer, senior researcher at Pacific Northwest National Laboratory, explains the situation well, saying, "One thing that BPS have in common is that compliance targets will change over time. For lighting, if you choose analog controls, how do you know where your energy is going, or how to enable more savings in the future? Digital systems, with addressable components and monitoring, enable buildings to determine energy use at a granular level and make informed decisions about the next level of savings." Building Energy Codes and Standards. BPS, are not happening in a vacuum. We are seeing changes along the same trend lines within the latest versions of ANSI/ASHRAE/ IES Standard 90.1-2022 and IECC 2021. Both standards are now requiring energy credits in addition to existing prescriptive baselines. For example, IECC 2021 paragraph C406.4 specifies how credits can be earned by using enhanced digital lighting controls. Digital addressability to individual luminaires is one
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of the credit options, which in turn enables load shedding and digital reconfiguration of controls. Codes are finally pulling digital lighting technology into existing buildings.
Why Digital? Here is the North American dialogue: “Digital is the future.” “Well of course, but…in North America we use 0-10V drivers because it’s the devil we know. It’s easier and cheaper, and nothing will ever change that. It is what it is. ” What I find fascinating is that it’s the devil we don’t know. It’s not actually easier, it’s just familiar. 0-10V may be a lower first cost, but DALI drivers are faster to install. In buildings larger than 50K sq.ft., the reduced labor hours for installation and startup will almost always make up for equipment costs, and then some. One of the things I find most surprising is that the ugly truth about 0-10V drivers is one of the best kept secrets in the industry. We hear about the difference between linear and logarithmic curves, and that the energy savings numbers aren’t as accurate as digital real-time monitoring, but it doesn’t seem like a big deal. Without going down the rabbit hole, allow me to burst your bubble quickly. Energy savings estimates based on calculated savings with 0-10V drivers are wildly inaccurate. The latest research makes this painfully clear.3 If you want to know how much energy you are saving, digital monitoring is a must.
Why DALI-2™ and D4i™? Energy savings matter within the context of BPS, but it’s not the only important factor. BPS is a long-term play; when you are investing heavily into a long-term asset, the risk of ongoing maintenance problems is not to be taken lightly, and proprietary components are considered high risk. Products need to be trustworthy and replaceable. DALI (Digital Addressable Lighting Interface) is the internationally standardized protocol for digital communication between lighting control devices. DALI-2™ is a certification program that tests products against the relevant specifications to ensure interoperability.