Leveraging Digital Electricity™ to Radically Simplify and Accelerate Deep-Energy Retrofits
Because fossil fuels are commonly used for heating and cooking, buildings directly generate around 8% of global energy related carbon emissions. The single largest contributor is heating, so the single most effective way to reduce energy use and emissions is to replace fossil fuel powered water and space heating with electric heat pumps, which are up to three times more energy-efficient. To promote adoption, governments and utilities have introduced new regulations combined with substantial incentives.
But a major obstacle has emerged. Many buildings across North America, particularly in cities like New York, are decades old and were not designed to handle this substantial increase in electricity demand. That means millions of buildings’ electrical systems were not designed to support electric heating and cooking. This leads to costly, complex, and time-consuming electrical upgrades that often delay or prevent reaching efficiency and decarbonization goals.
This whitepaper illustrates how an electrical distribution technology called Digital Electricity™ solves the challenge. It enables the replacement of all gas appliances in a building while cutting the cost of deep-energy retrofits by nearly 50%, reducing installation time by months or years, and improving energy efficiency by approximately 29% through smarter load management. When considering the enhanced efficiency of the new appliances, the overall system efficiency can improve by up to 50%.
What’s Preventing Buildings from Installing Heat Pumps?
Converting buildings from gas and oil to electric power is crucial for improving energy efficiency and reducing harmful emissions. However, replacing gas-powered systems with electric ones can increase a building’s electricity demand by up to 500%.
Figure 1. Peak electricity demand for an average NYC apartment before and after electrifying cooking and heating.
Many buildings across North America were not designed to handle this substantial increase in electricity demand. The median age of a U.S. home is almost 40 years old, whereas the median age of a commercial building is almost 50 years. New York State has the most ambitious building electrification ordinances and the oldest buildings. For instance, most buildings in New York City were constructed before the 1950s. Those buildings’ electrical systems were designed around the typical set of appliances used decades ago. That didn’t include many electricity intensive appliances that are common today including vacuums, washers and dryers, air conditioners and, most recently, heat pumps. Moreover, heat pumps can have up to three times the peak electricity demand of an air conditioner when the heat pump is responsible for heating in cold climates.
Below, we use a New York City apartment building as a case study. Most NYC homes are equipped with electrical panels rated between 40 Amps and 60 Amps (A) and will need an upgrade to install heat pumps. An apartment with standard appliances typically consumes around 40 A, which leaves very little capacity for additional loads. Installing a heat pump, which can draw up to an additional 30 A, would push the system beyond its limits, making substantial electrical upgrades necessary. These upgrades often involve
- Replacing the feeder cables that run from the main circuit breaker panel in the basement to a circuit breaker panel in the apartment
- Upgrading the utility transformer feeding the building.
Transformer upgrades are complex and can alone cost hundreds of thousands of dollars in material and labor. They can take months or even years to complete, including the time needed for necessary approvals. Furthermore, the limited space within older buildings can make it nearly impossible to run new feeder cables without significant structural modifications, making many retrofitting projects too expensive to complete.
Case Study: 109-unit, 17-floor apartment building in NYC
Each apartment’s panel box is rated for 60A. These panel boxes are fed by meter banks located in closets on floors 2, 5, 8, 11, and 14 (Figure 1). Each meter bank supplies 23 apartments and is connected to a 400 A feeder cable that originates at the main circuit breaker panel in the basement and travels vertically through an electrical riser channel to the meter bank closet (Figure 3).
Figure 2: 5th Floor Meter Bank
This means that although each apartment’s panel is rated to handle up to 60 A, the existing feeder cables can only deliver up to 17.4 A per apartment (400 A/23 apartments), which is only 4,174 Watts of power at 240V. The electrification upgrade calls for the removal of gas heat and the addition of two new 9,000 BTU/h heat pumps per apartment that have a Minimum Circuit Ampacity (MCA) of 12 A each. This results in a continuous power demand of 5,740 Watts, which exceeds the rating of the apartment feeder before considering any other appliances.
Figure 3: Electrical Riser Leaving Vertically from Basement
The problem is most severe for disadvantaged communities
The older and more densely populated the building the more costly and complex is the work. Unfortunately, lower-income individuals are more likely to live in older, densely packed buildings. This creates a risk of widespread electrification inequality if new methods are not developed to overcome these obstacles.
What is Digital Electricity
Clearly the cost, complexity, and time of upgrading buildings’ electrical infrastructure is a major threat to our climate and energy efficiency goals. The good news is that there is a form of electrical distribution technology called Digital Electricity™ that not only enables the installation of heat pumps, but dramatically reduce the cost, complexity, and time to full electrify entire buildings.
Digital Electricity (DE) is a brand name for a new form of electricity categorized in the National Electric Code as Fault Managed Power (FMP). It offers power density significantly higher than traditional AC distribution found in buildings. DE converts conventional AC power using transmitters located in a building’s electrical room into a series of energy “packets” that are transmitted on copper communication cables. Each packet contains tracking and control data and only a small amount of energy—not enough to start a fire or shock a person. By checking each packet for faults, the system can determine if electrical energy is going to the wrong place, such as into a person. If this is detected, the system stops transmitting energy until the problem is resolved, and often routes the energy to the load using another pathway. The packets are sent on thin communication cables to a Zone Box in an apartment where they are converted back to regular AC or DC power. DE transmits high amounts of power on thin cables by operating at a relatively high DC voltage, in this case, 336VDC. The innovation is that DE is certified to UL standards to ensure it does not cause harm to people if touched and not to start fires if it contacts the building structure, so it can be installed using ethernet-like wiring methods. This flexibility allows it to overcome the physical constraints that make it complex to upgrade building electrical systems using traditional electricity. For instance, the size of the proposed cable for an apartment is comparable to the cross-section of a common pencil – a fraction of the size and weight of the cable required when using traditional technology. Moreover, DE cable can be installed in many raceways where traditional electrical wiring is prohibited, such as trash chutes, elevator shafts, stairways, or any raceway approved for communication cables.
Figure 4. Digital Electricity cable diameter compared to that of a #2 pencil
Summary of Features and Benefits of Digital Electricity (DE)
- DE does not require conduit and does not need to be separated from data wires like conventional electricity, offering many more options for upgrades since it can be routed through communication ducts, risers, and other tight spaces.
- DE typically does not require permits to install.
- DE can share pathways with other datacom cables like Ethernet or fiber optics. By code it does not need to be separated from other data communication signals, unlike AC. DE can be routed through communication ducts, risers, and other tight spaces, eliminating the need for new conduit, core-bores, and poke-throughs.
- Digital Electricity’s ability to combine data and energy in the same conductor allows precise control and monitoring of energy distribution, making it ideal for managing power across building loads, lowering peak demand, and enabling more loads to be supported on the same infrastructure compared to traditional, uncontrolled electricity.
In summary, the critical DE features that enable the full electrification of buildings without upgrading the existing primary or secondary distribution are:
- ability to run skinny cables that deliver high levels of power without the need for conduit and permits;
- the integration of data and enabling the precise management of each Watt of power distribution to each appliance.
How Digital Electricity (DE) Solves the Problem
Figure 5. Digital Electricity design delivering power for heat pumps and stoves
DE enables the installation of heat pumps in all the apartments, with the option to add electric stoves, and without the need to upgrade either the feeders or utility transformer. This is achieved by installing two freestanding IT racks containing DE transmitters in the basement electrical room. These two racks have the capacity to serve the entire building (110 units). Skinny DE cables exit the transmitter racks without the need for conduit and travel vertically through new pathways installed in the trash chute closets. The DE cables terminate in each apartment in a Zone Box. The Zone Box contains components that convert DE back to AC power, supplementing the apartment’s circuit panel to power the heat pump. Additionally, the Zone Box provides enough extra power and power management to allow the option of replacing a gas stove with an electric cooking range, thereby completing the electrification process.
Results
The DE system enables deep-energy retrofits through two key functions: First, DE cable is permitted by the National Electric Code to be installed similarly to communication wires. This allows for a quick and cost-effective creation of a parallel electrical pathway from the main panel to the existing meter banks—something that would be prohibitively expensive or even impossible with traditional electricity.
Second, DE inherently carries data. This integration allows the Building Energy Management System (BEMS) to precisely balance and optimize energy allocation to apartments, reducing peak loads and enabling the addition of new electrical appliances to the existing system. The system also significantly improves energy efficiency by up to 29%, and up to 50% when factoring in the installation of more energy-efficient appliances. For example, during the brief peak period when a microwave, hair dryer, and iron are operating simultaneously, the thermostat for the system can temporarily adjust the heat pump to free up extra power without compromising occupant comfort.
The estimated cost of the system, including installation, is approximately half that of traditional electrical distribution when feeder and transformer upgrades are needed, and it can be installed in days or weeks rather than months or years, with minimal disruption to occupants.
Digital Electricity’s Impact
Digital Electricity has been used across North America and Europe for over a decade, particularly in the telecommunications, agriculture, and smart buildings sectors. Notable installations include:
- powering mobile communication systems in the London Underground Transport, powering ubiquitous 5G coverage and capacity across all 270 stations and 250 miles of subway tunnels;
- providing safe electricity for IoT upgrades in all 777 rooms at Circa Resort and Casino in Las Vegas, NV, enabling an enhanced guest experience;
- helping the Hotel Marcel in New Haven, CT reduce energy consumption by 50% and earn its LEED Platinum certification.
With over a thousand large-scale deployments, Digital Electricity has made such a significant impact that the National Electric Code introduced a new classification—Class 4 or Fault Managed Power (FMP)—marking the first creation of a new class in 50 years.
