So You Want to Build a Grow-op...
Commercial Buildings and the Trend Towards Larger Electrical Services
August 10, 2018 by Curtis Craig
New technology trends are rapidly increasing the power requirements for buildings. New markets seem to have sprung up almost overnight, including cryptocurrency mining and legal cannabis cultivation. Other technologies are reaching maturation and increasingly being adopted, including electric vehicles for commercial use, automated distribution warehouses for online retailers, and continuing growth in data storage. What all of these specialized sectors have in common is an exponential increase in power use, with massive implications for building owners, utilities, and the electrical industry.
For example, a traditional light industrial warehouse requires approximately 2.5-5 Watts (W) per square foot, plus a little extra as required for air conditioning, electric heating, and capacity for future growth. For 100,000 sq. ft., a basic service could be 600 Amps at 600 Volts 3-phase, which is approximately 623.5 kilo-Watts (kW).
By contrast, a cannabis growth and processing facility of the same square footage requires about 10-15x the power for the traditional building, thanks to high-output grow lights and specialized HVAC, irrigation, and processing equipment. Even with LED, Lighting alone can be 50W per square foot. Therefore, the same 100,000 sq. ft. building may require 7000A at 600V 3 phase. To put this in perspective, this is approximately 7 MW, the equivalent demand of about 5000 houses.
Outside of cannabis cultivation, we see similar trends in the cryptocurrency mining & data center segments, requiring similarly large amounts of power to run specialized computers, HVAC equipment, and UPS systems.
Facilities with fleet charging for electric vehicles pose a similar challenge. Electric tractor-trailer units could become common for short-haul trucking in the next 5-10 years. And why not? Electric motors are perfectly suited to trucking with instantaneous maximum torque, no greenhouse gas or particulate emissions (at the vehicle), and simpler, with no need for a transmission or differential.
Now imagine a future distribution center for a major retailer such as Walmart or Canadian Tire, with a fleet of 20 electric tractor-trailers. For context, the current Tesla Model X SUV has a 90kWh battery and can be charged in a couple hours with a Tesla Super-Charger. Electric semi-trucks are likely to have batteries sized around 800-1000kWh, and would be charged with a Tesla Mega- Charger. Internet speculation estimates the Mega-Charger will likely be rated around 1.6MW. Now recall our 20 truck fleet. The proposed facility would require 32MW just to charge the trucks. At 600V, that is a staggering 30,000A.
Wire service providers (utilities such as Enmax, Fortis, and Epcor) generally won’t provide a 600V service to a building for ampacities beyond 3000-4000A. Instead, a primary voltage is served to the building. These are usually 15kV, 25kV, or 35kV, and are called “primary metered services”.
For developers, this means two things: a very large and expensive customer-owned transformer is now required on the site, and the nearby utility substation needs to be evaluated to ensure it has capacity to feed the building’s large electrical load. The evaluation will reveal the capacity of the utility system in the area. If there are no spare breakers in the nearest utility substation, an application will need to be made to the Alberta Utilities Commission (AUC) to add one. The application, assessment, and substation construction could take as long as 2-3 years to complete.
Another approach is to add on-site electrical generation. In the case of a greenhouse or cannabis growth operation, on-site co-generation (combined heat and power) could be installed to meet the base heat and electrical requirements for the facility, reducing the size of the electrical service required to something more reasonable. If high electric loads are anticipated for an entire development, a district co-generation facility may be a cost-effective option to explore in partnership with a local utility. Finally, if the majority of the electrical load can be scheduled to run during the day, solar photovoltaics (PV) can assist in reducing grid reliance and provide additional value through peak shaving.
Electricity requirements for specialized buildings are growing at an astonishing rate. In order for developers to attract specialized tenants with high electricity requirements, consideration needs to be made as to how electrical services will be provided to these buildings. Primary metered services may be required, resulting in a large customer owned and maintained transformer being installed on the site. Other strategies to reduce grid requirements are on-site cogeneration and solar photovoltaics that can assist in reducing electrical demand.