Case Study 3
Sacramento Indoor Agriculture Operation.
Project Issues
Customer has indoor agriculture facility resulting in a high electricity density operation
Utility provider (municipal utility) service upgrades were quoted as very expensive and would take approximately one year to complete
Facility designed for very tight environmental tolerances including temperature and humidity control
Grow facility designed and built out in stages
Balance of moderately-high power rates, moderately-high demand charges and delays in accessing energy
Customer-Specific Solution
An energy facility was designed with 2 combined heat & power (CHP) units and a single prime-power (supplemental electricity generation) natural gas fired unit
Excess heat from the CHP systems was utilized to generate chilled water and to provide energy to a thermal air desiccant system that supported specified humidity control requirements
The prime power unit (no heat recovery) was included to provide electricity during peak usage periods and electrical backup during maintenance periods for the CHP units. The result was a system that can operate “off the grid” as a fully functioning microgrid.
Additional electric cooling was included in the project scope to supplement environmental controls, including air quality
Multiple smaller CHP units provide redundancy and electrical load variability that was greater than that provided by a single unit
The “power house” was sized to accommodate a doubling of the energy supply for future facility expansion.
Lessons Derived:
This project demonstrates that a self sufficient microgrid can be designed to meet a number of site needs, including the creative use of thermal energy from CHP systems to meet air dehumidification needs. This allowed for optimized sizing of the CHP and the prime power units. The non-CHP prime power unit provided lower facility cost, redundancy and quicker access to necessary power; all while delivering reduced peak demand electricity usage.