Strategies to Maximize Whole-Building Energy Savings
Any long-term disruption of ordinary routines creates opportunities to do things differently, and this rings true for the operations of commercial office buildings. The nearly 2-year pandemic-induced disruption has highlighted that the industry must better align energy consumption with occupancy, and there are solutions to not only align energy consumption with occupancy but also to reduce whole building energy consumption in general. Regardless of whether building owners and tenants proactively implement hybrid workplace strategies as discussed in Part 3, owners and tenants should explore the following ideas to reduce whole building energy consumption within commercial office buildings. These strategies were recommended by owners, tenants, engineers, and consultants who focus on optimizing energy performance in commercial office buildings.
Lease ModificationsThe pandemic has highlighted that status quo leasing practices lock in inefficiencies and impede efforts to reduce carbon emissions. Several modifications should be considered to facilitate whole-building energy reduction in commercial offices. These clauses have a goal of motivating landlords and tenants to actively collaborate in reducing whole-building energy use by making reasonable accommodations to minimize energy consumption and demand from base-building systems and tenant premises.
1. Long-Term Low-Occupancy Provision for Building Services ClauseThe standard building services clause in office leases, which, among other things, sets forth standards that landlords must meet when providing HVAC to tenant spaces, acts as a perverse incentive during the pandemic. Fearful that tenants will not pay rent or will try to terminate their leases, landlords have continued to cool, heat, and ventilate their tenants’ premises during normal business hours to the letter of the lease requirements despite very low occupancy. The direct result is whole building energy use reductions in barely occupied New York City office buildings that are far from what might be anticipated or desired. A new “Extended Very Low Occupancy” provision should be added to the standard building services clause that defines the rights and responsibilities of the landlord and the tenant in the event of an extended period of very low occupancy in the building or in the tenant’s premises, whether caused by a public health crisis, extreme weather, or some other reason. This provision should give the landlord the right to make reasonable modifications to services provided to the tenant’s premises or to the building’s common areas with the goal of optimizing whole-building energy use during the period of extended very low occupancy.
2. Thermal Comfort Standards / ClausesCooling and heating temperature requirements in leases are a major culprit in whole-building energy waste. In most leases, offices need to be maintained at an ambient temperature of 72 degrees, condenser water needs to be delivered to tenant premises at 75 degrees, and chilled water needs to be delivered to tenant premises at 53 degrees. Just modifying the ambient temperature requirement to 74 degrees in the cooling season and 70 degrees in the heating season (both well within ASHRAE guidelines) should generate substantial whole-building energy savings according to engineers and building owners; moreover, these relaxed temperature standards would be easier for managers to implement rather than micro-managing HVAC distribution within tenant premises to match HVAC delivery to fluctuating occupancy levels.
3. Standards for Server RoomsServer rooms that require 24x7 cooling to be provided by the base-building system or by the tenant’s stand-alone air conditioning units are a significant contributor to whole-building energy use. According to a recent Better Buildings webinar, data centers are 10-100x more energy intensive than plain office space and it may be time to take a fresh look at cooling and humidity requirements for data centers. IT rooms and data centers are often held in the mid-60s but can be safely kept at 77 degrees or warmer according to a building owner interviewed for this project.
4. Landlord-Tenant Operations and Maintenance (O&M) Plans and Periodic Coordination MeetingsLandlords and tenants should enter joint operating and maintenance plans aimed at optimizing whole building energy performance and minimizing greenhouse gas emissions. Had the practice of joint O&M plans and regular coordination meetings to review performance under the joint O&M plans been widespread at the start of the pandemic, landlords would not have needed to overcome their reluctance to initiate energy-use discussions with tenants, and course-corrections to reflect very low occupancy of office buildings would have been made in the ordinary course of business. These joint O&M plans and periodic coordination meetings should be codified in the lease.
5. Hybrid Workplace Clauses
To facilitate implementation of the people-clustering strategy for the new hybrid workplace and to advance best practices in whole building energy management, a “hybrid workplace” clause should be added providing that if a tenant elects to implement a “hybrid” or “flex” work arrangement after the pandemic, with its employees working partly in the office and partly remotely, then the tenant will be obligated to use good faith reasonable efforts to (a) cluster its employees actually on the premises at any given time into the fewest possible HVAC zones, (b) install vacancy sensors that will limit HVAC supply air in unoccupied HVAC zones and will turn off lighting in unoccupied HVAC zones, and (c) ensure that electrical equipment in unoccupied HVAC zones is turned off to minimize plug loads.
Additionally, to facilitate implementation of the three- or four-day in-office workweek should a tenant elect that hybrid workplace strategy: (a) the definition of Business Hours for HVAC purposes should be modified to exclude any weekdays that the tenant elects to have its employees work remotely; and (b) the cleaning specification attached to the lease should be modified to exclude from cleaning requirements any weekdays that the tenant elects to have its employees work remotely.
Check out this high-performance lease that includes many of these types of clauses and is designed to help buildings in New York City meet the performance targets set forth in Local Law 97. At the heart of this lease is a desire to equitably apportion costs and benefits of energy savings between landlords and tenants. You can learn more about the high-performance lease on the Institute for Market Transformation’s website.
Throughout the pandemic, the search for the cause of persistent high energy use on the tenant side focused on plug loads. This is because most lighting in office space that is not being used likely is turned off either by sensors or manually and because building HVAC is predominately operated and controlled by building owners. Landlords and third-party providers have been quick to point to the IT plug loads needed to support remote work as a key reason why office tenant energy performance during the pandemic has been disappointing, and, by extension, why whole-building energy use did not decline more despite very low occupancy in office buildings. Therefore, in addition to adopting effective plug load management programs throughout their premises, tenants should explore the following IT solutions to significantly reduce their energy consumption.
1. Virtual Private Networks
The pandemic has shone a harsh light on the widespread practice of requiring employees working remotely to log into their company networks through their office PCs. The result has been empty office buildings filled with always-on, energy-consuming PCs. Instead of requiring employees to log into their company networks through office PCs, corporations should replace PCs with laptops that enable employees to log in to networks via virtual private networks or VPNs. An ongoing study exploring this solution at an engineering firm’s headquarters suggests how effective it can be in reducing office energy use when employees are working remotely. An energy audit revealed 75% of this engineering firm’s baseload electricity demand during the pandemic was attributable to always-on office PCs. When 55% of the office’s PCs were replaced with laptops, and the employees with laptops were enabled to connect to the firm’s network via a VPN, baseload electricity demand dropped by one-third.
2. Cloud Based Servers
The same engineering firm is exploring the replacement of physical servers located in server rooms with virtual servers in the cloud. Approximately 10% of the tenant’s baseload electricity demand during the pandemic was attributable to servers, which consume electricity and cooling services 24x7. The transition to cloud-computing centers, which are found to be far more efficient in their energy use than traditional computing centers located in offices, serves a dual purpose of not only reducing tenant and whole building energy consumption but also freeing up usable space for the tenant to use differently.
Retrofitting Building HVAC Systems
While tenants should focus on reducing energy consumption from IT plug loads, building owners should focus on reducing energy consumption from base-building HVAC systems. HVAC systems use much more energy than lighting or plug loads and were the hardest systems to optimize for energy efficiency even before the pandemic. Options to explore are listed below.
1. More HVAC Zones
The pandemic highlighted that many landlords are hampered in their efforts to rein in whole building energy use due to a lack of sufficiently granular building system HVAC zones and a lack of up-to-date building system HVAC controls. In older buildings, there can be as few as 2 or 3 building system HVAC zones even in a 1MM square foot building. The result is that even a few occupants on a few floors can require delivering HVAC to hundreds of thousands of square feet. Engineers should take a fresh look at the costs and energy savings opportunities of adding more HVAC zones to be nimbler in the future in response to fluctuating occupancy.
2. Distributed HVAC Systems
Some experts have even questioned whether centralized building HVAC systems – common in Class A office buildings – are preferable efficiency-wise to systems with assignable floor-by-floor DX units in conditions of very low or fluctuating occupancy. Another potential solution to consider is a distributed VRF (variable refrigerant flow) split unit HVAC system that makes it easier to shut down AC distribution in unoccupied office areas. VRFs may have better applicability in suburban office parks than in high-rise office buildings in New York City, as there needs to be outdoor space for compressor / heat exchanger units, but this option should be further explored.
Data Accountability and Transparency
Information sharing enables building owners and tenants to identify and address inefficiencies in energy usage, learn from each other, and foster a more collaborative relationship. The revelation that a major financial services industry tenant has only one submeter for multiple floors of its New York City office space and is unable to troubleshoot even big spikes in its own electricity consumption is a stark reminder that many (if not most) tenants lack the granular electricity consumption and demand data needed to efficiently manage their electricity use. Without actionable data, tenants are hamstrung in their ability to effectively manage their own energy use much less collaborate effectively with their landlords.
1. Real Time Energy Management
NYSERDA’s Real Time Energy Management (RTEM) program is one solution for providing more granular data. RTEM is the combination of building data collection systems with data analytics that can show building management and tenant facilities managers the actual state of energy performance at the system and end-user levels in real time. Third-party service providers continuously capture data such as set points, power loads, flow rates, temperature, and humidity, and feed the information back to site operators with detailed recommendations for improving operations and cost-effective capital projects. To accelerate the adoption of RTEM, NYSERDA is offering cost-shared support for integrating RTEM systems and services (e.g., hardware, installation, and ongoing support) into existing building operations and tenant premises.
This project’s interviews with key stakeholders involved in the energy management of commercial buildings disclosed many missed opportunities to save energy during the pandemic. These missed opportunities led to whole building energy reductions of only 10-30% while occupancy dropped to near zero. At the same time, however, the pandemic-induced disruption has revealed a far greater number of energy-saving opportunities, both for operations in general and for the new hybrid workplace. These forward-looking opportunities have the power to help commercial buildings reach closer to carbon neutrality, achieve the ambitious carbon reductions necessary to align with the Paris Agreement, and comply with recent New York State and New York City climate action laws.
This series, co-written by Stephanie Margolis of the NYC Climate Action Alliance and Marc Rauch of the Environmental Defense Fund, is adapted from Marc’s report titled “Aligning Energy Use with Occupancy in New York City Office Buildings: Lessons Learned from the ‘Great Disconnect’ and Strategies for the New Hybrid Workplace.” Data supporting all claims was drawn from a literature review on pandemic and post-pandemic office energy use, more than two dozen interviews with building owners, tenants, data analytics providers, engineers, architects, and other professionals conducted by Marc, then Senior Specialist, Energy Transition Strategy at EDF, between October 2020 and May 2021, and energy-use data provided by building owners, large tenants, and third-party providers. We would like to acknowledge that the term ‘The Great Energy Disconnect’ was first used by Urban Green Council at an event of the same name on December 8, 2020.