Building industry professionals are largely in agreement about the need for aggressive decarbonization to reduce greenhouse gas emissions, both in new construction and in the existing stock. To this end, a preliminary study developed by Buro Happold illustrates what would be required to achieve one of the most important solutions in support of this goal: the shift to all-electric buildings, connected to grids that are supplied primarily by renewable energy sources.
The study reviews new construction typologies and their implementation in several U.S. cities, evaluating the viability of sustainable engineering solutions, including systems like heat recovery, high-performance envelopes, system resiliency, and heat pumps. Introduced and managed properly, these readily available and cost-effective strategies can reduce or eliminate carbon output related to energy use without additional strain to the electrical grid, according to the study’s approach to producing all-electric buildings.
To produce a holistic engineering evaluation of various all-electric solutions, it was important to study the effect of technology and greenhouse gas emissions, as well as the impact of these strategies on project cost and to the electrical grid. Particularly in cold climate regions, most buildings currently rely on fossil-fuel energy for heat and hot water. Analyzing the impact of all-electric buildings is based on moving these loads from fuels like oil and natural gas to renewable-supply electric. Additional factors like humidification or added plug load demands may occur in energy-intensive facilities like those supporting research science laboratories and hospitals.
Analyses found in the study reference four distinct categories of impact:
Connecting all-electric buildings to electrical grids supplied by renewable sources of energy is the key to significantly reducing greenhouse gas (GHG) emissions, which is the aim of decarbonization strategies. In many states, achieving an all-electric building profile with lower GHG emissions in the near-term is entirely possible, based on recent progress in introducing renewable energy on the grid. In other locations the timeline for GHG reductions through transitioning to all-electric may be considerably longer. In these geographical regions and jurisdictions, electric-ready solutions may therefore be more applicable for realizing immediate and long-term carbon reductions.
Some owners and facility managers waiting for grids to connect to more renewable energy could also consider purchasing offsets, and there are a number of operational carbon offsets that effectively promote decarbonization. A virtual power purchase agreement can be a good choice, but only if it supports the creation of a renewable energy production plan that would not otherwise be realized. High-quality offsets should align with the goal of additionality. Likewise, those stakeholders considering offsets should confirm that renewable energy certificates that emerged from the renewable energy project will be retired, so they won’t be double-counted.
The Buro Happold study includes an example comparing all-electric construction models to the median existing building in New York City to illustrate how each performs, as well as against thresholds for GHG emissions from 2024-2050 as set by New York's Local Law 97, with similar comparisons for the Boston metro region and that city’s BERDO 2.0 standards for carbon thresholds. The resulting GHG emissions in all-electric configurations are all lower when compared to a traditional fossil fuel-fired heating system.
Grid resiliency
Reliability is critical to determining the feasibility and best strategies for an all-electric building. The possibility that peak power demand could swing from cooling to heating is a key risk factor, especially since outages can impact both comfort and safety in winter. Recent improvements in associated technology – power production and storage, demand management systems, efficient electric heating, and high-performance building envelopes – are making it increasingly promising to move to all-electric without overtaxing the grid.
Emergency power backup continues to be primarily fossil-fuel based, and onsite power generation and storage technology that would meet GHG emissions reductions benchmarks may not yet be available at scale, but will likely become better options over time. Robust strategies for reliability begin with designing a high-performance building envelope to reduce heating and cooling needs, supported by strategies for avoiding demand strain at peak electrical-use hours. These strategies could include applying zone controls and setbacks, or shifting power production, to the extent possible, to off-peak hours.
Notably, existing buildings present a significant challenge, requiring deep-energy retrofits that can support a transition to electric without over-burdening the grid. Many utilities and municipalities are currently studying grid capacity along with policies and incentives to foster the development of resilient solutions.
Technology
Perhaps the most important pillar supporting a potential shift to all-electric buildings is heat pump technology, which is readily available and highly efficient. Likewise, the latest in materials and systems supporting innovative, energy-efficient, and high-performing building envelope designs are also readily available, contributing to reductions in energy consumption and related emissions. For all material selections, a whole-building carbon footprint is an important metric to understand the embodied carbon investment alongside operational carbon savings. Where technology still needs to catch up to the aspirations of the industry is in the area of backup power, still dominated by fossil-fuel energy sources as noted above.
Because these systems can be combined in multiple ways depending on the strategy or approach, the Buro Happold study compared results from various envelope performance and system configurations among commercial office, labs, residential, and higher education building types in five major cities representing various climates. All typologies showed reductions in energy consumption when a high-performing envelope was employed to moderate heating and cooling demand, and enhanced reductions with a decoupled HVAC system, in which ventilation with maximum heat recovery is separate from the heating and cooling – usually hydronic or refrigerant-based rather than airflow-based. Zero-emissions operation by 2050 is achievable for all typologies, assuming access to a grid supplied predominantly by renewable sources.
Impact on cost
There are a variety of ways to consider and calculate the financial impact of an all-electric strategy. Owners of certain types of properties may want to consider the impact on space planning, for example. The study’s findings suggest that mechanical requirements for all-electric configurations may reduce the space available for rooftop tenant amenities by 10 to 15 percent. Air source heat pumps occupy a considerable area, though this may be offset by the reduced need for space for a cooling tower, depending on the systems design and building needs. Of course, capital costs and operational utility costs are critical to a serviceable cost assessment and comparison.
In some regions the difference in capital costs will be marginal because, as in Massachusetts, the existing energy codes necessitate some level of thermally high-performing enclosure. The capital cost impact for all-electric projects in jurisdictions that lack these base requirements appears larger. But the considerations for the particular systems differ across typologies. For new construction of office buildings, the capital cost impact is usually under 1 percent, and under 2 percent for commercial laboratory facilities. The next version of the study will investigate cost impacts for existing building retrofits, including the high-thermal-performance upgrades to envelopes that we already know are needed to reduce heating loads in colder climates.
As for utility costs, there is likely a small increase in many configurations: for office buildings the range of the increase is likely between 3 and 5 percent, and potentially as high as 10 percent for labs, as compared to natural-gas burning analogs.
The feasibility study referenced throughout this article acknowledges the various obstacles while sharing a path to holistically assessing the viability of an all-electric future. With a growing number of jurisdictions introducing codes and standards that emphasize efficiency and reducing GHG emissions, there are more and more incentives for stakeholders to explore all-electric approaches. Future follow-up work in this area will address embodied carbon, social equity, and other elemental considerations including strategies for evaluating existing buildings for all-electric retrofits.
Julie Janiski and John Swift are partners at Boston-based Buro Happold, an integrated and sustainable design firm. Janiski directs projects at all scales achieving sector-leading levels of carbon reduction and water conservation as well as social equity and human health and wellbeing. Swift is Buro Happold’s Global Healthcare, Science and Technology Sector Lead. He has more than 25 years of experience in the creation of engineering systems for research, commercial and academic facilities.
