The direct consumption of fossil fuels by buildings, burned in water heaters, furnaces and other heating sources, represents almost 10 % of US greenhouse gas emissions. Switching to an electric system that powers heating through renewable energy sources, rather than coal, oil and natural gas — the process known as building electrification or building decarbonization — is a crucial step towards achieving global zero-climate goals.
However, most building decarbonization models have not considered seasonal fluctuations in energy demand for heating or cooling. It is therefore difficult to predict what an eventual switch to cleaner all-electric heating in buildings could mean for the nationwide electricity grid.
A new study by researchers from Boston College College of Community Overall health (BUSPH), Harvard TH Chan College of Public Health and fitness (Harvard Chan University), Oregon State University (OSU), and the nonprofit team Property Electrical power Efficiency Crew (HEET) looked at these seasonal changes. in energy demand, and found that monthly energy consumption varies widely and is highest during the winter months.
Published in Scientific Reviews, a review of the mother nature portfolio, the study presented new modeling of several building electrification scenarios and revealed that this seasonal increase in winter energy demand will be difficult to meet with current renewable resources, if buildings switch to low performance systems. electrified heating.
The results highlight the need for buildings to install more efficient home heating systems, such as geothermal heat pumps.
“Our research reveals the degree of fluctuation in the energy demand of buildings and the benefits of using highly efficient heating systems when electrifying buildings,” says Dr. Jonathan Buonocore, Professor environmental health assistant at BUSPH, study leader and corresponding author. “Historically, this fluctuation in building energy demand has been largely driven by gas, oil and wood, all of which can be stored throughout the year and used during the winter. Electrified buildings and the electrical system that supports them will need to provide this same reliable heating service in the winter. More efficient electric heating systems will reduce the electrical load put on the grid and improve the ability to meet this heating demand with non-combustion renewable energy.
For the study , Buonocore and colleagues analyzed building energy data from March 2010 to February 2020 and found that the monthly average total U.S. energy consumption — based on current fossil fuel use, as well as long-term winter electricity use — varies by a factor of 1.6x, with the most low demand in May and highest demand in January.
The researchers modeled these fluctuations seasonal curves in what they call the “hawk curve” – since a graph of the evolution of monthly energy consumption represents the shape of a hawk. Data shows that winter heating demand pushes energy consumption to its highest level in December and January, with a secondary peak in July and August due to cooling, and the lowest levels in April, May, September and October.
Researchers also calculated how much additional renewable energy, particularly wind and solar, would need to be generated to meet this demand increased in electricity. Without storage, demand response, or other tactics to manage network demand. the buildings would need an increase of 28 times the wind production of January or an increase of 303 times the solar energy of January.
But with more efficient renewable energies, such as air-source heat pumps (ASHP) or geothermal heat pumps (GSHP), buildings would only need 4.5 times more wind power generation in winter or 36 times more solar power – thereby “flattening” the Falcon curve as less new energy demand is placed on the power grid.
“This work really shows that technologies, both on the demand side than supply, have a vital role to play in decarbonization,” says study co-author Dr. Parichehr Salimifard, assistant professor at the University of Engineering at Oregon Point out College. Examples of these technologies on the energy supply side are geothermal building heating and renewable energy systems that can supply power around the clock, she says – such as renewables coupled with at-home storage. long-term, distributed energy resources (DER) at all scales, and geothermal power generation wherever possible. “These can be combined with systems on the demand side – that is, in buildings – such as passive and active building energy efficiency measures, peak shaving and energy storage. energy in buildings. These building-level technologies can both reduce the overall energy consumption of buildings energy demand by reducing both base energy demand and peak energy demand, as well as by smoothing fluctuations in building energy demand and , therefore, flattening the Falcon curve. “
“The Falcon Curve draws our attention to a key relationship between the choice of building electrification technology and the impact of building electrification on our power grid. ,” says study co-author Zeyneb Magavi, co-executive director of HEET, a nonprofit climate alternatives incubator. Magavi cautions that this research does not yet quantify this relationship based on seasonal efficiency curves measured for specific technologies, or for timescales or more granular regions, or fail to assess the many strategies and technologies that can help meet the challenge. All of this needs to be taken into account in decarbonization planning.
Yet, according to Magavi, this research clearly indicates that “the use of a strategic combination of pump technologies (air, ground and grid), as well as long-term energy storage, will help us to electrify buildings more efficiently”. economically and fairly. The Falcon Curve shows us a faster path to a clean and healthy energy future.
“Our research clearly shows that when taking into account seasonal fluctuations in energy consumption energy elements in the Falcon Curve, the drive to electrify our buildings must be coupled with a commitment to energy-efficient technologies to ensure that building decarbonization efforts maximize climate and health benefits,” says the lead author of the study, Dr. Joseph G. Allen, Associate Professor of Exposure Assessment Science and Director of the Wholesome Buildings Program at Harvard Chan University.
“Our work here shows a pathway for building electrification that avoids reliance on fossil fuels and avoids renewable combustion fuels, which can still produce air pollution and possibly perpetuate the disp arities in exposure to air pollution, despite being climate neutral,” says Buonocore. “Avoiding problems like this is why it is essential that public health experts are involved in the development of energy and climate policies.”