TheREoptweb toolis a techno-economic decision support platform used by researchers to optimize energy systems for buildings, campuses, communities, microgrids, and more. Users enter site-specific data to determine the optimal size and combination of energy systems to maximize cost savings while meeting resilience or energy performance goals.
Buildings and campuses making renewable energy and energy storage investments can use REopt to model and optimize system sizes and dispatch strategies to achieve emissions targets. Photo by Dennis Schroeder, NREL
With the current administrations ambitious new goals to reduce economy-wide greenhouse gas (GHG) emissions to50% below 2005 levels by 2030, there is no time to waste in optimizing our energy systems for tomorrows built environment. In response, REopt has greatly expanded emissions accounting functionality to support industry and government in making smart energy investmentswhile also helping tackle the climate crisis. Users can now model climate and health-related emissions and their costs to consider the impacts of potential future carbon emissions costs, quantify environmental justice considerations related to emissions, or set renewable energy or emissions reduction targets for their site.
Clear Eyes on Clear Skies: Sharpening the Focus on Emissions for Environmental and Energy Justice
REopt already allows users to quantify the hourly impact distributed energy systems have on year one carbon dioxide (CO2) emissions (by offsetting grid-purchased electricity or on-site fuel burn). With the newest version of REopt, planners, engineers, and energy and facility managers can also model and optimize:
- Health-related emissionsfrom grid-purchased electricity and on-site fuel burn a key consideration for energy justiceand local health impacts of our electricity systems
- Total life cycle emissions, which factor in future changes in grid emissions intensity a more dynamic metric offering insights as to how a new distributed energy system will perform in our wider energy ecosystem in the decades to come
- Optional total life cycle emissions costs to estimate potentialsocial, climate, and public health cost savingsrelated to the projects CO2, NOx, SO2, and PM2.5 emissions impacts
- Least-cost pathways to achieve arenewable energy or emissions reduction targetat a particular site and quantify the associated investment and savings
- Flexiblerenewable energy and emissions accounting methodologies, with options to include or exclude exported clean electricity as an emissions offset and/or in renewable energy calculations allowing users to tailor their analysis to varying GHG or renewable energy policies or research approaches.
In developing new REopt capabilities, National Renewable Energy Laboratory (NREL) engineersKathleen KrahandAmanda Farthinghave been researching applicable policies and data sets needed to make the tool usable for stakeholders across the United States.
According to Krah, Its been interesting to learn about the emissions rates and factors especially where the data is coming from and the renewable energy and emissions modeling and accounting approaches. The REopt team currently leverages the U.S. Environmental Protection Agencys Avoided Emissions and Regeneration Tool(AVERT) for regional hourly grid emissions profiles and allows users to assume a fixed annual percentage change in emissions rates, applied to each timestep. In the future, the team hopes to incorporate NRELsCambiumdata sets, which contain projected long-run marginal emission rate estimates through 2050 for the contiguous United States.
Farthing says the team was surprised by the relative cost of health-related emissions impacts compared to CO2emissions impacts, explored in a forthcoming study. Theyre both significant and part of the national conversation, but health-related emissions costs arent as frequently discussed as a social cost of carbon. It surprised me that those costs ended up being so substantial. By default, the location-specific health costs in REopt currently draw from theEstimating Air pollution Social Impact Using Regression(EASIUR) model developed at Carnegie Mellon University. Looking forward, the team would like to explore more detailed health impacts by accounting for the expected location of marginal power plants and their proximity to communities.
REopt evaluates the economic viability, resiliency, and emissions impacts of renewable energy and battery storage systems at a site. This interactive graph shows an energy dispatch strategy optimized by REopt.Photo by Deborah Lastowka, NREL
Tailoring Analysis to Individual Clean Energy Goals
REopt users can tailor their analyses to help them pursue different types of clean energy goals. These include, for instance:
- Percent renewable electricity targets, to help users answer a question such as, How do I achieve a 25% renewable electricity target at my site at the lowest cost?
- Percent climate emissions reduction targets, to help users answer a question such as, How do I reduce my sites CO2emissions by 50% with an investment in distributed energy resources, relative to current operations?
- Climate and/or health emissions costs, to help users answer questions such as, How does the cost-optimal system change if I consider the costs of climate and health emissions?
New REopt capabilities address a growing desire to assess the climate and health impacts of buildings energy use, and the emissions savings that can result from investment in distributed energy resources.
Learn more about theREopt web tool.
Article courtesy ofNational Renewable Energy Laboratory.
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