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It isn’t easy to trace the flows of electricity across a high-voltage transmission grid that spans 15 states from Louisiana to North Dakota. It’s harder still to differentiate the clean electrons from the dirty ones.
But doing so is necessary for states, companies, and other entities to track real progress toward decarbonization goals. Ultimately, it can be done — so long as you have the right data sources and the willingness to conduct some tricky analysis on power plant emissions and how power moves on the grid.
Just ask the Midcontinent Independent System Operator (MISO), the country’s largest grid operator by geography, and Singularity Energy, a startup developing open-source carbon emissions accounting software. In March, the partners unveiled a “consumed emissions” dashboard, revealing the carbon footprint of electricity within MISO regions, states, and even individual counties, measured on an hour-by-hour basis.
That data is useful for utilities offering “green tariff” programs that promise climate-focused customers a certain share of renewable or carbon-free energy. It also helps states with zero-carbon or renewable energy targets determine the emissions impacts of importing power from out of state versus shuttering fossil-fuel power plants and building clean generation within their own borders.
Those were the two use cases detailed by Jordan Bakke, MISO’s director of strategic insights and assessments, during an April 23 workshop. “Our members and states are pursuing emissions goals both on their own behalf and on behalf of end customers,” he said. “The request that has been given to MISO is to fill that need for temporal, spatial, and timely granularity of emission estimations across our footprint.”
Greg Miller, research and policy lead at Singularity, said similar approaches could help companies that have contracted with wind and solar farms or nuclear power plants to determine how much of that carbon-free power is actually reaching their data centers, factories, and office buildings from hour to hour. That’s a big deal for corporate clean-energy buyers like Google and Microsoft that have committed to serving a growing amount of their enormous power needs with carbon-free electricity.
Singularity is one of many companies working on providing these increasingly complex grid-emissions calculations.
Software providers such as Electricity Maps, Flexidao, and Kevala are tracking power plant emissions and energy flows across swaths of Europe and North America. Companies like REsurety and WattTime have built “marginal emissions” methods to calculate the impact of clean energy generated at different times on regional grids. Major clean energy investors like Quinbrook Infrastructure Partners and HASI are building carbon-tracking methods. And the EnergyTag international consortium has developed “granular certificate” standards to track hourly emissions associated with clean energy contracts.
But MISO’s consumed-emissions dashboard brings a new level of detail, Miller said. “We can’t trace individual electrons, just like we don’t trace water molecules in a river,” he said. “But we can trace larger power flows from generators to the loads where these flows are going.”
Two key data inputs feed Singularity’s emissions outputs for MISO’s new dashboard. The first is its fine-grained estimates of how much carbon is being emitted from individual fossil-fuel power plants — a seemingly simple calculation that’s actually quite complicated to nail down.
“Every generator’s efficiency is described in its heat rate — how much fuel it needs to burn to generate a unit of electricity,” Miller explained. Heat rates change from hour to hour, depending on factors ranging from the outdoor temperature to whether generators are running at maximum efficiency or are just being started up.
Singularity worked with nonprofit and research partners on a project called the Open Grid Emissions initiative to develop a method for calculating those constantly shifting emissions rates using public data and open-source methodologies. In the past year, it has developed a way to use available historical data to estimate those emissions changes in real time, Miller said. Experts in the field can check the methodology themselves “because it’s all modeled off publicly available data.”
The second key source of information at play for MISO’s dashboard is more proprietary — the power-flow data used to assess how much electricity from fossil-fueled power plants and all other sources is reaching the nodes on MISO’s transmission network on an hourly basis. That includes “information about how much power is getting generated and injected to the grid, how much power is getting withdrawn for loads, and the power flows for each transmission line in that network,” Miller said.
The platform that Singularity developed for running that analysis, dubbed CarbonFlow, uses open-source methods to reach its conclusions, he said. But the input data itself is kept confidential, both to protect the competitive interests of the power plant operators in MISO’s energy markets and to comply with federal mandates meant to protect critical infrastructure.
The end result isn’t as complete a picture as some might imagine, Miller emphasized. MISO only tracks power down to the individual substations that convert high-voltage power to lower voltages for use on distribution grids, for example, not to individual customers.
And while the dashboard’s emissions data will be made available on a near-real-time basis at the regional and state level, users have to wait a month after the end of each quarter to look at the hourly data for counties. That’s to avoid revealing operational information about fossil-fueled power plants in those counties to competitors, at least in timeframes that would allow them to act on it in ways that could give them unfair advantages.
Nonetheless, publicly accessible data at the hourly and county level is breaking new ground in the world of grid carbon accounting, Miller said. “This may be for only one region in the U.S. But it proves it’s possible to calculate this data — and other grid operators can do it too, if this data were required more broadly in accounting standards.”
Kathleen Spees, a principal with consultancy The Brattle Group, would like to see MISO and Singularity’s approach picked up by more grid operators. “At the least, they have to start providing the data,” she said.
Brattle was hired by the Illinois Commerce Commission to help develop the state’s Renewable Energy Access Plan, a road map for how the state can meet its mandate to reach 100% carbon-free power by 2045. Illinois already gets more than half of its power from in-state nuclear plants and is aiming to dramatically expand its use of solar and wind power from both within and outside its borders.
“But Illinois, like many states, is highly interconnected with its neighbors,” Spees said. “You can’t just reduce the fossil emissions in your state and say you’re done.” In fact, “if you ramp down gas in Illinois and ramp up coal somewhere else, that’s counterproductive” to the state’s carbon-cutting goals.
That’s why grid operators must be in the picture. The energy markets they run don’t account for carbon emissions today, although some grid operators are starting to make certain emissions data available to participants. But “over time, they have to create the mechanisms for trade,” Spees said, “so that the states that value green energy and avoiding carbon emissions have valid signals.”
Utilities and regulators need hard data to start translating these commonsense understandings of how grids work into real policy decisions with dollars and cents attached to them, Spees said. “We’re not talking minor academic interest here — we’re talking real money. What fraction of the enormous amount of capital going into our sector can ignore carbon implications? It has to be validated.”
That’s going to be complicated, particularly in Illinois, which is served both by MISO throughout most of the state and by PJM Interconnection, a grid operator serving 13 states from Virginia to the Chicago region. But the work has to start somewhere, and “the contribution that MISO is making here is really pushing the envelope in terms of the technical advance of what they can offer,” she said.
Singularity CEO Wenbo Shi pointed out another key use case for MISO’s data: informing “green tariff” programs that are available in most states. Green tariffs offer customers — usually corporate buyers looking to add clean power — the option to pay higher rates to secure a greater share of renewable or carbon-free electricity than what is available from the utility’s general mix of generation.
But to balance things out, each transfer of clean-power ownership rights from a utility to a customer must then be subtracted from the utility’s mix for other customers, lest it be “double-counted” as the same resource belonging to multiple end users.
“Once you can do that, you know exactly who gets what, and what’s left,” Shi said. “This eliminates the risk of double-counting.” The new MISO dashboard can help utilities make these calculations, he said. To accurately allocate clean electricity to the right customers, utilities must first understand their whole supply mix — and those that are part of a regional grid like MISO also need to factor in the energy that they purchase from the wholesale market.
Singularity has worked with utility Southern Co. to deploy such a system to provide customers with unprecedented visibility into their energy mix and emissions, Shi said. In MISO, one of the first users of the grid operator’s consumed-emissions data-tracking capabilities has been utility Entergy Arkansas, which offers green tariffs for customers such as steelmakers.
To be clear, MISO is explicitly not using its consumed-emissions data to inform “market-based” carbon accounting, Miller said. That’s the term for contractual arrangements that establish ownership of a unit of clean energy, such as the renewable energy certificates created under Greenhouse Gas Protocol Scope 2 Guidance, the gold standard in emissions accounting.
At the same time, the GHG Protocol is in the midst of changes that may make the kind of tracking Singularity is doing quite useful for market-based accounting, Miller noted.
Today, companies can offset emissions associated with their electricity use through clean energy purchases that are averaged out over the course of a year, and which can come from sources far removed from a company’s power-using facilities.
Those loose accounting rules helped enable corporate spending in building more clean energy when solar and wind were rare and expensive, and when linking their generation and delivery to a corporate customer’s actual energy consumption was less important. But clean energy has now become the cheapest and most common source of new grid capacity, which means that when and where new clean energy is being built — and whether it’s actually being used by the facilities of the companies claiming it — matters much more.
The data center boom is pushing these issues to the forefront for utilities and regulators. Data center expansions being proposed to feed the AI ambitions of tech giants are threatening to overwhelm the capacity of power grids in key markets across the country, including states like Wisconsin that lie within MISO’s grid footprint.
These ballooning load forecasts are driving utilities and grid operators to propose fast-tracking new fossil gas-fired power plants. But that threatens to undermine the aggressive clean-energy targets set by Amazon, Google, Meta, Microsoft, and other companies driving the data center boom, giving them impetus to seek cleaner options.
Just how the GHG Protocol’s rules on clean electricity accounting should work is a contentious subject, with major clean-energy buyers split on issues such as the well-publicized debate over whether they should aspire to 24/7 clean power at their facilities or invest in projects that will reduce the most emissions.
Singularity hasn’t waded into those debates, Shi said. But the technology that it and competing firms are developing can provide the tools necessary to allow clean-energy buyers and states to go beyond high-level and potentially misleading understandings of their emissions — and get closer to actually measuring those crucial figures.
Singularity is “tracing everything, whether it’s based on power flows or contracted,” Shi added “There are technologies that are being deployed that can solve that problem.”
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