Mapping the Peaker plants most susceptible to replacement by batteries

We know for certain that lithium-ion batteries are starting to knock off gas Peaker plants in select circumstances. But given the vast variety in Peaker plants' runtime, capacity, age, emissions and location, it can be difficult to predict which plants are the best candidates for replacement by batteries. 

Now, battery challengers needn’t stare at a blank map, blinking hard until the vulnerable gas plants reveal themselves. A free interactive data tool lets users cut and slice the key parameters in a far more scientific manner. 

A non-profit group called Physicians, Scientists, and Engineers for Healthy Energy research the connections between the energy system and public health, with an emphasis on presenting science in accessible ways for communities and policymakers. Mention of the group first came across my desk with a 2016 study about how energy storage policy could be tweaked to prioritise emissions-free batteries over the most polluting Peaker plants on days with severely unhealthy air quality.   

PSE’s latest project digs deeper, compiling data on all the Peaker plants in nine states that are favourable for grid battery development. By homing in on sensitive characteristics — like plants that run infrequently, emit the grossest air pollution or are just really old — community members or storage developers can focus on the cases where batteries are most likely to succeed in replacing the fossil-fuelled forebears.  

The cross-sectional approach points out that power plants affect different public interests simultaneously: They produce power, but they also erode public health in their immediate vicinity and tend to disproportionately affect minority populations. States often have different bureaucratic divisions tackling these issues independently, but they rarely focus on them all at once. 

“We’re at this turning point where energy storage is becoming economically competitive with power plants,” PSE Director of Research Elena Krieger said in an interview. “But there are a lot of different siloed policy efforts that are not aligned. […] We wanted to bring together data from across lots of areas and fields to inform the conversation around the clean energy transition.” 

This week in Storage Plus, we'll walk you through this tool and reflect on what we can learn from the early successes in the batteries vs Peakers contest. 

Pick your Peaker 

Each of the nine states (Arizona, California, Florida, Massachusetts, Nevada, New Jersey, New Mexico, New York and Texas) has its own interactive mapping page. To start with, you see a map of the state with each Peaker plant, visualised with its capacity and fuel type. 

Let's zoom in first on Massachusetts because its new Clean Peak Standard explicitly seeks to onboard energy storage for peak power. What’s striking about its current peak power fleet is that the biggest plants in the state burn oil. That has to do with the use of natural gas as a heating fuel in the frigid winters that residents there put up with; pipeline constraints and heating demand create winter peaks during which alternate fuels such as oil play a crucial role. 

But oil is very dirty, especially for a state that prides itself on modelling the pathway to a clean energy system. 

Take Canal, a 52-year-old oil-burning steam turbine unit. The 1,165 MW plant had a capacity factor of 1% between 2016 and 2018. A creaky old plant like that, which hardly ever runs, may be eligible for replacement. 

But there’s another level of analysis to dig into - the cumulative vulnerability index. PSE compiled this with health, environmental and demographic indicators, which provide an aggregate assessment of how vulnerable the community around a plant is to its emissions. Turns out, Canal scores below the state median in nearby health risks, pollution levels and socioeconomic burdens. It appears less susceptible to community mobilisation to shut it down, however, because the data does not indicate a clear case of undue impact on its surroundings. 

The worst offender on the Vulnerability Index, instead, is the West Springfield plant. Its neighbourhood scores off the charts for asthma rates and air pollution metrics and the population has above-average rates of minority and low-income residents.  

Checking out that one reveals a gas-powered steam turbine that’s creaking along at 71 years old. The 114 MW system only ran 0.7% of the time between 2016 and 2018. It’s paired with a bright, young 52-year-old gas turbine, 137 MW’s, that ran 2.1% of the time during that period. 

Further down in the data tool, you can zoom in on plant operations. Turns out the West Springfield steam turbine has been starting up roughly 16 times a year, running for 12 hours per start on average. That’s a long time compared to typical battery plant duration, so a replacement may need to take a portfolio approach, bringing in solar, distributed resources and dynamic load, for instance. 

At least on paper, this plant looks like a better candidate for replacement than Canal. West Springfield is old, hardly ever runs, and when it does, it contributes to an already high environmental burden forced upon a population that is largely low-income and minority.  

That’s not to say a battery necessarily makes sense there. But the tool is meant to help people analyse what factors are at play so energy companies, public health advocates and utilities can think strategically about their options. 

“In most cases, a mix of resources is probably going to be useful,” Krieger said. “You have to go and look at each plant, talk to the community, talk to the utility and figure out what is going to be best across the board.” 

Lastly, a dataset comparison tool lets you pick which variables to plot. For instance, graphing runtime on the x-axis and capacity factor on the y-axis reveals which plants are operationally impossible for current battery technology to replicate. But it also shows a cluster of plants that hardly ever run, and when they do, it is typically for less than four hours per start-up. Those smell like opportunities.  

Make the right connections at the right time 

I wanted to think through the implications of this tool by reflecting on early cases of successful Peaker replacement. 

The landmark case in that category is Oxnard, California's proposed Puente plant, which NRG was on the cusp of building when regulators yanked it and demanded a new look at cleaner options. This resulted in Southern California Edison selecting 200 MW of batteries, the largest of which is about to start installing its Tesla Megapacks. 

What’s notable there is that a passionate grassroots movement against the new gas plant — to be built on the beach, no less — had opposed it locally for years before the state energy bureaucracy started examining whether alternative technologies could work. The outcome was only possible thanks to the existence of viable energy storage projects, but the energy storage industry did nothing to galvanise that outcome until the utility asked for a new round of bids. 

That was in the early days of grid batteries' rise to prominence on the California grid, a period when general knowledge of the commercial readiness of energy storage was still scarce. Subsequent developments informed the more recent Peaker replacement effort at Oakland, California’s Jack London Square.  

Community members seeking better air quality got together with the clean energy planners at the local power provider East Bay Community Energy and utility PG&E, which maintains the wires in the area. They worked with power plant owner Vistra to swap the aging generator for a battery, while PG&E upgraded some wires to alleviate constraints. The new battery won’t be as powerful as the old plant, but as a portfolio of fixes, it meets the local capacity needs. 

Both examples show that community engagement can succeed in pushing from a fossil-fuelled power plant to a cleaner option. And that case gains strength when states have policies designed to accelerate energy storage adoption. 

But awareness of batteries as cleaner alternatives to Peakers has not reached all the communities that could benefit from them. If Oxnard had fought its new gas plant in some other state, it wouldn't have had the same options. The storage industry should try to find the other Oxnards, organising on their own for cleaner air, and work to build the Oakland-style collaborations that create the buy-in for a cleaner future. 

“These conversations are happening in some places; the tool is useful for finding out where else they should happen,” Krieger said. 

The Peaker Plant Replacement Project can't predict where storage project economics will make sense. But it's a great place to start when looking for opportunities. As California has proven multiple times, anticipating future capacity needs lets developers react quickly when the time comes.