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Mistaken Assumptions: Analysis from Pipeline Proponents Significantly Overestimates Oil and Coal Consumption and GHG Emissions

Making smart policy decisions on any issue requires sound objective analysis. To contribute to the public debate on a range of regional energy and environmental decisions, including evaluation of proposals for electric ratepayers to finance new regional natural gas pipelines, Acadia Center recently released a fact sheet that takes a comprehensive look at several different regional trends for greenhouse gas (GHG) emissions, electricity generation, and fuel consumption across all sectors.

Recently, Concentric Energy Advisors (Concentric) produced a report that includes an emissions analysis of this past winter’s electricity generation on behalf of a coalition of advocates for ratepayer-funded expansions in natural gas pipelines. Acadia Center’s Climate and Energy Analysis Center (CLEAN Center) reviewed this analysis, and it seems clear that the Concentric analysis significantly overestimated winter greenhouse gas (GHG) emissions from oil and coal generators in New England this past winter, likely between 15–20% higher than actual emissions from these sources.

This is because the Concentric report, like most analyses, makes assumptions as a part of its calculations. Assumptions are often used when data is incomplete or to avoid additional analysis that will only provide small improvements in accuracy. A frequently used assumption in electricity generation calculations is called a “heat rate,” which measures how efficiently a power plant turns fuel into electricity. A lower heat rate means a plant uses less fuel to generate the same amount of electricity. This information can be used to estimate the amount of fuel that a power plant consumes based on the amount of electricity it has generated. The estimated level of fuel consumption can then be used to estimate greenhouse gas emissions. However, fuel consumption data is often reported directly and can be used to more accurately estimate greenhouse gas emissions. Acadia Center’s recent analysis used fuel consumption data from the U.S. Energy Information Administration (EIA) to estimate GHG emissions for recent months where emissions data isn’t directly available.

The Concentric analysis begins with electricity generation data from ISO New England and then uses assumed heat rates to calculate fuel consumption. The calculated fuel consumption is then combined with an assumed emissions rate to estimate GHG emissions. In this case, Concentric used assumed heat rates based on S&P Global Market Intelligence data to represent the heat rates of power plants in New England. The Concentric analysis does not state if this assumed heat rate data is based on regional or national figures, nor does it compare it to other published data for regional heat rates as a check on its accuracy.

The Acadia CLEAN Center examined recently reported EIA data on fuel consumption and generation for individual power plants in New England from December 2017 through February 2018. This data can be used to directly calculate actual heat rates. Based on Acadia Center’s analysis of this EIA data, it appears that the assumed heat rates in the Concentric analysis for oil and coal generation in New England are significant overestimates. In other words, the Concentric analysis assumed those types of power plants used more fuel to generate electricity than they actually did.

Table 1 – Concentric Assumed Heat Rates and Actual Heat Rates (MMBTU/MWh)

Concentric assumed heat rate versus actual heat rate

As shown in Table 1, the assumed heat rate in the Concentric analysis for oil generation is 25% higher than the actual heat rate for oil generation in New England this past winter. Similarly, the assumed heat rate in the Concentric analysis for coal generation is 9% higher than the actual heat rate for coal generation in New England this past winter.

There can be many reasons that assumptions do not accurately represent reality. Assumptions based on historical data or national data do not necessarily reflect recent local conditions in New England. The assumptions in the Concentric analysis about the relative inefficiency of oil generation could also be reflecting a more general misconception about oil generation in New England. The older oil generating units in New England are more inefficient. However, newer units, including combined cycle and combustion turbines that can run on both natural gas and oil, are much more efficient.

Table 2 – Oil Heat Rates for Electric Generation Sites with Significant Oil Combustion from Dec. 2017-Feb. 2018 (MMBTU/MWh)

As this data shows, many of the electric generation sites in New England that used a significant amount of oil this past winter were much more efficient than assumed in the Concentric analysis and only one site, New Haven Harbor, was less efficient than the overall average assumed in the Concentric analysis.

The impact of this inaccurate assumption by Concentric flows through to subsequent calculations. This means that the estimates in the Concentric analysis for combined GHG emissions from coal and oil generation would be much higher than actual GHG emissions from coal and oil generation, likely between 15–20% higher. As a result, calculations of incremental GHG emissions during the winter cold snap are likely significant overestimates, as well as the other calculations in the Concentric analysis based on the estimate of incremental GHG emissions.

No one who is concerned with climate change wants fossil fuel plants to continue releasing greenhouse gases. But using emissions data to justify any policy case requires accuracy. To better inform the broader energy and environmental debate in New England, Concentric should update its analysis based on actual heat rates in New England this past winter. More broadly, all of the tools available to meet our energy needs—market reforms, energy efficiency, energy storage, solar, wind, and fixing gas leaks among them—need to be fairly evaluated in order for the right conclusions to be drawn.

Clearing the Air: Long-Term Trends and Context for New England’s Electricity Grid

Some entities and stakeholders have raised concerns about the environmental performance of New England’s electricity system during a particularly cold multi-week period in December 2017 and January 2018. Specifically, they have called attention to emissions due to the amount of oil and coal used for electricity generation during that time. Acadia Center takes these concerns very seriously and advocates strongly for reducing pollution that hurts public health and the climate in order to meet the region’s science-based requirements.

In addition, some of these stakeholders are advancing a specific proposal that they argue would solve the region’s emissions issues, a multi-billion-dollar electric ratepayer-funded investment in new natural gas pipeline capacity. Public investments in natural gas pipelines would have significant consequences for the region and the claimed benefits of such an investment should be scrutinized closely.

To provide perspective on the grid’s environmental performance this past winter and the impacts of a proposed major expansion of natural gas pipeline capacity, Acadia Center has developed a fact sheet which takes a comprehensive look at several different regional trends for greenhouse gas (GHG) emissions, electricity generation, and fuel consumption across all sectors. The results demonstrate that the selective statistics used by pipeline advocates are incomplete at best and significantly misleading at worst.

Policymakers in the region should not be misled by pipeline advocates and must consider a full set of options to ensure that New England continues to progress toward a clean, reliable, and affordable electricity system in the coming years. Eight charts on relevant issues are presented in the fact sheet, but the most important points are included here.

New England is making significant progress reducing GHG emissions from the electric sector over the long-term. New England GHG emissions from electricity generation from March 2017 through February 2018 were 53% lower than in 2001-02, 26% lower than in 2012-13, and 8% lower than in 2016-17. Progress reducing GHG emissions in the electric sector is undeniable, even accounting for emissions related to the cold snap in December 2017 and January 2018.

Figure 1 – Annual GHG Emissions (Mar. to Feb.) from Electricity
Generation in New England

The region has historically seen significant monthly variation in GHG emissions from electricity generation. While GHG emissions from electricity generation in New England were higher in December 2017 and January 2018 than some other months, seasonal and monthly variation in GHG emissions is normal. Monthly GHG emissions from electricity generation in New England are typically higher in hot summers and cold winters. January 2018 was the 10th highest month of GHG emissions dating back to the beginning of 2014, while February 2018 was the lowest in the 21st century.

Figure 2 – Monthly GHG Emissions from Electricity Generation
in New England

GHG emissions from electricity generation are falling in New England because of several drivers, including energy efficiency, increased renewables investment, and a major decrease in the amount of electricity generation from coal and oil. Annual electricity generated by coal and oil from March 2017 through February 2018 was 91% lower than the levels in 2001-02 and 49% lower than just five years ago in 2012-13.

Figure 3 – Annual Electricity Generation from Coal and Oil (Mar. to Feb.)
in New England

New England is rapidly approaching the limit of the GHG reduction strategy of replacing electricity generation from coal and oil with natural gas. As might be expected, coal and oil generation has been reduced in part through increases in natural gas generation. However, as a long-term strategy, shifting from one fossil fuel to another will not allow for the GHG emissions reductions the region needs to meet its science-based commitments.

GHG emissions from natural gas combustion across all sectors, including those from gas delivered through two recent regional pipeline expansions, will be an increasingly significant percentage of overall regional GHG emission limits over time. Looking at combustion emissions in isolation also understates the overall impact of emissions from natural gas because it ignores the significant GHG emissions during extraction and delivery. Adding a major new regional pipeline would only exacerbate this issue, potentially increasing combustion emissions from natural gas to 49% of the overall regional GHG emissions target in 2030, and that would rise to 72% in 2040, and 135% in 2050.

Figure 4 – Natural Gas Combustion Emissions in New England from All Sectors Versus Overall Regional GHG Emissions Requirements

Of course, emissions are not the only important policy consideration for the successful operation of New England’s grid. Other serious considerations are reliability and consumer costs. Some stakeholders have argued that there is a medium-term reliability risk, which could lead to rolling blackouts or other harms. However, a recent report from Synapse Energy Economics demonstrates that, with reasonable expectations for growth in demand for electricity and natural gas and accounting for planned investments in renewables and transmission for clean energy, the risk of major reliability issues is close to zero. Keeping on this path will take some effort but should be achievable.

On the consumer costs side, using hard-earned ratepayer dollars for major new natural gas pipelines would not have any impact on electricity prices until construction is finished, which could be in 2022 or even later. Furthermore, there are good reasons to think that purported consumer benefits would not outweigh the guaranteed costs that ratepayers would have to pay. Major investments are currently being planned for offshore wind and new transmission lines for clean energy that would come online in the same timeframe as a pipeline, and these investments undercut many of the alleged benefits of a pipeline. Additional pipeline capacity would also increase the chances of exporting natural gas out of New England, which would drive up natural gas prices.

In the shorter term, many other available policy options can help improve the reliability of New England’s grid and reduce costs, while simultaneously lowering emissions. This year, ISO-NE is implementing “pay-for-performance” market reforms, which provide additional incentives to generators to respond during times of high demand and high prices. Additional investments in energy efficiency for natural gas and electricity, fixing leaks in the natural gas distribution system, advanced energy storage, local renewables, and grid modernization will start to help right away with energy prices and reliability, while simultaneously advancing the region’s long-term emissions requirements.

The usefulness of using natural gas as a “bridge” over the last two decades is at an end and the region needs to avoid further long-term public investments in fossil fuels. New England’s economic and environmental future depends upon building a clean, reliable, and affordable modern energy system. Acadia Center’s EnergyVision 2030 shows a path to meet economy-wide GHG emissions reductions of 45% from 1990 levels by 2030 using market-ready technologies, with no additional natural gas pipeline capacity needed.  It’s time to move forward with a smart portfolio of investments to benefit consumers, create well-paying local jobs, improve public health, and lower the risks of climate change.