[author’s note April 2019 – Although the original intent of this article was to prove whether we could shutter all coal and natural gas steam turbines with existing combined cycle natural gas, it required first obtaining a baseline of where the US is in terms of its energy transition within the power generation fleet and more importantly, the disaggregation of power generation based on not only fuel consumed, but also Prime Mover technology employed in the energy conversion process itself.
This information is not only not transparent within the US, but it is locked arguably by legacy power generation data-management orthodoxies fixated upon “spinning masses” and “fossil fuel type dictates the outcome indifferent/ignorant to conversion technology employed” conventional wisdom that has resulted. This accounting/analysis is not about “natural gas” per se, but advancements in natural gas prime mover technology and its impact on the US power generation carbon intensity reduction “successes” the past 2 decades cannot be simply ignored either.
To get us the data transparency and details we need to progress forwards in our energy transition intelligently and strategically, the natural gas CCGT – Combined Cycle plant must be recognized as the 800 pound gorilla in our room.
As my colleague Simon Todd states accurately, “What gets measured, gets done.”
And That is what this article is about, measuring transparently, so we can get our energy transition done. ~Hans]
“Could the US shutdown its coal fleet today by using its Combined Cycle Gas Turbine fleet?”
The answer is complicated, but largely it is …maybe.
If you are unfamiliar with how a Combined Cycle (CCGT) plant works, you can watch this tour from GE. Simply put, a CCGT is a CHP – Combined Heat and Power plant, which directly generates electricity from the Gas Turbine (GT), then sends the hot exhaust through a HRSG “her-sig” – Heat Recovery Steam Generator, directing the steam through a Steam Turbine (ST), producing additional electricity. In the US, we have multiple combinations of GT/HRSG and ST; 1 to 1, 2 to 1 and some 3 to 1. In addition, some plants use the low grade heat from the ST to deliver more value out of the conversion processes, such as the Holland Energy Center in Michigan, for a snow melt system. The more “beneficial” use of the primary energy into the system, the greater its efficiency, as well getting more energy value out of its resulting carbon emissions.
I have completed this analysis for the Eastern 30 States dividing the US roughly at the Mississippi. Notably I have included Arkansas, Louisiana and Missouri, while excluding Iowa and Minnesota for known energy landscape-based reasons… the former have not engaged in significant renewable energy or transmission expansion deployments, while the latter has in a substantial way.
There are two outliers within the Eastern 30. Michigan, whose wind production accounts for 11% of all Eastern 30 wind and solar production and North Carolina, whose solar production accounts for 11% of all Eastern 30 solar and wind production.
Michigan has another defining “non-Eastern 30” aspect, it has built new transmission specifically to support wind deployment, the dual circuit 345kV “Thumb Loop”. It is on par with Texas’s CREZ (Competitive Renewable Energy Zones) expansion, Oklahoma’s Woodward EHV (Extra High Voltage) system, the Kansas Electric Transmission Authority (KETA) project, Nebraska’s V-Plan (with further efforts towards a “R-Plan”), and the Iowa and Minnesota centric CapEx2020 project spearheaded by Xcel. The big news in the South Central Great Plains is utility scale wind deployment, however its presently realized success would not have been possible without these transmission projects unlocking the potential of wind power.
This, transmission expansion, unfortunately, has largely not happened in any of the other US states, East or West. Wind and transmission in the US has experienced significant maturation in the past decade, and the most successful projects have converged on the 345kV system common, but not uniform throughout every region or state. All of the above states share this feature.
Returning to the Eastern 30, a rough accounting of hydro, nuclear and wind generation imports from Canada of 35-40 Terawatt-hours (1 TWh equals 1 million Megawatt-hours or 1 billion Kilowatt-hours) puts this net influx of electricity at between 70-80% of total Eastern 30 wind and solar production combined. I have not included any of the US Energy Information Agency (EIA) estimated 24 Terawatt-hours generated in 2017 from small scale solar (under 1 MW nameplate capacity) as most industry experts understand the vast majority of this is coming from the Western 17 states plus Hawaii, and most notably, California.
Eastern 30 hydro, for all practical purposes is maxed out, with no notable production growth opportunities here. The largest current additions to Eastern 30 hydroelectric production is via the 4-stage HydroQuebec Romain project, upon completion adding an estimated 8 Terawatt-hours to the Eastern Grid.
What about biogas and biomass? The Eastern 30 is already harnessing 6.5 Terawatt-hours per year of “biogas” or more appropriately defined, landfill gas. This resource is not unlimited… maybe there is untapped landfill potential for 4-5x max growth potential, however EIA generator data reveals landfill gas fueled internal combustion engines and combustion turbines are by count, the most numerous of any prime mover type in the US.
Biomass? The Eastern 30 has been harnessing this resource for decades at lumber mills & paper factories, as well as at “waste-to-power” municipal waste incinerators. All combined this netted 50 Terawatt-hours in 2017, partially fueled by coal and natural gas, particularly at the mills and factories with onsite generators. Depending upon prime mover and primary fuel classification methods used, there is between 12,000 and 20,000 MW of “biomass” capable steam turbines within the Eastern 30. Heat rate of these units tells us they are roughly one-half as efficient as a natural gas Combined Cycle unit, and many increasingly question the environmental benefits for harvesting biomass specifically for power generation.
The one bright spot I see in the Eastern 30, existing pumped hydro capacity at 16,500 MW. This could nearly offset the bulk single cycle “peaker” production in Megawatt-hours, although not by instantaneous capacity, Megawatts by itself over the year. In order for the Eastern 30 to realize the environmental benefits of its existing pumped storage fleet, it would require surplus no/low carbon “renewable energy” production from wind and solar. Unlocking a “dual daily cycle” utilization regime for pumped storage, and displacing its current charging by “filling the trough” backup for non-ramping nuclear and coal plants (or Canadian imports of hydroelectricity), would require far less chemical battery deployment from a bulk storage perspective, while filling their associated role in offsetting NOx production in dense urban centers from natural gas “peakers”.
And we’ve not even scratched the new load demands from electrification of transport or home space and water heating. Efficiency improvements within the electric sector is one thing, displacing oil for mobility and natural gas for space and water heating bringing it into the electric sector is additive, not reductive to our electric power generation needs.
So how much are “renewable energy” sources, such as wind and solar providing to the Eastern 30, so we can begin to answer the question above? The unfortunate reality… not enough, by a very long shot. To be exact, wind and solar are providing less than 2% of the Eastern 30 demand as measured in 2017. This is extremely discomforting to me as we are fast approaching a decade of real wind and solar deployment throughout the US and the world in general. Costs of wind and solar continue to decline, storage costs also. Announcements of new wind, solar or combinations including storage projects are breaking daily. Consumers are demanding more no or low-carbon generation from wind and solar. And the pipeline of projects in the US is not insubstantial, particularly in light of Production Tax Credit set to begin phasing out in 2020.
But “Houston, we have a problem”, increasingly in the Eastern 30… opposition to large scale energy projects is crossing traditional divides. New transmission is being fought as voraciously as pipelines. Utility scale solar PV is meeting resistance on par with new natural gas combined cycle units. Wind farms are finding strong resistance in terms of noise production, erroneously, but not significantly different than that of natural gas pipeline compressor stations, that too are targeted based on real or perceived acoustical impacts. Rural communities, long the economic beneficiaries of large energy projects far exceeding their local demands for export to high demand urban centers, are mobilizing in greater numbers and gaining significant capital in small community political structures. Hundreds of “Populist Movements” around the Eastern 30 are racking up “wins” at a disturbingly high rate, and energy project developers of all strips can no longer move a project through completion “under the radar” like has happened over the past decade.
For the past year, I have been battling in favor of 3 wind projects here in NY. Breaking the unsubstantiated negative narrative, turned out by regional media outlets more focused on “clicks” and fueling controversy, has been challenging to say the least.
Reducing our carbon intensity, by means of adding new low carbon generation resources, is hitting an invisible wall twice as strong as any physical wall ever constructed.
Which forces me to examine the above question again. And one all Eastern 30 States residents need to consider also, in particular if their greatest concern is the same as mine… targeting the most cost effective reduction of carbon emissions in the quickest manner possible.
“Could the US shutdown its coal fleet today by using its Combined Cycle Gas Turbine fleet?”
To answer this question, we will need to look at individual states through the lens of US Energy Information Agency (EIA) data for existing generation resources and electric generation. Which is what I intend to do in future articles.
If you are interested in assisting on this project or would like to use data for your own reporting, please contact me.
Hans Hyde 
3 Comments