Opportunities and Challenges for NuclearRenewable Hybrid Energy Systems

Mark F. Ruth, Paul Spitsen, Richard Boardman, Shannon Bragg-Sitton

October 23, 2018

IAEA Technical Meeting on Nuclear-Renewable Hybrid Energy Systems for 

Decarbonized Energy Production and Cogeneration
JISEA—Joint Institute for Strategic Energy Analysis 2

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Connecting technologies, economic 

sectors, and continents to catalyze 

the transition to the 21st century 

energy economy.

JISEA

Joint Institute for 

Strategic Energy Analysis 

Founding Members
JISEA—Joint Institute for Strategic Energy Analysis 4

NICE Future Initiative Began at CEM9 2018

Lead Participants 

USA CANADA JAPAN

Participants

ARGENTINA POLAND ROMANIA

RUSSIA UAE UK

Vision 

NICE Future envisions nuclear power as an important 

energy option for clean, reliable, and resilient baseload 

electricity and non-electric applications and includes 

advanced and innovative designs and applications.

Areas of Work: 

1. Evaluations of innovative systems, technology, 

storage, uses

2. Engagement

3. Economics

4. Communicating nuclear energy’s role in clean 

energy systems
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Working Definition of an N-R HES

Tightly-Coupled

Individual facilities which 

take two or more energy 

resources as inputs and 

produce two or more 

products, with at least one 

being an energy commodity 

such as electricity or a 

transportation fuel

Source: RUTH, Mark F., ZINAMAN, Owen R., ANTKOWIAK, Mark, BOARDMAN, Richard D., CHERRY, Robert S., BAZILIAN, Morgan D. “Nuclear-renewable hybrid energy systems: Opportunities, interconnections, and needs,” Energy Conversion and 

Management, Volume 78, February 2014, Pages 684-694, ISSN 0196-8904, http://dx.doi.org/10.1016/j.enconman.2013.11.030. (http://www.sciencedirect.com/science/article/pii/S0196890413007516)
JISEA—Joint Institute for Strategic Energy Analysis 6

Analysis Objective

• Financial (economic) analysis of N-R HES use cases

• Testing

– Profitability

– Profitability compared to natural gas alternatives 

– Competitiveness in grid resource adequacy markets

– Potential for flexibility to improve profitability
JISEA—Joint Institute for Strategic Energy Analysis 7

Use Cases Analyzed

Electrical 

interconnection 

No purchase of 

grid electricity

Electrical interconnection

Thermal interconnection 

for high temperature 

electrolysis.

Possible purchase of grid 

electricity

Thermal 

interconnection

Thermal 

interconnection 

(primarily)

Possible purchase of 

grid electricity

Ruth, Mark, Spitsen, Paul, Boardman, Richard, Bragg-Sitton, Richard “Opportunities and Challenges for Nuclear-Renewable Hybrid Energy Systems” Proceedings from IAEA 

Technical Meeting on Nuclear-Renewable Hybrid Energy Systems for Decarbonized Energy Production and Cogeneration. October 2018.
JISEA—Joint Institute for Strategic Energy Analysis 8

Analysis Methodology

Identify optimal configurations and 

internal dispatch under various product prices

Full Configuration Partial Configuration Another Partial Configuration

Other configurations: (1) nuclear-generated electricity only and (2) wind only

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
JISEA—Joint Institute for Strategic Energy Analysis 9

Analysis Methodology

Identify optimal configurations and 

internal dispatch under various product prices

One Dispatch Option Second Dispatch Option

Adapted from Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
JISEA—Joint Institute for Strategic Energy Analysis 10

Analysis Methodology

Hourly Electricity 

Price Estimates

Subsystem Sizing and 

Operational 

Optimization

Additional 

Financial 

Capital & Analysis

Operating 

Costs

Capacity 

Payment

Generation 

Mix

Other 

Costs

Dynamic 

Performance

Adapted from Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
JISEA—Joint Institute for Strategic Energy Analysis 11

Analysis Methodology

Hourly Electricity 

Price Estimates

Subsystem Sizing and 

Operational 

Optimization

Additional 

Financial 

Capital & Analysis

Operating 

Costs

Capacity 

Payment

Generation 

Mix

Other 

Costs

Developed from 

Standard Scenarios: 

Used the 2036 mix 

for the RPS80 

scenario as the 

baseline 

Estimated as marginal 

operational costs using 

PLEXOS unit commitment 

modeling

Based on historical 

costs and competition 

from natural gas 

combustion turbines: 

$50/kW-yr 

Required to provide 

power during 50 

highest load hours in 

the year

From Annual 

Technology 

Baseline and 

INL estimates

Used REopt to identify 

optimal configurations 

and internal dispatch

Maximum sizes for all 

subsystems set to 50 

MWe equivalent

10% after tax IRR 

on 100% equity 

financing. 25 

year analysis life. 

35% tax rate. 3% 

inflation rate.
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Electricity Prices

Price Set Primary Arizona Volatile

Wind generation 

percentage

21% 11% 8.6%

PV generation 

percentage

20% 22% 37%

Hours at $0/MWh 

annually 704 700 2,246

Developed and used generation mixes 

that cause volatile electricity prices

Energy Price Duration Curve for Texas Use Cases

Ruth, Mark, Spitsen, Paul, Boardman, Richard, Bragg-Sitton, Richard “Opportunities and Challenges for Nuclear-Renewable Hybrid Energy Systems” Proceedings from IAEA 

Technical Meeting on Nuclear-Renewable Hybrid Energy Systems for Decarbonized Energy Production and Cogeneration. October 2018.
JISEA—Joint Institute for Strategic Energy Analysis 13

Optimal Configurations Liquid Fuels Use Case

N-TPC: Nuclear reactor and thermal 

N-IP: Nuclear reactor and industrial process 

RE: Renewable electricity generation

Nuclear- & 

WindGenerated 

Electricity

Nuclear 

Heat to 

Reforming 

and WindGenerated 

Electricity

WindGenerated 

Electricity 

Only Nuclear 

Heat & 

Industrial 

Process 

Only

Conditions Optimal Configurations

Low gasoline prices & high 

electricity price multiplier

Both nuclear- & wind-generated electricity

High gasoline prices & lower 

electricity price multiplier

Nuclear heat and industrial process only

High gasoline prices & high 

electricity price multiplier

Nuclear heat and industrial process with 

wind generation

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
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Subsystems are Optimally Included if Independently Profitable

N-TPC: Nuclear reactor and thermal 

N-IP: Nuclear reactor and industrial process 

RE: Renewable electricity generation

Nuclear- & 

WindGenerated 

Electricity

Nuclear Heat 

to Reforming 

and WindGenerated 

Electricity

WindGenerated 

Electricity 

Only Nuclear Heat 

& Industrial 

Process Only

Conclusion #1:

Under our analytical method and most of our assumptions, 

the primary driver for whether a subsystem is included in 

the optimal configuration is whether it would be profitable 

independently

Major Caveats:

• Negligible grid connection costs

• No value for inertia or resilience

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
JISEA—Joint Institute for Strategic Energy Analysis 15

Optimal Operation: Maximize Hours that Industrial Process Operates

N-TPC: Nuclear reactor and thermal 

N-IP: Nuclear reactor and industrial process 

RE: Renewable electricity generation

Nuclear- & 

WindGenerated 

Electricity

Nuclear Heat 

to 

Reforming 

and WindGenerated 

Electricity

WindGenerated 

Electricity 

Only Nuclear Heat 

to 

Reforming 

Only

Conclusion #2:

Industrial processes usually 

maximize profitability by 

operating the maximum 

number of hours possible in a 

year

In other words:

Our electricity price 

assumptions are insufficiently 

volatile for arbitrage (even 

with high renewables & 

capacity payments)

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
JISEA—Joint Institute for Strategic Energy Analysis 16

But Lower Cost Equipment Partially Overcomes Second Conclusion

Exception to #2:

Systems with lower hourly income 

required from the industrial process 

may optimally reduce the industrial 

product to receive a capacity 

payment (white & lighter blue 

regions in water production graph)

Nuclear-

& PVGenerated 

Electricity

Full N-R HES

NuclearGenerated 

Electricity 

Only

NuclearGenerated 

Electricity & 

RO 

Desalination

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, Stark, Greg, Jenkin, Thomas, Simpkins, Travis, and Macknick, Jordan. The Economic Potential of Two NuclearRenewable Hybrid Energy Systems, 2016. NREL/TP-6A50-66073. http://www.nrel.gov/docs/fy16osti/66073.pdf
JISEA—Joint Institute for Strategic Energy Analysis 17

Flexibility Benefits N-R HESs with Lower Capital Cost Industrial Processes

LTE: low temperature electrolysis subsystem

NR: nuclear reactor

RE: renewable electricity generation (wind power plant)

TPC: thermal power cycle

Capital Investment: $616/kW $154/kW Low Temperature Electrolysis (LTE)

Conclusion #3:

• Lower capital cost industrial processes are 

more likely to utilize their flexibility to switch 

between electricity and the industrial 

product more often than their higher capital 

cost configurations

• This flexibility increases the number of 

profitable situations

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, and Stark, Greg. The Economic Potential of Nuclear-Renewable Hybrid Energy Systems Producing Hydrogen (2017). 

NREL/TP-6A50-66764. http://www.nrel.gov/docs/fy17osti/66764.pdf
JISEA—Joint Institute for Strategic Energy Analysis 18

Flexibility Benefits N-R HESs when Electricity Prices are High & Volatile

Primary Elec. Prices

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, and Stark, Greg. The Economic Potential of Nuclear-Renewable Hybrid Energy Systems Producing Hydrogen (2017). 

NREL/TP-6A50-66764. http://www.nrel.gov/docs/fy17osti/66764.pdf

• N-R HES can produce electricity when price is 

high and industrial product when electricity 

price is low as shown in the yellow polygon 

• High and volatile energy prices necessary to 

realize the benefits of arbitrage

Low Temperature Electrolysis (LTE) Volatile Elec. Prices
JISEA—Joint Institute for Strategic Energy Analysis 19

• Oil & Gas and the 

Energy Economy

• Power System 

Integration and 

Transformation

• Advanced Energy 

Manufacturing: 

CEMAC

Thermal Energy May Be an Opportunity for Nuclear Energy

Conclusion #4:

Nuclear reactors may be 

competitive selling thermal energy 

Providing a thermal energy market 

exists and they can access that 

market

Ruth, Mark, Spitsen, Paul, Boardman, Richard, Bragg-Sitton, Richard “Opportunities and Challenges for Nuclear-Renewable Hybrid Energy Systems” Proceedings from IAEA 

Technical Meeting on Nuclear-Renewable Hybrid Energy Systems for Decarbonized Energy Production and Cogeneration. October 2018.
JISEA—Joint Institute for Strategic Energy Analysis 20

High Temperature Electrolysis N-R HES: Impact of Capacity Payments

$50 / kW-yr $100 / kW-yr $150 / kW-yr

Source: Ruth, Mark, Cutler, Dylan, Flores-Espino, Francisco, and Stark, Greg. The Economic Potential of Nuclear-Renewable Hybrid Energy Systems Producing Hydrogen (2017). NREL/TP-6A50-66764. 

http://www.nrel.gov/docs/fy17osti/66764.pdf

Conclusion #5:

• Higher capacity payments lead to more optimal 

configurations that provide grid support

• But a sufficient industrial product price is still 

critical

High Temperature Electrolysis (HTE)
JISEA—Joint Institute for Strategic Energy Analysis 21

1. Under our analytical method and most of our assumptions, the primary driver for 

whether a subsystem is included in the optimal configuration is whether it would be 

profitable independently

2. Industrial processes usually maximize profitability by operating the maximum 

number of hours possible in a year

3. Lower capital cost industrial processes are more likely to utilize their flexibility to 

switch between electricity and the industrial product more often than their higher 

capital cost configuration. This flexibility increases the number of profitable 

situations

4. Nuclear reactors may be competitive selling thermal energy providing a thermal 

energy market exists and they can access that market

5. Higher capacity payments lead to more optimal configurations that provide grid 

support but a sufficient industrial product price is still critical

Conclusions - Reiterated
Thank you!

NREL/PR-6A20-72564 www.nrel.gov

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, 

LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by U.S. 

Department of Energy Office of Energy Efficiency and Renewable Energy Office of Strategic Programs and Fuel Cells 

Technology Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. 

Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges 

that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce 

the published form of this work, or allow others to do so, for U.S. Government purposes.

www.JISEA.org

mark.ruth@nrel.gov