NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Metrics for Evaluating Conventional 

and Renewable Energy Technologies

Natural Gas And The Transformation Of The U.S. Energy 

Sector: A Program Studying Multi-Sector Opportunities 

And Impacts Scoping Workshop

Margaret K. Mann

National Renewable Energy Laboratory (NREL)

December 2012

NREL/PR-6A20-57497
Outline

• Numerous pathways for greater use of natural gas – ho

if we’re going down the “best” pathways?

• Choosing between pathways can be done methodically

• Choose metrics wisely

1. Stakeholders have varying views2. Markets have varying needs

a) Commercial viability

b) Environmental sustainability

c) Seasonal demandd) Price sensitivity

3. Some metrics are actually misleading

4. Trade‐offs are very likely

• Communication of impacts is one of the most difficult 

analysis: Visual presentation helpful.

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Gas Destinations

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Transportation

Power

Central DG Peaking/ Load Level

Public

Transport

Commercial

Light

Duty

Delivery

Airport

Trash

Haul

School

Buses

Shuttles

DG 
Choosing Metrics

Metrics should be:

– Relevant to multiple stakeholders

– Able to cover a range of scenarios

• Technology• Time• Location

– Able to provide a systems‐level and

local‐level view of impacts

– Ideally quantifiable– Linked to actual impacts

– Easily communicated.

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Proxy Metrics

There’s a long history of wanting to designate a singvery few metrics) that can be a proxy for the larger s

• Net energy

• Biggest con: Not all resources available in the

same quantities and with the same impacts

• LCOE (cost)

• Biggest con: Variations in finance assumptions (e.g., de

hurdle rate, inflation); not singing from the same song b

• Combined score(s)

• Biggest con: Value judgments and personal experiences

Different stakeholders care about different impacts

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The wrong metric can mislead or cloak the real issuFor Example:

• Energy Use

• Metrics seeking to define energy use, particularly bet

different energy sources and for different end uses, d

the societal, economic, or environmental costs.

• Resources

• Knowing how much of a non‐renewable resource is c

unimportant without an understanding of the societa

and environmental costs of the alternative.

• Impacts

• All energy systems have impacts. Metrics to elucidat

economic and environmental impacts between syste

decision makers understand the pros and cons of diff

Choosing Metrics Wisely
Determining the “Best” Pathways

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Social Environmental 

 Health impacts New technology

acceptance

 Education

opportunities and

needs

 Employment GDP Gender impacts

 Rural development

 Energy access

 Safety and security

 Energy security

 Food security

 Cultural preservation.

 GHG emissions

 Primary energy use

 Biodiversity Water use and

impact

 Air quality

 Land use impacts

 Soil health.

 Cost  Emp Indu

 Trad

 Ener

secu

 Mar Clim

 Socia

oper

 Infra

“lock

 Tech

inno

Some Examples of Informative Metrics
Visualization

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The challenge is 

across stakehold

Trade‐offs between impacts

are very likely.The goal is to inform decision‐

makers.
Geographic Differentiation

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Analysis and presentatio

offs should include locat

technology, and time.
Analysis Certainty

Analysis rarely gives you “The Answer”

• If done well, it will point you in the right direction an

the next set of questions

• Insight is the goal.

Most important step in any analysis is the sensiti

• Even more important than data collection

• Must work to understand the impact of variation in 

• Think about “What if” scenarios and “What if not” s

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Metrics

• Choosing between pathways can be done met

• Choose metrics wisely

1. Stakeholders have varying views

2. Markets have varying needs

a) Commercial viabilityb) Environmental sustainability

c) Seasonal demandd) Price sensitivity

3. Some metrics are actually misleading

4. Trade‐offs are very likely

5. Include interactions between markets6. Visual presentation helpful.

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Research Recommendation

• Perform a multi‐metric analysis to more 

define the pros and cons of the various 

for increased natural gas use. Choose m

illuminate the market, economic, and su

trade‐offs.

• Incorporate these multi‐metrics into

complementary analyses and models.

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