GENerators for Small Electrical and

Thermal Systems (GENSETS)

J.C. Zhao

December 14, 2016

What We Learned After Year-1 of GENSETS

Advanced Research Projects Agency - Energy

Outline

Reminder of the original GENSETS Vision

Select GENSETS technical highlights

Open questions and goals of this meeting

US residential sector annual energy use

Overall efficiency: 50% Overall efficiency: 83%

e-

5 Quads

Heat loss9.7 Quads

4.7 Quads

“19.4 Quads”

Centralized Electricity Generation

2

e-

Combined Heat and Power (CHP)

e-

40% electrical efficiency

11.7 Quads

11.7 Quads

4.7 Quads

5 Quads

CHP

2 Quads excess heat

• 5 quads of energy savings potential (residential + commercial)

• 200 millions tons of CO2 reduction (4% US total ≈ 40 M cars)

• 8% reduction of US fresh water withdrawal

Why haven’t you bought a generator for your home?

3

<1,000 of 110,000,000 US homes have CHP systems

• Low fuel to electricity efficiency (<26%)

• High cost for long durability ones (>$6,000)

• Low lifetime for low-cost generators (<1 yr)

• Large kW size than optimal

~ 500,000 US homes have backup generators

70 million US homes have

piped-in natural gas already

GENSETS: GENerators for Small Electrical and Thermal Systems

4Improve Efficiency Reduce Emissions Reduce Imports

> +25% – 200 million tons

• 1 kW electricity system

• 40% electrical efficiency

• 10 year durability/life

• $ 3,000 system cost

Technologies to enable

widespread deployment of

CHP systems for residential

& commercial sectors

• Save energy (~ 5 quads)

• Save $ (~ 4-5 year payback)

• Reduce CO2 by 200 million tons

• Reduce fresh H2O withdrawal

(~8% of US total)

• Increase power reliability

• $240 billion business opportunity

Long-Term Objectives and Metrics (Primary)

5

Number Property Primary Target

1.1 Electrical power generation capacity 1 kWe

1.2 Fuel to electricity conversion efficiency (LHV) ≥40%

1.3 Useful heat energy output (>80°C) >1kW/kWe

1.4 Capacity factor ≥99.9 %

1.5 Complete system cost excluding

installation/balance of plant costs

≤$3,000

1.6 System lifetime ≥10 years

1.7 Total system-out NOx ≤0.07 lb/MWh

1.8 Total system-out CO ≤0.10 lb/MWh

1.9 Total system-out VOC ≤0.02 lb/MWh

1.10 Total system-out PM ≤0.40 g/kWh

1.11 Total system-out CO2 equivalent (CO2 & CH4) ≤1100 lb/MWh

1.12 System noise ≤55 db(A) 3 ft. away

Long-Term Objectives and Metrics (Secondary)

6

Number Property Secondary Target

1.13 Methane number for operation ≥70

1.14 Number of regular maintenance services ≤1/year

1.15 Operation and maintenance cost ≤$ 0.005/kWh

1.16 Time for regular maintenance ≤60 minutes/service

1.17 System mass ≤150 Kg

GENSETS Program Awards

7

$32 million total for 12 teams

• 6 ICE teams

• 4 Stirling engine teams

• 2 Microturbine teams

9 small businesses, 2 universities, 1 large business

GENSETS Timeline and Critical Milestones

8

2014 2015 2016 2017 2018 2019

Year-1 Year-2 Year-3

NOTE: This is a notional figure and timeline for each individual award may vary

Critical Milestone in Year-2

Outline

Reminder of the original GENSETS Vision

Select GENSETS technical highlights

Open questions and goals of this meeting

GENSETS Portfolio Summary: 3 technology areas

10

Single-Cylinder Two-Stroke

Free-Piston Internal Combustion

Generator

Spark-Assisted HCCI Residential

Generator

Oscillating Linear Engine and

Alternator Advanced Lean Burn Micro-CHP

Genset

High Efficiency Split-Cycle Engine

for Residential Generators

A High Efficiency SACI 1 kW

Generator System with Integrated

Waste Energy Recovery

1kW Recuperated Brayton-Cycle

Engine Using Positive-Displacement

ComponentsAdvanced Microturbine Engine

for Residential CHP

Sustainable Economic mCHP

Stirling (SEmS) Generator

Free Piston Stirling Engine Based

1kW Generator

Kinematic Flexure-Based Stirling-

Brayton Hybrid Engine Generator for

Residential CHPAdvanced Stirling Power

Generation System for Combined

Heat and Power

Stirling engines

ICE

Microturbines

GENSETS Portfolio Technologies (Page 1 of 2)

Project Technology

type

Key Technologies

West Virginia University

(WVU)

ICE Free piston, spark-ignited stoichiometric ICE

Aerodyne Research Inc. ICE Free piston, homogeneous charge compression

ignition ICE

Wisconsin Engine Research

Consultants, LLC (WERC)

ICE Spark Assisted Compression Ignition (SACI)

ICE

Mahle Powertrain ICE Turbulent Jet Ignition (TJI) ICE

Tour Engine Inc. ICE Novel split cycle ICE with a shuttle valve for

transferring working fluid

Air Squared Inc. ICE Scroll expander based waste heat recovery for

SACI ICE

Brayton Energy Microturbine Sub-atmospheric microturbine employing screw

compressor and expander

Metis Design Corporation

(MDC)

Microturbine Microturbine with rotating vaneless diffuser

(RVD) and low swirl burner

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GENSETS Portfolio Technologies (Page 2 of 2)

Project Technology

type

Key Technologies

Temple University Stirling engine Free Piston Stirling Engine (FPSE) manufactured

using additive manufacturing with a high temperature

heater head

Sunpower, Inc. Stirling engine FPSE based on their 80 W Advanced Stirling

Converter for space applications with gas bearings

Infinia Technology

Corporation (ITC)

Stirling engine FPSE with a high temperature heater head and

flexure bearings

Sencera Energy Stirling engine Kinematic Stirling engine employing flexures instead

of pistons

12

Microturbine: Brayton Energy

13

System Schematic of the microturbine CHP system

Microturbine: Brayton Energy

14

Ceramic main and gate rotors

(Screw Expander)

Thermal imaging of combustion-heated test article

FEA model predictions

Stirling Engine: Sunpower

15

ICE: Mahle Powertrain Combustion System

– Developed 1D/3D efficiency model with empirical data input from multiple sources

– Model indicates target indicated thermal efficiency of 45% is achievable

– Developed MJI pre-chamber geometry variants

– Identified target FMEP

Engine Design

– Completed prototype single-cylinder design

Design centered around Jet Ignition combustion system

– Targeted subsystems for low friction and long life

Incorporated numerous MAHLE low friction engine components and best practices

ICE: Mahle Powertrain Aftertreatment

– Established anticipated emissions scenarios

– Identified aftertreatment strategies

– Performed bench-scale testing to evaluate strategies

– Best performance: MOC + LNT

Tailpipe NOx, VOC should be below program targets

CO should meet targets

Significant challenge remains for meeting GHG target

– Developed controls parameters for regen cycles

Outline

Reminder of the original GENSETS Vision

Select GENSETS technical highlights

Open questions and goals of this meeting

Open Questions: Internal Combustion Engines

‣ What is the optimum combustion strategy for high efficiency at this

scale?

– HCCI, SACI, Stoichiometric combustion or Lean combustion?

We have different teams approaching the problem differently

‣ Can ICE achieve CARB emissions limits?

– Can methane emissions be reduced using Methane oxidation

catalyst (MOC)?

– How much will be the cost penalty of After-Treatment system?

‣ How much impact will thermal barrier coatings have?

– Are they durable?

– What is the ideal thickness and will it only lead to higher

exhaust energy?

‣ Can the oil change intervals be reduced (low O&M cost)?

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Open Questions: Stirling Engines

‣ Can the combustor be effectively integrated with the Stirling

engine?

– If so, is a combustor efficiency north of 85% feasible while

being cost effective at such a scale?

‣ What should be the ideal recuperator cost-to-effectiveness

tradeoff?

‣ Is an engine efficiency (heat to mechanical work) north of 45%

feasible at 1 kW scale?

– What is the not-to-exceed heater head temperature for 10 year

life?

‣ Can the combined alternator and power electronics efficiency for

FPSEs be north of 90% while being cost-effective

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Open Questions: Microturbines

‣ What should be the ideal recuperator cost-to-effectiveness

tradeoff?

‣ Are compressor and expander efficiencies north of 75% feasible

at such a scale?

‣ Can the compressor and expander be cost-effectively

manufactured at the required tolerances?

‣ Will the turbomachinery components survive for 10 years?

‣ Can the combined alternator and power electronics efficiency be

north of 90% while being cost-effective

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Open Question: T2M

Who will be the Market Makers for µ-CHP?

‣ HVAC

– Traditional HVAC companies are highly competent in and familiar with HVAC technology, customer, supply chain, etc.

• Existing sales & service infrastructure ideal for market entry

– How will they consider the risk of behind the meter (BtM), electrical generation that requires a relationship with the Utility?

• Will conservative HVAC companies look to take any technology risk?

‣ DER Electrical

– New entrants in BtM (Solar City) for the Residential/Commercial market may be better suited to consider µ-CHP as part of a suite of products

– More innovative on financing options

-> As CHP systems get larger and address front-of-the-meter opportunities, this differentiation becomes more important

22

High- Level Lessons from GENSETS after Year 1

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‣ Design and analysis of several teams show potential to achieve

35-40% fuel-to-electricity conversion efficiency.

– Predictions yet to be vetted by testing. Year-2 technical effort

should focus on prototype development and demonstration for

independent testing

‣ Several teams may need a high efficiency and cheap compressor

for natural gas compression for boosting engine efficiency →

Parasitic loss and cost penalty

‣ Several teams show initial cost estimates exceeding $3,000/kWe

– Year-2 effort should focus on device-level techno-economic

analysis

Meeting Agenda

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Core Technology

•Combustor Designs for Small-Scale CHP (Peter Therkelsen, LBNL)

•Aisin 1.5kW Internal Combustion Engine CHP (Yoshi Sekihisa, Aisin)

Testing and Certification

•UL 2200, Utility Interactive Engine Generator System Assemblies (George Langton, UL)

•NREL Energy Systems Integration Facility (ESIF) (Ben Kroposki, NREL)

HVAC Integration

•HVAC Integration for Residential and Light Commercial Applications (Richard Lord, UTC CCS)

•Thermally Activated Technologies (Craig Walker, UTRC)

•Building Technologies Office – Perspectives on µ-CHP (Antonio Bouza, DOE-BTO)

General T2M

•DER Technology to Market / Device-level TEA (John Tuttle, ARPA-E)

•Utility Perspective on DERs (Noah Meeks, Southern Company)

•Additional Revenue Potential for Behind the Meter DG (Richard Fioravanti, Exponent)

• Insights on the Global Micro-CHP Market (Steven Ashurst, Delta-EE)

Early Markets

•E2S2 Needs for Small Generators (Chris Bolton, Army E2S2)

•ONR needs for Small Generators (Billy Short, ONR)

•Stranded Natural Gas for Distributed Power Generation (Ben Azar, Blackbird O&G)

• Team presentations and poster session - Day-1

• Panel to discuss market makers for µ-CHP - Day-2

• NREL ESIF tour - Day-2