Preliminary Design & Analysis of Low-Cost

Concentrating Offshore Solar Energy Innovations

SOLAR 2018

Mithra Sankrithi

drsankrithi@gmail.com

RIC Enterprises

Preliminary Design & Analysis of Low-Cost Concentrating Offshore Solar Energy Innovations

Dr. Mithra Sankrithi CEO, RIC Enterprises

Synopsis

Innovations in offshore floating solar energy systems will be presented that cost-

effectively leverage simple, low risk & elegant configurations for synergistically

harvesting electricity & usable heat. Preliminary designs along with technical & cost

analyses will be presented for several systems suitable for private owners, public or

commercial waterfront entities, utility-scale applications & enabling applications for

cities with 100% renewable goals. Examples include use of low-cost inflatable

subsystems for low-concentration reflectors, low-cost dual-axis tracking for a floating

array, and CPV liquid cooling that can also transfer usable heat for hot water, building,

swimming pool or process heat as well as desalination.

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If Antarctic & Kalaallit Nunaat Icecaps Melt, Sea Level Rises 79 Meters

Low LCOE Offshore Solar Systems Can be Instrumental in Preempting this Scenario

http://www.dailymail.co.uk/sciencetech/article-2609338/Would-YOU-underwater-

polar-caps-melted-Map-reveals-planet-look-like-sea-levels-rose-260ft.html

A WORST-CASE CLIMATE CHANGE SCENARIO ?

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➢ Forecast 2040 mean rate of world energy consumption ~ 27,300 GW; Forecast electric production ~ 4,170 GW

➢ Solar radiation at Earth’s surface ~ 90,000,000 GW

➢ Recoverable solar power > 1,000,000 GW far exceeds human needs

➢ 71% of Earth’s surface is water !

World Solar Radiation, Center for

Global Development,

http://www.cgdev.org/userfiles/imag

e/blog/solar%20radiation.jpg

Outlook 2016 ”

https://www.eia.gov/outlooks/ieo/world.cfm

https://www.eia.gov/outlooks/ieo/electricity.cfm

https://water.usgs.gov/edu/earthhowmuch.htm

Boyle, Godfrey, Renewable Energy – Power for a Sustainable

Future, Oxford University Press, Oxford, England, 2002

THE SOLAR OPPORTUNITY

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➢ U.S. kW-hr/sq.m./day =

average daily hours

direct radiation with two-

axis tracking

➢ Usable solar resource

through most of the U.S.

THE SOLAR OPPORTUNITY

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http://www.akenergyauthority.org/Useful%20pics/solar/Alaska%20Annual%20Solar%202-Axis%20Track%20Big%20Ima.jg

THE SOLAR OPPORTUNITY

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… even Alaska!

THE SOLAR OPPORTUNITY

http://www.irena.org/publications/2018/Jan/Renewable-power-generation-costs-in-2017

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Low Levelized Cost

of Energy (LCOE) is

critical to accelerated

replacement of fossil

fuel energy

Over 25 million square kilometers of ocean are in “sufficient” insolation areas for Concentrating

Offshore Solar (COS) Systems, within the 200 nmi “Exclusive Economic Zones” of the nations of

the World. Use of just 3% of this area is more than sufficient to meet 100% of forecast

human energy needs of around 240,000 terawatt-hr per year for 2040.

https://www.nationstates.net/page=dispatch/id=545595 “ International Energy Outlook 2016 ”

https://www.eia.gov/outlooks/ieo/world.cfm

100% RENEWABLE WITH ZERO LAND USE ?

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The 13.7MW floating solar PV plant on the Yamakura Dam reservoir, Chiba Prefecture, Japan.

50,904 Kyocera solar modules on Ciel et Terre Hydrelio floating HDPE platforms.

Estimated generation 16,170 MWh per year.

https://www.pv-magazine.com/2018/03/27/kyocera-jv-inaugurates-13-7-mw-floating-pv-plant-in-japan/

https://spectrum.ieee.org/energywise/energy/renewables/japan-building-worlds-largest-floating-solar-power-plant

https://www.thenational.ae/business/energy/japan-s-biggest-floating-solar-plant-sparks-into-life-1.718330

TODAY’S OFFSHORE SOLAR - EXAMPLES

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150 MW floating solar PV plant at Huainan City, Anhui Province, China.

Three Gorges New Energy $151 million project ($1 million / MW)

https://www.pv-tech.org/news/worlds-largest-floating-solar-plant-comes-partially-online-in-china

https://www.thenational.ae/business/energy/japan-s-biggest-floating-solar-plant-sparks-into-life-1.718330

TODAY’S OFFSHORE SOLAR - EXAMPLES

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http://task55.iea-shc.org/Data/Sites/1/publications/SDH%20Inspiration%20Experience%20DK%20v5.pdf

SOLAR DISTRICT HEATING – DANISH EXAMPLE

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Current solar paradigm uses rural land

Could a future paradigm go offshore?

PRAGMATIC INNOVATIONS TO ENABLE:

Capital Cost Reduction & ‘LCOE’ Reduction

Cogeneration of Electricity & Usable Heat

Energy Storage for Nights & Periods of Cloud-cover

Increased Capacity Factor & Increased Efficiency

Synergistic Services including Hot Water, Space Heating, Pool Heating, District Heating & Cooling, Process Heat & Desalination

Synergistic Integration with Offshore Wind, Tidal / Ocean Current Energy, Wave Energy & Ocean Thermal Energy Conversion (OTEC)

Robust, Reliable, Maintainable, Weather & Storm Tolerant

Cost-Effective Service to Cities & Jurisdictions with 100% Renewable Goals

TOMORROW'S OFFSHORE SOLAR – GROWTH ENABLERS

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RIC Enterprises Solar Paradigm-Shifting Inventions

Claims value benefits from the

synergistic combination of:

➢ Linear CPV @ ≥ 2 suns

➢ 1 or 2 axis Sun-tracking

➢ Inflatable structure with a

transparent top that protects a

simple linear concentrating

reflective surface

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Low-Cost enablers include:

Use of a low-concentration photovoltaic subsystem, e.g. 5 to 10 suns, with cooling

kWe / Sq.m. of PV receiver can increase by ~ 400% to 800%PV receiver cost / kWe can decrease ~ 70% to 80%

➢ Use of low-concentration (5 to 10 suns) enables cost-effective simple & robusttracking and cooling subsystems; cost-effective silicon solar photovoltaics

➢ PV subsystem cost savings can be somewhat offset by costs of concentration andheliostatic tracking subsystems

Use of a low-cost inflatable concentration subsystem with a framed membranelinear concentrating reflector with an inflatable upper volume and transparentmembrane protective cover

Relative to a typical steel & toughened glass concentration mirror:

➢ Concentration subsystem weight & capital cost can decrease ~ 50% to 80%➢ Concentration subsystem cleaning & repair costs can decrease ~ 60% to 90%

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PROTOTYPE PROGRESS – INFLATABLE HELIOSTAT

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PROTOTYPE PROGRESS – ‘SURYA’ DEMONSTRATOR

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PROTOTYPE PROGRESS – ‘SURYA’ DEMONSTRATOR

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Low-Cost enablers include:

CPV liquid cooling that also transfers usable heat for hot water, home or building spaceheating, swimming pool heating, solar cooling or process heat including solar desalination.

➢ Harvested energy increases from ~ 12% - 22% to ~ 60% - 80% of insolation➢ Usable heat in kWt can be ~ 300% to 500% added harvest over electricity➢ Cogeneration system cost may increase ~ 15% - 30% over pure electric CPV system

LCOE cost can be reduced 10% - 20% even relative to simple rooftop solar panels

Assumptions:➢ 75% of harvested energy is usable heat➢ capital cost up from $2100/kW to $3000/kW➢ capacity factor up from 18% to 35%➢ O&M costs triple➢ Using the NREL Simplified Life Cycle Cost of Energy (LCOE) calculator

NOTE: Because of many complexities in the business case analysis of cogeneration systems,an NPV business case analysis of alternatives is a recommended best practice.

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RIC Enterpriseshttps://www.cibsejournal.com/cpd/modules/2017-09-dhw/

Example of an NPV analysis of alternativesSpace Heating + Domestic Hot Water for Two Student Accommodation Buildings (643 Occupants)

BACKGROUND INFORMATION LEVEL-SETTING

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BACKGROUND INFORMATION LEVEL-SETTING

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‘SuperSurya’ Low-Cost Solar Concentrating Cogeneration System

Concentrating Reflector

CPV Solar Receiver

Azi

mu

th &

Ele

vati

on

Co

ntr

ol

ETFE Cover Above Inflatable

Roof

Base Support Pipe

Support Post

Base Legs

Co

nce

ntr

atin

g

Ref

lect

or

Reflector Rib

Roof

End Support

ETFE Cover

Above Inflatable

Upper Frame

Key Design Drivers:

• Harvest 15-20% of Solar Electricity Plus 50-60% for Usable Heat

• Sturdy, Simple, Reliable, Easy to Maintain and Cost-Effective

• Tolerant of Rain, Snow, Hail, Wind & Storm Conditions

• Residential, Commercial, Public Service Building or Utility Uses

• Rooftop or Ground Mounting

Target Design Features & Metrics:

• 10.5 sq.m. Sun Receiver Area; 6.5 Suns Concentration

• Sun Sensor Guided 2-Axis Heliostatic Tracking

• 7 kW rated power with 1.75 kWe plus 5.25 kWt

• Usable Heat for Hot Water, Space Heating &

Optional Swimming Pool Heating

Electric Output

Heat Transfer Fluid Output

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Upper Frame

Support Post

CPV Solar Receiver

Estimated LCOE 9.6 c/kW-hr

➢ Size to 1.75 kW electricity plus 5.25 kW usable heating @ 65 – 75o C

➢ Meet typical electricity, hot water & heating needs with 1-2 SuperSurya modules & net-metering

➢ Length < 19’4” to enable transport in standard 20’ container

➢ Low-concentration ratio enables cost-effective liquid-cooled Si solar cells

➢ Framed inflatable concentrating reflector modules with ETFE self-cleaning covers

➢ Modular design for low-cost transportation, installation, maintenance & repair

➢ Sun-sensor and two-axis actuators for elevation and azimuth control

➢ Aluminum welded structure for low cost, strength and aesthetics

➢ Base structure adapts easily for roof or ground mounting

SUPERSURYA CONFIGURATIONFeatures to Maximize Value for Home Rooftop Use

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Economic Drivers For Efficient Concentrating Cogeneration Offshore Solar (ECCOS) Systems

➢ Majority of solar energy falls offshore

➢ Offshore design avoids displacement of land use

(for food production, housing, public benefit, industrial or commercial purposes)

➢ Maximizes % sunlight harvested for beneficial use by:

- synergistically combining CPV and solar thermal electric power subsystems

- cogenerating added-value outputs: usable heat & desalinated water

➢ Innovative architecture including lightweight framed membrane reflectors & inflatable structures

enables low cost through simplicity, reliability, maintainability, modularity & upgradability

➢ Robust, weather-tolerant and scalable designs enable small, medium, large and ultra-large solar harvest systems with worldwide applicability

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RIC Enterprises Solar Paradigm-Shifting Inventions

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Claims value benefits from the

synergistic combination of:

➢ Connected array of inflatable

linear heliostatic CPV modules

with fluid cooling

➢ Harvest of electricity and usable

heat in heat transfer fluid

➢ Optional floating array with

azimuth rotation

➢ Optional solar thermal subsystem

for added electric generation

➢ Optional integration with offshore

wind, ocean/tidal current, or

ocean thermal energy

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Low-Cost enablers include:

Use of heliostatic azimuth control by rotating an entire floating array ratherthan individual solar modules

Number of azimuth control actuators decreases by ~ 50% to 99.9%Azimuth control subsystem cost decreases by ~ 40% to 99%

Offshore installation yields elimination or near-elimination of land cost,partially offset by floatation, anchoring and underwater transmissionsubsystems

Mini-Scale ECCOS System

Innovative simple robust design

5 kWe + cogenerated 10 kWt

Suitable for grid-connected or off-grid applications

CPV electricity plus usable heat- solar hot water tank- solar building heat- swimming pool heating

Efficient, cost-effective, no land use

Rain or Spray wash to clean

Solar Modules inverted stow for storm survival

Modular design for easy replacement of modules

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Estimated LCOE 10.6 c/kW-hr

Mini-Scale ECCOS System for Residential & Rural Users –

Example Locations

Farm on Small Lake, Nepal

Riverfront Homes, California

Source: Google Maps

RIC Enterprises Lake Homes, Switzerland

Array of Mini-Scale ECCOS Systems

Ideal For Community, Commercial & Small Industrial Users

Array of low-cost mini-scale systems

(or small-scale systems)

Perimeter wave & safety boundary

CPV electricity plus usable heat

Rectangular, hexagonal or triangular arrays

Efficient, cost-effective, no land use

Modular design

Shippable in standard containers by sea, rail, road

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Estimated LCOE 9.6 c/kW-hr

Array of Mini-Scale ECCOS Systems Ideal For Community,

Commercial & Industrial Users -Example Locations

Rural America – Oklahoma Example

Source: Google Maps Urban America – Seattle Example

Hospital and Buildings, Cairo, Egypt

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Riverfront Industrial, Educational, Residential, India

Source: Google MapsMixed-Use Waterfront, Australia

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Array of Mini-Scale ECCOS Systems Ideal For Community,

Commercial & Industrial Users -Example Locations

SMALL-SCALE / PROTOTYPE ECCOS SYSTEM

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MEDIUM-SCALE ECCOS SYSTEM WITH DESALINATION

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Estimated Equivalent LCOE 10.2 c/kW-hr

Assuming value of desalinated water

equivalent to value of kWt -hr to

produce it using low temperature desalination

ENABLE LOW TEMPERATURE DESALINATION

http://www.gwpc.org/sites/default/files/event-sessions/Gude_Veera.pdf

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Offshore low-temperature desalination technologies have already entered service in India.

A promising variant applicable to ECCOS Systems uses heat from solar energy for an efficient , simple multi-stage low-temperature desalination process:

“Solar-Powered Multi-Stage Natural Vacuum Low Temperature Desalination Process,” J. Steinwinder & E. Martinez-Guerra, Mississippi Water Resources

Conference, April 2016

http://www.wrri.msstate.edu/conference/pdf/steinwinder_jeff2016.pdf

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Low-Temperature Desalination Technology

for ECCOS Systems

MEGA-SCALE ECCOS SYSTEM

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25 MWe from CPV plus

65 MWt for district heating / cooling

with optional steam cycle 5-10 MWe for baseload

Tethered barge with power conditioning equipment;

Thermal storage tanks (0, ambient, 70, 95, 140- 600);

Steam powerplant; Solar cooling absorption chillers;

Monitoring, control, maintenance & repair equipment

Underwater cables and insulated piping

connecting to landside electrical customers,

district heating and cooling customers,

commercial customers, industrial customers,agricultural customers, public sector customers

Estimated LCOE 5.6 c/kW-hr

Best Economics for

Waterfront Cities

MEGA-SCALE ECCOS SYSTEM Rankine (Steam) Cycle Subsystem Can Supplement CPV Subsystem

https://www.ohio.edu/mechanical/thermo/Applied/Chapt.7_11/Chapter8a.html

https://www.researchgate.net/publication/223824147_Modelling_of_Parabolic_Trough_Direct_Steam_Generation_Solar_CollectorsRIC Enterprises

Options range between:

➢ Low Temperature & Pressure steam subsystem leveraging geothermal generation technologies -

130oC low thermodynamic efficiency but simple, robust & cost-effective supplement to CPV electricity,

that can also support base load in conjunction with insulated tank thermal storage

➢ Direct Steam Generation (DSG) subsystem, up to 600oC for high thermodynamic efficiency (but at a cost)

can also be combined with optional high temperature In1-xGaxN CPV subsystem

MEGA-SCALE ECCOS SYSTEMS – EXAMPLE LOCATIONS

San Francisco Bay Area

Use of just 2% of bay water areas (8 sq.mi.) can accommodate 200 Mega-Scale ECCOS Systems:

• 5 GWe from CPV plus

• 13 GWt for district heating / cooling

• plus optional steam cycle 1-2 GWe for baseload

• avoided land cost ~ $10 billion @ $2 million / acre

Mean electricity consumption by County (GWe )San Francisco 0.66

San Mateo 0.50

Santa Clara 1.92

Alameda 1.23

Contra Costa 1.10

Solano 0.37

Sonoma 0.34

Marin 0.15

Total Bay Area 6.27

ECCOS Systems plus some thermal and electricalstorage could plausibly meet 100% Bay Area energyneeds with low risk, lowest-cost-renewable generationwhilst avoiding land use.

Sources: Google Maps,

Rand McNally Road Atlas

http://ecdms.energy.ca.gov/elecbycounty.aspx

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MEGA-SCALE ECCOS SYSTEMS – EXAMPLE LOCATIONS

Chicago Area (with unfrozen ring perimeter

bubbler / de-icer for winter operations)

Source: Google Maps

Great Salt Lake & Salt Lake City area, Utah

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MEGA-SCALE ECCOS SYSTEM – EXAMPLE LOCATIONS

Orlando, FloridaSource: Google Maps

New York City, New York

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MEGA-SCALE ECCOS SYSTEM – EXAMPLE LOCATIONS

Singapore

Source: Google Maps

Guanabara Bay, Rio de Janeiro, Brazil

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Istanbul, Turkey

ULTRA-LARGE OPEN OCEAN UTILITY-SCALE ECCOS SYSTEM

Plan View

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Tethered barge with power conditioning equipment;

Thermal storage tanks; Steam powerplant; Monitoring,

control, maintenance & repair equipment; Optional

desalination; Optional hydrogen generation.

Estimated LCOE 5.5 c/kW-hr

Best-in-Class LCOE for

Offshore Renewable Energy

ULTRA-LARGE UTILITY-SCALE ECCOS SYSTEM –EXAMPLE LOCATIONS

Salton Sea, California

Source: Google Maps

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Delaware Bay

Laguna Madre, Texas

ULTRA-LARGE OPEN OCEAN UTILITY-SCALE ECCOS SYSTEM –EXAMPLE LOCATIONS

Pacific Ocean, Southern CaliforniaSource: Google Maps

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ULTRA-LARGE OPEN OCEAN UTILITY-SCALE ECCOS SYSTEM –EXAMPLE LOCATIONS

Gulf Of Mexico, USA and MexicoSource: Google Maps

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ULTRA-LARGE OPEN OCEAN UTILITY-SCALE ECCOS SYSTEM –EXAMPLE LOCATIONS

Mediterranean Sea & Black Sea, Europe, Africa and Asia

Source: Google Maps

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ULTRA-LARGE OPEN OCEAN UTILITY-SCALE ECCOS SYSTEM –EXAMPLE LOCATIONS

Persian Gulf, UAE

Source: Google Maps

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Arabian Sea, India

ULTRA-LARGE OPEN OCEAN UTILITY-SCALE ECCOS SYSTEM –EXAMPLE LOCATIONS

Pacific Ocean, South China Sea, China and East AsiaSource: Google Maps RIC Enterprises

ECCOS Systems Synergistic With Other

Renewable Technologies

To achieve increased capacity factor and even more LCOE reduction relative to best-in-class utility-scale ECCOS Systems, these ECCOS Systems can, in selected geographic locations, be synergistically integrated, with shared placeholding & transmission infrastructure, with:

Offshore wind energy technologies

Ocean and tidal current technologies

Ocean thermal energy conversion (OTEC)

Transmission technologies including high voltage / superconducting power lines

and insulated piping for district heating and cooling

Storage technologies including thermal storage, phase change storage, seasonal storage,

batteries, hydrogen, pumped hydro, etc.

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SYNERGY OPPORTUNITIES FOR ECCOS SYSTEMS WITH

VERTICAL AXIS OFFSHORE WIND & OCEAN / TIDAL CURRENT SYSTEMS

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SYNERGY OPPORTUNITIES FOR ECCOS SYSTEMS WITH OFFSHORE WIND

http://renewableenergyst.org/wind.htm

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SYNERGY OPPORTUNITIES FOR ECCOS SYSTEMS WITH

TIDAL CURRENT ENERGY & OFFSHORE WIND

http://bayoffundy.blogspot.com/2008/10/nifty-bay-of-fundy-tide-height-map.html

100 billion tonnes of seawater flow back and forth every day in the Bay of Fundy

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Target

Best-in-Class

LCOE for

Bay of Fundy

SYNERGY OPPORTUNITIES FOR ECCOS SYSTEMS WITH

GULF STREAM CURRENT ENERGY & OFFSHORE WIND

https://www.cruisingworld.com/changes-in-gulf-stream

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Target

Best-in-Class

LCOE for

Eastern Seaboard

from Florida

to the Carolinas

SYNERGY OPPORTUNITIES FOR ECCOS SYSTEMS WITH

OCEAN THERMAL ENERGY CONVERSION (OTEC)

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Target

Best-in-Class

LCOE for

Hawaii

Enable Hawaii

to achieve

100% renewable

energy without

land use

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Efficient Concentrating Cogeneration Offshore Solar (ECCOS) Systems Can Play a

Key Role in Fulfilling 100% Renewable Goals for Cities, Counties, States & Nations

https://www.sierraclub.org/ready-for-100/commitments

Preliminary Design & Analysis of Low-Cost Concentrating

Offshore Solar Energy Innovations

SOLAR 2018

Questions? Comments?

RIC Enterprises Welcomes Collaborations to Accelerate Beneficial Implementations of

Efficient Concentrating Cogeneration Offshore Solar (ECCOS) Systems

Thank You!

Mithra Sankrithi

drsankrithi@gmail.com

RIC Enterprises