Water-Energy Nexus: Can Innovative (nano)

Technology Provide Solutions?

Shaurya Prakash

Department of Mechanical Engineering

The Ohio State University

WIA – Water Infrastructure Summit

May 18, 2012

Societal Operations

Water

Materials Food,

agriculture

Energy

Functional modern society

Economic development

Environment

sustainability

Health and Wellness

Security

Water and Energy are Interdependent

• Thermoelectric

cooling

• Hydropower

• Energy

minerals

extraction/

mining

• Fuel Production

(fossil fuels, H2,

biofuels)

• Emission control

• Pumping

• Conveyance

and

Transport

• Treatment

• Use

conditioning

• Surface and

Ground

water

Michael Hightower, Sandia National Labs, 2010

Energy and power

production require water

Water production,

processing, distribution, &

end-use require energy

United States Water Usage

Public and Self-supplied Potable Water

40,738.5 (12%)

Industrial-Mining 27,159.0-

(8%)

Irrigation-Livestock 139,189.7 MGD

(41%)

• Total water withdrawn per year 123.9 trillion gallons, which is ~ yearly

outflow of Mississippi river

• Direct energy demands (TE power generation) currently accounts for

~ 39% of all water withdrawal

Water Withdrawn in the US for All Uses

Thermoelectric Power

132,400.0 (39%)

“Consumptive Water Use for U.S. Power Production,

P. Torcellini, et.al., National Renewable Energy Laboratory, 2003.

Energy Consumes Water

• Coal use for generation increases water loss by

33% over natural gas and nuclear

• Coal to H2 doubles loss rate over some other

methods

• “New” sources of energy (biomass, syngas,

hydrogen) will more than double current use per

gallon or kW hr (3-5 gal. H2O/gal ethanol)

• Total water withdrawals expected to increase by

TWO orders magnitude with new energy

Courtesy: Mark Shannon, U. Illinois

Impact on Energy

Without sufficient water:

Transfer to a hydrogen economy will be challenging

Biomass and clean coal derived fuels will be impacted adversely

Cannot get to shale oil/gas without lots of water

• US is Saudi Arabia of shale oil/gas

• Hydraulic fracturing requires 3-5 million gallons per well

Plug-in hybrid vehicles will be impacted

Courtesy: Mark Shannon, U. Illinois

Trends Making Problems Worse

Population Growth (>1% per year )

Population Shifts to Urban Areas: Changes and increases demand in water, food, and energy • Local problems growing

• Logistics for distribution, management, maintenance will only get harder

Over-pumping of Ground Water Aquifers

Cannot generate more energy and food without sufficient water. Cannot get a lot more water without energy

Increasing contamination of source waters – more treatment is needed • Finite (and increasing) energy costs

• Emerging contaminants

Current centralized water infrastructure is capital, energy, and chemically intensive

Challenges to water use and sustainability driven by:

Courtesy: Mark Shannon, U. Illinois

How Do We Meet These Challenges?

Water-energy nexus is a challenging problem • Can we innovate our way out?

• What tools do we have at our disposal to make the path forward easier?

Several technology advancements can be exploited • IT, Sensors, Material Science, Heterogenous Chemistries,

Systems Engineering, Manufacturing, Physics of the Nanoscale, Smart Grid Technologies, Distributed Infrastructure, …

Nanotechnology examples for illustration of possible innovations to solve Water-Energy challenges

Why Nanotechnology?

Nanotechnology provides unique opportunities

• Nanotechnology operates at same length scales as many natural laws that govern water processes

• Therefore, can contribute disruptive technologies by manipulating the basic building blocks of materials and systems

~1.6 nm

Next generation NF, RO membranes

being developed at OSU, LLNL, Illinois,

Siemens, GE for high flux applications.

Critical dimensions range from 1-100 nm

But, Is New S & T Needed for Water?

Technologies focused on either energy or water coupling not explored

• e.g., takes 3-5 gal/water to refine 1 gal/ethanol from corn

• ~ 1000x times more to grow the corn

Do we have enough technology to meet future demands?

• Let’s start with the prevailing wisdom:

• “We have more technologies than we need”

• Most new techs sit on the shelf

• What we need is better management and distribution of water

• Full cost pricing will fix the problems

In the Ideal World, Water Purification Will…

Use chemicals as needed: move away from homogeneous

chemical mixer systems to heterogeneous chemistry

systems: catalysts, separators, absorbers, membranes

(passive and active), biochemical, nanotechnology,…

Wastewater is Resource-water: Recovery of chemicals

from wastewater – nutrients, ammonia, methane,…

Less exogenous energy: More use of sunlight, recovery of

energy from wastewater, harvesting pressure, microbial

fuel cells for wastewater…

Sustainability from nature: develop bio-inspired processes

for detection of contaminants and pathogens (including

viruses) in water, separation of contaminants and salts,

bio-remediation of solids in wastewater, …

Opportunities for Innovation

Basic science

Conservation

Public-private

partnerships

Economic opportunities in

emerging markets

Technology development

Systems development

Implementation to

central infrastructure

Creation/implementation to

point-of-use infrastructure

Water-energy sustainability

Desalination Energy Needs

Current water desalination methods can be energy intensive

Process MSF MED/TVC RO ED*

Heat Consumption (kJ/l) 290 145-390 -- --

Electricity Consumption (kJ/l) 10.8-18 5.4-9 9-25.2 4.32-9

Total Energy Consumption (kJ/l) 300.8-308.8 150.9-399 9-25.2 4.32-9

Typical Production Capacity (m3/day) ~ 76,000 ~ 36,000 ~ 20,000 ~ 19,000

Conversion to Freshwater 10-25% 23-33% 20-50% 80-90%

Pretreatment required little little demanding moderate

* For brackish water

We are far from the natural law limits for separating contaminants from water:

Currently at 4-100X times higher for nearly all methods

Lots of room to improve!

Prakash, S. et al., in Bionanotechnology II, CRC Press, 2011, Reisner, D. (Ed.)

Nanotechnology Solutions for New Desalination Systems

Biological systems are close to the these limits, and operate at the nanoscale

New water purification technologies using point-of-source supply, point-of-discharge, and point-of-use systems: The new (oldest) paradigm in infrastructure

New technologies can greatly improve how clean water is supplied and sanitation discharged – Can change everything

Kim, S. J., S. H. Ko, K. H. Kang, and J. Nature Nanotechnology 2010

Chip-scale system at MIT to

deliver de-salted water from

seawater at a fraction of the

energy cost

First generation lab device at OSU

inspired by biology for desalination at

thermodynamic limits Prakash, S. et al., in Bionanotechnology II, CRC Press, 2011, Reisner, D. (Ed.)

Paradigm Shift: Wastewater is Resource-

Water – Extract Energy

U.S. municipal wastewater contains 7.2x109 kg of “dry solids”

annually

• ~ 25 MJ/kg (7 kW.hr/kg) of energy content

• Total energy available ~2x1017 J (51 billion kW.hr)

Currently, most municipalities do not generate energy from bio-

solids:

• 49% treated & applied to land, 45% incinerated or landfilled, 6%

to other

U.S. 2008/2009 electrically generated: 14x1018 J

Energy content in wastewater is ~ 2% of US electrical demand

Total Energy in US ~ 97% comes from thermal sources (coal, oil,

nuclear, etc.) WW can nearly match all other methods (wind,

solar, etc.)

Integrated Anaerobic Digester for Bio-

Ammonia Harvesting

Harvest bio-gas (methane) and

ammonia

Integrate with anaerobic digester

with novel thermophilic microbes

resistant to high ammonia

concentration

Integrate with fuel harvesters

40% total enhancement in energy

with hydrogen from ammonia in

addition to methane possible!

Prakash, S., et al. (2012)

Summary and Conclusions

• Water and energy form a coupled problem

• Cannot solve one without the other

• Technological innovation through R&D can provide one

pathway to solutions, but

• To solve:

• All pieces of the puzzle must come together including:

• Funding local, federal, private

• Science and technology development

• Economically feasible partnerships

• Infrastructure updates and development

Questions and More Information

Thank you!

Further Information:

Shaurya Prakash

prakash.31@osu.edu

http://www.mecheng.osu.edu/lab/mins