1. “California’s Water-Energy Nexus, the role of Natural Gas Engines.”
Urban Water Institute
February 21st, 2013
Ranjiv Goonetilleke P.E.
Certified Energy Manager
Principal Engineer, SoCal Gas Co.

2. Outline Energy Supply/Pricing
Foundation Fuel that mitigates the intermittency of renewable energy sources
Natural Gas Engines benefits and challenges
CO2 Capture & Algae Cultivation Concentrated Solar Power
Life Cycle costs

3. Shale Gas and Alaska drives supply growth
trillion cubic feet
Alaska
Projections
History
Associated with oil
Coalbed methane
Net imports
Non-associated onshore
Shale gas
Non-associated offshore
Non-associated offshore
Source: EIA Annual Energy Outlook 2010

4. Energy Prices – Gas vs. Electricity
$ / MMBtu
Electricity
Natural Gas
Note that natural gas prices have fallen since this slide was created.
As of August 2012, gas prices are less than $3/MMBtu.
Source: EIA Energy Prices by Sector and Source, United States, AEO2011 Reference Case, Industrial Sector nominal prices
1/ Includes energy for combined heat and power plants, except those whose primary business is to sell electricity, or electricity and heat, to the public.
2/ Excludes use for lease and plant fuel.

5. Natural Gas Driven Engine vs. Electric Motor
Consider a HP- Hr,
By definition, the physical constants
Electric
Motor
Natural Gas
Engine
1 HP =
.746 kW
Therms
Efficiency
95%
36% w/o waste heat
Energy Input
(per HP-Hr)
.785 kWh
Therms
Unit Cost
$0.12 / kWh*
$0.50 / Therm
1 HP-Hr
= $0.0942
= $0.0354
In this scenario, Natural Gas represents a 62% savings
2/23/2019

6. Transitioning to a clean & sustainable energy economy
It’s notable that 35% of electricity is driven by natural gas prime movers.
Comparable to water pumping w/natural gas, but efficiency gains are available by direct drive w/variable speed as opposed to fixed speed electric motors.
Hydro is a significant component of CA’s power and is predominantly attributed to DWR’s plants.
This energy has zero GHG footprint and requires no offsets.
Any freed up hydropower becomes a valuable commodity on the open market.

7. Compiled from data in CPUC Study2
Just 7 Water & Wastewater Agencies Alone Contributed to 93MW of SCE’s peak demand in 2008
The seven agencies contributed 93 MW, the coincident water related demand for all the agencies in Southern california may well exceed 1,000 MW.
Water & wastewater agencies have more flexibility to change the amount, time and place of their electric use
Reducing on-peak demand could eliminate need for power plants that are only used about hours per year
New, efficient gas engines would help electric reliability and accelerate shutdown of old, inefficient fossil fuel power plants, reducing GHGs.
Not surprisingly, most groundwater pumping occurs during hot summer months in which electric demand is at it’s highest.
Compiled from data in CPUC Study2

8. Natural Gas Engines Industrial Grade Engines
Internal Combustion, Rich/Lean Burn
30 to 40 year life

9. Tehachapi- Cummings
Uses Natural Gas Engines to pump water more than 3000 feet from the Central Valley
Notes From Interview w/John Martin – General Manager of Tehachapi-Cummings
SWP from turnout just prior to Edmonston gravity feeds to Pump Plant 1
Each pump plant as (4) motors and (4) engines w/max of (3) on at any given time
Pump Plant 1 to Pump Plant 2 is 1,035 feet – Waukesha V12
Pump Plant 2 to Pump Plant 3 is 1,035 feet – Superior L6
Pump Plant 3 to Stallion Springs is 1,035 feet with gravity feed pressure zone 1 (Cummings Basin) for retail use, groundwater recharge and Pump Plant 4 – Superior L6
Pump Plant 4 pumps 350ft to reservoir which serves pressure zone 2 (Tehachapi Basin) – (3) Superior L6 and (1) Waukesha V12
Reservoir above pressure zone 2 gravity feeds to the zone and sometimes flows back down to pressure zone 1
Flow meters aren’t accurate and don’t totalize
Studies have shown EI of about 50 therms/AF
Wholesale to:
City of Tehachapi
Bear Valley CSD
Stallion Springs CSD
Golden Hills CSD
Tehachapi-Cummings is water master for much of the area

10. Schematic: Integrated System Solution
Pump
CO2 Capture
HRSG
Steam
PhBR/CSP
Condensate
Natural
Gas
Exhaust
Algae Byproducts:
Biofuels
Nutraceuticals
Animal Feed
Electric Power
Engine – 18MW; 24000hp
Waste heat from exhaust steam is 2.8 MW
CO2 bubbling into water to photobioreactor (Phbr) ~ 247 acres
Concentrated solar close to NG engine capacity
NG Engine/Pump = operational benefit
Recovery = Environmental benefits
This is what the director of the DWR requested by SCG. Variable speed solution with a renewable energy component and a way to mitigate the intermittency of renewable energy. (ref. RG)
Animal feed
Biodiesel
Examples of final product from Algae process
PhBR –Photo Bio Reactors, CSP- concentrated solar power

11. Algae Growth & CSP System
Photo bio-reactors (PhBR) float in shallow pools
0.5 ft diameter
1,000 ft long
Concentrated solar power
Flexible plastic tube photo bioreactors (PhBR)
Benefits
Renewable energy supply
Beneficial CO2 recycling
Revenue from algae sales
Algae Revenue
Animal feed
Nutraceuticals
Fuel production

12. Summary of Benefits & Challenges
Energy cost savings
Increases Operational flexibility
Improves system reliability
Facilitates reliance on renewables
Stringent Air Quality Regulations
Increased initial capital costs
Requires diverse personnel

13. Life Cycle Cost Ranjiv Goonetilleke 562 -355-3899
2/23/2019