(498f) Ammonia Renewable Energy Fuel Systems at Continental Scale: Transmission, Storage, and Integration for Deep Decarbonization of World's Largest Industry at Lower Cost Than As Electricity

Authors: 
Leighty, W. C., The Leighty Foundation
We must soon “run the world on renewables” but cannot, and should not try to, accomplish this entirely with electricity transmission. New, abundant, low-cost, unconventional natural gas supplies are finite; burning adds CO2 to Earth's atmosphere.

Humanity's goal must be nothing less than: Transforming the world's largest industry from ~ 80% fossil to ~ 100 renewable, CO2-emission-free, energy sources as quickly as we prudently and profitably can.

We should now carefully consider using pipeline networks, rather than the electricity grid, for solving the three salient technical problems of renewable energy (RE) at lower cost:

1. Transmission: from diverse, stranded, remote, rich RE resources

2. Storage: intermittent RE becomes annually firm and dispatchable

3. Integration: with conventional, extant energy, for firm quality supply

Electricity systems are not well suited for gathering, transmission, storage, and delivery of time-varying solar, wind, and other renewable energy resources. The renewable energy industry should consider emulating the natural gas and ammonia industries, because:

1. Gaseous hydrogen (GH2) fuel may be stored in large, deep, solution-mined salt caverns for ~ $ 0.20 / kWh capital cost;

2. Liquid anhydrous ammonia (NH3) fuel may be stored in large, refrigerated, steel, "atmospheric" surface tanks for ~ $0.10 / kWh capital cost

We need to supply all energy, not just electricity, from diverse renewable energy (RE) resources, both distributed and centralized, where the world’s richest RE resources – of large geographic extent and high intensity – are stranded: far from end-users with inadequate or nonexistent gathering and transmission systems to deliver the energy. Electricity energy storage cannot affordably firm large, intermittent renewables at annual scale, while carbon-free gaseous hydrogen (GH2) and liquid anhydrous ammonia (NH3) fuels can.

Thus, we need to now investigate and plan for a diversity of complementary RE transmission and storage systems: media, fuels, and strategies. GH2 and NH3 are especially attractive. Transmission pipelines for both have multi-GW capacity over hundreds of km and provide valuable inherent storage. Capital costs per GW-km capacity, and transmission losses and costs per GWh-km, are comparable.

Therefore, we should now:

• Design and optimize complete RE systems, at local and continental

scales, from sunlight, wind, and water resources to dispatchable,

delivered energy services:

- Generation, Gathering, Firming storage, End use

- Conversion, Transmission, Combined-heat-and-power (CHP)

• Render annually-firm and dispatchable RE supplied, via very low capital cost storage, less than $US 1.00 / kWh:

- Gaseous Hydrogen (GH2) in large salt caverns, where geology is available

- Liquid Ammonia (NH3) in carbon steel surface tanks

- Interconnected via continental underground pipelines, adding storage

- Lower cost than any contemplated “electricity” storage components

• Design and build pilot plants for both GH2 and NH3 RE systems, by which to:

- Discover and demonstrate scaleable technical proof-of-concept and economics

- Explore optimum system topology for sources, components, and end-uses

- Motivate private-public collaboratives to conceive RPF’s and RFQ’s for the plants

To achieve this goal, we must overcome these obstacles:

- Earth’s richest RE is stranded, far from markets with no transmission

- We cannot do this entirely via electricity, and should not try to do so; “Smart Grid” is primarily demand side management (DSM); it adds no inherent or physical new capacity , and only slight effective new capacity.

 Now, we need to simultaneously pursue the several RD$D projects and pathways below, because we:

a. Must deeply decarbonize humanity's entire energy system quickly, prudently, and

profitably, optimizing our investment strategy, avoiding overinvestment in electricity;

b. Don't know whether future RE-CEF energy will be most conveniently and economically

harvested as electricity, as from wind and PV, or as GH2 directly from photo-, thermo-, or

biochemical processes, splitting water molecules in both "central" and "distributed" sites;

c. Need both R&D and pilot plants by which to discover and demonstrate the technical and

economic advantages -- if any -- of GH2 and NH3 as complete RE-CEF energy systems

vis-a-vis electricity systems, at local, regional, continental scales, for all energy services;

d. Must prevent suboptimal investments in enlarging and "Smartening" the electricity Grid,

insuring that "electrifying transportation" includes GH2 and NH3 as on-board, CEF fuels.

1. Complete RE-CEF energy systems. Conceive, design, build, and demonstrate complete RE-CEF energy systems optimized for capturing energy, in all ways, from incident photons and moving air and water molecules, from which to deliver an affordable, annually-firm, always-dispatchable supply of distributed energy services, for all purposes, to everyone on Earth. GH2 and NH3 systems may be technically and economically superior to electricity systems at regional to continental scales. Attempts to upgrade, enlarge, and "smarten" the electricity Grid must be evaluated in this context, to avoid suboptimal investments in the Grid: http://energy.gov/eere/articles/revolutionnow-rewind-modernizing-grid-ac... powered-future Collaborators in this major work should include: NREL Energy Systems Integration, with LBL and other DOE labs, EPRI, GTI, IGU, EEI, other industry groups, solar, wind, other energy OEM's, Oil & Gas industry, universities, and NGO's.

2. Wind and solar industries need to think "beyond electricity". "Transmission" now means to them only electric wires; "storage" generally means batteries. By 2050, hydrogen and ammonia fuels may be a bigger market for CEF energy than the electricity grid. http://leightyfoundation.org/w/wp-content/uploads/WP16-A-1.pdf OEM's and project developers shall embrace GH2 and NH3 systems.

3. Pilot plants: wind and solar dedicated to Hydrogen and Ammonia fuel production. Discover and demonstrate reduction in cost of wind-source and solar-source H2 and NH3 fuels from plants with no Grid connection, simplified in design without transformers, underground wire, electronics, delivering only "wild DC" to electrolyzers and NH3 synth reactors instead of Grid-quality electricity.

Wind-to-H2 example: http://leightyfoundation.org/w/wp-content/uploads/WP16-B.pdf

4. Embrace Anhydrous Ammonia, NH3, as "the other Hydrogen". ARPA-E's 2016 "REFUEL" FOA includes NH3 because of its high Hydrogen volumetric energy density, ease of transportation and handling, and low-cost energy storage. It is a C-free fuel for the ICE, CT, and direct ammonia fuel cell (DAFC); we need more R&D to improve energy conversion efficiency, in both NH3 synthesis and energy recovery, and to prevent NOx. Pipelining and storage in low-cost carbon steel, at ~10 bar and in large, refrigerated "atmospheric" storage, are well known. Siemens has embraced "Green Ammonia": http://www.siemens.co.uk/en/insights/potential-of-green-ammonia-as-ferti... Japan includes Ammonia in its "Strategic Innovation Promotion" (SIP) program, "Energy Carriers": http://www.jst.go.jp/sip/pdf/SIP_energycarriers2015_en.pdf Fig. 6.

5. Dedicated "distributed" GH2 and NH3 fuel plants. With no connection to, nor energy delivery to, the electricity grid, wind and solar plants are simplified, eliminating field transformers, power wiring, substations necessary to deliver grid-quality electricity. Turbine and PV output is "wild DC" close-coupled to electrolysis stacks and / or to NH3 synthesis reactors. Capex and O&M cost savings may pay for electrolysis and NH3 plants and for some energy conversion losses. These tradeoffs must be engineered, field-tested, and quantified at GW scale.

The “smarter” grid may be more vulnerable to cyberattack. Adding storage, control, and quality adjunct devices to the electricity grid, to accommodate very high renewables content, may be technically and economically inferior to GH2 and NH3 RE systems. Thus, we need to look beyond “smart grid”, expanding our concept of “transmission”, to synergistically and simultaneously solve the transmission, firming storage, and RE integration “balancing” problems now severely constraining our progress toward “running the world on renewables”.

At GW scale, renewable-source electricity from diverse sources can be converted to hydrogen and byproduct oxygen, and/or to NH3 fuels, both processes producing copious by- product oxygen, and pipelined underground to load centers for use as vehicle fuel and combined-heat-and-power generation on the wholesale or retail side of the customers’ meters.

This enables very low cost energy storage: less than $ 1.00 / kWh capital cost:

- Gaseous Hydrogen (GH2) in large, deep, solution-mined salt caverns, where the salt geology is available: Gulf of Mexico coast

- Liquid Anhydrous Ammonia (NH3) in large, refrigerated, "atmospheric", carbon steel surface tanks, extant in the Corn Belt

- Interconnected via continental underground pipelines, adding "free" storage by packing the GH2 pipelines (not liquid NH3 lines)

- At lower cost than any contemplated “electricity” storage technology, components, or systems

Pipelined GH2 and NH3 fuels free those wind and solar PV plants, which would be dedicated to delivering all their captured RE as GH2 and NH3 fuels to pipelines, from the capital and O&M costs of generating and delivering grid-quality AC or DC electricity: the required complex generators and power electronics, field transformers, cables and substations, transmission lines.

The internal combustion engine (ICE), combustion turbine (CT), and direct ammonia fuel cell (DAFC) operate very efficiently on GH2 and NH3 fuels. USA has extensive extant NH3 pipeline and tank storage infrastructure serving the N-fertilizer industry.

Humanity’s goal is to eventually “Run the World on Renewables” – plus perhaps some nuclear. Therefore, we design alternatives to, and adjuncts to, the electricity grid:

â–ª Convert all RE at sources to Gaseous Hydrogen (GH2) or Ammonia (NH3) fuels

â–ª Deliver these C-free fuels via underground pipelines for transport and CHP