Energy Generation

Fuel Cells

Basic Operation

According to the US DoE, fuel cells are the most energy efficient devices for extracting power from fuels. Capable of running on a variety of fuels, including hydrogen, natural gas, and biogas, fuel cells can provide power for applications ranging from less than a watt to multiple megawatts.

Stationary fuel cells can be used for backup power, power for remote locations, distributed power generation, and cogeneration (in which excess heat released during electricity generation is used for other applications). While they can take advantage of inexpensive natural gas and low-carbon fuels like biogas, hydrogen fuel cells with no carbon emissions is the cleanest. Fuel cells can power almost any portable application that typically uses batteries, from hand-held devices to portable generators.

How Do Fuel Cells Work?

A single fuel cell consists of an electrolyte sandwiched between two electrodes, an anode and a cathode. Bipolar plates on either side of the cell help distribute gases and serve as current collectors. In a Polymer Electrolyte Membrane (PEM) fuel cell, which is widely regarded as the most promising for light-duty transportation, hydrogen gas flows through channels to the anode, where a catalyst causes the hydrogen molecules to separate into protons and electrons.

The membrane allows only the protons to pass through it. While the protons are conducted through the membrane to the other side of the cell, the stream of negatively-charged electrons follows an external circuit to the cathode. This flow of electrons is electricity that can be used to do work, such as power an electric motor. On the other side of the cell, air flows through channels to the cathode. When the electrons return from doing work, they react with oxygen in the air and the protons (which have moved through the membrane) at the cathode to form water.

This union is an exothermic reaction, generating heat that can be used outside the fuel cell. The power produced by a fuel cell depends on several factors, including the fuel cell type, size, temperature at which it operates, and pressure at which gases are supplied. A single fuel cell produces roughly 0.5 to 1.0 volt, barely enough voltage for even the smallest applications. To increase the voltage, individual fuel cells are combined in series to form a stack. (The term “fuel cell” is often used to refer to the entire stack, as well as to the individual cell.) Depending on the application, a fuel cell stack may contain only a few or as many as hundreds of individual cells layered together.

This “scalability” makes fuel cells ideal for a wide variety of applications, from vehicles (50-125 kW) to laptop computers (20-50W), homes (1-5 kW), and central power generation (1-200 MW or more).

For more information and a comparison of Fuel Cell Technolgoy see;

DOE Fuel Cells

Hydrogen Fuel Cells

Electricity can be generated in a fuel cell. They look like an electrolyzer working in reverse. Hydrogen is introduced to one side of the cell and air on the other. Electricity is generated as the hydrogen is oxidized to water, a clean waste stream.

If the hydrogen is generated by an electrolyzer the systems uses such 'green' hydrogen as an energy carrier. Such hydrogen is then operating as an energy storage option.

If the hydrogen is derived from geologic sources, the hydrogen is the energy source.

Hydrogen Fuel Cells are an option for transportation, especially when the battery capacity exceeds design requirements because of their weight.

Methane Fuel Cells

Fuel cells with the right design and catalysts can operate on methane and air to generate electricity.

New Clean Energy Process Converts Methane to Hydrogen with Zero Carbon Dioxide Emissions - Pacific National Lab - March 2021

Fuel Cell Companies in New Mexico

Pajarito Powder LLC (PPL) is headquartered in Albuquerque and manufactures advanced catalysts for PEM and alkaline fuel cells and electrolyzers. Their products include catalysts and components for fuel-cell EVs (FCEV) and catlaysts fro electrolyzers.

In December 2023 PPL announced the completion of a new 28,000 square-foot chemical production complex that will enable the company to make 200 times as much catalyst material for hydrogen-powered fuel cells. It will also allow a 100-fold increase in production of catalysts used for green hydrogen.

Concentrated Solar

Concentrating solar power (CSP) plants use mirrors to concentrate the sun's energy to drive traditional steam turbines that in turn drive electricity generators. The thermal energy concentrated in a CSP plant can be also stored and used to produce electricity when it is needed, day or night. Today (mid 2020), roughly 1,815 megawatts (MWac) of CSP plants are in operation in the United States.

The Solar Energy Industry Association provides many details:

Concentrated Solar Power

The NREL working with Solar Dynamics, LLC published a best practices report:

"Concentrating Solar Power Best Practices Study" - June 2020

Reports from the US Department of Energy and others point to progress with alternative ways to make Green Hydrogen:

Like Two Lost Souls, Hydrogen & Concentrating Solar Power Find Each Other - CleanTechnica - January 2nd, 2018

Solar/PV

There are four approaches to utilizing solar PV panels, each have their own pros and cons.

Utility Solar

Where big utility companies build big solar panel farms and wind farms with associated storage. Such installations require expensive transmission lines and large load control systems.

Municipal Solar

Where cities and towns get together to build renewable energy installations to serve a single municipality. This may be the sweet spot where power is distributed locally, without the requirement for expensive transmission lines and management control systems are only needed once.

Community Solar

Where local communities get together to build renewable energy installations to serve them. Community land may be at a premium that could limit available space.

Residential Solar

Where individual home owners and businesses install their own solar panels, storage (infrequent) and controls. Costly transmission lines are avoided but the investment in control systems per kwh generated makes this option less desirable than municipal solar.

Wind

New Mexico has many sites suitable for the development of wind farms. According to the American Wind Energy Association (AWEA) in 2019, the industry in New Mexico provided

• 2000-3000 jobs
• $3.4 billion invested
• Zero (0) of the 500 manufacturing facilities in the US
• Installed wind capacity: 1,952 MW
• Potential wind energy production: 652,575 MW
• Produced 19.40% of all in-state electricity generated

See:

Wind Energy in New Mexico" - AWEA

Hydropower

According to the National Hydropower Association (NHA), New Mexico generates hydropower at these locations in the state:

• Elephant Butte, Truth or Consequences
• Navajo Dam, Farmington
• El Vado Dam, Tierra Amarilla
• Abiquiu Dam, Abiquiu
• Animas River Penny Lane Dam, Farmington
• Santa Fe Canyon Hydroelectric Project, Santa Fe

Hydropower in the state produces:

• 146,000 Conventional Hydropower in MWh
• 33,010,000 Total Electricity in MWh
• 12,627,000 Total Renewable Energy in MWh
• 0% Hydro as a % of the Total Energy
• 1% Hydro as a % of the Renewable Energy
• 6 Total Powered Dams
• 8 Unpowered Dams

(MWh - assumed to be annually)

California, for comparison has 386 powered dams.

While hydropower is clearly a renewable energy source, it may not be 100% clean or without other environmental impacts. New hydropower dams for example may promote:

• methane release from rotting submerged vegetation
• leaching of toxins like mercury from submerged soils
• long term hydrodynamic impacts on fisheries and aquatic species

Geologic Hydrogen

Geologic or White hydrogen can be found in very pure quantities in some geologic formations. While it's not a fossil fuel it is a naturally occurring source of fuel that can be used in fuel-cells or combusted to produce power.

Geothermal

Geothermal energy is heat from the Earth. It's relatively clean and sustainable. Resources of geothermal energy range from the shallow ground to steam, hot water, and hot rock accessed by drilling wells up to thousands of feet beneath the Earth's surface. The extremely high temperatures in the deeper geothermal reservoirs are used for the generation of electricity.

Geothermal power, from any source, is not truly renewable, since the heat extraction rate is faster than the rate at which natural processes can replenish it. Even in hydrothermal energy sources, heat is usually extracted at a greater rate than it is being replaced but the lifetime of well is of the order of decades.

350NM, Tom Solomon presented his "Developing New Mexico’s Geothermal Heat and Electricity" to the Economic Development and Policy Committee on Oct 12, 20022. The promising technology is closed-loop system that doesn't require fracking or having to deal with contaminants in the returned hot water.

Eavor Technologies Inc has demonstrated their loop technology and are working on scaling up via their EavorDeep Project - "the deepest & hottest directional geothermal well".

Two approaches can be used Hot Dry Rock Geothermal vs Hot Wet Rock Geothermal, the latter can bring up dissolved minerals that may need careful handling for toxicity and corrosiveness. See:

Geothermal Energy: The Basics - Geothermal Rising.

Los Alamos National Labs tested geothermal sources but the facility is reportedly now closed. Work on Hot Dry Rock at LANL is reported at:

"Hot Dry Rock Geothermal Energy Development in the USA" - David Duchane and Donald Brown

Currently Cyrq Energy operates six geothermal power plants around the western US, including the 15.3 MW Lightning Rock Geothermal Power Plant in Animas, NM, near Lordsburg. The plant operates a closed loop water circulation system.

For a review of the state of the art of geothermal energy and some of the engineering obstacles, see;

Geothermal energy is poised for a big breakout - Vox -- October 2020

Climate activist Jamie Beard explains in a TEDTalk how we might access geothermal energy with today's technology and resources:

The untapped energy source that could power the planet - TEDMonterey - Jamie Beard - July 2021

MIT spinoff company Quaise is investigating gyrotron hybrid technologies for deep well drilling where energy generation efficiencies rise substantially.

Fusion tech is set to unlock near-limitless ultra-deep geothermal energy - New Atlas - Feb 25, 2022

"Quaise is working on full-scale, field-deployable demonstration machines, which it says will begin operating in 2024. It plans to have its first "super-hot enhanced geothermal system" rated to 100 megawatts in operation by 2026."

Biomass

In the long run, using the sun to grow trees and other vegetation for fuel is one way to avoid burning fossil fuels to meet our energy demands. Biomass fuels take CO₂ from the atmosphere and puts it back when burned, releasing the sun's energy. It's considered 'carbon neutral'. However, this steady state behavior is not what is practiced if we take our current inventory of carbon in trees and forests and burn them now. We get a boost in atmospheric CO₂ just when we don't need it. It may take 50-100 years for reforestation and afforestation programs to take that CO₂ back out of the atmosphere. We don't have that time.

So any benefits from biomass for energy generation will have to come from growing short term crops such as annuals or fast growing perennials. There are several ways to get the energy out of biomass, including:

• by direct combustion
• via methane digesters

A key benefit with both of these processes is that they can participate in dispatchable energy systems.

See:

"Biomass pros and cons" - EnergySage - December 24, 2019

Nuclear Power

From the Union of Concerned Scientists:

"Nuclear Power & Global Warming" - May 22, 2015 updated Nov 8, 2018

"The Nuclear Power Dilemma Declining Profits, Plant Closures, and the Threat of Rising Carbon Emissions" - Oct 9, 2018

who expect nuclear power to play a role with increased safeguards, from Nov 2018. Some quotes:

“Without new policies, natural gas and coal will fill the void. Closing unprofitable and marginal at-risk plants early could result in a 4 to 6 percent increase in US power sector emissions. [my emphasis]”

UCS Recommendations

If the current situation continues, more nuclear power plants will likely close and be replaced primarily by natural gas, causing emissions to rise. Policymakers should consider the following recommendations as they think about how to respond:

• We need carbon pricing. A robust, economy-wide cap or price on carbon emissions would help provide a level playing field for all low-carbon technologies.

• We need a low-carbon electricity standard. A well-designed LCES could prevent the early closure of nuclear power plants while supporting the growth of other low carbon technologies.

• Financial support for nuclear plants should be conditioned on consumer protection, safety requirements, and investments in renewables and energy efficiency. Policymakers considering temporary financial support to avoid the early closure of nuclear plants should couple that support with strong clean energy policies, efforts to limit rate increases to consumers, and rigorous safety, security, and performance requirements.

See the full report:

"The Nuclear Power Dilemma" - November 2018

Palo Verde Nuclear Generating Station

Public Service Company of New Mexico (PNM) has rights over 402 MW of the total capacity of 3,937 MW of Arizona’s Palo Verde Nuclear Generating Station. According to the Nuclear Energy Institute it is America’s largest, has three pressurized water reactors and produces 27.7% of Arizona's electricity. See:

Arizona and Nuclear Energy Fact Sheet

The facility is also unique in the world, in that it uses treated waste water from the metropolitan Phoenix area to run its cooling towers, according to PNM.