U.S. National Science Foundation
New Home of the UVA Virtual Lab:
We Can Figure This Out.org
University of Virginia
  > WCFTO Home > Energy Home

An Introduction to Sustainable Energy Systems

As individuals, we most often focus upon a single energy technology: One we particularly like (e.g., solar or wind), or one we particularly dislike (e.g., fossil fuel or nuclear).

And then we all start arguing.

At Bell Labs I researched semiconductor devices for fiber optic communications. These were kissing cousins to solar cells, and I got to know a lot of people in the solar cell field (including the founders of two U.S. solar energy companies). So, naturally, for me, that "single energy technology" was solar cells. But for years, my friends told me that "when the cost of cells falls below $X.YZ / Watt, they will take over the world!" And then they fell below that cost. And they did not take over the world. I was clearly missing something. So I began reading almost every article, paper and book on energy I could find. And I eventually figured out what I'd missed: Sustainable energy is not just about the component technologies, it's about how they fit together to create a complete energy system. Put another way, the individual technologies are only pieces of a much larger puzzle. And, frustratingly, many of those pieces still have shapes that are blurred, ill-defined, and/or changing with time.

But why not build an energy system based on just one "piece," for instance solar cells? Because, for now, no single "piece" can affordably produce the amount of energy we need, when we need it. To illustrate, say that solar cell efficiencies suddenly skyrocketed, and costs plummeted. Wouldn't that make an all-solar energy system possible? Yes, but only if you were willing to spend your evenings in the dark, either shivering or sweating. The problem? Solar cells require intense sunlight to produce energy, which only happens (with luck) near midday. But our power consumption peaks in the evenings. So for a solar-based energy system to work, we would also need an effective and affordable way of storing huge quantities of midday energy for many hours - a technology "piece" we do not yet have. Or, if you lived on the U.S. east coast, you might tap into solar cells on the west coast, where the solar peak comes three hours later. But this would require another missing technological piece: efficient and affordable long-distance power transmission lines. So, even with miraculously improved solar cells, we would still need other (miraculously improved) pieces to build an energy system. And without such miracles, it's more likely that we will need many different energy-producing pieces, and many different complementary energy storage/transmission/ . . . pieces.

In my class, and now through this website, we'll examine the science and technology behind those energy "pieces," trying to define at least their present day shapes. But the real goal will be to then use that knowledge to figure out how those pieces might someday complete the "puzzle" of a truly sustainable energy system.

Recommended Textbook:
Sustainable Energy without the Hot Air
David J.C. MacKay
Downloadable for free at: Without the Hot Air.com
Or as a paperback from: UIT Cambridge England, ISBN 978-0-9544529-3-3

Class Notes & Resource Webpages

Lecture Notes


Lecture Notes


Where Do We Go from Here?
(Cap & Trade / Carbon Tax?)


Web Notes & Resource Webpages
(under construction)

For a university class, lectures have to be of fixed length and number. That meant that I had to continuously edit and rearrange things as I added new material to the class. On the other hand, because my students were responsible for all class material, the exact order of presentation was not critical. Which freed me to enhance learning by revisiting critical topics multiple times, treating them in increasing depth, weaving them together with related topics.

But this new website is intended as an online resource for you, the citizen-researcher. And you will likely arrive here searching for information on a single specific energy topic. I hope to lure you into broader study. But to facilitate your immediate research, I am rewriting my class notes into what I will call "web notes." For these web notes:

- Material will be reordered so that single topics are mostly covered in a single place (either a single noteset, or consecutive notesets)

- Text descriptions of each noteset will be included in their listing (immediately below).

- Each noteset will begin with a full outline.

- Notesets will be of whatever length their topic naturally demands.

I expect this rewrite will take me into 2018. This is mostly because, in my classes, I required every student to be a fellow investigator by submitting weekly, midterm, and final exam research papers. And I have thus accumulated a large backlog of new material that I am now anxious to add to this website.

But to pique your interest and provoke your input, I am posting my still incomplete and evolving outline of these new "web notes" immediately below. Please send your suggestions to me via this website's Contact webpage.


 My Personal Introduction to Sustainable Energy

How and why I became interested / How I learned that full energy systems are almost always required

 Electricity: What it is / How we make it / How we try to transmit it / How we then use a major portion of it

Part I: Electric & Magnetic Fields (resources webpage)

Part II: Magnetic Induction: Motors, Generators & Transformers (resources webpage)

 A Generic Power Plant & Grid (resources webpage)

How AC power + "transformers" greatly enhance our local use of electricity
But how AC greatly complicates long distance transmission: Synchronization and power loss problems
How transforming electricity to high voltage mitigates power loss problem
But how weird magnetic fields then introduce another crucial limitation: "Reactive Power"
Likely compelling us to build a new Grid around local use of AC + long distance transmission of DC

 Power from Carbon:

Part I: Conventional Fossil Fuels (resources webpage)

State-by-state data on where the U.S. now gets its electrical power
Fossil Fuels: The non-green source of 2/3 of that power
Heat producer for common power generation process of: Water + Heat => Steam => Electricity
Why combustion of solid > liquid > gas gets progressively more energy efficient
Coal Power: Conventional vs. IGCC vs. Sequestered IGCC (= so-called "clean coal")
Natural Gas Power: Not so efficient (OCGT) vs. very efficient (CCGT)
Fracking basics / wastewater impact / earthquake potential

Part II: Biomass and Biofuels (resources webpage)

Biomass = Burning of already available organic waste & garbage

Biofuels = Deliberate cultivation of fuel crops
Their too often abysmal ratio of energy output to net energy input
Their surprisingly large impact upon the environment & world food prices
But how they might provide the solution to air transportation's huge carbon footprint

 Hydroelectric Power (resources webpage)

The 2nd biggest "greenish" U.S. energy source (but with #1 - Nuclear - still almost 3X larger!)
The Science of Hydro
Conventional dams and their issues of drought, fish migration, and concrete's carbon footprint
The alternatives of "Run of the River" and "Pumped Storage Hydro"
The saltwater potential of wave and tidal energy

 Wind Power (resources webpage)

Now growing to challenge Hydro as 2nd biggest green U.S. energy source
The Science of Wind
The extreme importance of height + peak wind speed
Wind Turbine Technology
Wind Farm Layout
Optimal location => Critical need for efficient long-distance power transmission
Peak vs. Average Power + Consumption Cycles => Critical need for energy storage
Offshore wind farms exploiting higher winds / reduced "NIMBY"
Growing technology behind offshore wind turbines & possible deep-water floating wind turbines
Turbines vs. Birds & Bats

 Solar Power:

At present only a bit player in green U.S. energy (with #3 - Wind - 5X larger!)

Part I: Today's Solar Cells (resources webpage)

The critical difference between mere photoconductors and true photovoltaic cells
Why one material cannot efficiently convert sunlight's broad spectrum (=> the "S-Q limit")
Possibility of beating that limit via solar cells of multiple materials

Part II: Tomorrow's Solar Cells (resources webpage)

Exotic broad-spectrum technologies ranging from quantum dots to perovskites to . . .
Or side-stepping the spectrum problem by transforming sunlight's color?

Part III: Solar Thermal Power / Solar Thermal Energy Storage

Why simple solar thermal is today's most expensive energy technology
But solar thermal with built-in energy storage might be a green energy champ

Part IV: Building Large Solar Power Plants

Echoing Wind Power:
Optimal location => The critical need for efficient long-distance power transmission
Peak vs. Average Power + Consumption Cycles => Critical need for energy storage

With storage requirement playing to strength of solar thermal or Grid-scale solar photovoltaics
World-class plants: Quarzazate-Morrocco, Crescent Dunes-Nevada, Topaz-California

  Exotic Power Technologies (resources webpage)

Small potential / Unproven: Flying Wind Turbines
Medium potential / Proven but thus far in only exceptionally favorable locations: Geothermal
Large potential / Unproven and hugely expensive: Orbiting Solar Power Stations
Huge potential / Unproven and still elusive after the better part of a century's R&D: Nuclear Fusion

 Electrochemical Energy Storage:

Part I: Today's Batteries (resources webpage)

As seen around the house vs. in electrified transportation vs. for Grid energy storage

Part II: Tomorrow's Batteries / Tomorrow's Fuel Cells

ARPA-E's push for cheaper / more efficient / safer batteries including:
"Saltwater" (aqueous hybrid ion) batteries, solid-electrolyte Li batteries & quinone flow batteries

Fuel cell basics
Fuel cells as enabler of a "hydrogen economy" - or least electrified transportation
But only with radical improvement in their surprisingly poor energy storage efficiency

 Nuclear Energy

Part I: But they blow up! (resources webpage)

Fundamental principles of fission reactors & bombs / Three Mile Island, Chernobyl & Fukushima

Part II: Prehistoric Nuclear Reactors? (resources webpage)

Part III: Gen III / III+ Reactors: Confronting Cost & Operational Safety (resources webpage)

AP-1000 / ES-BWR / Small Modular Reactors

Part IV: Gen IV Reactors: Two Designs that Might Radically Reduce Nuclear Waste (resources webpage)

Liquid Fluorine Thorium Reactor / Traveling Wave Reactor

Part IV: A Brief Review of Other Gen IV Reactors

 Providing Power Plants with Necessary Land - Especially "Green" Power Plants
 Providing Power Plants with Necessary Water, Fuel and Minerals
 Lifetime Energy Out vs. Energy In => "Energy Return on Investment - EROI" for Competing Technologies
 Power Plant Economics => "Levelized Cost of Energy - LCOE" for Competing Technologies
(with much more to come)



Suggested Energy News Sources:

Copyright: John C. Bean