Tag Archives: order of magnitude

Sustainability by the Numb3rs: Can Vertical Farming Scale?

Can Vertical Farming Scale?

Thursday, May 29th, 5:30 pm – 7:00 pm
Fuse @ The Riverside
1724 Broadway St, Boulder, CO 80302

Register Here

This is the third class in a series of classes hosted by Clean Energy Action and Boulder Free School.  Find out more on the main course index page.

Class Outline:

Resilient Communities |Vertical GardeningTo some, vertical farming has a certain futuristic appeal.  Growing food in the green urban towers, or in space-aged plant factories with controlled climates, free from pests and pesticides, recycling the same water over and over again has been pitched as a way to reduce the land, water, and energy impacts of farming, and bring food production closer to where most people live.

In this class, we’ll take a look at some of the numbers behind this kind of agriculture, and try to figure out what its impacts are — how much energy does it use?  How does that compare to traditional agriculture?  How much food can it produce?  Is it a good use of urban space?

Homework

Read these two articles on a couple of recent vertical farming projects:

What numbers we will need to find in order to estimate the energy and climate impacts of these facilities.  Do the articles provide those numbers?  Can you find those numbers on the websites of the vertical farming companies?  Do any of them publicly make specific, testable claims?  You might want to start with:

  • How much electricity do they use each year?
  • Where does their electricity come from?
  • How much water do they use each year?
  • What is their annual product yield?
  • How much area does the growing facility take up?
  • Where are the energy savings claims coming from?

And then for comparison, we’ll need to find similar information for traditional agriculture — what are the greenhouse gas emissions associated with the production of similar foods that are grown traditionally?  How does that number differ between conventional and organic agriculture?  What about water use?  How much of the crop can be produced per acre of land?

Feel free to contact the companies directly if you can’t find this information on their websites.  For instance, the phone number for Farmed Here in Chicago is 847-846-8610.  If you can find other large indoor/vertical food producers to contact, that would be great!  The more numbers, the better.

If we can’t get the real numbers, then we’ll fly by the seat of our pants and try to estimate, but real numbers are always more fun.

Sustainability by the Numb3rs: The Scale of Global Energy Systems

The Scale of Our Energy & Power Systems

April, 24th, 5:30 pm – 7:00 pm
Fuse @ The Riverside
1724 Broadway St, Boulder, CO 80302

Register Here

This is the second in a series of classes hosted by Clean Energy Action and Boulder Free School.  Find out more on the main course index page.

Class Outline:

In this class we will revisit the relationship between energy — which is a quantity of work (measured in Joules, or perhaps more familiarly on your electricity bill, in kilowatt hours) — and power, which is a rate of energy usage or flow (measured in Watts).  We’ll look at the power density of various renewable energy sources — especially solar — and see when and where that becomes an important constraint.  We’ll try and get a sense of the scale of our global energy system, where the energy comes from today, what it goes to, and where we might be able to get it from in a zero carbon future.  We will also talk about the difference between electricity and energy, which are often and mistakenly conflated.

Today it takes about 15 Terawatts (1.5 x 1013 Watts) of power to run human civilization.  On average, that’s about 2 kW (2,000 Watts) per human being, but energy use is not evenly distributed.  North Americans on average use more like 10 kW (10,000 Watts — equivalent to having about 100 human energy slaves working tirelessly for you day and night), while Bangladesh clocks in at less than 300 W per capita.  If everyone were to aspire to the North American way of life, we would need to increase global energy production by about a factor of 6 or 7, to something like ~100 Terawatts (1 x 1014 W).  What would it take to do that?  Is it practical for Colorado?  For the US?  For the UK?  For Bangladesh?

Homework:

Watch a 90 minute long talk (60 minutes of talk + 30 minutes of Q&A) by MacArthur fellow Saul Griffith on energy and climate.  You must join the Google Group for this course, so we can give you a private link, because this talk is not publicly available in its entirety.

Read Chapter 2 (The Balance Sheet) and Chapter 6 (Solar) in part one of Sustainable Energy Without the Hot Air (download the full PDF of the book).  This is 14 pages of reading.

Look up information about two large (utility scale) solar power facilities.  One of them should be in Germany, and the other should be in a sunny place — Southern California, Spain, Australia, etc. For both facilities, find:

  1. The total land area of the facility.  This will probably be measured in acres or km2.
  2. The total annual energy produced by the facility.  For electricity, this is usually reported in Watt-hours, probably Megawatt hours (MWh) or Gigawatt hours (GWh).
  3. The nameplate capacity of the facility — this will be measured in Watts — probably Megawatts (MW).

Background Resources

If you still feel uncomfortable with the basic mechanics of and motivations behind doing order of magnitude calculations, go check out the resources from our first class.  We’ll also try and make sure that every class starts with an easy warm-up calculation to give everyone a chance to get comfortable.

Teacher Bio

Once upon a time at NASA, Zane got a PhD studying the climate history of Mars, and the geology of the icy moons of Jupiter and Saturn.  Now he’s Clean Energy Action’s director of Research and Policy, working on climate and energy policy, and trying desperately to get everyone to turn off the terraforming machines before it is too late.  Zane also works on sustainable transportation, land-use, and community housing in Boulder.  He lives in a co-op with 11 other people, and his two bicycles and zero cars.

Sustainability by the Numb3rs: Understanding Order of Magnitude Calculations

Understanding Order of Magnitude
Calculations

March, 27th, 5:30 pm – 7:00 pm
Fuse @ The Riverside
1724 Broadway St, Boulder, CO 80302

Register Here

This is the first in a series of classes hosted by Clean Energy Action and Boulder Free School.  Find out more on the main course index page.

Class Outline:

Order of magnitude calculations or estimates are a tool commonly used in the natural sciences to understand the general shape and scale of an interesting system.  They use approximate numbers and simple arithmetic to make educated, quantitative guesses or estimations.  The rest of this course will rely on order of magnitude calculations extensively, so it’s important that we make sure everyone has the basic tools required to do them.  They’re also known as “Fermi problems” or “Fermi estimates” after the Italian physicist Enrico Fermi, who was famous for making very fast, roughly correct, estimates of all kinds of crazy things.  This little video from TED-Ed gives a quick intro:

For Example:

If you’re going on a backpacking trip for a week, and a friend tells you their backpack weighs either 5 lbs or 500 lbs, you know intuitively that something is very wrong — you have a grasp of the scale of a backpack — 50lbs is about right. Maybe 35lbs if you’re going ultra-light, maybe 70lbs if you’re a mule, but definitely not 5 or 500.

If you know how to do order of magnitude calculations, you can quickly develop a similar intuition about lots of other kinds of physical systems, including those that are much bigger or smaller than your everyday experience.

Why is this important or useful?

This is important in the context of sustainability, because many of the systems we interact with and affect today are global, and far larger than it’s easy for us to grasp based on our normal daily experience.  Instead we have to build this intuition up for ourselves by playing around with the numbers.  It’s also important because there are a lot of “solutions” out there which might sound good as stories, but when you look at how big an impact they can actually make numerically, they turn out to just be marketing hogwash or outright disinformation.  The media doesn’t do a good job of differentiation between real solutions and hogwash, but with just a little bit of arithmetic and access to the Wikipedia and other online resources, you can get a good idea for yourself.

In this class:

We will explore…

  • The difference between accuracy and precision, and why it’s often desirable to make estimates which are imprecise, but relatively accurate.
  • Scientific notation — what it is, how to use it, and why it’s useful.
  • Units — the importance of keeping track of them, and what they mean, more generally.

Then we’ll do some easy warm-up calculations to try and wrap our heads around the scale of various pieces of our energy system.

Homework:
Teacher Bio

Once upon a time at NASA, Zane got a PhD studying the climate history of Mars, and the geology of the icy moons of Jupiter and Saturn.  Now he’s Clean Energy Action’s director of Research and Policy, working on climate and energy policy, and trying desperately to get everyone to turn off the terraforming machines before it is too late.  Zane also works on sustainable transportation, land-use, and community housing in Boulder.  He lives in a co-op with 11 other people, and his two bicycles and zero cars.