GEOL 241 Fall 2017 Lecture 23: The Transportation Problem

Homework Essay #4 due via Blackboard, Friday November 24th, 5pm

2 page limit (see formatting guidelines on syllabus) – works cited can be in addition

Assume you are called upon to provide advice to the US Department of Energy (DOE) about where it should focus its attention strategically for the next 10-20 years. Based on what you have learned in this class, write an essay that makes the case for the one most important area where you think the DOE should put its effort. What do you think the greatest challenge will be in developing the energy system for the future? What are some ways that we might overcome the challenge you have identified?

As in the case of the prior essay assignments for this class, we are not looking for a “right answer” but are interested in you thinking about this issue. Establish the basis for your argument in what we have learned in class, supplemented by your own reading.

Transportation à ~30% of U.S. energy consumption

Transportation is the major use of petroleum, and relies on oil as an energy source

Some questions we want to answer about energy in transportation

1. What is so great about petroleum-derived gasoline? Why do we rely on it today for transportation? What are some of the

problems with relying on petroleum?

2. What are the alternatives to oil, and what are their pros and cons? Natural gas? Biofuels? Hydrogen? Electric cars?

3. How can efficiency play into the transportation picture? Can we change our basic approach to transportation (including public transport) and save energy? How do other modes of transport, such as airplanes and trains, fit into the picture?

Transportation is mostly about petroleum!

Remember that gasoline, diesel, and jet fuel are all different products from petroleum refining…

so pretty much all of our transportation fuels ultimately come from oil today (and conversely, the predominant use for oil is for transportation…)

Transportation is predicted to remain about petroleum in the future…

But will it, should it, and what are the alternatives?

Why we rely on petroleum-derived gasoline for transport: Energy density!

Recall from last lecture:

Fossil fuels have very high energy density – think about why this is so important for transportation!

High energy density

by volume, but low

by mass

Highest energy density

by mass

Some of the problems with relying on petroleum for transportation

1. Economic security – reliance on imports affects the US national balance sheet

In 2012, deficit of oil import was 55% of total US deficit

1. Energy security – in terms of maintaining supply, and the sociopolitical costs that are involved

2. Potentially destructive CO2 emissions and other pollutants (e.g. photochemical smog)

Oil affects our national economic balance sheet!

So we should be thinking carefully about securing

petroleum for the future – and about alternatives.

Possible alternatives to dependence on petroleum for transport

1. Reduce consumption (e.g. through higher efficiency, or less use of transportation)

1. Replace with biofuels

2. Replace with natural gas

3. Use electric vehicles

4. Replace with hydrogen

BIOFUELS

Energy density is lower than for petroleum fuels, but not that much lower

BUT we have seen some of the problems with biofuels at the large scale – think about your calculations in lab about the land area required for these to replace oil…

NATURAL GAS • Plentiful & inexpensive today • “Clean” relative to diesel and petrol/gasoline • Used in some public bus systems, government car fleets, etc.

BUT energy density by volume is low – requires very large tanks & limited range Or can compress gas, but: • Little compression infrastructure in place • Will eventually run out • Produces CO2

HYDROGEN FUEL

Packs a big punch per mass, though also bulky like natural gas

BUT big problem is source – there are no “natural pockets” of H2 gas!

If H2 is not a naturally abundant fuel, what is this “hydrogen economy” revolution all about?

HYDROGEN FUEL

How hydrogen works as a fuel:

2 H2 + O2 à 2 H2O + energy (note that this is a chemical reaction – it is not the nuclear reaction we discussed related to H-fusion!!!)

If we put energy in, we can run this reaction backwards and “make” hydrogen from water.

In effect, H2 becomes a (convenient and efficient?) way to store energy. Of course – just like with electricity – we have to get this energy from somewhere else! It is a secondary source of energy.

So how could this actually work in practice?

Hydrogen fuel is basically an energy storage solution It is not a primary source of energy. But it’s potentially a

good way of storing energy – high energy density.

How does it work? How do we get the H2 fuel?

One way to get H-fuel: Hydrogen from natural gas

Overall process: CH4 + 2 H2O + heat à CO2 + 4 H2

This is the source of most H2 fuel produced today

It is: Relatively clean

BUT it also: Produces CO2 (though less than gasoline/diesel)

Requires (non-renewable) natural gas source Requires additional heat input

An alternative way to get Hydrogen fuel: H2 from electrolysis

• pass electrical current through water

• hydrogen dissociates from oxygen and collects on positive terminal

• bubbles of H collected for use as fuel

The problem: low efficiency (requires a lot of electrical energy to get a little H fuel)

Electrolysis requires input of electrical energy

Most electricity comes from coal – which we have seen has nasty side effects (CO2, SO2)

There is also an efficiency problem:

Efficiency of power plant ~33% Efficiency of electrolysis ~65% (optimistically) Total efficiency ~21% at absolute best

This compares to ~20% efficiency for car engine running petroleum, so maybe just as well to use a “normal” car?

Electrolysis requires input of electrical energy

Could use renewable energy source (wind, solar) but would need to greatly increase total electricity production to make this possible.

This is currently a long way away and in the meantime does it make much sense to try to shift to electrolysis-derived H2?

Current cost of H2 from methane ~ $0.80/kg Current cost of H2 from electrolysis ~ $3.80/kg

What the future might hold:

Photolytic (solar-driven) water splitting

A potential alternative to electrolysis

Looks simple and attractive, but we don’t currently have the technology to make this work!

Clearly an exciting area of ongoing research… and if it works, a total game changer?

The other problem is how we use the H2 fuel!

How hydrogen works as a fuel:

H2 + O2 à H2O + energy

We actually need to get this energy out in a useful form.

Not like this, hopefully….

The Hindenburg disaster in 1937 – a hydrogen airship explosion

Hydrogen Fuel Cells

Run electrolysis in reverse, to produce electricity and water from H2 and O2.

Theoretical efficiency ~85%

Practical efficiency ~65% or less

Compare to heat engine efficiency ~20%... not too bad

So what’s the catch?

Hydrogen Fuel Problem #1: Efficiency

Overall efficiency for H2 storage estimated at about 20-30%, lower than for battery technologies

(though most of the efficiency losses with H2 are in the production, e.g. via electrolysis)

Hydrogen Fuel Problem #2: Cost! • Toyota Mirai, one of first production-line hydrogen cars • Available for sale in California in 2015 (where there are 10

fuel stations) • Total 700 cars to be made this year • Costs $57,500, but Toyota loses money on each one sold

(as much as $100,000 including development costs?)

Possible solutions

1. Reduce consumption of petroleum based fuels

2. Replace with biofuels

3. Replace with natural gas

4. Use electric vehicles

5. Replace with hydrogen

The showdown for the future? Electric vs. Hydrogen

VW, Tesla, Nissan: electric all the way!

Toyota, Hyundai, GM: more into the hydrogen (but not ignoring electric vehicles)

Electric • Convenient to charge (needs only a plug)

• More efficient that fuels cells (by about ~3x in total) • But short range

• Can the electricity infrastructure cope with wide adoption?

Fuel cells • Long range (300 miles without refueling, vs. Tesla S requiring

minimum 20 minutes for 200 mile charge) • No need for heavy and expensive batteries

• Few fueling stations at the moment – and who will build them?

NOTE: The total “lifecycle” environmental costs of electric vs. fuel cells cars remains unclear.

Possible solutions

1. Reduce consumption of petroleum based fuels

2. Replace with biofuels

3. Replace with natural gas

4. Use electric vehicles

5. Replace with hydrogen

REMEMBER: Both of these require a primary source of energy… e.g. electricity from coal or other renewable source…

They are NOT “free energy”

Electric cars rely on the electricity grid

How does nighttime demand interface with production of renewable electricity?

Is there enough infrastructure for widespread adoption of electrical cars? Could residential grids cope?

Possible solutions

1. Reduce consumption of petroleum based fuels

2. Replace with biofuels

3. Replace with natural gas

4. Use electric vehicles

5. Replace with hydrogen

What about changing the way we use transportation, to increase efficiency of energy spent per mile travelled, etc.?

We’ve talked about looking at alternatives to using oil for transportation, and many of these have promise.

But are there also ways that we reduce energy consumption for transportation overall?

• Less driving? More public transport?

Trains are much more efficient than cars… in fact they are in principle amongst the most efficient means of transportation.

So we should just build more trains in the US and Australia, right?

Trains are only a solution if they get enough use! San Jose light rail has been cited as an example of a train system

that gets so little use it consumes more energy per passenger mile that solo drivers!

Low urban density in some countries (such as the US and Australia) makes public transport likely to be less efficient than in

places with high urban density (e.g., Europe or Asia)

We’ve talked about looking at alternatives to using oil for transportation, and many of these have promise.

But are there also ways that we reduce energy consumption for transportation overall?

• Less driving? More public transport?

• More efficient cars on the roads?

FEDERAL FUEL ECONOMY STANDARDS PROGRAM (CAFE):

Each model year, manufacturers are required to (1) achieve average of 27.5 mpg for fleet of new passenger cars (2) achieve average of 20.7 mpg for fleet of new light duty trucks

Gasoline consumption is down roughly 2.8 million barrels/day from what it would be without CAFE (translates to a 7% reduction in CO2)

Makes a small but substantive difference

Why don’t we increase efficiency standards yet further?

Fuel Efficiency

We’ve talked about looking at alternatives to using oil for transportation, and many of these have promise.

But are there also ways that we reduce energy consumption for transportation overall?

• Less driving? More public transport?

• More efficient cars on the roads?

• Less transport in the first place?

Telecommute: only 5% of employees do so today

Internet shopping: reduce travel to stores, delivery to shops (as long as using serial delivery, e.g. US Mail, etc)

Telephone or Video conferencing or selling, rather than air transport

Internet websites saving journal, book and document production from trees, and trips to the library

E-books and newspapers

More home entertainment

BUT AT WHAT SOCIAL COSTS???

Transportation Substitutions

Where does air travel fit in this picture?

Where does air travel fit in this picture?

Planes are actually quite efficient ways of going quickly…

but we also go a go quite fast in them, and total a lot of transportation miles that way, so use a lot of fuel!

Across the US, air travel is a small portion of total energy use

What would it actually take for everyone to be able to fly?

Fuel consumption for 787 Dreamliner is ~0.024 liters of jet fuel per km per seat

Distance from LA to San Francisco: 390 miles = 630 km People in the world: 7 billion

Fuel needed for everyone to fly from LA to SF: 0.024 x 630 x 7 x 109 = 105 x 109 liters fuel… just for everyone to

be able to fly LAX->SFO one way!

Global airline fuel production ~ 5000 barrels per day 5000 x 119 liters/barrel x 365 days/year =

217 x 106 liters fuel produced per year Almost 1000x less than needed for everyone to be able to fly

But if you fly a lot….

Assuming we drive about 10,000 miles/ year, we use about 40 kWh/day for cars

One intercontinental flight (8,800 miles) would equate to 12000 kWh per passenger – or about 30 kWh/day over a year

But remember… need to add another 30 kWh/day for each 9,000 miles flown. Think about what this means for someone flying 100,000 miles in a year...

From David Mackay’s Sustainability without the hot air

GEOL 241 Fall 2017 Lecture 25: The Consumption Side – It is down to you and me!

Homework Essay #4 due via Blackboard, Friday November 17th, 5pm

2 page limit (see formatting guidelines on syllabus) – works cited can be in addition

Assume you are called upon to provide advice to the US Department of Energy (DOE) about where it should focus its attention strategically for the next 10-20 years. Based on what you have learned in this class, write an essay that makes the case for the one most important area where you think the DOE should put its effort. What do you think the greatest challenge will be in developing the energy system for the future? What are some ways that we might overcome the challenge you have identified?

As in the case of the prior essay assignments for this class, we are not looking for a “right answer” but are interested in you thinking about this issue. Establish the basis for your argument in what we have learned in class, supplemented by your own reading.

Is there an energy “problem”?

All sources of energy have costs – financial costs, and also environmental costs.

We want to grow our economy, and grow energy use. That requires finding additional sources.

These are clearly energy challenges.

There are only a few things we can do in the future: (1) Use less energy, either via:

• less consumption or • higher efficiency

(2) Find more sources of energy

Sources of energy in the U.S.

Fossil fuels have two big problems:

(1) They are non-renewable, so eventually (but hard to predict exactly when…) we will run out.

(2) They are thought to contribute to potentially

devastating climate change and other environmental

degradation (e.g. from fracking).

Sources of energy in the U.S.

Fossil fuels have two big problems:

(1) They are non-renewable, so eventually (but hard to predict exactly when…) we will run out.

(2) They are thought to contribute to potentially

devastating climate change and other environmental

degradation (e.g. from fracking).

Sources of energy in the U.S.

There is a lot of promise from many renewable energy

sources, but none come without drawbacks.

There is no “silver bullet” solution that would provide easy, abundant, cheap energy

with no cost to the environment or pocketbooks.

There are only a few things we can do in the future: (1) Use less energy, either via:

• less consumption or • higher efficiency

(2) Find more sources of energy

There are only a few things we can do in the future: (1) Use less energy, either via:

• less consumption or • higher efficiency

(2) Find more sources of energy

Focus today on this

question

Let’s think about efficiency: What is the scope to “lose” less energy?

Most of the energy we “produce” is “lost”! (these are in quotes because remember we don’t make or lose

energy, we just transform it… but we can lose the energy from the forms that are useful to us)

Efficiency = Useful energy output/Total energy input

If we increase the efficiency of our energy use we can achieve: • less pollution/environmental damage

• more socioeconomic/sociopolitical “energy security” • increased potential for future economic growth

But how much can we do this, realistically? And what are the best ways to do it?

Efficiency of some common devices

Efficiency = Useful energy output/Total energy input

DEVICE EFFICIENCY (%) Electric motor 90 Home oil furnace 65 Steam boiler at power plant 89 Thermal power plant 36 Gasoline auto engine 25 Light bulb (incandescent) 5 Light bulb (fluorescent) 20

Overall system efficiency

Consider a power plant

There is a boiler, a turbine, and a generator

System efficiency esystem = eboiler x eturbine x egenerator e = 0.88 x 0.41 x 0.97 E = 0.35 or 35%

This should be the same as esystem = electrical energy output/chemical energy input

The efficiency of a system is equal to the product of efficiencies of the individual devices (sub-systems)

System efficiency of a light bulb

STEP STEP EFFICIENCY %

CUMULATIVE EFFICIENCY %

Extraction of coal 96 96 Transportation of coal 98 94 Electricity generation 38 36 Transportation of electricity

91 33

Lighting Light bulb (incandescent)

5 1.7

Light bulb (fluorescent)

20 6.6

So, in absolute terms (i.e. in terms of the total amount of energy), increases in efficiency of energy use (e.g., more efficient light

bulbs) save more energy that expected from the final step alone.

System efficiency of an automobile

STEP STEP EFFICIENCY % CUMULATIVE EFFICIENCY %

Crude oil extraction 96 96 Crude oil refining 87 84 Transportation of gasoline

97 81

Combustion engine (chemical to thermal to mechanical)

25 20

Transmission 50 10 Rolling efficiency on the road

20 6.6

Limits to increasing efficiency Typically, most energy is lost in one or two key transformations for

example in the cases on the last two slides:

-- generating electricity at a power station (38% efficient) -- internal combustion engine in a car (25% efficient)

2nd Law of Thermodynamics – we always “lose” energy during conversion from one form to another, and these losses are

governed by basic physics (e.g., efficiency of heat engines that produce most of our electricity)

These physical laws cannot be escaped and mean that small steps to improve efficiency can make a meaningful difference to

total energy demand, but they can only go so far. So efficiency can only go so far to sustaining future energy (and

economic) growth.

If there is only so much we can do to increase the energy system efficiency, what is the scope for reducing future energy demand

by using less energy?

Could potentially achieve the same goals as increasing efficiency: • less pollution/environmental damage

• more socioeconomic/sociopolitical “energy security” • increased potential for future economic growth (if we can

deliver the same economic services for less energy)

How could be reduce our energy use? First, we need to understand a bit more about our uses of energy.

What about changing patterns of energy consumption

19

You are going to measure your personal electricity use in your take home lab next week.

Let’s think about how your electricity use “adds up” to your total energy “footprint,” in the context of “your” other energy uses

Energy footprint: the total amount of energy used by you (or another person or organization) for all purposes

Measuring your use of electricity

A highly recommended resource: David Mackay’s Sustainable Energy Without the Hot Air

Tally of typical electricity use: • Microwave (1000 W) 12 mins (0.2 hr) =

0.2 kWh • Clothes washer (300 W) for 1 hour =

0.3 kWh • Clothes dryer (5000 W) for 1 hour =

5 kWh • TV & DVD (200 W) for 2 hour =

0.4 kWh • Desktop computer (100 W) on all day =

2.4 kWh • Refrigerator (average 75 W) on all day =

1.8 kWh • Lights (total 400 W) for 5 hours =

2 kWh Total: 12.1 kWh – think about this once you measure your own use… (note this would cost about $1.50/day at $0.13 per kWh)

A typical day of energy use in the U.S. …

Courtesy of Tom Murphy, UCSD

Tally of typical electricity use: • Microwave (1000 W) 12 mins (0.2 hr) =

0.2 kWh • Clothes washer (300 W) for 1 hour =

0.3 kWh • Clothes dryer (5000 W) for 1 hour =

5 kWh • TV & DVD (200 W) for 2 hour =

0.4 kWh • Desktop computer (100 W) on all day =

2.4 kWh • Refrigerator (average 75 W) on all day =

1.8 kWh • Lights (total 400 W) for 5 hours =

2 kWh Total: 12.1 kWh – think about this once you measure your own use… (note this would cost about $1.50/day at $0.13 per kWh)

A typical day of energy use in the U.S. …

Courtesy of Tom Murphy, UCSD

Add other energy use:

• 12.1 kWh/day of electricity • 26 kWh/day of natural gas for

heating • 10 gallons of gasoline every 2

weeks ® 26 kWh/day

Note that heating and transportation are the larger items here…

Total is 64 kWh/day = 2580 W, or 1300 W per person for a 20 person household

US energy services ~ 41.7 Quads per year ~ 122 x 1011 kWh/year

US population ~ 319 x 106 people

Energy use per person ~ 38000 kWh/year ~ 105 kWh/day

Compare to “personal” estimate of 64 kWh/day

Where is the “extra” energy we use?

So what about the rest of our energy use?

From David Mackay, “Sustainable Energy – without the hot air” http://www.withouthotair.com

Here (on the left side of this diagram, in red) is the wider breakdown of the energy footprint in a typical western economy: including uses in the home, but also the indirect uses of energy (e.g. embodied in products we buy, or food we consume)

(on the right side of this diagram, in green, Mackay has summarized his best estimates for how much energy we might optimistically hope to get from different renewable energy sources…)

An overview of how we use energy: A more complete view

From David Mackay, “Sustainable Energy – without the hot air” http://www.withouthotair.com

Embodied energy

energy consumed by all of the processes associated with making a product (could be anything from a can of coke to skyscraper), from the mining and processing of natural resources to manufacturing, transport and product delivery

An overview of how we use energy: A more complete view

From David Mackay, “Sustainable Energy – without the hot air” http://www.withouthotair.com

An overview of how we use energy: A more complete view

From David Mackay, “Sustainable Energy – without the hot air” http://www.withouthotair.com

How much of a difference do “gadgets” make?

From David Mackay, “Sustainable Energy – without the hot air”

http://www.withouthotair.com

“Vampires”: devices that draw electricity without serving any good (e.g., television on standby, etc.)

How much of a difference do “gadgets” make?

From David Mackay, “Sustainable Energy – without the hot air” http://www.withouthotair.com

Energy efficiency at home saved Mackay about 2kWh/day, by turning off vampires, using efficient bulbs, etc.

Not negligible, but consider in context of total energy use – or even choice to eat meat, or have a pet!

Tom Murphy tried going a bit further than David Mackay: starting in 2007, he and his wife: – never turned gas furnace/pilot on – shorter showers, with cutoff for soaping up – line-dry clothes – all bulbs compact fluorescent, some LED – diligent about turning off unused lights – bike/walk around neighborhood (and bus to work) – install experimental (small) solar photovoltaic system (off-

grid; battery-based) to run TV & living room

How much difference can home energy use make?

Courtesy of Tom Murphy, UCSD

Courtesy of Tom Murphy, UCSD

• decreased electricity use = 5-10 kWh/day energy use; • not including additional energy saved by not driving and using

less gas for heating

The results of Tom Murphy’s experiment

Courtesy of Tom Murphy, UCSD

• decreased electricity use = 5-10 kWh/day energy use; • not including additional energy saved by not driving and using

less gas for heating

The results of Tom Murphy’s personal experiment

An interesting lesson that our individual actions do “matter.”

But if you want to reduce your energy footprint, it’s worth knowing it is that you do that consumes energy,

so you can take smart action, rather than uneducated and ineffective action.

The bottom line on our energy use

So what are the most energy consuming activities we do on a daily basis?

• Flying • Driving cars and trucks • Home heating, hot water, and air conditioning • The stuff you buy • Eating meat and poultry

Does that mean you should stop doing these? NO! But worth being aware of them and what they require in terms of your own energy use.

From David Mackay, “Sustainable Energy – without the hot air”

http://www.withouthotair.com

What you can do and what it means: Simple actions to reduce your energy use

From David Mackay, “Sustainable Energy – without the hot air” http://www.withouthotair.com

Think about which actions you would be prepared to take – and which do you think should be prioritized – to reduce your energy footprint? Or should we not be worried about reducing energy footprint, and if not, why not?

What you can do and what it means: More serious actions to reduce energy use

Perhaps most importantly: • You can be aware of your own energy use and encourage

others (friends, family, public) to be aware of theirs. • We don’t have to give up our lifestyles… but we should be

having a discussion about energy, since it’s such a central part of our lives and our economy, and it comes with a price!

From David Mackay, “Sustainable Energy – without the hot air”