Urban Sustainability

UC Davis Urban Sustainibility (ECI 123) Midterm

I = PAT Equation

I - total environmental impact

P - population

A = affluence per capita consumption

T = technology effect on environmental damage per unit of consumption

Carrying Capacity

Population < Carrying Capacity

Examples in restrains in carrying capacity

food production, freshwater, renewable energy

Examples of what can maximize population in the context of carrying capacity

technology and consumption rates

Affluence

• wealth

• countries consume on per capita basis

• effect of wealth is not just individual, but a function of infrastructure provided

• ex: consistent and inexpensive access to electricity, gas, water, etc.

How much energy does the U.S. consume yearly? What is the distribution?

100 Quads (10^15 Btu)

• 40% buildings

• 30% industry

• 30% transportation

Primary/Total life cycle energy calculations:

EX: It takes 3 MJ of primary energy for every 1 MJ of delivered electricity. Hairdryer uses 375 Wh_elec. What is the primary energy consumption?

375 Wh_elec * [(3 Wh_primenergy) / (1 Wh_elec)] = 1125 Wh_primenergy

What energy source dominates our energy systems? What are some examples?

Fossil Fuels: coal, natural gas, oil (non-renewable)

How is nuclear energy classified in terms of renewability?

It is a non-renewable, low-carbon energy resource.

Order these fuels by GHG intensity (most to least) - Coal, Natural Gas, Nuclear

• Coal (800 to 1,300 gCO2)

• Natural Gas (360 - 900 gCO2)

• Nuclear (10 - 100 gCO2)

Describe the US electricity grid distribution.

• 40% natural gas

• 20% coal

• 20% nuclear

• 20% renewables

Describe the California grid reliance.

• 50% natural gas

• 40% renewables

What is a Sankey diagram?

It is a flow diagram where the width of the arrows/bands are proportional to the flow quantity. Used to visualize energy and material transfers.

What relationship represents unsustainable resource consumption?

When the rate of depletion > (exceeds) rate of resource renewal.

Tragedy of the Commons

Condition where common pool resources (CPRs) are often exploited beyond their capacity.

• Why? Individuals usually have individual incentives to take more than just a “share”

Collective Action

The idea is if a group  has a common interest they’ll band together to achieve the common goal.

What are the conflicting forces opposing collective action?

self-interested behavior and free-riders

What is a free-rider?

A free rider is an individual, company, or entity that benefits from a resource, good, or service without paying for it or contributing to its cost.

Prisoner’s Dilemma

• Golden Balls

Dilemma is about how individuals or groups make decisions about cooperating or not cooperating.

What are the characteristics that make CPR institutions endure?

• Clearly defined boundaries

• Rules restricting quantity/timing/extraction

• Collective choice arrangements

• Monitoring and accountability

• Graduated sanctions

• Conflict resolution mechanisms

CPR Institutions: Clearly defined boundaries

Who has the right to the resource in the first place?

CPR Institutions: rules restricting quantity or timing or extraction

Paying for maintenances, extraction rates matching regeneration/capacity.

CPR Institutions: Collective choice arrangements

people affected by operational rules participate in making/modifying policy

Graduation sanctions

• Punishments that fit the crime

Life Cycle Assessment (LCA)

A method for characterizing and quantifying environmental sustainability of a product or system that applies a cradle-to-grave perspective.

What are the key elements of the LCA?

• Goal and Scope Definition

• Life Cycle Inventory Assessment

• Impact Assessment

• Interpretation

LCA - Goal and Scope Definition

• define audience (recipients, stakeholders, etc.)

• system boundary (what is included and excluded)

• function/functional unit (quantified measure of the performance or service)

  • ex: 1000 liters of potable water rather than mass or volume alone

LCA - Life Cycle Inventory Assessment

• tracking inputs and outputs

• resources and pollution/services/products (respectively)

LCA - Impact Assessment

• translates inventory into meaningful metrics

• impact on environment and human health

• applied to inputs and outputs

LCA - Impact Assessment Categories

• resource depletion

• human health

• ecosystem health

• global warming

• eutrophication

• acidification

• biodiversity loss

• + more!

Main gasses worried about in this class

CO2, CH4, N2O

Material Flow Analysis (MFA)

Examines the stocks and flows of a substance(s) over a region.

What are steps in a MFA?

• System definition

• measurement

• calculation

• illustration and interpretation

• recommendations

MFA - System Definition

• problem definition

• system boundaries

• selection of processes and flows

• qualitative model

MFA - Measurement

• data collection (flows and stocks)

• characterizing uncertainties

MFA - Calculation

• calculating unknown quantities by balancing materials

• principle of mass conservation

Stock

the amount of material contained in a reservoir

Flow

all input and outputs to a reservoir

Urban Metabolism

City is an organism, with inputs (eat) as resources and outputs as waste.

How can a MFA inform a decision to identify where environmental harms might arise for people?

The MFA can help analyze where resources and effort are used, and where they end up/produce. By conducting a MFA, stakeholders can understand where large wastes come from. This can help understand harms and potential prevention, avoidance, and awareness.

What is the ratio of the total life cycle energy for delivered electricity?

3:1

Where does electricity come from in the US? What is the distribution?

• 20% Coal

• 40% Natural Gas

• 20% Nuclear

• 20% Renewables

How much of all water consumption in the U.S. is in thermoelectric power generation? What’s the next biggest user?

Almost half (about 40%) of all water consumption in the U.S. Irrigation is the next big user.

How much of the total US energy consumption goes to transportation?

30%

What resource is the transportation in the US dependent on?

Petroleum

Freight Energy: order these modes of transportation in terms of decreasing efficiency. Rail, air, truck, barge.

Barge —> rail —> truck —> air

What are the limitations for the more energy efficient modes of transportation?

• limited barge routes (waterways)

• rail accessibility

• typically slower

• truck and air move faster

• The more energy efficient, the slower the movement of goods!

Which renewable energy source provides to most electricity in the U.S.?

WIND

What is the energy efficiency ratio?

Useful OUTPUT to total INPUT

What does GWP mean? Why would a GWP100 of N2O be 265?

Over a period of 100 years, 1 kg of N2O has about 265 times the heat trapping capacity in the atmosphere of 1 kg of CO2

It analyzes the trapping capacity of a substance in terms of CO2 over a period of time.

Why is GWP 20 for CH4 85 while GWP 100 for CH4 is 30?

Methane has a higher GWP within 20 years compared to 100 years because it degrades over time. GWP 20 is intense but short lived, while GWP 100 is in reference to a longer time frame, showing that CH4's affect degrades over time and is less potent.

What are the 4 dimensions of sustainable transportation?

1) Safety

2) Air Quality and Climate Change

3) Equity/Justice

4) Economics

What are the 7 dimensions of dynamics systems?

• Interconnectedness

• Positive Feedback and Exponential Growth

• Inertia of Huge Stocks

• The Effect of Delays on Feedback

• Internal System Structures Versus Triggering Events

• Information Bias Effects

• Individual Behavior Versus “Macro” Results