TAE020: Sustainable Energy

Energy Problem

• High carbon emissions

• Oil

• Expanding global demand (1-2% increase per year)

Factors

• Slow progress for fossil fuel alternatives

• Changing limitations

  • Policy

• Late response (yesterday was to act, act now)

Global Energy Use/Development

Consumption increased 2.5 times from 1970 to 2015 about 2% per year until 2013, and around 1.0 % from 2014-2016.

• Most growth occurred up to 2000 in the developed countries and after 2000 in the developing countries.

Non-OECD (82% population) consumes energy at a rate of:

52 MBtu per capita

(compared to whopping 184 MBtu in OECD countries)

Energy per capita increased by __% in non-OECD countries, while it dropped by __% in the US and 8% in all other OECD countries

58, 15

Core indicators of human welfare/standards of living/education/income are reflected in the use of:

high-quality energy

Energy Use in the USA

The energy intensity of the economy improved by 27%, and per capita consumption dropped by 15%.

• Electricity consumption increased significantly from 2000-2007

• Petroleum consumption has decreased since 2006, and

  reliance significantly (25-60%) on imports.

Agri-food sector currently consumes __ percent of the total energy demand globally,

30

Around _-_% of total final energy consumption is used directly in the agriculture sector, about _._% of total US primary energy consumption.

3-5, 1.9

Greenhouse Effect

1. Specific molecules transmit short-wavelength solar radiation but block irradiated long-wavelength

2. Equilibrium surface temperature increases

3. All energy establishing equilibrium is from the sun

4. Geothermal only accounts 0.1% of earth’s total heat

Equilibrium w/o atmosphere is __^oC

-19

Solar power absorbed by the planet: Formula

Solar power radiated from the planet: Formula

Global energy balance from the above two sources & sinks:

The earth's surface temperature will be higher (+__°C) than predicted by the simple model, which excludes the atmosphere (-__°C).

11, 19

The atmosphere traps heat, causing the greenhouse effect and increasing the earth's average temperature by more than __°C

30 (degrees)

Climate Change (Carbon Emissions)

Combustion of fossil fuels produces CO₂

This CO₂ adds to GHG → equilibrium raised

Evidence of Global Warming

Reduction in Arctic sea ice: The area has decreased by about 9 % in the past decade, and the thickness has decreased by 15 – 40 % over the past 30 years.

• I.e. migration routes, geographic ranges

• Increased sea levels

Predicted Temperature Changes for the Next Century

Global temperature increases of 2 to 8 C ° above the preindustrial level can be expected by 2100

Carbon Sequestration

Capturing and storing atmospheric carbon dioxide. It is one method of reducing the amount of carbon dioxide in the atmosphere with the goal of reducing global climate change.

Climate Change Scientific Consensus/Initiatives

• Reduce energy consumption to mitigate enviro. effects

• Major industrialized countries: binding 6-8% reduction in greenhouse gas emissions relative to 1990

• IPCC

• Paris Agreement/Accord

• Kyoto Protocol

• UNFCCC

100% Solution: Hypothetical Roadmap

Transition energy infrastructures to clean, renewable (Wind, Water, and Solar) (WWS) using existing technologies for 80% of all electricity, transportation, heating/cooling, industry, and agriculture/forestry/fishing by 2030 and 100% by 2050.

Energy

The ability/capacity to work

Work (W)

The product of force (F) and the distance (d) over which it acts

Force

Newton’s Law

• F = ma

Work done against a gravitational field to lift an object to a height (h) is:

W = mgh

Power

The rate at which the work is done

Energy

The product of power (P) times time over utilization (t)

Kinetic Energy

Associated with the movement of an object

Two Types of Kinetic Energy

Translational motion (E = 1/2(m)(v)²)

Rotational motion (E = 1/2(l)(w)²)

Potential Energy

Most commonly associated with the energy of an object in a gravitational field given by:

E = mgh

Thermal Energy

Kinetic energy associated with the microscopic movement of molecules

E = 3/2(nRT)

A quantity of energy supplied Q supplied to material of mass and specific heat will increase the temperature by delta T.

Delta T = Q/mC

Chemical Energy

• Energy associated with chemical bonds between atoms

• Exothermic and endothermic reactions

• Energy released in combustion reactions →

Nuclear Energy

Energy associated with bonds between neutrons and protons in the nucleus

• Much greater than chemical energy

• Energy release during an exothermic nuclear reaction → changes in total mass of system

Electrical Energy

Energy associated with flow of electreons in a conductor

• Current (I) in conductor will experience voltage drop

  • Ohm’s law

• V = IR

• Energy of the electric and magnetic fields associated with electromagnetic waves (such as light).

• Waves have a wavelength (λ) related to the frequency (f) and the velocity (c, speed of light).

Laws of Thermodynamics

0: Two systems both in thermodynamic equilibrium with a third system are in equilibrium

1: Energy is conserved

2: A closed system will move towards equilibrium

3: It is impossible to attain absolute zero temperature

Zeroth Law Thermodynamics

Implies that the thermodynamic state of system can be defined by a single parameter, the temperature

• PV = nRT

• Ideal Gas Law: linear relationship between temp and pressure

First Law Thermodynamics

When energy is applied through heat:

1. Internal energy of the gas increases if piston of tube is fixed

2. Energy is used to lift piston if piston moves

Second Law Thermodynamics

Heat naturally flows from hot to cold

• Analogous to gravitational potential energy: object in a gravitational field only works if it moves from point of high potential to low

Total Energy in a system is calculated simply as:

= useful energy delivered + wasted energy

Energy efficiency (Ƞ) =

Useful energy delivered/energy input

Overall efficiency of a system =

product of all individual efficiencies

Efficiency

reducing the amount of energy input needed to meet our energy output needs

Conservation

reducing energy output needs or waste, e.g., through behavior/lifestyle changes

Types of Efficiency

• Conversion efficiency

• Functional/system efficiency

• Heating your home

Specific Heat

Energy to raise a unit of mass by one degree

Heat Capacity

Ability of a substance to store heat