energy and the environment

What is energy?

Energy- the ability to do work

What is work?

Work-force x distance

Energy

the ability to do work

Work

force x distance; force is a push or pull on an object resulting from the object's interaction with another object.

Energy Consumption and Population Growth

As the population and the standard of living increase, energy consumption goes up as well.

Renewable Resources

energy sources that naturally replenish themselves at rates that support their ongoing use, such as wind, cycling water, solar energy.

Non-renewable Resources

energy sources that are NOT naturally replenished at rates that support their ongoing use, such as fossil fuels and uranium.

Difference between Energy and Power

Energy is the ability to do work whereas power is the rate of energy use.

Power Equation

Power = Energy/time (watts)

Energy Equation

Energy = Power x time (usually in Joules)

Watt

a unit of power, commonly used for electricity; Watt = 1 Joule / second.

Energy Used Calculation

Energy = 100W * 8 hours = 800 Wh for a 100W lightbulb left on all day.

Ohm's Law

I = V/R, where I = current (Amperes), V = voltage (Volts), R = resistance (ohms).

Electric Power Equation

P = I * V or P = I^2 * R.

Faraday's Law

A changing magnetic flux through a circuit will induce a current to flow in the circuit.

Induced Electromotive Force

The induced electromotive force (~voltage) is equal to the negative of the time rate of change of the magnetic flux.

Transformers Purpose

They transmit electricity from one server to the next, changing input voltage to a different output voltage.

High Voltage Transmission

Transmitting electricity at high voltage helps reduce resistance loss.

Balancing Authority

An organization that constantly balances supply and demand, important to prevent energy blackouts.

Baseload

The generally constant amount of electricity demand, covering energy used for appliances that run continuously, such as nuclear energy.

Peak Load

The maximum electricity demand at a given time, typically higher than baseload.

Energy Return on Investment (EROI)

EROI = energy obtained / energy input.

Capacity Factor

Actual power output/nameplate capacity (power output at maximum efficiency).

Wind or Tidal Power Equation

P = 1/2ρv³πr²C, where ρ = fluid density, v = wind velocity, r = rotor radius, C = efficiency factor.

Energy Efficiency

Energy efficiency = work done/energy input.

Peak load

Peak load is the time when the demand for electricity is highest, and utilities are required to provide more power than usual.

Dispatchable energy sources

Can provide electricity on demand, can be turned on or off relatively quickly.

Non-dispatchable energy sources

Timing and/or amount of electricity generation cannot be controlled by operators.

Challenges of non-dispatchable energy sources

Not able to control it, wasting energy, can't change if you need to change the amount for a specific use, and it's not reliable.

Petroleum emissions

Petroleum is responsible for the majority of emissions from transportation.

Natural gas emissions

Natural gas is responsible for the majority of emissions from electricity generation.

Demand-side emissions reductions

How much energy is used ("demanded") and how many products/which goods are used.

Supply-side emissions reductions

How energy is produced ("supplied") and how food/products are made.

Resource

Concentration of a naturally occurring material in the Earth's crust that can potentially be extracted for a profit.

Reserve

Portion of a resource that is identified and currently available resources to be extracted for a profit.

Factors determining reserves

Economy, technology, legality, etc.

R/P ratio

Reserve (amount) / production rate (amount/year); R/P ratio = years of reserve left at current production rates.

Reasons for using fossil fuels

Energy-dense, readily available with current technology and economics, relatively cheap, storable, transportable.

Main precursor material to coal

PEAT.

Requirements for fossil fuel formation

Large organic productivity, deposition of organic materials in anoxic environments, and rapid burial for preservation.

Hydrocarbon molecules and boiling points

The longer the chain, the higher the boiling point.

Requirements for petroleum and natural gas formation

High organic productivity in marine and lacustrine environments, anoxic conditions at seafloor or lakebed, deposition of overlying sediments.

Common precursors for oil and gas

Oil shales; organisms died and drifted to the seabed, buried under layers of plants and sediment, decomposed, and transformed into kerogen.

Key elements of a petroleum system

Source, Reservoir, Seal, Trap.

Source in petroleum system

Rock rich in organics, heated to produce hydrocarbons (oil and gas) is at the very bottom of the system.

Reservoir in petroleum system

Porous and permeable, receives migrating hydrocarbons, above the source rock.

Seal in petroleum system

Overlying impermeable rock prevents upward migration; the seal is above the source rock.

Trap in petroleum system

Geometric container that allows hydrocarbons to collect in a reservoir; traps are usually below the seal rock.

Trap

Geometric container that allows hydrocarbons to collect in a reservoir. traps are usually below the seal rock.

Seals

Generally shales or evaporites (halite).

Reservoir

Sandstones and limestones.

Porosity

Percent of space in a rock that can be filled with fluid.

Permeability

Measure of the ease with which a fluid can pass through the pore spaces of the rock.

Mud in drilling process

Helps prevent blowouts, cools and lubricates the bit, maintains borehole stability, balances fluid pressures.

Cement in a borehole

It helps keep the hole from collapsing in on itself.

Distillation

Separating hydrocarbon compounds based on their molecular densities and weights.

EROI

Energy Return on Investment; it determines whether or not something is profitable or not.

Shale gas revolution technologies

Horizontal (lateral drilling) and hydraulic fracturing (fracking).

Tight Gas

Natural gas mined from low-permeability rocks that require fracking.

Shale Gas

Specifically natural gas from shale, one type of 'tight gas.'

Hydraulic fracturing

Used to generate the fracture and keep it open after pressures are reduced.

Additives to fracking fluids

These are used to weaken the rock, hold open the cracks, and control the viscosity.

Reclamation in mining

Returning the land to pre-mining conditions.

Bonding

Fees are posted to cover the cost of reclamation, even if the company fails to extract, etc.

Induced seismicity

What is most likely to cause it?

Oil and Gas production

Production, refining, and transportation.

In-situ removal of oil

Thermal injection of steam, solvents, and/or CO2 through vertical or horizontal wells.

Distillation tower principle

The column works on the principle of differential distillation, where a mixture is heated to create vapors.

Bitumen in tar sands

Sands with up to 20% bitumen that are mined or 'pumped' and processed to generate synthetic crude oil.

Shale gas extraction

Shale gas is considered 'unconventional' because it is trapped within a low-permeability shale rock formation.

Fluids injected under pressure

Can relieve the stresses perpendicular to natural faults, promoting rupture and inducing earthquakes.

Acid mine drainage

Outflow from operational and abandoned mines can be highly acidic, contaminating subsurface and surface groundwaters.

Effects of hydrocarbon contamination

Coating and smothering organisms, ingestion and metabolic disruption.

Hydrocarbon solubility

The weight of the hydrocarbon determines how soluble they are.

Natural remedies for oil spills

Evaporation of light hydrocarbons (20-20% removal), Biodegradation (>90 organisms naturally degrade hydrocarbons), Sedimentation.

Biodegradation effectiveness

It can be extremely effective (e.g. 73,000 barrels removed from the Amoco Cadiz spill).

Human remedies for oil spills

Includes offloading, burning, sinking, hot-water washing, chemical dispersal, bioremediation, physical containment, and prevention.

Chemical dispersal

Detergents attach to low-weight hydrocarbons, disperse into small droplets, enhancing biodegradation but may cause other issues.

Co-produced waters and gases

Co-produced CO2 is re-injected or released, unless local regulations require its sequestration.

Sour gas

Gases that contain some H2S, can contain up to 50% H2S, and are highly toxic.

Criteria air pollutants

Include Carbon monoxide (CO), Nitrogen oxides (NOx), Sulfur oxides (SOx), Ozone (O3), Particulate Matter (PM), and Lead (Pb).

Acid rain formation

Principally due to SO2 emissions from power plants that burn coal, impacting downwind places.

Impacts of acid rain

Hazardous to acid-intolerant species, leaches nutrients from soil, mobilizes toxic metals, causes deforestation, and declines in agricultural productivity.

Mitigation strategies for acid rain

Using low-sulfur coal, removal of sulfur by washing coal, scrubbing SOx from emissions, and dispersing emissions.

SOx reduction effectiveness

Because the supply is dominated by utility and industrial sources, which are easier to regulate.

Cap and trade

Systems that set a nationwide cap on emissions and allow trading of allowances to meet that cap.

Controls on energy in Earth system

Energy coming in is from radiation from the sun and Earth's position relative to the sun; going out is affected by albedo and atmospheric composition.

Albedo

Percent of radiation reflected from a surface, with variations causing changes in the amount of solar radiation reflected back into space.

Low albedo

Dark objects that reflect less solar radiation.

High albedo

Water and soil that reflect more solar radiation.

Vegetation

(5-35%)

Fresh snow, ice

(60-90%)

Greenhouse effect

Earth has heat and gives off radiation

Incoming solar radiation

Short wavelengths

Outgoing earth radiation

Long wavelengths

Greenhouse Gasses

Transparent to short wavelength radiation (let is pass through) and trap longwave

Global Warming Potential (GWP)

Different gasses have different warming capacities (ability to trap radiation)

GWP comparison

Global warming potential (GWP) allows for a comparison of impacts relative to CO2.

Methane (CH4)

Has a GWP = 21, meaning it is 21x as strong a greenhouse gas (GHG) as CO2.

Human alteration of the carbon cycle

We have accelerated the movement of carbon into the atmosphere.