Nonrenewable Review & Renewable Introduction Monday, January 9th, 2016

Energy Use: World & US We get most of our energy by burning carbon-containing fossil fuels. Note that oil is the most widely use form of commercial energy and that about 79% of the energy used in the world (85% of the energy used the United States) comes from burning nonrenewable fossil fuels.

Energy Use WORLD US 85% Nonrenewable Use of coal decreasing Use of oil increasing Nuclear leveled off Developing countries depend on biomass (firewood, charcoal) for heating/cooking – can’t afford fossil fuels 93% Nonrenewable World’s largest energy user 5% of world’s population uses 25% of world’s energy

Nonrenewable resources cannot be replaced Fossil fuels are derived from biological matter (coal, oil, and natural gas) Nuclear is derived from radioactive materials Amount of energy use depends on availability and affordability Patterns of use in US Wood until 1875, than coal followed by natural gas and oil. Nuclear around 1950 and renewable in the 1970s

Patterns of Energy Use in the US

FOSSIL FUELS Composed of partially decayed organism remains Nonrenewable Form too slowly to replenish NOT sustainable EX: Coal, Oil, Natural Gas

Formation of Fossil Fuels Formation of Coal - Over time, plants die, covered by water and sediment - Heat and pressure convert material into carbon rich ore (COAL) and sedimentary rock. Formation of Oil - Death and buildup of microscopic aquatic organisms. - Heat and Pressure convert material to hydrocarbons (OIL) without oxygen in sediments that prevent decay. Formation of Natural Gas - Same as oil, just produced at higher temperatures than oil.

What is Net Energy and why is it important? Net energy is the amount of high-quality energy available from an energy resource minus the amount of energy needed to make it available. Total amount of useful energy available - Energy needed to make it available Net Energy = More formally known as EROEI

Basic Science: Net Energy is the only energy that really counts First law of thermodynamics: It takes high-quality energy to get high- quality energy Pumping oil from ground, refining it, transporting it Second law of thermodynamics Some high-quality energy is wasted at every step Before oil is useful to use, it must be found, pumped, refined, & delivered. Takes energy (high quality) to do this. 2nd law – some of high quality energy wasted at each step. Think of net energy like business net profit – total money taken in - expenses

Conventional Oil = HIGH net energy ratio, Energy Produced : Energy Used to Produce it Net Energy Ratio , Net Energy Conventional Oil = HIGH net energy ratio, But decreasing It takes energy to pump oil from underground or undersea Ratio less than 1 – energy is lost If it takes 9 units of energy to grow 10 units of corn, ratio is approx 1:1. Ratio increases net energy increases

Electricity generation Starts with sun, and the potential energy is converted into electricity Ultimate goal is to spin a turbine (fluid). Usually done with steam (burn coal to get steam) Spinning turbine spins a generator that creates electricity that gets sent through transmission lines Capacity is the maximum potential output Cogeneration is the use of fuel to generate electricity and heat Can be 90% efficient vs. 35% for just electricity

Reducing Energy Waste Improves Net Energy Yields and Can Save Money 84% of all commercial energy used in the U.S. is wasted 43% after accounting for second law of thermodynamics Drive efficient cars, not gas guzzlers Make buildings energy efficient

How can we use less energy? Energy conservation- finding ways to use less energy. For example, lowering your thermostat during the winter or driving fewer miles. Energy efficiency- getting the same result from using a smaller amount of energy.

Benefits of Conservation and Efficiency Many energy companies have an extra backup source of energy available to meet the peak demand, the greatest quantity of energy used at any one time. Variable price structure- utility customers can pay less to use energy when demand is lowest and more during peak demand.

Sustainable Design: Improving the efficiency of the buildings we live and work in. What is renewable energy? Renewable energy can be rapidly regenerated, and some can never be depleted, no matter how much of them we use.