Renewable Energy Resources

D8 D9 D25 D26 D8 - Describe the availability, current uses and environmental issues related to the use of fossil and nuclear fuels to produce electricity. D9 - Describe the availability, current uses and environmental issues related to the use of hydrogen fuel cells, wind and solar energy to produce electricity. D25 - Explain how land development, transportation options and consumption of resources may affect the environment. D26 - Describe human efforts to reduce the consumption of raw materials and improve air and water quality. Take a closer look at our conventional fuel resources (i.e., oil, natural gas, coal, and nuclear)

Many of our current energy sources are causing pollution The problems …. Many of our current energy sources are causing pollution 43% of energy in the US is wasted unnecessarily What is nuclear energy? In a nuclear fission reaction, neutrons split the nuclei of atoms such as uranium-235 and plutonium-239. In the process, energy (primarily in the form of high temperature heat) is released. In a nuclear reactor, the production of heat generated by this reaction is controlled and used to produce high pressure steam, which is in turn used to spin turbines that generate electricity. Nuclear fission is basically the splitting of nuclei of certain isotopes with large mass numbers. Neutrons are fired at them, which causes them to split into lighter nuclei and to release single neutrons and energy. These single neutrons can in turn cause additional fission, but there has be enough single neutrons (critical mass) in order for the reaction to sustain itself. If controllable, nuclear power can be an efficient source of power, but large government subsidies distort the true price of nuclear and the disposal of nuclear waste has proven to be an environmentalists nightmare. Disasters on the global scale, such as Chernobyl and Three Mile Island, also highlight the risk of this type of energy source.

Example 1… lighting choices

Example 2… Automobiles Changes in required mpg fuel efficiency would help to reduce gasoline consumption Minimum requirements by date 1974 – 12.9 mpg 2014 - 29 mpg 2016 – 35.5 mpg

Efficiencies – these percentages show how much of energy taken in is actually used for the designated purpose

Some Ways to Improve Energy Efficiency Insulate / Eliminate air leaks in homes / install high efficiency lighting Purchasing more efficient appliances Build efficient electric motors Increasing fuel economy for all combustion engines

Characteristics of Renewable Resources A Renewable Resource: Replenishes very rapidly Is in inexhaustible supply

Renewable Energy Resources Solar—passive and active Hydroelectric power Wind generation Biomass Hydrogen Fuel Cell Power Geothermal

Using Solar Energy to Provide Heat and Electricity Solar energy originates as energy derived from the sun in the form of solar radiation. This energy can be captured in passive or active systems (see image below).

Solar Energy PROS Fairly high energy acquisition, even on cloudy days Quick installation No CO2 emissions / low environmental impact Installed system lasts 20-40 years CONS Needs access to sun Low efficiency Requires an electricity storage system Expensive

Hydropower Hydropower is a method of producing electricity by harvesting the energy of moving water Currently, this supplies … 50% of West Coast electricity 7% of US electricity 20% of World’s electricity

Hydropower Pros and Cons More environmentally friendly than fossil fuels and Reliable, stable and high efficiency Does not create waste CONS High construction costs Major environmental impacts

Environmental Effects of Hydropower Pollution Disruption of water flow Loss of biodiversity Invasive species

Producing Electricity from Wind Wind energy is a form of energy conversion in which turbines convert the kinetic energy of wind into mechanical or electrical energy that can be used for power. Historically, wind power in the form of windmills has been used for centuries for such tasks as grinding grain and pumping water.

Pros and Cons of Wind Power Reduces greenhouse gas emissions All the turbines need to be able to function is wind It will also foster domestic economic growth. Cons: Land must be taken from its current uses to construct these turbines. Wind energy is not always consistent Blades of the turbines have in the past incidentally kill birds that get caught in their path. Turbines require maintenance

Producing Energy from Biomass Biomass energy is energy derived from plants or plant-derived materials. Biomass can be converted into biofuels for transportation, biopower for heat and electricity and bioproducts for making things such as plastics. Examples of biomass energy sources include wood, ethanol derived from grains and methane gas emitted from landfills.

Pros and Cons of Biomass 1. Renewable - We will always have the sources of biomass such as crops, manure and garbage. 2. Carbon Neutral – The carbon in biomass is already part of the carbon cycle, so this does not add more carbon to the cycle. 3. Cost-Effective - Energy harnessed from biomass is inexpensive compared to coal and oil. 4. Abundant - Biomass is available over the world. Cons: 1. Expensive - Extraction of biomasses can be expensive. In some areas, biomass projects may not be worth the price. 2. Requires Space - Big areas are needed for all the different processes that are required in harnessing energy from biomass.

Hydrogen Fuel Cell Power A hydrogen fuel cell uses the chemical energy of hydrogen to cleanly and efficiently produce electricity with water and heat as byproducts. Currently, this technology is being applied to automobiles

Hydrogen Fuel Cell Power PROS Less greenhouse emissions and lowered air pollution Reduced oil dependence CONS Expensive Fuel cell systems are not yet as reliable as internal combustion engines There is not yet infrastructure in place to get hydrogen to consumers

Geothermal Energy This term comes from the Greek roots geo, meaning earth, and thermos, meaning heat. This energy comes from heat inside the Earth's crust. It's clean and sustainable

Pros and Cons of Geothermal Energy 1. Environmentally Friendly - There are a few polluting aspects of harnessing geothermal energy 2. Renewable - Geothermal reservoirs come from natural resources and are naturally replenished. Geothermal reservoirs will literally last billions of years. 3. Massive Potential - Worldwide energy consumption – about 15 terawatts (TW) – is not anywhere near the amount of energy stored in earth. 4. Stable - Geothermal energy is a reliable source of energy. We can predict the power output of a geothermal power plant with remarkable accuracy. Cons: 1. Environmental Issues - There is an abundance of greenhouse gases below the surface of the earth that can be released. 2. Surface Instability (Earthquakes) - Construction of geothermal power plants can affect the stability of land. 3. Expensive - The exploration and drilling of new reservoirs come with a steep price tag (typically half the costs). 4. Location Specific - Good geothermal reservoirs are not present in every location.

Geothermal Reservoirs

Entering the Age of Decentralized Micropower Our current system involves producing energy in large quantities at a few locations and moving it long distances. A “decentralized micropower” system involved producing energy at more numerous smaller plants closer to where it will be used Fig. 16-39 p. 411

Creating a Sustainable Energy Future Increase fuel efficiency standards for vehicle, appliances, buildings Create tax and other financial incentives for energy efficiency Subsidize renewable energy use, research and development Internalize externalities for fossil fuels By 2050: Increase renewable energy to 50% Cut coal use by 50% Phase out nuclear altogether What is nuclear energy? In a nuclear fission reaction, neutrons split the nuclei of atoms such as uranium-235 and plutonium-239. In the process, energy (primarily in the form of high temperature heat) is released. In a nuclear reactor, the production of heat generated by this reaction is controlled and used to produce high pressure steam, which is in turn used to spin turbines that generate electricity. Nuclear fission is basically the splitting of nuclei of certain isotopes with large mass numbers. Neutrons are fired at them, which causes them to split into lighter nuclei and to release single neutrons and energy. These single neutrons can in turn cause additional fission, but there has be enough single neutrons (critical mass) in order for the reaction to sustain itself. If controllable, nuclear power can be an efficient source of power, but large government subsidies distort the true price of nuclear and the disposal of nuclear waste has proven to be an environmentalists nightmare. Disasters on the global scale, such as Chernobyl and Three Mile Island, also highlight the risk of this type of energy source.

Solutions: A Sustainable Energy Strategy