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Chapter 13. Achieving Energy Sustainability. Renewable Energy. Renewable energy can be rapidly regenerated, and some can never be depleted, no matter how much of them we use. How can we use less energy?. Energy conservation – finding ways to use less energy
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Chapter 13 Achieving Energy Sustainability
Renewable Energy • Renewable energy can be rapidly regenerated, and some can never be depleted, no matter how much of them we use
How can we use less energy? • Energy conservation – finding ways to use less energy • Ex: lowering your thermostat during the winter or driving few miles in your car • 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 • Sustainable design can improve the efficiency of the buildings we live and work in • LEED (Leadership in Energy and Environmental Design) is a voluntary program that provides third-party verification of green buildings
LEED Rating System • Sustainable sites credits encourage strategies that minimize the impact on ecosystems and water resources • Water efficiency credits promote smarter use of water, inside and out, to reduce potable water consumption • Energy & atmosphere credits promote better building energy performance through innovative strategies • Materials & resources credits encourage using sustainable building materials and reducing waste • Indoor environmental quality credits promote better indoor air quality and access to daylight and views
Solar Energy • Passive solar energy – a design that collects heat as the sun shines through south-facing windows and retains it in materials that store heat • Thermal inertia – ability of a material to retain heat or cold • Using passive solar energy can lower your electricity bill without the need for pumps or other mechanical devices
Modern Carbon vs. Fossil Carbon • Carbon found in biomass was in the atmosphere as CO2, then taken in by the tree, and by burning it we put it back into the atmosphere • Carbon in coal has been buried for millions of years and was out of “circulation” until we mined it • This results in a rapid increase in the concentration of CO2 in the atmosphere
Biomass • Solid biomass fuels: • Wood • Charcoal • Manure • Used to heat homes and cook food throughout the world
Biomass – Wood Benefits • Can be sustainable, if harvested appropriately • Can increase species diversity in harvested forests • Inexpensive Drawbacks • Often harvested unsustainably • Increases soil erosion, stream water temperature, and habitat fragmentation • Releases PM, CO, and NOx when burned
Biomass – Charcoal Benefits • Lighter and more energy dense than wood • Produces less smoke than wood Drawbacks • More expensive than wood • Releases PM, CO, and NOx when burned
Biomass – Manure Benefits • Kills microorganisms found in manure • Inexpensive • Renewable Drawbacks • Releases PM, CO, and NOx when burned
Liquid Biomass • Liquid biomass fuels: • Ethanol • Biodiesel • Biofuels are used as substitutes for gasoline and diesel fuel
Biofuels – Ethanol Benefits • Promotes energy independence • Emits fewer pollutants than gasoline • Is “carbon neutral” Drawbacks • Contains less energy than gasoline • Currently made mostly from corn, a food staple • Requires energy to grow and process
Biofuels – Biodiesel Benefits • Promotes energy independence • Emits less CO than regular diesel • Is “carbon neutral” • Can be generated from used cooking oil • Algae holds a lot of potential Drawbacks • More expensive than regular diesel • Requires energy to grow and process
Kinetic Energy in Water • Hydroelectricity – electricity generated by the kinetic energy of moving water • Is the 2nd most common form of renewable energy in the world
Types of Hydroelectric Power Systems • Water impoundment – water is stored behind a dam and the gates of the dam are opened and closed, controlling the flow of water
Types of Hydroelectric Power Systems Run-of-the-river systems – water runs through a channel before returning to the river
Types of Hydroelectric Power Systems Tidal systems – the movement of water is driven by the gravitational pull of the Moon
Solar Energy • Passive solar energy - capturing the energy of sunlight without the use of a pump or photovoltaic cell
Solar Energy Active solar energy – capturing the energy of sunlight with the use of a pump or photovoltaic cell and generating electricity
Geothermal Energy • Geothermal energy – using the heat from natural radioactive decay of elements deep within Earth, as well as heat coming from Earth
Wind Energy • Wind energy – using a wind turbine to convert kinetic energy into electrical energy
