Energy: renewable sources of energy Energy Sources 1
It is technically and economically feasible to phase out net greenhouse gas (GHG) emissions almost entirely by 2050. A report by energy consulting firm ECOFYS, "Feasibility of GHG emissions phase-out by mid-century", The scenarios can be categorized broadly as one of two types: - scenarios with nearly 100% of energy from renewable energy sources - scenarios with less than 100% renewable energy but carbon capture and storage. This can be done mostly with technologies currently available and at a cost of less than 5% of annual GDP until 2050 Biomass Organic substances produced by recent photosynthesis Corn Sugarcane 2
Biomass if done sustainably Beneficial if using crop residues Organic waste Life cycle GWE 0.04-0.2 lbs CO2 Vs. natural gas 0.6-2 lb Coal 1.4-3.6 lbs Transportation and combustion emissions are roughly equivalent for all types of biomass. However, global warming emissions from the sourcing of biomass feedstock vary widely. Same water use as coal plant Same concerns as with any crop Air pollution during combustion (NOx are lower than coal but Higher than natural gas) Competing with food crop land Hydroelectric power Hydropower results from the force of water flowing through a dam. 98% of U.S. rivers are dammed. 3
Hydroelectric power as long as water is NOT overdrawn No emissions Worumbo hydroelectric facility, certified low-impact Dams replace river conditions With a lake This harms native wildlife Prevents fish from moving up or down the river Protect or mitigate its impacts in the following areas: river flows, water quality, fish passage and protection, watershed protection, threatened and endangered species protection, cultural resource protection, and recreation. Solar energy Use of energy from the sun Huge potential: Each day Earth = to power 27 years, if we could somehow capture it all. Passive Solar Design for Buildings Solar Heat Collectors Solar Thermal Concentrating Systems (CSP) Convert solar energy heat Photovoltaic cells (PV cells) convert solar electrical energy 4
Solar energy Decentralized control over energy Life cycle GWE 0.07-0.18 lbs GWG kwh Vs. natural gas 0.6-2 lb Coal 1.4-3.6 lbs land use Water use by CSP Use of Hazardous chemicals (because some are expensive, they are recycled) Up front cost is high Putting solar panels on suitable undeveloped rooftop space in Los Angeles County could create about half of the electrical power California needs on a typical summer day Wind power Kinetic energy of wind electrical energy by use of wind turbines 5
Wind power Decentralized control over energy Life cycle GWE 0.02-0.04 lbs CO2 kwh Vs natural gas: 0.6-2 lbs Coal: 1.4 and 3.6 lbs Not everywhere is windy enough Some object to aesthetics (NIMBY) Birds and bats deaths High upfront cost The cost of electricity from the wind has dropped from about 25 cents/kwh in 1981 to averaging near 4 cents/kwh in 2008 Analysis by the DOE Lawrence Berkeley Lab found that wind prices have been competitive with wholesale power since 2003. The Bats and Wind Energy Cooperative concluded that keeping wind turbines motionless during times of low wind speeds could reduce bat deaths by more than ½ without significantly affecting power production We have done a lot of work studying how eagles respond to the presence of turbines. The key finding was that eagles demonstrated an awareness of the turbines, and usually actively avoided them. Dr Cindy Hull, avian ecologist Ocean energy Motion energy electricity Tidal power: Rising and falling of seas Wave power: Motion of waves Clean emissions Life cycle GWE are below 0.05 lbs Can take up coast area or ocean space Interfere with the coastal ecosystems Hydrology and salinity 6
Geothermal energy Geothermal energy is the energy stored in the form of heat beneath the earth's surface. Geothermal power plants, which use heat from deep inside the Earth to generate steam to make electricity. Geothermal heat pumps, which tap into heat close to the Earth's surface to heat water or provide heat for buildings. Geothermal energy Life cycle GW emissions 0.1-0.2 lbs. GWG per kwh Vs. 0.6-2 lbs of natural gas Not present everywhere Uses water for cooling and re-injection (can be lessen by using geothermal fluids) Air pollution (SOx, CO2 and methane) if not a closed loop system 7
Hydrogen In a fuel cell, hydrogen gas is used to produce electricity 2 H2 + O2 2 H2O + energy Clean emissions (except water vapor) source of hydrogen gas source of energy to produce hydrogen gas sources: Today 8
sources: Outlook As growth continues prices are decreasing Growth should increase reduction of costs in wind and photovoltaic energy in units of cents per kilowatt-hr Subsidies can help or hinder renewable growth 9
Smart Energy Solutions Increase Energy Decrease Coal Use Improve Energy Efficiency Nearly 1.5 million buildings in LA County were built before energy efficiency codes went into effect 10