Renewable Energy Perspective Byard Wood Emeritus Professor Mechanical &Aerospace Engineering RENEWABLE TECH – ECONOMIC & ENVIRNMENTAL VIABILITY Green Futures Learning Series February 17, 2016

GRAND CHALLENGES FOR ENGINEERING National Academy of Engineering, 2008  Foremost among the challenges are those that must be met to ensure the future itself.  The Earth is a planet of finite resources, and its growing population currently consumes them at a rate that cannot be sustained.  Widely reported warnings have emphasized the need to develop new sources of energy, at the same time preventing or reversing the degradation of the environment. Developing affordable renewable and non-polluting power sources is a priority!

Renewable Energy Resources and Technologies are non-depletable or naturally replenishable OptionsStatusCapacity Small hydro Low to high head turbines and dams. Run of river. Virtually all are commercial. Factor Intermittent to base load. Wind Horizontal and vertical axis wind turbines. Wind Pumps. Commercial. New designs under development. Variable, 20 to 40%. Solar Photovoltaic. Active thermal (low to high temp for heat or electricity). Passive thermal. Most commercial. Some under development or refinement. W/o storage: <25%, intermittent W/thermal storage: 40 to 60%, intermediate. Geothermal Cycles: Dry steam, Flash, and Binary Commercial. Exploration and drilling improvements underway. High, base load. Bioenergy Combustion. Fermentation. Digestion. Gasification. Liquefaction. Many commercial. More under development or refinement. US wood plants average 95+%. Intermediate, peaking also possible.

Global Energy Requirements & Resources I) Requirements (1 TW power plant= 200 5,000 MW power plants) 13 TW today 26 TW by TW by 2100 II) Available Resources 1) Fossil Fuel/Carbon Capture -25 billion metric tons of CO 2 /year -Volume of Lake Superior 2) Nuclear -10 TW requires 1 new GW fission plant every day for 50 years -Terrestrial uranium would be exhausted in 10 years -Fusion – no sooner than ) Renewable -Hydroelectric 0.5 TW maximum (UN estimates) -Tides and oceans <2 TW/year maximum -Geothermal 12 TW (but only fraction extractable) -Wind 2-4 TW maximum -Sun 120,000 TW (biomass + electricity <2% today)

Global Energy Requirements & Resources I) Requirements (1 TW power plant= 200 5,000 MW power plants) 13 TW today 26 TW by TW by 2100 II) Available Resources 1) Fossil Fuel/Carbon Capture -25 billion metric tons of CO 2 /year -Volume of Lake Superior 2) Nuclear -10 TW requires 1 new GW fission plant every day for 50 years -Terrestrial uranium would be exhausted in 10 years -Fusion – no sooner than ) Renewable -Hydroelectric 0.5 TW maximum (UN estimates) -Tides and oceans <2 TW/year maximum -Geothermal 12 TW (but only fraction extractable) -Wind 2-4 TW maximum -Sun 120,000 TW (biomass + electricity <2% today) More energy from the sun strikes the earth in 1 hour than all of the energy currently consumed on the planet in 1 year!

The cost profiles of renewables and fossil fuels are very different. Coal and natural gas plants have lower upfront capital costs, but are sensitive to fuel prices; technologies like wind, solar and geothermal have no fuel costs, but are far more capital intensive to build upfront, making them sensitive to financing costs. Capital Cost Fuel & Operating Costs Capital Cost

Stephen Lacey September 22, 2014 Levelized cost of energy (LCOE) per-MWh cost (in real dollars) of building and operating a generating plant over an assumed financial life and duty cycle.

US Historical & Projected Energy Consumption National Academy of Engineering Quad = energy in 170 million barrels of oil

25 % Waste

Take Away Message  Energy conservation technologies are the most cost effective options.  Solar energy technologies have the best potential large scale impact globally.  The potential for renewable energy is highly dependent on local conditions, e.g., Solar, Geothermal, Biomass.  Reducing reliance on fossil fuels is a multi decade process.  Without cost effective energy storage technologies large scale intermittent renewable energy will be limited.