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This article discusses the energy usage and emissions of the US industrial and building sectors, as well as the impact of proposed GHG legislation. It explores alternative solutions such as cap and trade and carbon tax, and highlights the potential of CO2 absorption and stripping in power plants. The impact of shale gas, optimization of design and operation, and the concept of a smart grid are also explored. The article concludes with a discussion on the future industrial environment and the use of thermal energy storage.
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The U.S. Industrial and Building Sectors • Industrial energy usage = 35 quads; building energy usage = 40 quads(total = 100 quads) • Building energy consumption split roughly 50:50 between commercial and residential buildings • These two sectors account for about 70% of total U.S. GHG emissions • By 2030, 16% growth in U.S. energy consumption, which will require additional 200 GW of electrical capacity (EIA) • Energy efficiency goals of 25% reduction in energy use by 2030(McKinsey and National Academies Press reports)
Impacts of proposed US GHG legislation if enacted in 2007 http://www.wri.org/climate/topic_content.cfm?cid=4265
Other Alternatives • Cap and Trade • Establishes firm limit on CO2 emissions • Auctioning/trading of emissions permits • Carbon Tax • Price Predictability • Favored by large chemical companies • Apply to all Carbon Sources • Regulated CO2 • Recent EPA announcement on reporting requirements
CO2 Absorption/Stripping of Power Plant Flue Gas Use 30% of power plant output Flue Gas With 90% CO2 Removal CO2 for Transport & Storage Absorber Stripper LP Steam Flue Gas In Lean Solvent Rich Solvent
Increased Generation Efficiency • Conventional efficiency: 40-55% • Cogeneration efficiencies: 75-85% • Used by 25% of U.S. petrochemical industry
Impact of Shale (Natural) Gas • Increasing supplies of domestic natural gas (+20%) • Increased usage in power generation • Makes U.S. industrial locations more globally competitive (feedstock, power) • Changes regional industrial development options (e.g., NY-PA), subject to local environmental pressures
Optimization of Design and Operation Can • Reduce energy consumption • Improve yields • Reduce pollutants • Increase processing rates • Increase profitability • Maximize efficiency
What is a Smart Grid? • Delivery of electric power using two-way digital technology and automation with a goal to save energy, reduce cost, and increase reliability. • Power will be generated and distributed optimally for a wide range of conditions either centrally or at the customer site, with variable energy pricing based on time of day and power supply/demand. • Permits increased use of intermittent renewable power sources such as solar or wind energy and increases need for energy storage.
Today’s Grid Smart Grid 1.0
Tomorrow’s Grid Smart Grid 2.0
Electricity Demand Varies throughout the Day Source: ERCOT Reliability/Resource Update 2006
Wind and ERCOT daily load Source: Dispatchable Hybrid Wind/Solar Power Plant, Mark Kapner, P.E
Three Types of Utility Pricing • Time-of-use (TOU) – fixed pricing for set periods of time, such as peak period, off peak, and shoulder • Critical peak pricing (CPP) – TOU amended to include especially high rates during peak hours on a small number of critical days; alternatively, peak time rebates (PTR) give customers rebates for reducing peak usage on critical days • Real time pricing (RTP) – retail energy price tied to the wholesale rate, varying throughout the day
Smart Grid Challenges/Unknowns • Design of the grid • Power storage • Redundancy and reliability for peak/base loads • Power flow management • Power stability • Cybersecurity • Automation/decentralized control • Distributed power generation (renewables) • Power electronics • AC vs. DC
Future Industrial Environment • Stronger focus on energy use(corporate energy czars?) • Increased energy efficiency and decreased carbon footprint • Increased use of renewable energy(e.g., solar thermal) and energy storage • Interface with smart grids.
Thermal Energy Storage • Thermal energy storage (TES) systems heat or cool a storage medium and then use that hot or cold medium for heat transfer at a later point in time. • Using thermal storage can reduce the size and initial cost of heating/cooling systems, lower energy costs, and reduce maintenance costs. If electricity costs more during the day than at night, thermal storage systems can reduce utility bills further. • Two forms of TES systems are currently used. The first system used a material that changes phase, most commonly steam, water or ice. The second type just changes the temperature of a material, most commonly water.
Grid Electricity Exhaust Demand Facility Electricity Auxiliary Power Chiller Power Electricity Produced Electric Chiller Chilled Fluid Power Generation (Gas Turbine) Heat Recovery System Heat Carrier Absorption Chiller Storage Tank Storage Tank Σ Heat Carrier Heat Exchanger Boiler Input Fuel Heat Carrier Waste Heat Electricity Flow Fuel Flow Thermal Flow Energy flows in a combined heat and power system with thermal storage (Wang, et al. 2010)
