Advanced Energy Perspectives

This post is one in a series featuring the complete slate of advanced energy technologies outlined in the report This Is Advanced Energy. 

Photo courtesy of EnerNOC.

Demand Response (DR) is a grid management tool through which utilities and grid operators provide information and/or incentives to customers to encourage them to reduce energy use
at specific times. DR can use control technology that automatically responds to prices or other signals, or customers may respond to a DR request manually. Load reduction is typically achieved by temporarily switching off or reducing usage from cooling or lighting or by postponing energy-using activities, although some customers may switch to onsite generation. Storage-backed DR is a growing application that enables load reduction without a shift in energy use.

Behavioral energy efficiency (BEE) employs messaging grounded in behavioral science to produce simple, actionable messages that are relevant to customers and motivate them to save energy. The average utility customer spends just nine minutes per year interacting with their utility or electricity provider. When they do, they are likely to have one basic question: How can I save money? BEE answers this question with communications delivered through multiple channels – e.g., web, mobile, mail – to help customers get engaged and focused on reducing energy consumption and saving money. These messages include information such as how the customer’s energy use compares to that of similar homes in the same neighborhood, as well as personalized energy efficiency tips, providing customers with voluntary ways to save. BEE programs consistently produce savings of 1.5% to 2.5% per household. For context, every 1% reduction in residential electricity use nationally is roughly equivalent to the electricity used by 1.3 million homes, or nearly $1.7 billion annually.

This post is one in a series featuring the complete slate of advanced energy technologies outlined in the report This Is Advanced Energy. 

Power generation from biomass (organic matter) covers a range of options. The most common technology is direct combustion, in which solid biomass is burned in a boiler to generate high-pressure steam that turns a steam turbine generator. Biomass resources used for this technology include logging and agricultural residues, forest product residues (e.g., bark, sawdust), agricultural field crop residues, and dedicated energy crops. Biomass co-firing is a similar technology in which biomass is burned along with fossil fuels, typically coal, in the same unit. Plants built with this capability can usually burn any mixture of biomass and coal, while retrofitted coal plants can co-fire up to about 2% biomass without major modifications, or up to about 15% if equipped with a separate biomass handling and feed system. Wood chips are the most common fuel for co-firing, but torrefied biomass is gaining attention. As an alternative to co-firing, old coal-fired power plants can be fully converted (repowered) to burn biomass. Gasification is an alternative to direct combustion whereby solid biomass is converted into a synthesis gas that can be co-fired with coal or used in a gas turbine.

Solar Thermal Electric (STE), often called concentrating solar power (CSP), uses mirrors or lenses to concentrate sunlight, generating temperatures high enough to produce steam and drive steam turbines. There are three configurations of STE systems in commercial use: power towers focus sunlight at a point, while parabolic troughs and Fresnel reflectors focus sunlight onto linear receiver tubes. Parabolic troughs and power towers are the most commonly used STE technologies today, and along with linear Fresnel configurations are deployed in large-scale projects that generally range in capacity from tens to hundreds of MW. STE plants can incorporate thermal energy storage, typically using molten salt, allowing them to generate electricity when it is needed even if the sun is not shining. A number of commercial and demonstration projects have also been built to integrate STE technology into natural gas and coal power plants, reducing the fuel inputs needed for the same energy output.