Residential combined heat and power (CHP) systems produce electricity onsite while utilizing waste heat to supplement home heating requirements, which can lead to significant reductions in CO2 emissions and primary energy consumption. 

Increasing the conversion efficiency of incident solar energy to electricity is a key goal in the solar R&D community. In this issue of Joule, a conceptual hybrid photovoltaic/thermal (PV/T) receiver design is reported by the research groups of Evelyn Wang and Gang Chen. High exergetic efficiency is achieved by absorbing below-bandgap and excessively high-energy photons as thermal energy, while allowing photons at the PV’s bandgap to pass through to the underlying cell.

ARPA-E’s impact assessment initiative documents the scientific and commercial successes achieved by a selection of ARPA-E-funded projects. The third installment of this series, “ARPA-E Impacts: A Sampling of Project Outcomes, Volume III” provides a glimpse into the diverse and sophisticated research portfolio of advanced energy technologies that will enable the United States to tackle our most pressing energy challenges.

Recent advances in wide band-gap (WBG) semiconductor materials, such as silicon carbide (SiC) and gallium nitride (GaN) are enabling a new generation of power semiconductor devices that far exceed the performance of silicon-based devices. Past ARPA-E programs (ADEPT, Solar ADEPT, and SWITCHES) have enabled innovations throughout the power electronics value chain, especially in the area of WBG semiconductors.

Additive manufacturing enables new approaches to chemical reactor design due to the ability to build complex geometries and topologies inaccessible to traditional manufacturing technologies.

In this Perspective, we focus on three tasks to guide and further advance the reversible lithium metal electrode. First, we summarize the state of research and commercial efforts in terms of four key performance parameters, and identify additional performance parameters of interest. 

Today more than 99% of thermoelectric power plants (coal Rankine, natural gas combined cycle, solar thermal, etc) in the United States utilize some form of wet cooling due to the superior thermal properties of water over air. Further, for large-scale building cooling applications, wet cooling of the condenser is employed as well. Globally, the projected growth of electrification and air conditioning deployment is a particular concern in water-constrained areas in northern Af-rica, the middle east, and India where further cooling load requirements will put stresses on limited water supplies.  

The deployment of solar technology has experienced incredible growth in the past decade. This deployment has been dominated by single-junction silicon photovoltaic (PV) technology. These devices are characterized by a single bandgap, which is unable to convert a significant fraction of the incident solar spectrum.

ARPA-E’s RANGE (Robust Affordable Next Generation Energy Storage Systems) program funded high-risk research projects to change the way electric vehicle battery systems are built. The program is a success both in terms of individual projects and in reshaping the paradigm about energy storage as a whole to include system-level considerations. 

The Agency’s first compilation booklet of impact sheets, published in 2016, began the process of analyzing and cataloging some of the agency’s most successful projects. One year later ARPA-E’s research investments continue to pay off, with a number of current and alumni project teams successfully commercializing their technologies and advancing the state of the art in transformative areas of energy science and engineering. This document is a compilation of the second volume of these impactful technologies.