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. 

Credit: SunPower

Solar photovoltaic (PV) power systems convert sunlight directly into electricity. PV modules (panels) produce direct current (DC), which is converted to grid-compatible alternating current (AC) through an inverter. Utility-scale PV installations are typically connected to the transmission grid, and range from about 1 MW to several hundred MW. Since PV can make use of diffuse or direct sunlight it can be installed anywhere. The majority of large solar farms use ground- mounted at-plate PV panels, which can be installed at a fixed-tilt or can use single-axis or dual-axis tracking systems that follow the sun. Tracking increases electricity production over the course of the day, but also increases costs. Concentrating PV (CPV) is a variation on at plate PV that uses arrays of lenses mounted in front of small PV cells to concentrate the sunlight reaching the cells. CPV requires dual-axis tracking and is more efficient, but more expensive, than regular at plate PV, so it is best suited to very sunny locations.

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

Image courtesy of GenZe and Chevrolet.

Plug-in electric vehicles (PEVs) are emerging as an important vehicle platform in the United States and globally. PEVs are powered completely or in part by batteries (typically lithium-ion) that can be recharged with power from the electric grid. PEVs include 100% battery electric vehicles (BEVs) such as the Nissan Leaf and Tesla Model S, and plug-in hybrid electric vehicles (PHEVs) such as the Chevy Volt and Toyota Prius Plug-in, which contain both a battery and a gasoline-powered engine. BEVs typically have ranges of about 80 to 250 miles, while PHEVs have electric-only ranges of about 20 to 40 miles, after which they operate on gasoline, giving them a driving range equivalent to any gasoline-powered vehicle. As with hybrid electric vehicles (p.57), all PEVs take advantage of regenerative braking to extend electric range.

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

Gas turbine technology is mature and widely used, with innovations driving new improvements in efficiency, performance, and cost. In its most basic configuration, the simple cycle gas turbine (SCGT), air is compressed and mixed with fuel (usually natural gas), then the mixture is burned in a combustor. The resulting hot, pressurized gases expand through the turbine section that drives the compressor and an electric generator. In a combined cycle gas turbine (CCGT) plant, also called a natural gas combined cycle (NGCC) plant, the hot exhaust gases leaving the turbine pass through a heat recovery steam generator, producing steam that is used to generate more electricity with no additional fuel. This process can increase efficiency to 60%, compared to about 40% for SCGTs. Most gas turbine plants in operation use so-called “heavy duty” or “industrial” turbines, with units ranging from about 1 MW to over 300 MW. The other main type of machine, an aeroderivative gas turbine, ranges in size up to about 90 MW. These turbines are more lightweight, compact, and even more efficient. Another class of machines, microturbines, have lower efficiencies than the larger turbines, but are well suited for onsite power and CHP due to their compact footprint and smaller size (25 kW to 500 kW).