Energy

Nonlinear extensions of the Kalman filter (KF), such as the extended Kalman filter (EKF) and the unscented Kalman filter (UKF), are indispensable for state estimation in complex dynamical systems, yet the conditions for a nonlinear KF to provide robust and accurate estimations remain poorly understood. This work proposes a theoretical framework that identifies the causes of failure and success in certain nonlinear KFs and establishes guidelines for their improvement. Central to our framework is the concept of covariance compensation: the deviation between the covariance predicted by a...

We introduce (U)NFV, a modular neural network architecture that generalizes classical finite volume (FV) methods for solving hyperbolic conservation laws. Hyperbolic partial differential equations (PDEs) are challenging to solve, particularly conservation laws whose physically relevant solutions contain shocks and discontinuities. FV methods are widely used for their mathematical properties: convergence to entropy solutions, flow conservation, or total variation diminishing, but often lack accuracy and flexibility in complex settings. Neural Finite Volume addresses these limitations by...

The “hydrogen energy station” is one method of hydrogen production at small and medium scales. Unlike more conventional hydrogen station designs where hydrogen is simply delivered or produced on-site with a fuel “reformer” or water electrolyzer and then compressed and dispensed, energy stations would provide multiple functions in the same facility. They would integrate systems for production of electricity for 1) local uses and/or the utility grid, 2) re-use of thermal energy “waste heat” for building heating/cooling needs, and 3) purified hydrogen for refueling vehicles. Hydrogen energy...

California's emissions reduction goals for criteria air pollutants (CAPs) and greenhouse gases (GHGs) have encouraged policies that support plug-in electric vehicles (PEVs). This paper explores current and planned policies that promote PEVs, potential emissions benefits from PEV adoption in California by 2020, and future policy directions. The reviewed policies include the zero-emission vehicle regulations, the low-carbon fuel standard, and the clean car standards, which all require GHG reductions. Policies prompted by the California Public Utilities Commission Alternative-Fueled Vehicle...