 Near-solid-state heat pumps using thermoacoustics are commonly used in cryogenic laboratories.The Alternative Energy Portfolio Standard (APS) was developed in 2008 to require a certain percentage of the Massachusetts electricity supply to be sourced from specific alternative energy sources.In October 2017, the Massachusetts Department of Energy (DOER) drafted regulations, pursuant to Chapter 251 of the Acts of 2014 and Chapter 188 of the Acts of 2016, that added renewable thermal, fuel cells, and waste-to-energy thermal to the APS.