While solar water heater devices have been around for over 100 years, the last 20 years have seen significant advances in absorber coating technologies, resulting in solar collectors that can reliably convert >50% of available sunlight for domestic hot water supply.
In a cover letter accompanying the Friday delivery of the 384 pages of new text messages, Assistant Attorney General Stephen Boyd explained that technical issues with the FBI's retention software prevented the bureau from capturing messages sent between the two employees on their agency-issued phones from December 14, 2016 to May 17, 2017.
Due to Session's decision, as well as public and Congressional pressure, Deputy U.S. Attorney General Rod Rosenstein appointed former FBI Director Robert Mueller as special counsel on May 17, 2017, to oversee the federal investigation into Russian interference in the 2016 election, including potential collusion between President Donald Trump's campaign associates and Russian officials.