Smart-grid networks that depend heavily on technology both for energy efficiency and for better management of electricity consumers are vulnerable to cyberattacks that can endanger entire cities, industry findings show. Ann Whyte, a spokeswoman for Defense Support Services LLC (DS2), a Lockheed Martin and Day & Zimmermann company, said suppliers that are planning to install electricity smart meters in every home by 2020 need to adopt new power-line communications technology to ensure the grids remain safe from cyberattacks.