Securing Photovoltaic System Deployments with Data Diodes

A survey of a typical photovoltaic (PV) system with and without the cybersecurity protections of a data diode is explored. This survey includes a brief overview of Industrial Control Systems (ICS) and their relationship to the Internet of Things (IoT), Industrial Internet of Things (IIoT), and Industry 4.0 terminology. The cybersecurity features of eight data diodes are compared, and the cyber attack surface, attack scenarios, and mitigations of a typical PV system are discussed. After assessing cybersecurity, the economic considerations to purchase a data diode are considered. At 13.19 cents/kWh, the sale of 227,445 kWh is needed to fund one $30,000 data diode. On average, a military installation, similar to a small city, requires approximately 48,516 kWh every hour and could fund a $30,000 data diode in 4.7 hours. Comparatively, a 25 kW communityscale PV system costing $75,000 and generating an excess of 20 kW annually (approx. 36,000 kWh), requires 6.3 years to fund a $30,000 data diode. Weighing the economic considerations, the employment of data diodes for cybersecurity protection is not economically feasible for residential or community-scale PV system deployment, but might be for large-scale utility providers. Finally, a discussion on the different communities involved in the design, cybersecurity, and operations of an ICS show that further work is needed to bridge the communities of systems engineers, cybersecurity specialists, and industrial operators.