Micro-Grid, Option for Restoring Electric Power to Puerto Rico

By Timothy Chen | Published: September 17, 2018 – 3:54 pm

I have read several interesting stories of organizations proposing and installing Micro-Grids as a means of restoring electric power to areas in Puerto Rico. The Micro-Grid systems incorporate electric power generation, electric power storage and/ or smart-grid connection to the electric utility distribution network. The installations goals are;
  • Restoring electric power.
  • Providing backup to critical infrastructure (e.g. hospitals) should the electric utility supply be inconsistent.
  • Incorporating alternative electric energy generation sources.
Hurricane Maria severely damaged the electric utility distribution grid. That damage coupled with the failing electric utility infrastructure left many areas without service for extended periods of time. These organizations are proposing to use solar arrays as the electric power generation source with battery backup for electric power storage. Technically, this solution is very doable. I would also assume that for remote locations that may not regain electric service any time soon, this may be the only solution. However, these systems are relatively complex to maintain and have the same miss-match between when power generation is at its mid-day peak and when usage is desired during evening and at night. I do believe that solar power will be part of the future electric generation mix. Maybe what has to change is our thinking and go back to the Thomas Edison idea of DC power. I have been exposed to the mathematics which justifies AC for transmitting electric power over distance. By taking the output of the solar array, converting the power to AC to power some usage, converting the electric power back to DC to charge the battery there are enormous loses. Maybe Micro-Grids should be DC, only using inverters to power the huge power loads (e.g. oven, washer, dryer).