The Evolution of Distributed Electrical Power

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Insights from the Global North | Nextek Power Systems: The Evolution of Distributed Electricity Generation

Presenters: Paul Savage, Nextek Power Systems

Rapporteur: Seren Pendleton-Knoll


Nextek Power Systems Inc. CEO Paul Savage addressed some of the business and technological challenges that face micro-grid energy stakeholders in his speech on 'The Evolution of Distributed Electricity Generation.'

DC electrical grids have as yet not been applied for widespread public utility use. Their limited distribution range (a result of their late 1800s technology) couldn't compete with AC’s transmission abilities. One of the primary uses for DC power is elevator motors, dating from before 1930, that are still in use. These “winding drum” motors, outlawed after 1940 for safety reasons, were grandfathered in. They persist due to the enormous cost of replacing them with new elevator systems. Despite this, there is one DC grid, located in San Francisco that has been operating since 1879, three years before Thomas Edison opened his New York DC power plant[1]. Learn more here.

File:Experience from First Solar Mini Grid Service in Bangladesh.pdf

Issues Presented

​​► Please see the presentation.

  • In our lifetime, the load (what we use electricity for), has gone from almost entirely AC to entirely DC. Not a lot of semi-conductors were in use before the 1970's.
  • Power converters can take AC to DC, or DC to AC, however, a more ideal state would have fewer conversions. What does this mean for battery storage?
  • The adoption of DC in developed countries has been mostly influenced by fuel optionality and efficiency factors. E.g.:
    • DTE Energy, the largest utilities in USA, have 2 floors of their headquarters for DC power to run their lighting systems. This DC house is built in their parking lot.
    • PNC Bank put DC lighting in their first net zero bank, and have 2,500 more to go!
    • In Japan DC micro-grids were the only source of electricity for miles after the tidal wave.
    • The Sun blazer One designed and built by Nextek, charging station has deep cycle batteries. It provides 3 days of light and cellphone charging. Whole Foods Berkeley was one of their first customers and they love the DC system which rides through their outages.
  • Areas with the largest changes taking place:
    • Lighting is intrinsically DC.
    • Displays: retail advertising on every shelf of the store.
    • Vehicles: as more electric vehicles, more charging stations needed, naturally gravitating towards DC.
    • Computing: giant consumer of DC.
    • Developing world issues are being addressed through micro grids. Most of the world isn’t waiting for AC infrastructure. Thus they are huge drivers economically – a big piece of business.
  • Efficiency gains from AC to DC:
    • It's beneficial to power storage to have batteries live in DC.
    • Increased safety.
    • You don’t need licensed electricians and it takes fewer hours to install.
    • The product costs less to install and is cheaper to own.
    • It's reliable. For example, NNT facilities in Japan researched stopped after 7 years and went DC.
    • Change over in buildings, you can move things around while people are working, and can work on everything hot.
    • Allows you to provide wireless control and cheaper cost. In the USA it is a big deal as federal investment tax credit gives 30% cost of solar back to customer. People can take this system (integrating solar and power for connected loads) –> ethical double dipping.
  • Large corporations are beginning to re-imagine their products as DC.
    • Intel have a whole power lab in New Mexico. Lennox have solar assisted products. All the autos are looking at integrated charging structure, economics of providing buffer to grid. Integrated battery system.
  • IEEE Pilot in Haiti: demonstrating how DC can advance efficiency and interoperability. Yellow box: has USB port for phone charging. 40 of the boxes can fit in charging container under solar panel.
    • System designed by one of the Nextek employees. A frame is also built to load and unload from a pickup truck. Designed for best use, and not for cost, in the beginning. Put together open source design book. Anyone can assemble the mechanical parts. Brings price down to $14,000 a unit, totally built = $28,000 a unit.
    • Deliver into the market that covers 80 families in four days after local infrastructure established. At the end of the day, the loads are the same, no reason to design around an old platform.

Q & A

1. Does the price include the power box?

  • Nope, just the solar boxes. Power boxes are about $46 a piece.

2. 1 cent per person per day means what?

  • Cost from the customer. First deployment, cost of kerosene in Haiti, built to that price. Drove open source plan. Could have business in accessories. To get the job done, can bring customer for 1 cent a day for a family of five.


  1. Secret DC Grid Has Been Powering Parts of San Francisco Since 1879. Nextek Power Systems.