Wednesday, July 29, 2015

Hitting Limits: For Molokai the Finite Grid Already A Reality

Recently, Dr. Marco Mangelsdorf, President of ProVision Solar, Inc. and the Secretary and a Director of the Hawaii Island Energy Cooperative shared with me his presentation at the 2015 Intersolar North America Conference held in San Francisco several weeks ago. Sitting on a panel entitled, "PV-Grid Integration: Maintaining Grid Stability," his presentation, "Growing Solar Capacity in Hawaii and the Electric Grid:  How much PV is too much?" gave a very pragmatic view of Hawaii's energy landscape.  More importantly, as some of his information reveals, no island demonstrates the finite nature of the electric grid as starkly as Molokai, with the rest of our islands not too far behind.  

Marco noted in a message to me, "the future is now on Molokai."  He goes on to say, "On Oahu, Maui and the Big Island, more and more circuits are hitting 250 percent DML [daytime minimum load] a helluva lot faster than anyone thought they would . . . Pre-approving more NEM DG on Molokai has been all but a no-go since the beginning of the year due to system-wide constraints and concerns as HECO studies what can be done to go to a higher level of solar PV penetration.  Also in the mix on the Friendly Isle is a proposed multi-megawatt central solar power plant with a mainland project developer who is the beneficiary of a $50 million special purpose revenue bond passed by the Legislature last year and signed into law by Governor Abercrombie."

Here's his analysis of the NEM-DG interconnection status as of December 31, 2014 and July 6, 2015:

Marco says several significant things stand out while comparing the two tables above:

  • There have been substantial increases in interconnected or approved for interconnection NEM capacity over just the past six months on Oahu, Maui and Big Island with a small increase on Lanai and flat on Molokai.
         - Oahu up 22%;  Maui up 33%; Big Island up 26%;  Lanai up 14%
  • The number of interconnection waiting in the queue have gone down as the queue has been clearing for Oahu, Maui and Big Island                                                                                            
  • On the other hand, the Molokai queue has increased from 300 kW to 700 kW [My comments: yes, with heavy subsidization the solar guys keep selling then scream when unable to interconnect]
  • Total interconnected or approved for interconnection NEM as a percentage of peak demand is at percentages no one would have thought possible a couple years ago when caps were set at one to four percent [My comments: the original NEM legislation (2001) set the cap at .5% (one half percent) of system peak]

Marco notes again, "the future is now on Molokai as far as grid’s inability to (not) accommodate more NEM due to system wide concerns.  Which causes one to wonder how far we, on the other islands, are from reaching the point where Molokai is today."

This graph, Molokai's net load profile on January 5, 2014, depicts the stark reality of the Molokai grid.  The black line is the system load, the dashed red line is the anticipated rooftop PV load with all PV systems in the queue interconnected (but conservatively calculated at 75% of output), the blue/green reflects the lowest point the power plant generators and regulation units can be turned down to maintain system stability. 

As the red dashed line enters into the blue/green area there is excess energy being generated with no place to be used.  However, as the rooftop PV output decreases later in the day, the generators then must be available to ramp up to meet evening peak demand. Falling short of increasing daytime demand on Molokai, these are the system type challenges that the electric utilities must address to balance out the system.

What is evident is Molokai has 3,177 electricity customers, but only 10% or 331 customers have rooftop PV systems.  From the DG load profile (red dashed line), it appears most of these PV systems were designed to net out the customer's electricity bill, not electricity use, to zero dollars, paying only the minimum monthly charge, but relying on the electric system when the PV system's output drops.  While there may be technical solutions available to address the limitations of the existing electric system, under the current NEM rate structure the burden of paying for system upgrades will fall unfairly on the non-PV electricity customer.  

It behooves the Public Utilities Commission to quickly respond to this important issue of unfairness in its Distributed Energy Resources investigation.  Again, it is pretty shameless for The Alliance for Solar Choice (TASC) to move for an evidentiary hearing to further delay any type of resolution to address this inequity.  And, if necessary, the Legislature should make it clear that net energy metering is not an entitlement and the PUC has full authority to make the necessary program and tariff adjustments applicable to all electricity customers to maintain the electricity system to benefit all.  

1 comment:

  1. Great post. This is very useful. I learned some new information. Thanks for sharing.

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