Sunday, November 10, 2019

Let's Make Ukiah "Power Down Resilient"

                                                                                              written 3 November 2019
                                                                                        published 10 November 2019

            Sitting in the dark last week, with none of my normal distractions available, I got to thinking.  We have an aging 20th century power grid which is failing due to 21st century problems. PG&E, for all of its faults, is doing the right thing to power down the system when weather and fire conditions threaten.  Peak winds in Sonoma County were over 100 mph in one spot, and over 74 mph (category 1 hurricane) in many others.  It is prudent to hunker down during extreme weather events.  
            Based on Ukiah sales tax income, gross annual business comes to $640M, averaging $1.7M a day.  This power down lasted 4 days, for a business loss of about $7M.  There are 6,500 homes in Ukiah, and most lost food with no power. At $150 each, that's another $1M. Commercial food losses might be another $1M, for a grand total cost of $9M for this one event.  This is probably an underestimate. 
            The power down of distribution lines actually started 3 days earlier for most of the area, but the transmission line feeding Ukiah from the south was kept energized.  There is evidence that a failure on this line sparked the Kincade fire near Geyserville. In the future, PG&E will probably shut down all transmission lines in threatened areas.  If they had done that this time, our economic loss would have been more than $14M.  
            This fire season has been relatively calm so far.  If power downs had been in place during the 2018 fire season, there would have been 19 of them.  If the grid shut down only 10 times during a fire season, each lasting 3 days, the annual business losses would be about $50M.  Even if commercial and residential food losses were reduced by 50%, that would still add another $10M, for a total annual loss of $60M.  This rough estimate is the cost of doing nothing different.
            Modern life depends on power, and in an emergency, even a little bit makes a huge difference.  If we don't like sitting cold in the dark, we must do something because this problem will bankrupt our community if not addressed, but will cost money to fix.  
            Burying power lines would avoid fire ignition and make power shut down unnecessary, but introduces other problems and requires massive investment from a bankrupt company, taking years, if not decades, to accomplish.  PG&E has over 100,000 miles of distribution lines, of which 24% are underground, at a cost of $3M per mile.  Their 18,000 miles of transmission lines are on towers, because undergrounding them costs more than $20M per mile and significantly increases radiative power losses.
            Some homeowners and businesses have bought generators to provide a portion of their power needs.  This is a short-term solution.  Ukiah power is currently 70% non-carbon, so burning fossil fuel exacerbates the climate issues which contribute to the power down in the first place.  The cost of generators can be significant, and will sit unused most of the time as a sunk cost.  If they aren't maintained and run periodically, they may not work when needed.  Generators operate most efficiently, with longer life, when operated near their rated capacity powering a constant load, and are not well suited to powering a house. Fuel storage requires care, and there is no certainty that more will be available during an extended emergency. Noise is also an issue.  Finally, installing some generators doesn't address the needs of the entire Ukiah community.  Any long-term solution has to recognize we are all in this together.
            We are fortunate that we have our own power system, and there are possibilities available that did not exist even a few years ago: renewable energy collection combined with energy storage.  A generator is a fixed cost device which requires further funding (the cost of fuel) to actually produce power, thus there is no real return on investment. In contrast, a renewable energy collector is a fixed cost device which collects ambient power for free for decades, giving a true return on the investment.  It is time we invest in our energy future rather than just burning money to keep warm.  
            There are many forms this could take, but I will examine one possibility: a large solar array and battery storage system designed to power the entire City of Ukiah at current levels, grid tied during normal operations, but able to stand alone as a micro-grid.  After Hurricane Sandy, east coast communities began investigating and installing micro-grids for power down resilience during weather emergencies.  In California, micro-grid interest is growing due to the last few fire seasons. 
            There are many advantages to designing a city-wide power system.  The power shutdowns and the numerous fires are beginning to affect the tourist industry, which is a large part of our economy. Making Ukiah fully power resilient would be a marketable asset.  During the first power shutdown, which affected the surrounding area but not Ukiah, people in the outer areas were able to come to town for supplies, gasoline, a hot meal, cell phone recharge, and relaxation during a stressful time.  These opportunities were missing when Ukiah went dark as well.  Ukiah with power can be an evacuation haven from surrounding fires, and allow orderly evacuation of our own community if needed.
            Ukiah consumes an average of 300MWhs a day.  To produce that much power in the solar minimum of winter would require a 100MW array and a 250 MWh battery.  An array of this size would cost $100M to install, covering about 120 acres of land. Assuming land costs of $200,000 an acre for another $24M, and including connection to the Ukiah gird, the array might cost $150M.  Grid scale battery costs, falling rapidly in the last decade as manufacturing scales up, are currently $0.275/Wh.  Our Ukiah grid storage battery would cost about $70M, for a total system cost of $220M. 
            To put this in perspective, we must consider what we are already paying for power. At a wholesale power rate of $0.035/KWh, Ukiah pays $3.85M annually, or $77M over 20 years.  Just one shut down a year like the last one, an unlikely minimum, would cost $90M over a decade.
            There are two fixed cost pieces here: the array and the battery.  The array will generate income.  An investment in a solar array buys decades of power in advance, at a fix, inflation proof rate.  The 100MW array in this example is sized to give sufficient power in the solar minimum of winter, so it will produce excess power in the summer, making Ukiah a net power producer.  Over 30 years it would generate $191M at current wholesale electric prices.  The array cost could be financed by the utility selling bonds, or by borrowing the money as a low interest, fixed rate loan.  
            The second fixed coat is the $70M battery.  Since there is no direct return on this investment, this is the price we pay to avoid the larger costs of doing nothing.  Spread over 10 years, the annual cost would be less than the loss of a single power down.  While grant funding might be available, it may require an increase in electric rates, or sales tax.  
            There are energy loan programs at the Federal and State level.  Even PG&E is looking for ways to invest to deal with the economic costs of a power down.  At every level, special funds are available for emergency preparedness. Humboldt County borrowed from the United States Department of Agriculture Rural Development to fund installation of a large array and storage at their airport in 2017.  In 2012, Jefferson County, in Washington state, bought their entire power system from an investor owned utility with such a loan. 
            One large micro-grid is only one possibility.  Maybe there should be 3 or 4 smaller systems, spread around the community. Perhaps small pump storage systems would be cheaper than a battery.  In an emergency, we could survive consuming less power, requiring a smaller investment. Modest collection and storage systems could be installed in every house and business throughout the community.  Installing such distributed systems would require training a large skilled work force.  Decisions about priority of installations would be necessary.  City regulations would need to be streamlined, and utility rebate programs developed and funded.  All this should be investigated and decided by the community.  The City Council can start by making a policy commitment to make Ukiah "power down resilient".
            If this vision of "power down resilience" interests you, I ask you to take two actions.  The first is to email City Council members Steve Scalmanini and Doug Crane, members of the ad hoc energy committee, and Tami Bartolomei, Community Services Administrator (email addresses below).  Tell all three of them you support making Ukiah "power down resilient", and want the council to direct staff, working with community input, to plan how to accomplish this as soon as possible.
            The second action is to send a copy of this document to everyone you know. We are all in this together, even if we live outside the city.  Having Ukiah functioning in a power down helps support everyone in the surrounding area. By spreading the word, building momentum, we can give the city leaders support to make "power down resilience" a reality in Ukiah.