Sunday, August 18, 2019

Investing In Solar Backup

                                                                                                 written 11 August 2019
                                                                                             published 18 August 2019
            We are currently killing the planet to create a few more billionaires.  If human civilization is to survive, we will have to change directions, and prioritize a livable planet above all else. Among other things, we must restructure our power system.  
            Since commercial electricity began, our civilization has grown to expect unlimited power at all times.  PG&E's proposed power shut downs, as many as 80 days a fire season, are a major disruption.   Almost all businesses will be closed, costing $1.7M per day, $136M annually in the worst-case scenario.  A power shut down will put most people out of work, risk the medically fragile, disrupt communications, and challenge our ability to feed ourselves.  Some people have bought portable generators for their homes, which are cost effective in the short run, but a noisy, polluting, and potentially hazardous step backwards as a community.  
            The 21st century habitable planet power grid will use renewable power, with distributed collection and distributed storage.  The grid will allow communities to import power from out of the area, without requiring every house or business to be totally self-sufficient. But, each house will have a small micro-grid, with the ability to collect and store enough ambient energy to power critical needs in an emergency.  The minimum basics needs are an energy efficient refrigerator, some LED lights, internet and phone communication, and essential medical hardware.  
            A system with 900 watts of collection, 2 kilowatt hours (Kwhrs) of storage, and a 2 kilowatt (Kw) inverter able to keep the batteries charged when the grid is functioning, would power all the above plus a small appliance and a washing machine, and cost about $10K for parts and labor (information and cost estimates come from conversation with a Real Goods solar technician).
            If the City were to install such a system in all 6,500 homes in Ukiah, it would cost $65M, less than the business losses PG&E are creating.  But these 6,500 systems, each with 900 watts of collectors, would produce an average of 30 megawatt hours (Mwhrs) a day of renewable power for the lifetime of the equipment.  Ukiah currently imports about 300 Mwhrs every day, of which 70% is green. That means that 90 Mwhrs a day are produced by brown power.  By state law, Ukiah has to use 100% green energy by 2045.  By installing these small battery backup renewable systems in every house, we accomplish 1/3 of that goal while becoming power resilient.
            This is expensive power compared to what we use right now.  30 Mwhrs a day at the residential rate of $0.13/Kwhr generates $1.45M/yr, which would take decades to pay back the original investment.  But this ignores the added value that everyone would be able to survive unlimited power outages without distress, while avoiding toasting off the planet.  Further, this power investment would generate numerous good paying local jobs.  These significant values are hard to fiscally quantify, but worth considering.
            If we installed larger systems in every home, the number are better.  Online, you can buy a system for $16K, with 4 Kw of collectors, and 19 Kwhrs of storage.  This $104M investment would generate 133 Mwhrs a day, accomplishing the mandated shift to 100% renewable, and pay back the principle in 16 years.
            Another option is small collective systems, where each house has a minimal battery backup, but the power comes from larger neighborhood collective arrays. This would deal with the issue that not every house has good solar exposure. 
            There are several mobile home parks in Ukiah, many occupied by seniors.  Each park has a common building, which could have a micro-grid to supply cooling, recharging capacity, and even cooking facilities for the park residents.
            All businesses should have micro-grids installed to allow most normal functions during a power down, without depending on fossil fuel generators. Currently only 10 businesses are prepared to be open in Ukiah, and none of them are gas stations.  Costco may be able to pump gas, but they only sell to members.
            Intermittent grid power is going to become more common as the climate continues to deteriorate.  Money is not the problem.  If our intention is to create a healthy planet for our kids, the issue is how we choose to invest our wealth.