What Do We Know About Our Solar Panels After (nearly) 2 Months?

The People’s Church solar photovoltaic system was fully installed on June 1, and the first full day of generating electricity was June 2.  We now have a lot of data, and 1 ½ billing cycles to help us begin to understand the impact of this new technology.  Of course these are not normal times in our world, so we will have to wait for the end of the pandemic and a return to the “new normal” church operations to fully understand.  Here is a quick snapshot.

How Much Electricity Are We Generating?

This is prime time for solar in Michigan, and our data reflects that.  Between June 1 and July 25, our system produced 7,402 kilowatt hours (kWh) of electricity.  For comparison, the church over the course of a year has averaged about 60,000 kWh per year of usage, and during the summer months the average has been between 3-4,000 kWh/month.  Households use between 4-10,000 kWh per year.  June 14 showed the highest daily production at 176.1 kWh, while July 19 was the lowest at 36.6 kWh.  The peak hour achieved nearly 20 kWh.  Electricity begins to be generated in the dawn hours and ramps up to its peak around 2:30 before slowly dropping off until sunset.

The above chart shows the last full day before this article was written.  You can see the effect of a partly cloudy day on the output of the panels.  Highlighted is the 15 minute period between 4-4:15 pm, when 3,905 watt hours were produced (3.9 kWh).  The day produced 138.4 kWh.

What Does that Mean in Terms of Our Carbon Footprint?

It’s hard to be precise about this because we don’t know what the mix of coal, gas, nuclear, and renewable energy is for Consumers Energy, but if we use a national average, the amount of carbon that we have kept from going into the atmosphere since we installed the system is about 3.1 metric tons (the common unit used for atmospheric carbon).  The production so far is equal to about 12% of our annual, pre-pandemic usage.  If the rest of the summer months follow, we will produce 20% of our average annual consumption by Labor Day.  The rest of the year should easily get us to the target of 35% reduction in our carbon emissions from electricity.

Are We Saving a lot of Money?

The simple answer to this question is no (but it’s complicated).  But we are buying our solar photovoltaic system with the savings from reduced payments to Consumers Energy.  The system cost the church no money up front, and once the first five years are over, we can purchase the balance for about half the initial cost.  At that time the cost of our electricity will be reduced to nearly ½ the electric rate from Consumers, and we will continue our reduced level of greenhouse gas emissions long into the future.  We can expect the system to last 25 years at least.  Our initial cash savings will be modest, but our capital investment will keep on giving well into the future.

Has the Pandemic had an Effect on our Electricity Consumption?

Yes, there has been a dramatic drop in electric use by the church since the shutdown began.  Normal usage in the June/July period has been 3-4000 kWh/month.  During the period for which we have current measurements, that has dropped to less than 1200 kWh/month. That means that we’ve been producing far more electricity than we have been using since the solar panels went up.  So far our surplus has been more than 5000 kWh over the last 55 days.  As a result, in the unusual circumstances of this year, we most likely will produce far more than the target of 35% of our annual consumption.

Thanks again to all those involved in this bold move: the Finance, Building & Grounds, and Green Sanctuary Committees, and especially the board of trustees and Rev, Rachel.  People’s Church has taken a big step in reducing its carbon footprint.

–Tom Hackley

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