The annual power purchased from each supplier for each year starting in 2016 was released. Here is a chart:
The big jump in 2017 was in the purchase of electricity provided by the natural gas powered generator, MEA. One might ask why is that? Look at the following chart:
This is hourly averaged wind output in the ERCOT system for a day in July 2018. Notice the wind output drops by more than 50% during the hottest hours of the day.
Georgetown had to purchase power from ERCOT through their MEA contract to meet the middle of the day demand.
Here is another look at wind supply and demand:
It is clear that when demand is high, supply is low and when supply is high, demand is low.
In 2018, demand for gas generated electricity went down as the solar farm came online in July.
It is projected in 2019 that the need for gas generated electricity will decline further as solar becomes available for the entire year. But, the need for gas generated electricity does not go to zero, because, wind + solar still will not meet the peak demand on the hottest days. So much for being 100% renewable!
Lets look at the buy versus sell for a typical day:
When the city needs the most electricity during the day, they have to purchase it and when the demand is low at night and when the city has a contract surplus at night, they have to sell.
Of course all of Texas has the same kind of demand curve as Georgetown, and so the market price goes up during the day when demand is high and price goes down at night when demand is low.
Since Georgetown is contracted to buy the wind and solar energy at fixed prices, they need to sell the excess energy at night when the price is low. That is how they have lost $26M over the past 3 years and will continue to lose money in the future unless gas prices increase- not likely.
Contrary to what the city is telling the citizens that the losses are primarily caused by low gas prices and the long-term contracts, the unreliability or consistency of the renewable energy caused the city to contract for 2 times more renewable energy than the city can use with the hope that peak demand can be met.
Otherwise, why would the city contract for twice the power currently needed. The city says they did that to get low prices and that the city demand will gorw to meet the supply.
At the historical rate of demand for electricity in Georgetown, it will take 13 years before demand equals current supply on an annual basis!
The reasons for the financial mess the city and rate payers find themselves in can be summed up as follows:
1. Fixed price long term contracts limits ability to adapt to market changes
2. Low gas prices caused by the abundance of gas released by fracking
3. Increased conservation efforts and higher efficiency electrical devices
4. Unreliability of renewable energy to meet demand when required without over purchasing.
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