Houston — Natural-gas fired generation took up half of the fuel mix in the Electric Reliability Council of Texas in August after topping 50% in July, an almost two-year high, with more nuclear generation in the stack due to fewer nuclear outages than in July, according to ERCOT's monthly demand and energy report.
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Natural gas-fired generation supplied 50% of the total demand in August, after reaching 50.6% in July, compared with the year-ago level of 49.1%. Before July, the last time natural gas supplied half or more of ERCOT's power was in August 2015, at 51.2%. Natural gas has topped in the fuel stack for six of the first eight months of the year, second to coal only in January and April, ERCOT said in the report, issued Monday.
Spot gas prices at Houston Ship Channel have averaged about $2.863/MMBtu in August, tumbling more than 3% from July's average of $2.966/MMBtu and over 5% from the average of $3.018/MMBtu year to date through August.
Accordingly, ERCOT North Hub day-ahead on-peak locational marginal prices averaged $30.58/MWh in August, compared with $35.69/MWh in July, a drop of over 14%.
Coal came in as the second most used fuel in August, supplying over 30% of the total demand, slightly higher than July's total of 30.4%.
The largest monthly increase in fuel percentage came from nuclear, as nuclear power's generation gained about 2% month on month to over 9% of the total generation, but this was below nuclear power's contribution in August 2016, which was about 11%.
Luminant's 1,124-MW Comanche Peak-2 nuclear unit went offline on June 5 due to problems with a steam turbine and has been back to service since August 15, making the average nuclear outage level about 0.5 GW in August, compared with an outage level of 1.1 GW in July, while no nuclear outages occurred in August 2016.
Wind generation, which set a record high of supplying over 25% of March's energy, produced only about 9.1% in August, the lowest level so far this year and lower than the year-ago level of 9.4%.
ERCOT's energy supply totaled over 36 TWh in August, which was about 5% lower than July's total at 38 TWh and slightly below the year-ago level. ERCOT forecast energy supply at 38 TWh in August.
Moreover, the grid operator expected to set an all-time high of nearly 73 GW in August, but the actual peakload only reached near 68 GW in August, below both the July peakload record of over 69 GW set in July and the current all-time high at over 71 GW, set on August 11, 2016.
US National Weather Service data showed that Austin, which lies near the center of ERCOT's footprint, had 610 cooling degree days in August, flat from seasonal average but 8% higher than last year.
So far this year, natural gas supplied about 40% of the total generation, with coal's share at 31%, wind at 17% and nuclear at 10%.
Looking ahead, ERCOT expected peakload to reach 56 GW from October through November, below the current fall record load of nearly 60 GW, but the current load projection put peak demand over 61 GW from December through February, higher than the current high of over 59 GW.
--Jeff Zhou, email@example.com
--Edited by Annie Siebert, firstname.lastname@example.org