On behalf of Mayor Watson:
We’ve received a question about why the local carbon intensity guardrail at 915 lbs of CO2/MWh is higher than the overall portfolio carbon intensity guardrail of 508 lbs CO2/MWh. The answer is that Austin Energy’s portfolio isn’t just in Austin – it spans the state.
I asked Austin Energy staff for a breakdown to explain the numbers, and to show where those resources are, exactly. Simply put, a lot of the opportunity for renewable wind and solar is out in West Texas, making a local guardrail important for us to set.
Thanks,
Kirk
From Austin Energy:
Austin Energy owns, operates, or contracts for energy supply resources across the state. See the link for Austin Energy’s resource locations, taken from page 14 of the draft 2035 Plan:
http://assets.austintexas.gov/austincou ... 161110.png
Last year, these resources combined produced over 14 million megawatt-hours of energy, which supports reliability of the grid and helps keep customer bills affordable. Approximately 75% of that total generation was produced by carbon-free resources, mostly large scale wind and solar facilities as well as the South Texas Project nuclear facility – resources that are not available locally. The scale and size of these facilities require large amounts of land and careful siting considerations. For example, 1 MW of utility-scale solar requires roughly 7 acres. So, a 150 MW solar facility requires around 1,050 acres.
The way the ERCOT market works, we all benefit from being able to use the cleanest resources most of the time – no matter where they are located. It’s only during the highest demand days that congested transmission lines prevent us from bringing these resources to the local area. Carbon intensity is carbon emissions divided by the amount of generation produced. Because resources like nuclear and large-scale wind farms cannot be local and because utility-scale solar projects are not as likely to be local, the local carbon intensity is higher than the portfolio’s overall carbon intensity. However, this is measured relative to the amount of production, and peakers only run as a last resort.
Locally we have clean resources as well, but it’s simply not at the same scale.