Stabilizing the grid has its challenges
Gas turbine generators must consider using Fast Start techniques to respond to the volatility of renewable energy output.
The business of power production is profoundly changing. In the not too distant future, all electricity generation, with the exception of nuclear power
and power from renewable energy sources, will need to be run on a completely flexible basis, responding rapidly to stabilize the grid. Here are some of the drivers for this paradigm:
- Renewable Energy installed capacity is increasing at an exponential rate; currently >13% or 80GW of US total installed capacity.
- Wind and solar power generation have fast changing output profiles due to the violent weather fluctuations.
- We will need 20–50 GW of power to come on line within just a few minutes or hours.
- Up to 100% of the non-renewable fleet will require daily start-stop operation, and load ramps of about 200 MW/minute will need to be covered.
- Thermal power generating systems typically need to be started an hour or more beforehand to reach full load.
Gas Turbine Peaking Plants are being challenged to provide the necessary fast response to maintain grid stability. Advanced power plant solutions can reach full load for power generation in just a few minutes.
Legacy gas turbines, which make up a significant portion of non-renewable power generation, were not originally designed for this kind of operation. However, that is not to say they can’t be more flexible. The complex architecture of a gas turbine, particularly combined cycle plants, presents formidable challenges to engineers and operators to handle major operational transitions like Fast Start without a negative impact on safety, reliability, availability and maintainability.
Fast Start can be achieved primarily through advanced control schemes. To achieve increased flexibility and reduce start time, there are several key points to consider:
- Test & Implement existing Fast Start capability.
- Improve starting reliability.
- Establish Purge Credit if required.
- Implement techniques from Advanced Class units such as “Fire-on-the-Fly” and Fast Sync.
In summary, Fast Start already exists in some form or other for Legacy Peaking Units. And, there are options to improve Flexibility that include: Major upgrades – Purge Credit through Fuel System redesign and Minor upgrades – Sequencing changes.
Turbine Technology Systems (TTS) has a prepared a presentation called Flexibility Enhancements for Gas Turbines that delves into some of the specific challenges and NFPA-85 standards.
View the presentation at www.TTSFastStart.com.