Meet Nick Miller, a power-systems engineer with a passion for integrating renewables into electricity grids. Here’s a guy who can ramp up a high-energy discussion just by rubbing wind and sun together. As Senior Technical Director for GE Energy Consulting, Miller also advises industry. He declares ours, “The Golden Age of renewable energy,” and his pragmatic take on the future of clean energy provides a cocktail-party season’s worth of thought-provoking conversation starters.
1. Revolutions like this don’t happen without missteps
I’ve spent the past 15 years leading research projects and wrestling with the inevitability that my world, the world of the power system, is changing at a disorientatingly fast rate. We don’t get every piece right. And yet we get a setback and people say, “Well, obviously we shouldn’t be doing this.” No, that’s not the answer. The answer is, what can you learn from a mistake like this?
2. The important things for running a power system with lots of wind or solar power are: No.1, flexibility; No. 2, flexibility; and No. 3, flexibility
The fact that there’s uncertainty of demand (higher demand from consumers at different times of day) and uncertainty of supply (somewhat unpredictable variations in when the wind blows and when the sun shines) means that everything else in the power system needs to be more agile. The term we use in the industry is flexibility.
Take the other forms of generation contributing to the grid—say it’s gas turbines.
Compared to previous turbines, they need to be able to start, not an hour from now, but 10 minutes from now, and they need to be able to ramp up to power faster than they ever used to be able to. And they need to be able to turn way back, and to sit there producing relatively small amounts of electricity in anticipation of the need to ramp up. And likewise in anticipation of the need to be able to go down quickly when the wind picks up or the sun comes out from behind a cloud. So that’s operational flexibility and GE has done very well in that space—the new stuff is dazzling!
Another piece of the puzzle is flexibility of institutions, politics, business.
3. People don’t like to live where it’s super windy
In places where you have a great wind resource, you generally don’t have good transmission infrastructure or easy access to the grid. Texas recognized that and they sought a whole bunch of public comment and did a whole bunch of slicing and dicing of the figures and said, “OK, here are some areas where there’s great wind resource and we’ve done enough homework to believe that those areas will be developed.”
They went ahead and found public money, and did all the pain of routing and permitting, and built transmission lines into these wind-rich areas — a field of dreams. Then the wind plants came along and subscribed to those lines. They covered the risk that the ratepayers had paid forward. They’re fully subscribed. It was wildly successful. That’s one of the ways Texas got to 15 gigawatts of renewable generation.
4. The most economical thing you can do for everybody is to revisit the stuff you already have and use it better
I have an industry “war story” that I hold up as an example of good industry practice. The government of the state of Hawaii has said it’s never going to build another fossil-fired power plant. All plants going forward are going to be renewable energy. HECO [Hawaiian Electric Company], the host utility, has this old fossil fleet, but we worked with them and they recognised up front that the operating profile of the fossil fleet is going to change significantly—more ramping, deep turnback, etc— as they have more and more wind and solar.
Ramping is hard on the equipment, but you have to have enough ramping to cover the system as the sun sets and the wind drops out—to ramp up and ramp down. So, they went through their fleet and said, “Right, what limits the up ramp and the down ramp and the start times?”
After identifying the low-hanging fruit in their fleet, they went to the regulator and said, “Look, if you want us to do all this wind and solar and reduce our carbon footprint in the state, we need to have agility from these plants.” And the state took that argument and said, “You’re right. Go forth. Put that investment in the rate base and make that improvement.”
They increased their ramping capability on Oahu by a factor of five. Five times the megawatts per minute. It’s a really cool story. So there are things you can do, but they don’t happen on their own. It takes some institutional nudging. They could just as easily have said we need five times the ramping rate, so we’re going to go and drop $200 million on a battery. You need this meeting of technology needs with people who are watching the money.
5. You have to ask the tough, “Where’s the beef?” questions
My view on energy-storage opportunities is positive but cautious. What the grid needs is flexibility. When energy storage is the most economical way to get the flexibility in there, it’s the right technology.
Energy storage makes more sense as the penetration of wind and solar increases. It makes more sense as you exhaust all the traditional thermal generation that’s already on the ground. When you’ve squeezed every last morsel of performance out of what you’ve already built, then it makes more sense. And, the per-unit cost of energy storage is coming down.
But there’s a fundamental truth that needs to temper our enthusiasm: Energy storage doesn’t create a single megawatt hour. It’s megawatt hours that make your economy run. Storage evens out your troughs and peaks, it does a whole bunch of good stuff, but all of that good stuff has to pay the rent.
6. Have mechanisms to watch the shop, look back and see how you’re doing
In crude vernacular, Texas runs its grid really tightly, and they demand, without exception, a high level of performance, including from all the wind plants.
For example, the Electrical Reliability Council of Texas (ERCOT) has put in place a retroactive requirement on all wind plants to add the capability to provide primary frequency response. That means the ability to change their output locally, autonomously, in response to a deviation in system frequency. That’s not standard practice, but ERCOT said: We need this. There are going to be operating conditions when we need that capability from the wind plants. We’re putting it in place. Some of the market participants were not necessarily pleased with the changes initially. In the end, though, it’s a relatively small cost, and it’s worked really well.
Read the full version of this Q&A, conducted by Natalie Filatoff, on GE Reports Australia, New Zealand & Papa New Guinea.
Nick Miller is Senior Technical Director for GE Energy Consulting. He was a principal contributor to the landmark New York State Wind study, and the California Intermittency Analysis Project.
All views expressed are those of the author.