You might have noticed that wind energy is doing the heavy lifting in moving Oregon toward its 2025 renewable energy goals. With a push from federal and state subsidies, lots of new turbines have gone up in the past few years. And power managers say they are likely to double over the next 15 years.
Free fuel and low maintenance costs make wind energy a relatively cheap energy option. But using wind energy isn’t as easy as putting up turbines.
The real trick of adding wind energy to our power mix is getting it to your home when you need it. High-voltage transmission lines – collectively known as the grid – deliver wind energy from the farms to the places where people need power. But our existing transmission system wasn’t built to deliver fluctuating wind power. It was built for much steadier supplies of coal and hydropower.
So, the Northwest has more and more wind power coming online, but it doesn’t have a very efficient way of getting it to your toaster. Several key costs of using wind energy are hidden in the pipes that deliver the region’s power. And as we add more wind power to our energy mix, experts say those costs will go up. To understand why, it’s helpful to understand a few things about the grid:
The No. 1 rule of grid management: Power in = Power out
Grid managers in the Northwest are bound by one fundamental rule: the power generated at any given time must equal the amount of power being used. Power in must equal power out … or you get blackouts.
It’s this fundamental principle of managing the grid that makes adding lots of wind power tricky, according to Jon Kaake, CEO of the independent grid analyst group Columbia Grid. When the wind changes unexpectedly, grid managers have to compensate for that change to make sure the power going into the grid matches the power going out:
“Electricity has to be generated exactly in the same time that it’s being produced in the system. In order for the system to work, power supply and demand have to match exactly.
As you now introduce more variable generation into the system like wind, and it’s fluctuating, you have to have generation elsewhere in the system that can respond to that. And wind doesn’t respond to directed signals to drop or increase load. So, somewhere else on the system you’ve got coal-fired or gas-turbine or hydro that are responding to the changes in demand and changes in other generation.”
A pricier balancing act
Grid managers including Bonneville Power Administration, which manages 75 percent of the Northwest power grid, have to maintain that power balance. And it’s becoming a bigger job as lots of new wind energy enters the system, according to BPA spokesman Michael Milstein:
“We know generally the pattern of power use over the course of each day. The steepness of it can vary from day to day but generally the patterns are the same. As more wind has come into the system, it’s added this new dimension to that because it’s changing the supply in a way that was never really the case before. Not only is the demand going up and down over the course of the day, now you have a piece of the power pie increasing and decreasing over the course of the day.”
Forecasting wind patterns and keeping potential power in reserve in case the wind dies down adds to the cost of delivering wind energy. Ultimately, customers are paying not only for the energy they get but also for the reserve energy that might be needed to balance out changes in the wind.
Wind energy is cheap; new transmission is expensive
Wind energy may be relatively cheap, but it’s unusable without a transmission system that can deliver it. Getting wind power to your house is not as simple as adding one power line from a wind farm to the city, Kaake said. Because there’s no way of controlling exactly where power goes once it enters the pipes, the entire network of high-voltage power lines have to be ready to carry all the new, variable wind power in the system:
“You can’t just go popping in generators 500 miles away from where the loads are without building some transmission. And it’s not just about putting in one transmission line. You need to get into the grid and reinforce the grid. We’re really talking about the grid from Alberta, Canada, to Northern Mexico. It all operates as one big network.
… Ultimately, you’re not going to get around the need for more wires in the air. The amount of new transmission needed compared with what’s here is very small. The problem is it’s really expensive.”
The limit for new wind power
Aside from the flailing economy, transmission is the top constraint to building new wind power, said Cameron Yourkowski, transmission policy expert for Renewable Northwest Project.
“It’s the number one bottleneck to renewable energy development. It takes five to seven years to build significant transmission, whereas wind energy projects can go up in a year. So, it slows things down considerably.”
It’s not prohibitively expensive to expand and upgrade the grid for renewables, he said. He estimates transmission costs make up 5 to 10 percent of the average electricity bill. The higher end of that range includes the costs of new transmission for renewable energy integration.
But they’re still costs someone will have to cover if we want to continue adding wind power to the system, Kaake said, and it will take time. If it doesn’t happen fast enough, he said, “we may find ourselves having to limit new generation wind power until the grid can handle it, or accelerate construction of transmission.”