Intermittent Nature of Green Power Is Challenge for Utilities
Friday, August 16, 2013
Mother Nature doesn't always have the best timing, and therein is one of the main challenges for utility companies that rely on renewable energy sources like wind and solar to meet customers' energy needs.
Truth in Advertising
Not all wind is created equal. Wind farms seldom produce energy equal to what is promised, and even the turbines in windier places like Kansas and the Great Plains states regularly produce only a fraction of their rated capacity.
If only 10 percent of your investment is available when it’s needed most (think peak energy demand days in the summer or winter), a utility company either has to have 10 times the rated capacity or supplement the short-fall with more reliable back-up generation which adds to the cost.
Think of it another way: if your car is rated to provide 30 miles per gallon but can only do so on rare occasions and usually only delivers 3 miles per gallon, you’d have some real problems.
And in Kentucky, we’re mandated to serve our customers at the lowest reasonable cost.
A poor availability of steady and strong winds in our state means that relying on wind to create energy on a larger size and scale – particularly on the hottest days of summer and coldest days of winter – would be an expensive endeavor, and one that would require a lot of land.
The image to the left puts this challenge into perspective. A wind turbine has been super-imposed over a part of Louisville's skyline.
At 23 stories, a typical wind turbine would be taller than most buildings downtown.
And, we'd literally need thousands of them to generate the same amount of energy as a typical coal-fired unit.
Within the U.S., wind energy can play a role in meeting our energy needs, but its low availability, particularly on hot summer days, and the relatively high cost of wind turbines means it’s not a good source for reliable, low-cost generation that we are obligated to supply in Kentucky.
Until next time, keep using energy wisely.
If too much energy is produced when customers don't need it, power lines can get overloaded and that can lead to real reliability problems on the electric grid. For instance, energy demand is lower at night. If the wind is blowing harder and turbines are generating more energy than is being demanded, it creates a troublesome situation for everyone.
If too little energy is produced -- say when the wind isn't blowing or the sun isn't shining -- when customers are cranking up the air conditioning on a hot summer day, utilities must tap into more dependable energy sources (like coal or natural gas-fired units, which are almost always available and ready to go) to meet the increased energy demand.
This dilemma is the focus of an interesting New York Times story this week.
From the article:
A number of factors can trigger curtailments in wind output, including reducing the danger to bats or birds flying around the spinning blades. But more commonly, regional grid managers, who must match demand and supply instantaneously, call for a reduction in wind power when more energy is produced than the system can safely transport, they say.Having a secure and reliable supply of fuel is essential for utility companies like LG&E and KU, which must generate and deliver energy as our customers demand it.
Truth in Advertising
Not all wind is created equal. Wind farms seldom produce energy equal to what is promised, and even the turbines in windier places like Kansas and the Great Plains states regularly produce only a fraction of their rated capacity.
If only 10 percent of your investment is available when it’s needed most (think peak energy demand days in the summer or winter), a utility company either has to have 10 times the rated capacity or supplement the short-fall with more reliable back-up generation which adds to the cost.
Think of it another way: if your car is rated to provide 30 miles per gallon but can only do so on rare occasions and usually only delivers 3 miles per gallon, you’d have some real problems.
And in Kentucky, we’re mandated to serve our customers at the lowest reasonable cost.
A poor availability of steady and strong winds in our state means that relying on wind to create energy on a larger size and scale – particularly on the hottest days of summer and coldest days of winter – would be an expensive endeavor, and one that would require a lot of land.
The image to the left puts this challenge into perspective. A wind turbine has been super-imposed over a part of Louisville's skyline.
At 23 stories, a typical wind turbine would be taller than most buildings downtown.
And, we'd literally need thousands of them to generate the same amount of energy as a typical coal-fired unit.
Within the U.S., wind energy can play a role in meeting our energy needs, but its low availability, particularly on hot summer days, and the relatively high cost of wind turbines means it’s not a good source for reliable, low-cost generation that we are obligated to supply in Kentucky.
Until next time, keep using energy wisely.
