Wind energy is a big part of DTE's plan to achieve the 10 % of capacity goal under Michigan's renewable energy law. DTE capacity is roughly 10,000 Megawatts (MW), and other green energy sources (except conservation) are limited in cloudy, flat Michigan.
Earlier this year, DTE signed a contract with Invenergy for 200 MW of generating capacity from a Gratiot County wind farm now under construction. This new contract with Tuscola Bay Wind LLC, a subsidiary of NextEra Energy Resources, will provide 120 MW of generating capacity from wind farms in Tuscola, Bay and Saginaw Counties. This 320 MW of wind energy, combined with other sources and types of 'green' energy, provides DTE with more than 500 MW of 'renewable' energy capacity.
DTE announced its commitment to green energy a couple of years ago, and asked customers to consider 'subscribing' to a green energy package by opting to pay a surcharge. The subscription sold out in less than two months.
Why a surcharge? The word 'capacity' should be a clue. Green ain't cheap. These are mostly 1.5 MW units, so to get to 120 MW, 80 windmills are required. Economies of scale do not apply here... either in the units themselves or in maintenance.
Any properly maintained generator can spin out its rated capacity at any given moment it is operating... but all power plants produce much less energy than their rated capacity in a year. Most coal-fired power plants, for instance, produce between 60% and 80% of their rating in any year, because they need maintenance, and maintenance often means shutting them down.
Just about very major coal-fired generator in America takes a full maintenance (periodic) outage of eight to twelve weeks in duration every four years. They have a steadily increasing rate of short outages, with declining production beginning at 80 to 85 percent of capacity in the first year, until the advent of the next periodic outage.
For a 1000 MW public utility coal-fired generator to produce at better than 65% capacity in its fourth year from a periodic would be a feat of operation and maintenance. For a wind energy turbine to produce 65% of capacity is simply not possible.
Wind turbines have two major shortcomings. First, generation is pretty much dependent on wind, and proportional to wind speed. The machines are geared to take advantage of low winds, and to negate the damaging effects of high winds, but wind availability and speed directly affect production... no wind - no wind energy.
The second problem is maintenance. A box roughly the size and shape of a city bus sits atop a 300 foot tower, accessible only by... climbing. All maintenance occurs in the box, unless the unit becomes useless, in which case it is brought down and replaced.
The reality is, DTE will be fortunate to average a three percent true 'green' power replacement with its five percent wind power.
Fair disclosure: The author is a Principal Environmental Engineer with DTE Energy.
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Comments: 7
A little more honesty would be good, too. Don't get me wrong... I'm proud of DTE for what they're doing. I just think they could be a little better at it.
Note also that, when an individual wind turbine is down for maintenance, only a small fraction of production is affected; when a coal, nuclear or natural gas plant goes offline, on the other hand, a large chunk of generation is lost, which can dramatically affect a utility. Backup for such eventualities can therefore be much more expensive, while the hazards associated with something going wrong in such large plants can be huge.
Similarly, variability of wind is not a problem, it's just another factor in overall cost. Note also that the potential of wind turbines can be significantly increased by storing surplus energy generated by wind turbines at night in the batteries of EVs (i.e. electric vehicles, see V2G). Michigan received most of the money awarded under the Recovery Act to develop such batteries. Rather than describing this as a problem, it would be appropriate for the major Michigan utility to describe V2G as an opportunity for the state.
In the past, subsidies may been awarded on the basis of peak capacity of wind turbines, resulting in higher expectations than actual supply. To avoid this, I propose rebates for clean electricity awarded in accordance with actual supply, while the utility varies prices according to demand. This will allow the utility to buy electricity cheaply from wind turbines at night, sell it to EV-owners, who can then make a profit by selling their surplus power back to the grid at times of peak demand.
The problem with alternative energy like wind turbines is that they have negative impact on the environment such as the impact on wildlife such as birds and bats, while most smaller birds can get out of the way of blades that turn at 200 mph larger birds such as Eagles fly into them, bats those small little horrible looking creatures that most of never see are being killed by the millions and that has a detrimental effect on crops that rely on them to kill and eat all the little bugs that will ruin crops.
We also see that CO2 emissions are only cut marginally as an alternitive power has to running at all times for when they shut down.
Well at least wind farms are better than nuclear power stations.
Maybe. It would take about 6000 wind turbines, spread over perhaps 40 square miles to produce as much electricity as the one coal-fired power station at Ferrybridge, or nearly 3000 turbines, spread over 20 square miles, to match one of the two nuclear reactors at Hartlepool. But in both cases the power stations would still be needed as back-up for the 110 days when all those wind turbines would produce no electricity at all.
I honestly don't know the answer to it all, what started out as a good idea as became one large white elephant that is costing countrys billions of £s $s and Euros. My brother does not care though its keeping him in a job for the moment and he had made quite a good living out of it all in the last few years.