The second installment of WMEAC’s four-part energy series was held at Calvin College Fine Arts Center on January 12, 2011. Due to time constraints not all of the questions asked of the panelists could be answered during the event. We will address the remaining questions in consolidated form here on the WMEAC Blog. Stay tuned for more to come!
Q: How does shadow flicker affect local residents and how far does it reach?
A: Shadow Flicker is the shadow of a moving wind turbine passing over the ground or a stationary object. How far the shadow flicker reaches depends on how high the turbine is and the sun’s location, but it usually can extend to about 1,000 feet and further in the early mornings and late evenings when the sun is at its lowest. A main concern about shadow flicker is the strobe-like quality of the light being obscured by the blades. This shadow ranges from 0.5 to 1.25 Hz (less then one rotation per second). Seizures are induced by flashing lights between 10 to 25 Hz, well above the rate of a wind turbine. The consistent disruption at certain times of the day can still be annoying and even considered disruptive, so it is recommended wind turbines be constructed at least 1,000 feet from residences.
Q: What is the life expectancy from a utility-scale turbine? Is there maintenance required?
A: A wind turbine can be expected to work for twenty to twenty-five years, although the wind energy industry is relatively young to say this is absolute. As far as maintenance is concerned, a wind turbine is meant to harness powerful and fluctuating winds, so it will wear down over time. Most of the maintenance involves the gearbox, the mechanism that converts the slow power of the turbine’s blades into a faster power used for the generator. Like a car engine, the turbine requires lubrication and replacement parts for its continued production of energy. These repairs ideally take place during hours of low energy production and usually only a few turbines at a time to minimize the loss of productivity.
Q: How do you account for the mismatch of maximum wind generation during nighttime and winter months vs. the maximum demand of power during the daytime and summer?
A: One concern about wind energy is that periods of peak production and peak demand do not necessarily correlate with each other. An environmentally friendly solution to this dilemma is not to move production to match demand, but to store energy when demand is needed and to manage demand to more closely align with supply. These types of changes could be enacted through a smart grid system, an electrical grid that can track and manage energy consumption. During peak hours the price of electricity would rise – promoting and shifting usage to use during times of more favorable, cheaper production.
Q: What would be the cost to install a residential wind power system and how long would it take to get a return on investment?
A: When installing a residential wind power system, there are several factors you have to take into account such as the size and make of the turbine and the zoning laws of the area you live in. Installation for a ten kilowatt can range from between $25,000 to $35,000 (according to the Superior Wind Turbine website $1,000 to $5,000 per kilowatt is a good estimate for a residential turbine). How long it takes you to get a payback from your wind turbine is also dependent on several factors. The size of the turbine, the location of your house, the initial cost, Federal or State tax credits, how much you are currently paying for electricity and whether you are able to sell surplus energy back to the grid – all impact the period for return on investment. Because of all these variables, a return on investment could be seen anywhere between five to fifteen years.