Wind Power
The states of Rhode Island and New York have announced grandiose plans of an ocean based wind farm 17 miles offshore with another 85 miles offshore. The news release by NYSERDA states that "A megawatt of offshore wind energy can power more than 360 homes." They plan 9,000 megawatts by 2035 powering 3,240,000 homes. There are two questions:
1) How is 1 megawatt of offshore wind energy defined?
2) How much power, on average, is delivered to each home?
Answers
1) A 'megawatt' comes from the rating of the turbine as stated by the manufacturer. A turbine rated at 4 megawatts can, supposedly, deliver 4 megawatts of power with a wind speed of 30 MPH. But, this is untrue and misleading.
The manufacturer bases its rating on using 100% of the kinetic energy available in the wind entering the turbine and converting 25% of this to electrical output power. The truth is the turbines that will be used by Rhode Island and New York State only utilize 4% of the available energy while 96% of the wind (and its energy) passes between the slender blades without even touching the blades. So, 4% of 4 megawatts is 160,000 kilowatts and just 40,000 kilowatts per megawatt of 'rated' output. Thus, not 360 homes but 4% of 360 homes will be delivered power from this proposal of using wind energy.
But, let's not stop there as there is more!
The wind does not blow at 30 MPH continuously. Actually, it reaches those speeds less than 1% of the time. With the current blade design, the stronger winds are almost never used and at the current 12 MPH average wind speed, even those winds (as we noted above) are hardly captured to produce energy. Now, since wind energy increases by the third power, there is 8 times as much energy at 30 MPH as there is at 15 MPH. This means that the 40,000 kilowatts is reduced to 16,650 kilowatts or 1/60 of the original 1 megawatt. Now we are down to about 6 homes, not 360 homes.
2) The announcement that 1 megawatt can supply 360 homes is based on 1 megawatt of electricity coming in 24 hours a day, 365 days a year, with the wind blowing in the acceptable speed range of the turbine 33% of the time. Well, when you actually have someone doing the calculations properly, the amount of power produced is now down to 8,000 kilowatt hours per year per home.
Uh oh! This is inadequate as the average home requires at least 25,000 KWH for heat and air conditioning, and another 10,000 to recharge our electric vehicles (which we are slowly switching to). When you do the math, we're down to 1.4 homes that will be supplied by the offshore power from 1 megawatt.
There's more!
There is a huge loss of power in the underwater direct current (DC) cable that connects the turbine to the Rhode Island grid. Calculations show a loss of 35% to 60% depending on distance. Now we are down to less than 1 home per 1 megawatt at an incredible cost per kilowatt hour and funded by our government agencies. Funded by our government agencies? That's right! Funded by you. The taxpayer pays for the current wind power proposed (and in use today).