Professionals within the energy industry say that low cost, clean, replaceable wind energy is the key in enabling global satisfaction in regard to energy needs. However, this agreement can only be reached upon brushing a side one’s political interests. Renewable energy also reduces the dangerous greenhouse gases, and hitherto offshore wind farms are non-existent in the U.S. In a letter published in the Geophysical Research Letters; some Stanford engineers recommend optimal installation of four wind farms connected to each other off-coast of the Eastern United States. The team developed a unique weather model which guided the aforementioned recommendation. Besides Eastern United states accounting for 34% of the U.S. electrical demand, it is responsible for 35% of the emitted carbon dioxide.
Mark Z. Jacobson, senior author and professor of civil and environmental engineering says that the uniqueness of their development will provide deep insight into the grid plan. He also adds that prior to their development, no high-resolution weather data has been used in the planning of an offshore wind grid.
The engineers started with 12 potential energy generation sites, but further scrutiny resulted in only four sites being selected. Approximately, 100 turbines with a maximum capacity of 500 megawatts will be installed on each farm resulting in generation of 2000 megawatts. The energy generated from the interconnected grid is almost 1.5 times the annual capacity generated by the traditional coal generating plants.
Jacobson, however, indicated that the 2000 megawatts and four farms are approximations that are subject to adjustment, to put into perspective the economic, environmental and policy factors.
Mike Dvorak, the main author of the study and a recent PhD graduate in civil and environmental engineering at Stanford also echoed the sentiments. He said that in addition to lowering the congestion and cost of energy between various locations, an offshore grid would be more reliable since it is an extension of the onshore grid.
Persistent natural sea breezes as a result of temperature variation between land and sea dictated choice of location. The enhanced grid was therefore placed in the shallow waters from Long Island, New York to Georges Bank that extend almost 100 miles to the east of Cape Cod. However, offshore wind farms experience stronger and infrequent storms.
Dvorak also noted that for a long time, large-scale wind resource assessments had not been taking the issue time into consideration. Their study relates production to demand since they considered peak production and peak demand at various times of the year.
Wind farms located on land record high energy output at night when there is low demand. Moreover, demand sores during summer afternoons when the air-conditioning services are mostly needed. Yet, Summer periods are also associated with storms, and a weather phenomenon called the Bermuda High which is a high-pressure center that affects winds along the coastline.
Dvorak also says that although the Bermuda High bolsters sea breezes in areas like Massachusetts, it impedes sea breezes in the south of Long Island, NY, which is coincidentally one of the grid installation spots.
A number of technical issues in the models had to be well-adjusted after matching production and demand cycles.
Jacobson said that the wind farms had to be installed in waters not exceeding 50 meters so that bottom-mounted turbines, and near urban load centers like Bolton could be used. Uninterrupted power output, faster hourly rates of power and a reduction in power lack issues were given top priority.
In most parts of the world, offshore wind farms are individually connected to onshore grids but in their approach, the engineers interconnected to the offshore wind farms.
Dvorak also said that interconnection evenly spreads produced peaks and the valleys. Moreover, in this model, high-cost instances when individual farms wouldn’t generate electricity, the output of connected farms would be 9% to 45% due to interconnection.
Analysis of the interconnected grid showed that a reliable average of 1000 megawatts could be generated to sustain the annual capacity of 48%.
Jacobson also reported that an average capacity of 35% or higher is considered excellent.
The role of a Location should not be underestimated.
There has been some contention regarding the Cape Wind site and those resisting say that the tall turbines would interfere with Nantucket’s attractiveness. Nonetheless, the Stanford model proposes Nantucket Sound, as one of the sites to install a wind farm.
The weather and season model is to be installed in the shallow waters of Georges Bank, which is located 100 miles offshore. In addition to being far, the area is associated with the extraordinary amounts of cod. The final site is off central Long Island.
The engineers endeared themselves to politicians, however; after analyzing the economic aspects, they concluded that cost sharing across several states would be beneficial.
Jacobson concludes by saying that the paper highlights energy issues, and it should therefore be used by stakeholders when making decisions pertaining to renewable energy in highly populated areas. He also adds that it is a win-win plan since besides sharing of systems, the costs are lowered and the U.S. energy demand is sufficiently met.
The Charles H. Leavell Graduate Fellowship, the US Environmental Protection Agency and the Otto Mønsted Foundation supported this research. Computational resources and global weather data were provided by NASA Advanced Supercomputing (NAS) Division and NCAR Computational & Information Systems Laboratory (CISL), respectively.