Wind, Solar and Biomass have enjoyed significant growth as a result of RPS (Renewable Portfolio Standards), tax incentives and public opinion. The relative cost of fossil fuels, energy security, national security and concern for global warming has renewed interest and brought expansion to these sectors; In addition America's power companies have realized they will soon have to pay for Co2 as EU counterparts are already doing so.
Last year was a record for investments in renewable energy, with more than 11.7 billion invested in the sector. Renewable energy is growing at a rate in excess of 25% per year for the past decade (20% in 2002 thru 2004, 41% in 2005 and 32% in 2006). Even with concerns such as intermittency of production with wind and solar, as well as transmission constraints, and regulatory risk regarding tax incentives, E.R.E.C. (European Renewable Energy Council) claims renewable energy sources can provide as much as 35% of the worlds energy needs by 2030. The price of oil may change and hostile governments may change but it will continue to be more expensive to produce oil as we try to retrieve it from deeper wells, from shale and from sands.
World population is expected to grow by more than 41% by 2050 from 2002 levels. This is going to require greater electricity capacity, efficiency programs and technological advancements. The U.S will have to take a leading position in green production by investments in electricity infrastructure, research and development, technology advancements, as well as training more scientists and engineers.
U.S. E.I.A. (Energy Information Administration) 06
Dept. of Energy, May 07
"The first windmill for electricity production in the U.S was built in Cleveland, Ohio by Charles Brush in 1888, and in 1908 there were 72 wind driven electric generators from 5 KW to 25 KW" [Wikipedia]
After reaching 1000 MW of wind energy in 1985 it took more than a decade for wind to reach the 2,000MW mark in 1999. Since then installed capacity has grown five fold providing enough to power 2.5 million homes. [US Department of Energy]
Potential Turbine Power
The amount of power transferred to a Wind Turbine is directly proportional to the area swept out by the rotor, to the density of the air, and the cube of the wind speed.
P = ½1t x p x rv3
P= Power in Watts
p = mass density of air in Kilograms per cubic meter
t = an efficient factor determined by design of the turbine
r = radius of the wind turbine in meters
v = velocity of the air in meters
Source: Iowa Energy Center Wind Energy Manual
Wind is an increasingly cost competitive form of electricity generation, it's inexhaustible and free; it reduces the dependence of fossil fuels and lowers Co2 emissions.
AWEA (American Wind Energy Association) states wind projects account for about 30% of all new power generating capacity added in the U.S in 2007, the second fastest source of electricity in the U.S. behind Natural Gas. As environmentalism grows in popularity, so does the prevalence of socially responsible investors.
A consulting firm, Emerging Energy Research, conducted a study estimating comparable costs of energy using 30euro A ton Co2 found onshore wind power to be $ .113 a kWh matching Natural Gas and Cheaper than coal. ($ .114) and coal gasification ($ .138)
The energy needed to build a modern wind turbine and operate and maintain it through its twenty-year design life is recouped within 7 to 9 months after which Co2 emissions are effectively zero. As per S.E.I (Solar Energy International) using 100kWh of wind power each month is equivalent to planting 1/2 acre of trees or not driving 2,400 miles.
Winds that sweep across Northeast blow at an average of about 4 meters per second, offshore more than twice as fast (offshore turbines cost 50% more)
* Winds blowing at 10 m/s can produce five times as much electricity as wind blowing half as fast
* 3 megawatt wind turbine is enough power 825 homes.
As mentioned the advantages of wind include it being inexhaustible, non polluting but also include no chemicals being involved in its production, low operation and maintenance costs ($ .8cents /kWh similar to fossil fuel plants), the surrounding land is useable, as well as the anticipation of creating new jobs and it diversifies our energy sources.
The disadvantages include intermittent power, installation costs, transmission line costs, danger to wildlife, shadows and noise. The location will determine it's output, while noise could be compared to a kitchen refrigerator up to 1000 feet.
Wind, Solar and Biomass projects will qualify for the production tax credit (PTC) under section 45 of the international revenue code and for the first 5 years Accelerated Depreciation (MACRS – Modified Accelerated Cost Recovery System). Solar will qualify for the energy investment tax credit (ITC)
The PTC is .02 per kWh credit
The ITC is a credit equal to 30% of the invested capital. For instance the net present value of these benefits in a wind energy project may approximate 60% of the total capital cost.
Horizontal Axis Wind Turbines (HAWT) Vs. Vertical Axis Wind Turbines (VAWT)
Horizontal Axis Wind Turbines have main rotor shafts and electrical generators at the top of a tower, and must be pointed into the wind (small wind turbines are pointed by a simple wind vane, large ones use a wind sensor coupled with a servo motor)
The advantages are the variable blade pitch can provide an optimal angle and that they have a tall tower base, which allows access to strong winds.
The disadvantages are that there is difficulty in operating them near the ground and in turbulent winds. The blades are large and difficult to transport. Reflections can affect radar installations. They are obtrusive (NIMBY – Not In My Back Yard). And lastly downwind variants suffer from fatigue caused by turbulence, cyclic stresses and vibration.
Vertical Axis Wind Turbines are different from traditional wind turbines in that their main axis is perpendicular to the ground. VAWT's configuration makes them ideal for both rural and urban settings.
The advantages of VAWTs are that they are not affected by the direction of the wind, which is useful in areas where wind changes direction frequently and quickly. No large tower structure is needed, therefore they outperform HAWTs and are better able to handle turbulent air flow typical near buildings and other structures. VAWTs are ideal for both rural and urban applications, including roof top installations. Depending on the shape of the roof, the wind flow over the roof can be concentrated, leading to an increased energy output. The VAWTs have slower start up speeds than HAWTs; typically they start creating electricity at 6MPH. VAWTs are less likely to break in high winds due to their lower tip speed ratio, but still , they are more simple to maintain as well as install. Most VAWTs are pleasant in appearance and can more easily be seen by birds; also VAWTs are quieter in operation.
The disadvantages of VAWTs are that they produce energy at 50% of the efficiency of HAWTs and that their parts are located under the weight of the structure.
As we head toward a Cap and Trade program in the U.S. the public will have to recognize the Carbon Footprint of everything in their lives and correlate it to the price of Carbon. This new reality is going to propel interest and investment to new levels. With the recent drop in prices of steel and copper there will be a reduction in the cost of making turbines; hopefully passed on to perspective buyers.
There are many challenges such as a flagging economy, cuts in investments due to a credit crunch, and the weakness in Carbon prices. These factors may delay progress and success of renewable energy sources providing an integral solution to global climate issues, but only delay. Steve Bolze of GE Energy says he has no doubts about the industry's long-term prospects.
In 2011 TLR Energy begins distributing a solar-powered portable Medi-fridge to remote locations without access to electricity in South Africa... more