Renewable Energy Technologies have Matured as a Source of Electricity and have caught the attention of our industry. They are seen as the clean, emissions-free alternative to fossil fuels. Many also see renewables as an increasingly significant part of the resolution to the quandary of energy security and climate change facing the world today.

Worldwide, the need for energy continues to increase, while in India and China, energy growth has reached explosive proportions. Fossil-fuel supplies are becoming more expensive and more difficult to remove from the Earth. The Intergovernmental Panel of Climate Change's “Fourth Assessment Report” published in 2007 (latest year for data) identified the power sector as the single-largest source of greenhouse gasses, accounting for 38% of CO2 emissions and 25.9% of the overall anthropogenic greenhouse gasses.

According to a recent Worldwatch Institute report, more than 65 countries have national goals for accelerating the use of renewable energy and are enacting policies to achieve those goals. In 2007, USA Today reported the global capacity for photovoltaic equipment at approximately 9740 MW with projections of 12,500 MW by the end of 2008. The Earth Policy Institute in Washington, D.C. reported more than 10,000 MW of geothermal generation installed worldwide by the end of 2007. In 2008, the Global Wind Energy Council estimates the world's total wind-generation capacity at roughly 100 GW.

IT IS THE LAW

China's Renewable Energy Law, which went into effect on Jan. 1, 2006, was created to help China meet its goal of providing 15% of the country's electric energy from renewable sources by 2020. By the end of 2007, China had installed more than 6000 MW of wind generation and estimated its 2008 installed capacity would be about 9000 MW.

The European Union (EU) leads the world with installed renewable capacity. In fact, the 2001 EU Renewable Energy Directive encouraged the development of a renewable national policy. Overall, 2007 saw the EU generate approximately 3.7% of its electricity with wind power. With more than 56 GW of installed wind-generation capacity, the European Wind Energy Association reports the EU has set a binding target of generating 20% of its electricity from renewable sources by 2020 for its 27 members.

“Europe has had a long-term, stable policy for a decade, and it has given stability to their wind development,” said Charles Smith, executive director of the Utility Wind Integration Group. “The policy framework gives investment certainty, and has lead to significant investment in manufacturing capacity and interconnection of wind generation. They have interconnection queues in each country, but national laws require the utilities to connect the wind generators, reinforce the system if necessary and to do it quickly.”

By the end of 2007, 35 U.S. states were generating approximately 21 GW from wind power, which is about 1.5% of the U.S. electricity needs. In May 2008, the U.S. Department of Energy's (DOE) Office of Energy Efficiency and Renewable Energy released the report “20% Wind Energy by 2030: Increasing Wind Energy's Contribution to U.S. Electricity Supply.” Black & Veatch (Overland Park, Kansas, U.S.) analyzed the market potential for significant wind energy growth, evaluated the U.S. wind supply and developed cost-supply curves for the wind resources to establish the basis of this report. In addition, the DOE worked with the National Renewable Energy Laboratory, Sandia National Laboratory, the American Wind Energy Association and other wind industry partners to produce this extensive report.

The report found the United States has more than sufficient wind resources to generate 20% of the nation's electricity and that wind generation is affordable. The report stated, “The data suggest that as much as 600 GW of wind resources could be available for US$60 to $100 per megawatt-hour.”

“The wind technology exists. It doesn't requiring any major technological breakthroughs to reach this level of wind generation. It does require action,” said Steve Lindenberg, team leader, DOE technology applications. “The installation rate has to increase from 2006's 3 GW to more than 16 GW per year by 2018 and continue at roughly that rate through 2030. With the 5329 MW installed in 2007 and the projected 7500 MW in 2008, the United States is on track.”

IT IS POSSIBLE, BUT THERE ARE CHALLENGES

The DOE has identified several challenges to meeting the 20% goal. The United States needs a national renewable electricity standard (also referred to as a renewable portfolio standard or RPS), a national interstate transmission grid under the jurisdiction of the federal government and more transmission capacity. A RPS would signal a long-term national commitment to expanding the use of renewable energy. (Currently, 28 states and Washington D.C. have a RPS). But perhaps the biggest obstacle to increasing generation of any type is the process to install generation on the grid and a lack of available transmission capacity.

“We have a very dependable 57 Chevy, but we need an efficient, dependable 2009 vehicle to meet today's challenges,” commented Lindenberg.

WHEN THEORY AND REALITY MEET

In theory, we have an open-access system in each state for interconnection to the grid (Federal Energy Regulatory Commission [FERC] Orders 888 and 889). Unfortunately, when theory met reality, it did not mesh as well as expected. No one predicted the volume of the requests for interconnections from wind power producers. Also, the process takes a bottom-up approach. The interconnector files a request for service and pays the fee. The project then has to be studied, and each study is done individually. Network upgrades are determined for the specific project, with associated costs assigned to the project.

If the requestor withdrawals from the queue, the projects following the withdrawn project have to be restudied. In many cases, it becomes an endless loop of studies, restudies and more studies. As a result, it is not uncommon for interconnectors to file multiple requests to secure the least-cost position in a queue. This has added additional burden to an already overloaded system. The queues have become even more congested than the electrical transmission system. It is not unusual for a project to take three to five years or longer to work its way through a queue.

  • In February 2008, the Electric Reliability Council of Texas (Austin, Texas, U.S.) reported it had 222 projects representing approximately 100 GW in its interconnection queue.

  • By late April 2008, PJM (Norristown, Pennsylvania, U.S.) had 360 generation projects totaling 84.2 GW, the Southwest Power Pool (SPP; Little Rock, Arkansas, U.S.) had a queue of 106 projects representing over 26.8 GW, and ISO-New England had a queue of 104 projects representing about 13.4 GW.

  • California ISO (Folsom, California, U.S.) had 361 interconnection requests in its July queue totaling over 105 GW with more than 68 GW of renewable resources.

  • As of Oct. 31, 2008, the Midwest ISO (Carmel, Indiana, U.S.) had 408 (349 for wind) requests for interconnections totaling 82.7 GW (67.1 GW of wind) in its queue.

These projects represent substantial investments and significant amounts of generation, and they are not able to move forward on a reasonable schedule due to congestion.

OPEN SEASON

The FERC acknowledged that there are significant interconnection queue issues and there must be changes. The FERC has been working with transmission providers and has taken several proposals under advisement. These include sizeable increases in the financial commitments (fees) required from interconnectors to assure that only genuine requests are submitted. It also has been suggested that additional fees be applied on interconnectors who make changes that require restudy and fees for dropping out of the queue.

One such proposal came from Bonneville Power Administration (BPA; Portland, Oregon, U.S.), which had 316 interconnection requests in the queue representing 14.4 GW. It was determined that it was unable to perform meaningful studies with this number of requests. Therefore, BPA proposed a Network Open Season (NOS) to break up the logjam in the queue.

BPA asked all those seeking transmission capacity to sign a Precedent Transmission Service Agreement (PTSA), which committed them to take service at a specified time under specified terms. Those who did not sign the PTSA were removed from the queue.

As a result of the NOS, BPA reduced the queue by 163 interconnectors to 153 PTSAs signed, representing about 6.4 GW, down by roughly 8 GW. With the traffic jam broken, BPA is performing transmission system impacts and facility requirements in a cluster study for the interconnectors represented by the PTSAs.

After following the BPA process closely, the FERC issued a declaratory order on June 19, 2008. The order substantially approves the BPA NOS process including the cluster studies for processing service requests and the PTSAs used in the NOS process. Queue reforms are now underway across the country, with transmission providers, regulators and interconnectors supporting the effort.

INTERSTATE HIGHWAY FOR TRANSMISSION

Once the congestion of the interconnection process has been resolved, the issue of increasing the transmission capacity to reach a 20% increase of capacity required to meet the nation's goal still remains.

American Electric Power (AEP; Columbus, Ohio, U.S.) has an interesting proposal to increase capacity by building an interstate highway system of 765-kV extra-high-voltage (EHV) transmission lines to connect major wind developments to the load centers. To help achieve this vision, AEP has joined forces with its subsidiary MidAmerican Energy Holdings Co. (Des Moines, Iowa, U.S.) to build and own electric transmission assets. The joint venture, Electric Transmission America, is a 50-50 partnership to identify and invest in high-voltage transmission projects (345 kV or higher) located in North America outside of the Electric Reliability Council of Texas.

“Today's transmission is much like 1956 with respect to the nation's highways. It was a congested system built to serve each state and did not encourage long-haul trucking,” said John Stough, vice president of Electric Transmission America and director of AEP Transmission Business Development. “President Eisenhower had a vision of an interstate highway overlay rather than just-in-time upgrades to the states' existing roadways. Interstate commerce flourished with increased access and mobility.”

AEP offers a unique perspective. It has been operating a 765-kV system since 1969 and has more than 2100 miles (3380 km) of this voltage in its system. AEP has approximately 39,000 circuit miles (62,764 km) of overall transmission lines in 11 states (from Ohio to Texas) serving approximately 5.1 million customers.

“One six conductor bundled 765-kV transmission line can carry the same amount of power as approximately three 500-kV lines or six 345-kV lines,” explained Stough. “In addition, higher voltages have lower losses, especially as loadings increase. The typical 765-kV has losses of less than 1%. Plus, the environmental footprint would be significantly smaller for the same capacity.”

AEP estimates the cost per mile for a 765-kV line is about $2.2 million. Comparing this to typical 345-kV construction at $1 million per mile, it may appear expensive until you factor in the fact the 765-kV line carries six times the power. Therefore, the equivalent 345-kV capacity would cost $6 million per mile. Consequently, 765-kV transmission is a more efficient and cost-effective transmission line.

Electric Transmission America, working with the SPP, has recently received FERC approval for the first stage of the SPP EHV overlay. The phases are the 765-kV Tallgrass Transmission project in Oklahoma and its 765-kV Prairie Wind project in Kansas. These two projects consist of approximately 400 miles (643 km) of 765-kV transmission connected at the Oklahoma/Kansas border. According to Stough, this will be the first 765-kV built west of the Mississippi River.

The lines will give the SPP the capacity to interconnect the approximately 14 GW of wind power in its queue. The two phases are scheduled to be in service by 2012/2013. “We believe the future is bright for renewable generation and transmission development in America,” said Stough.

For many years, the industry has been on the gentle portion of the exponential curve describing the introduction of renewable energy to the grid. Over the last couple of years, technology improvements have moved renewable energy generation into the knee of that curve. As a result, thousands of megawatts are being installed yearly in countries around the world. But there are many hundreds of thousands of megawatts hung up in interconnection queues, too. That is generation waiting to be brought on-line. Open season on transmission queues, governmental support with tax credits and carbon caps, and building a national super grid with superhighways of 765-kV transmission lines are a few of the measures that will help the industry increase the percentage of renewable energy in the generation portfolio.

Wind Power Classification
Wind power class Resource potential Wind power density at 50 m W/m2 Wind speed at 50 m m/s Wind speed at 50 m mph
2 Marginal 200 to 300 5.60 to 6.40 12.50 to 14.30
3 Fair 300 to 400 6.40 to 7.00 14.30 to 15.70
4 Good 400 to 500 7.00 to 7.50 15.70 to 16.80
5 Excellent 500 to 600 7.50 to 8.00 16.80 to 17.90
6 Outstanding 600 to 800 8.00 to 8.80 17.90 to 19.70
7 Superb 800 to 1600 8.80 to 11.10 19.70 to 24.80

NREL's composite wind resource map with AEP's 765-kV interstate transmission system overlay. In the table, wind speeds are based on a Weibull k value of 2.0.