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The Green Mountain Wind Farm Meeting Renewable Energy Demand in a Competitive Electric Environment

First presented at the AWEA WindPower 2000 Conference Palm Springs, California, May 2, 2000Steven Macken

National Wind Power
405 14th St., Suite 712
Oakland, CA  94612
(510) 208-7172

Green Mountain Energy
55 Green Mountain Drive
South Burlington
Vermont  VT  05407-2206
(802) 846-6113

Pennsylvania and Deregulation

In January, 1999, Pennsylvania opened up its electric energy industry to allow for the entry of competitive retail energy service providers.  With an attractive shopping credit established, the market quickly responded with a relatively high number of consumers switching to competitive suppliers.  After more than a year under a deregulated environment, approximately 10% of Pennsylvania’s 5.35 million electric consumers that are eligible to switch have decided to make the move away from their incumbent utility to a competitive energy company.

It is apparent that Pennsylvania also ranked high in willingness to pay more for energy from renewable energy resources; current estimates show that 15% of the switchers have chosen a company that offers a green energy product.

Green Mountain Energy

 At the time Pennsylvania opened up to retail competition, Green Mountain Energy had been doing business in the California deregulated market offering several green electric products.  With the greater incentive for consumers to switch in Pennsylvania, Green Mountain Energy recognized the ability to attract customers that want to switch and are willing to pay more for above-market energy from renewables.  Pennsylvania is the country’s eighth largest consumer of electrical energy, and also one of the dirtiest in terms of emissions from fossil facilities, thus the business and environmental prospects of selling retail renewable energy in the state looked quite promising.

The challenge is that the mix of existing renewables in and around the Pennsylvania market is limited, and furthermore, little is being done in the way in developing new renewable resources. Due to the large amount of trash imported into Pennsylvania from surrounding states, most renewable development activity in the state has centered around new landfill gas-to-energy projects.   However, even these opportunities are relatively low, as the number of landfills are limited in the state.  Some signs of wood-based biomass development are emerging, but near-term cost-of-electricity estimates from these facilities approach that of wind.

Wind in PA

Building upon the success of a wind-based product in California, Green Mountain Energy felt it important to quickly investigate the opportunities for adding wind to meet its new renewable requirements in Pennsylvania. The marketing aspects of wind are attractive to a retailer of green energy.  Wind generation is generally viewed as a premium resource over other forms of renewable energy sources such as biomass (NOx emissions and fuel source harvesting issues) and hydro (dam impoundment issues and fish impacts).  Images of wind turbines spinning has certain intuitiveness to consumers when presented in materials that are intended to educate and promote renewable energy.

With all the environmental aspects of solar, geothermal, and biomass, wind arguably has the most visual appeal and impact.

Furthermore, with no emissions and fuel source/water impacts, the introduction of new wind development into the Pennsylvania grid has meaningful environmental benefits for the region.  An annual production from 10 MW of wind will eliminate approximately 135 tons of sulfur dioxide, 35 tons of nitrogen oxides, and 17,000 tons of carbon dioxide from being emitted based on the region’s system mix.

Prospecting

Estimates from the Pacific Northwest Laboratories show that  PA ranks as the 22nd best state for wind development. The state’s primary regions of class 4 sites, as expected, follow the mountain ridges of the Allegheny and Appalachian Mountains in the south-west portion of the state to the Pocono Mountains in the north-east portion of the state.  Many of the state’s strip-mined land also fall in those regions, providing for the opportunity to utilize open, low-priced reclaimed land.

In late 1998, GreenMountain contracted Colorado based Distributed Generation Systems to identify candidate wind farm sites in Pennsylvania.  A number of promising sites were selected in accordance with strict environmental and social criteria, in line with GreenMountain’s philosophy to minimize environmental impact and benefit the local economy.  The site chosen for the Green Mountain Wind Farm is located in southwestern Pennsylvania, close to the town of Garrett. Used formerly for strip mining coal and currently farmed, the site has the following advantages:

The decline in the local coal industry has been an economic burden to the area.  The tourism, tax and landowner revenues that the wind farm will bring are welcome in the local community.  It is also quite symbolic that such a new, clean technology will generate electricity on land that was formerly used for mining fossil fuel.

In parallel with Disgen’s pre-construction development efforts, Green Mountain Energy set out to identify an owner/operator of the planned wind farm, who shared its vision for market driven renewable resource development and would be willing to proceed on a fast-track construction basis.  After discussions with several potential partners, Green Mountain Energy reached agreement with UK developer National Wind Power, and, as part of a rather unique arrangement,  the two parties developed wind resource and production tax credit risk sharing which allowed the project to proceed at a time when much of the other US activity was stalled.

As a result, less than a year after entering the PA market and stating its intention to pursue wind farm development, a 10 MW project was under contract.

Gaining Marketing Momentum

Consistent with its mission to change the way power is made, GreenMountain took advantage of the opportunity around the construction of the wind farm to continue an aggressive marketing and education campaign in PA.  GreenMountain believes the effort taken to educate consumers, besides bringing new customers to its business, will accurately convey the environmental problems associated the production of electricity from fossil and nuclear fuels, and inform them that they have a choice to make a difference.  A number of opportunities were realized to insure the message was put out:

Upcoming dedication ceremony in late May

These events have shown to be highly successful in making consumers aware of the benefits of wind farm projects to the local community and the environment.  Evidence of this is seen in the well-attended events leading up to commercial operation and the overwhelming positive response and interest at the local level.
This level of enthusiasm and awareness at the retail level will only help to set the stage for future development of wind projects in Pennsylvania and beyond to serve the growing competitive green retail market.

Development and Construction

National Wind Power became involved in the Green Mountain Wind Farm project in July 1999, having recently completed its first project in the US, the 30MW Delaware Mountain Wind Farm in Culberson County, Texas, the previous month.

The project is located in an area close to the small town of Garrett and amongst scattered dwellings and farmsteads, so the protection of local residents’ amenity and minimizing local environmental impact were of paramount importance in developing the project to its ultimate completion and operation.

Environmental Assessment

When NWP became involved in this project, the following permits had already been secured by the original project developers, Disgen:

Furthermore, a Phase 1 Avian Risk Assessment had been carried out.  This indicated no potential risk to bird populations as a result of the construction and operation of the wind farm.

With these in place, the project could have been built on completion of the grid connection agreement with the local electric co-op subject to equipment lead times, although NWP felt it vital to carry out further environmental assessment before placing construction contracts.

Geotechnical Work

As much of the site was formerly (20+ years ago) used to strip mine coal, this presented two related significant risks; the stability of the ground for placement of wind turbines, and the potential liability of local water contamination as a result of breaking reinstated ground which had a high risk of containing pollutants from its previous use. 

In order to mitigate these risks, both a detailed Geotechnical Survey and a Phase 1 Environmental Survey were commissioned.

The Geotechnical survey revealed the locations of fill areas around the site, some of which were up to 90ft deep, and as Murphy’s law dictates, were mostly co-incident with the windiest parts of the site!

The Phase 1 Environmental Survey highlighted no significant risks of local contamination as a result of constructing and operating the wind farm, and drew very much on the results of the Geotechnical survey, field work and recorded historical data about the site.

Noise Impact Assessment

In the absence of any building permit conditions limiting noise levels at local dwellings, UK wind turbine noise assessment regulations were applied to the project, which are arguably the most stringent wind turbine noise standards in the world.  These standards were applied to give an  assurance that local residents would not be disturbed by the operation of the wind farm, and to help NWP to develop parameters by which to help design the project and select the most appropriate turbine type for the site.

The assessment method, now standard for all wind projects in the UK, involves the monitoring of background noise levels at nearby properties for around a two week period, and correlating these with on site wind data from the anemometer mast.  This gives a relationship between the on-site wind speed experienced by the turbines, and the ambient background noise levels at each property monitored.  By comparing this data with the aggregated noise output versus wind speed relationship of all the wind turbines on the site, turbines can be positioned to ensure that noise levels at each property are within acceptable limits in relation to existing background noise levels at each dwelling.

This exercise can be a major factor in determining how much capacity and what type of turbine can be installed on the site to ensure acceptable noise limits at local dwelling, which in turn are defined in the noise standards. 

Designing the Layout

Within an overall design brief to build a 10MW wind farm on 500 acres of land, a range of turbines were considered in the 660kW to 1.3MW range. 

Whilst there is theoretically plenty of space for 10MW, the layout development was constrained considerably by the poor ground conditions over half of the site, and by NWP’s self imposed noise constraints.  Fortunately, there were no ecological, avian or archaeological constraints, especially due to the site’s previous industrial history.

In particular, placing wind turbines in areas of poor ground – which often coincided with areas of wind resource - could easily be overcome by innovative foundation design, but this comes at a price which had to be carefully considered against the generally more favorable wind resource in fill areas.

Given all these constraints, the Windops Windfarmer optimizer program was used to help plan the layout, and was programmed to take into account the noise and geotechnical constraints which  had been established from our surveys, and of course the energy resource for site derived from on-site anemometry.  Once set up, this was run for a range of turbine types.

Ultimately, 8 Nordex N60 1.3MW turbines were chosen as the most appropriate turbines for this particular site.  Apart from the usual criteria of price, warranty and operation and maintenance, a large capacity machine such as this lent itself well to this technically constrained situation, especially as  the fewer turbines required to make up the 10MW considerably reduced the risk of building on fill areas of the site. Ultimately, just one of the eight turbines is built on fill land.

Construction Program

Construction contracts were let in December 1999 and major works started in January of this year.  All eight turbines were erected during March and April, and the wind farm was fully commissioned and completed on May 1st.

Serving Customer Demand

In an effort to fulfil customer commitments to new renewables and maintain a competitive position in the market, an aggressive schedule was developed to have wind energy placed on the Pennsylvania grid quickly, yet insure an economically viable project for all parties involved. 

This remarkable time from inception to commercial operation of a major commercial wind facility - 17 months - was possible due to a collaborative effort between GreenMountain, National Wind Power, Disgen, and Nordex.  Various project risks were shared in order for the project to remain on track.  It is felt that this type of collaborative effort will become the model for future wind development as the U.S. electric industry continues to deregulate and to provide for competitive green power.