Brownfield sites, including closed landfills, sometimes also referred to as legacy landfills, are financial liabilities to their owners whether they be a municipality, a county or the former operators or owners of the site. The owners of such sites may never see an end to the perpetual monitoring requirements mandated by federal and state laws governing solid waste disposal facilities. Monitoring costs are derived from such activities as groundwater and gas probe monitoring; upgrades, repairs or maintenance to landfill gas and leachate collection systems; and maintenance, monitoring or repair of final cover systems, including potentially expensive erosion control. In this challenging economy, it may be more difficult to convince developers to build new construction on closed landfill sites. Despite these challenges, closed or legacy landfills can also be positive attributes to a community or owner wanting to take advantage of a large platform for producing alternative energy. Wind farms, the capture of landfill gas (methane) and conversion to electricity (known as landfill gas to energy or LFGE) or solar farms are all excellent uses for legacy landfills.

Many old landfills and brownfield sites are located near urban areas with adequately developed utility infrastructure. With electrical lines nearby, close-in Brownfields and legacy landfills can more efficiently produce and transmit power to areas in need of renewable energy supplies and less investment in costly utility infrastructure will be required.

Time is Right
Why solar energy? It's more than just the new craze. Once installed, solar energy requires no fuel, has no moving parts, produces no emissions, generates no waste products, reduces the U.S. dependence on coal and oil; and the manufacturing of solar power-generating equipment has minimal impact on the land. According to the U.S. Dept. of Energy (DOE), solar energy is a rapidly expanding industry with a double-digit annual growth rate in the U.S. The DOE is focused on supporting the U.S. industry's growth of manufacturing, production, and distribution so the technology can become cost competitive with conventional sources of energy. DOE will provide $117.6 million in American Recovery and Reinvestment Act (ARRA) funding to accelerate widespread commercialization of clean solar energy technologies across America.

The DOE has an initiative called Brightfields, which specifically promotes the redevelopment of brownfields to use solar technology to generate both clean energy and revenue for the community. Closed landfills may be considered brownfield sites in some areas, particularly in older urban environments where the landfills are close to the city's urban core.

According to information posted on DOE's website (http://epa.gov/brownfields/html-doc/brightfd.htm): Brightfields is a revolutionary concept that addresses three of the nation's biggest challenges—urban revitalization, toxic waste cleanup, and climate change—by bringing pollution-free solar energy and high-tech solar manufacturing jobs to brownfields. The Brightfields approach offers a range of opportunities to link solar energy to brownfields redevelopment and thereby transform community hazards and eyesores into productive, green ventures. This unprecedented campaign will help our nation put its hundreds of thousands of brownfields back into productive use and at the same time create high-tech jobs in blighted urban neighborhoods, improve air quality, and reduce greenhouse gas emissions.

Solar on Legacy Landfills
The characteristics of large closed landfill sites can often be quite advantageous for the installation of solar power production facilities. An example project evaluated by the U.S. EPA Brownfields Technical Assistance to Pilot Communities program consisted of a 300-acre closed landfill near Houston, Texas. The pilot evaluated the feasibility of installing solar panels on the closed Holmes Road landfill site with the intention of generating up to 10 megawatts of electricity from the installation. The result was a recommendation to install solar panels on 150 acres of the 300-acre site, yielding an estimated 1 megawatt for every 15 acres of panels installed, including space between panels and other equipment to avoid row-on-row shading, etc. One Florida utility is operating a demonstration solar photovoltaic (PV) system on a closed landfill in Sarasota. Their system, utilizing 1,200 flat panels laid directly on the landfill geo-membrane cover, provides 250 kilowatts (kW) of power to the grid and covers about 28,000 square feet.

Republic Services, one the nation's largest landfill owners and operators, recently implemented a project at the active Tessman Road Landfill in San Antonio, Texas. The innovative project included covering a closed portion of the site with synthetic geomembrane landfill cover material and then affixing flexible laminate solar panels to the geomembrane materials. The cover with the adhered solar panels was placed on the top deck and south facing slopes of the site, and combined with the site's already active LFGE system, is producing 9 MW of power for use on site to continue operations of the still-active portion of the landfill. This is reportedly enough electricity production to provide power to over 5,200 homes.

The many key issues that come into play with a solar installation on closed landfill projects include:

• Funding sources and economics. Determining how to finance the project and where the capital investment will come from. What is the average cost of energy in the relevant market and is there approximate grid parity between solar and conventional sources? If there is not grid parity, are there incentives or regulatory drivers that overcome parity issues?
• Nature of real property transaction. Is the project subject to a long term ground lease or an actual sale? Generally large scale PV or solar power generation projects tend to focus on a negotiated power purchase agreement (PPA) with an offsite utility. These types of arrangements often lead to a long term ground lease with a portion of the monies generated through the sale of the electricity being given to the land owner.
• Zoning and entitlements. What are the underlying zoning requirements, and will it support a solar project without a zoning change or major use permit? What entitlements are necessary to develop the project, what are their costs and what is the timing? Will an environmental analysis, such as an Environmental Impact Report, Environmental Impact Statement or finding of no significant impact, be required? In California, the California Solar Rights Act (AB2473) could significantly reduce the time spent obtaining permits and the costs of zoning and entitlements for a solar project.
• Environmental liabilities and indemnity. How will environmental liability be addressed? For example, if a landfill operator or land owner alleges the solar operator caused or contributed to a notice of violation, how will this be accounted for?
• Site characteristics. Is the site large enough, is it old enough to have settled sufficiently to make the project feasible or will significant additional engineering be required? Is the site in a Sunbelt state? Where in the U.S. is the site to the extent that it requires sufficient year round sunlight to make solar feasible? (see the U.S. EPA's Re-Powering America's Lands Google Earth Tool www.epa.gov/renewableenergyland/mapping_tool.htm ) to determine if your site is in an area considered generally suitable for solar power generation.
• Power uses and proximity to grid. What are the potential uses of the electricity: used on-site only or could the power be sold to a local utility? What is the closest grid location? Is it close enough to existing power lines to tie into the local power grid? Is there a clear avenue to structure a Power Purchase Agreement (PPA) with the local utility offtaker? For sites in California owned by a county or municipal agency, a PPA may not be required for projects that produce less than 1 MW of power.
• Other considerations include: coordination of parties (owners, permitting agencies, cities, utilities, solar developers, installers); Are Renewable Energy Credits (RECs) available for your project and how can they be obtained; and Permitting. What is the critical path and feasibility of obtaining the various permits required? This should be planned out in advance and evaluated as part of the feasibility analysis. How the existing operating or post closure care permit will be impacted should also be evaluated and planned for.

Alternative energy production on brownfield sites and closed or partially-closed landfills is an initiative with significant momentum, government support and community relations benefits. Not unlike the early years of brownfield development, coordination of many parties and bringing stakeholders on board is essential to a successful project.

With the appropriate political and financial incentives available in the current environment, the desire on the part of landowners and businesses to create positive community outcomes from their properties and projects and the growth of the alternative energy industry in the U.S. and abroad, the time is right to capitalize on these opportunities.

Funding Sources and Tax Credits
A bill, H.R. 1424 Emergency Economic Stabilization Act of 2008 (Division B: Energy Improvement and Extension Act of 2008 - Energy Improvement and Extension Act of 2008 - Title I: Energy Production Incentives - Subtitle A: Renewable Energy Incentives - (Sec. 101), passed in October, provides financial incentives for local and state governments, companies and utilities to develop more renewable energy projects. In Section 107, the bill authorizes $800 million of bonds to finance clean renewable energy facilities that generate electricity and creates a new category of tax credit bonds to finance state and local government initiatives designed to reduce greenhouse gas emissions. Solar projects could potentially qualify under both of these provisions.

Private sources of capital are also available for solar projects and alternative energy projects, including these types of large scale projects on Brownfields and closed landfills. Traditional lenders such as banks will underwrite a development proposal to install solar or other forms of alternative energy on buildings or other commercial properties (vineyards, farms, and landfills). These arrangements are often negotiated through solar developers that have relationships with financial institutions familiar with providing debt or equity for these types of projects. A private brownfield lender based in Sacramento, Calif., EnviroFinance Group, is currently exploring its options to jump into this arena with options to place debt on these types of projects.

Federal Tax Credits
H.R.1424, extends critical Federal Investment Tax Credits for solar customers and other renewable energy projects. This bill contains $18 billion in incentives for clean and renewable energy technologies, as well as for energy efficiency improvements.

As part of this legislation, the solar investment tax credit (ITC) has been extended for 8 years through December 31, 2016. Some key provisions of the ITC are:

• The 30% federal investment tax credit for both residential and commercial solar installations is extended for 8 years through December 31, 2016.
• Eliminates the $2,000 cap on the tax credit for the purchase and installations of solar electric on residential properties.
• Addition of small wind energy and geothermal heat pump projects as qualifying installations for tax credits
• Utilities may now benefit from the credit as eligible tax credit recipients.
• Extends through 2009 the authority to issue clean renewable energy bonds.

California also offers financial incentives through a utility rebate program for photovoltaics. This program applies to systems up to 1 MW. Specific eligibility requirements also apply such as all flat plate PV modules and inverters must be on the State of California Energy Commission list of eligible equipment and must have full 10-year warranty on equipment and labor. Additional incentives apply for non-profit organizations and government organizations (rebates are higher per watt for these groups). Tax exempt organizations cannot qualify for federal investment tax credits on their systems, which is why California created the Performance Based Incentive system.

Florida, like many states, also has a grant program for innovative renewable energy projects. Private equity partners can provide a "package" that would include funding of construction and maintenance in return for lease rights and other concessions.

Site Characteristics
Not every landfill may be suitable for a solar panel installation. Some of the issues to consider are similar to any other building construction project on a current or closed disposal site. The types of engineering analysis to determine the feasibility or for planning for the installation include:

• Plan for differential settlement or select a site that is old and where most or all of the settlement has occurred.
• Landfill gas collection system components may restrict the use of some areas.
• More often than not, the site will have the proper sun exposure, but on very old sites trees might have to be removed. This was the case with the Holmes Road landfill example mentioned early on in this article.
• Maintaining the integrity of top liners, either synthetic or natural will be required when installing a solar PV system. One manufacturer of thin film flexible solar panels has a product that can be laid directly on a landfill cover and these can be installed on the top deck or south facing slopes (only) with slope steepness provisions and limitations. This application in particular is excellent for partially closed landfills where the most recently closed cell requires a geomembrane cover and can accommodate the thin film panels.
• If cover vegetation is removed for panels, there must be provisions to divert runoff so that erosion of the soil cap does not occur.
• Solar panels can be wind collectors; sufficient engineering design and construction will be required to ensure that the panels and their foundations are properly anchored and will not be impacted by the elements (wind, snow, hail, etc.)

Coordination of Parties
There can be several entities involved in a solar project. There is likely to be a private equity partner involved who may be the actual financial driving force behind the project and ultimately owns/operates the system. Many projects require a grid-tie to ensure that normal power from the utility line is available if the PV system output is not available. There can be considerable cost and time spent working with a utility to negotiate interconnect issues, assuming power near or at the site already exists. It could be expected to take longer if no such service is available. Suffice it to say that early planning discussions should include the utility so that coordination is smooth. A successful project of any significant magnitude will likely involve or require the services of a solar developer or a firm with considerable experience negotiating the nuts and bolts of all of the agreements required for the endeavor to be successful. If the project is large enough to be considered a utility scale application, there will be few solar developers that would get involved without some form of assurance that the utility is on board with your project and is willing to purchase the electricity produced by the system installation.

Renewable Energy Credits (RECs)
These projects may qualify for renewable energy credits if the power produced is sold to the local utility. Decisions to pursue this option will largely be financially-based but if they are available, it could make the project pencil more easily than without.

Permitting
Last, but not least, the landfill's operating or post-closure care permit would likely have to be amended to include the new use and related solar equipment. These rules will vary somewhat depending upon location (e.g. from state to state), but overall the integrity of the landfill cover, stormwater management and runoff, integrity of the landfill gas system (if applicable) and other engineering issues will need to be maintained under any revisions to the permit. Working with an engineering firm with experience in negotiating post closure care permits and modifications of those permits, including landfill redevelopment, will be helpful to site owners, solar developers and utilities in ensuring that the project can move forward.

Alternative energy production on brownfield sites and closed or partially closed landfills is an initiative with significant momentum, government support and community relations benefits. Not unlike the early years of brownfield development, coordination of many parties and bringing stakeholders on board is essential to a successful project. Like in a real estate transaction, you must have a willing buyer and seller with several service providers or middle men to assist in the execution of the project. Solar or other alternative energy developers, installers, engineering and environmental firms, utilities and financial partners are but a few of the required parties. An optimal solution to reducing greenhouse gas emissions even further and providing more public and environmental benefit would be to marry a solar or other form of alternative energy production with a LFGE project on a closed landfill.

With the appropriate political and financial incentives available in the current environment, the desire on the part of landowners and businesses to create positive community outcomes from their properties and projects and the growth of the alternative energy industry in the United States and abroad, the time is right to capitalize on these opportunities.

We're From the Government and We're Here to Help!
The National Association of Local Government Environmental Professionals (NALGEP) recently (July 23, 2009) held a "webinar" or webcast entitled Development of Renewable Energy on Contaminated Lands. During this web-based seminar, several speakers discussed the opportunities to use Brownfields, landfills and other forms of large underutilized properties for renewable energy. The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response launched a program in 2008 called RE-Powering America's Land. This program tracked the redevelopment potential of nearly 13 million acres of sites in the U.S. including Superfund/CERCLIS sites, abandoned mine lands, brownfield sites and Resource Conservation and Recovery Act (RCRA) sites. In concert with the National Renewable Energy Laboratory (NREL), the two agencies mapped (using a Google Earth tool) a number of data points that were favorable and salient to the use of landfills, Brownfields and contaminated sites for development of renewable energy. These data points included proximity to existing infrastructure such as highways, railroads and transmission lines. In addition, EPA and NREL also evaluated the following potential energy generating aspects of some of these sites:

• Utility Scale Wind Energy Generation
• Community Wind Energy Generation
• Utility Scale Concentrated Solar Power (CSP) Energy Generation
• Utility Scale Photovoltaic (PV) Solar Energy Generation
• Biopower Facility Siting
• Biorefinery Facility Siting
• Non-Grid Connected Wind Energy Generation
• Non-Grid Connected Photovoltaic (PV) Solar Energy Generation

Clearly there is a great deal of interest for this type of project, including federal agency and non-profit initiatives and programs aimed at developing more closed landfill and brownfield sites into alternative energy producing properties. In addition, market forces appear to be more favorable as more players enter the solar market and more manufacturers face the reality of competition and downward price pressure for their products.

Chris Nelson, SCS Engineers. Contributing Authors: Dan Johnson, Bruce Clark, Dan Cooper and Amanda Moore, SCS Engineers

SCS Engineers can provide numerous engineering and construction services to assist legacy landfill owners and solar power developers, utilities or installers to get "plugged in" to this new, promising concept.