DENVER — Comments Woods Allee, director of capital planning and special projects at Denver International Airport (DEN), “In 2001, the state passed a statute with a RES (renewable energy standard) which required some incentives on the part of the State with regard to solar. We’ve kept a close eye on what was being developed in terms of photovoltaic (PV) technology.”
PV technology takes solar energy and converts it directly to electrical energy, explains Allee.
“The airport chose that technology because the RES specifically recognized PV, and from our perspective, given our real business of operating an airport, we are going to be very careful in deploying any technology that requires reflectors; that’s a safety issue related to a pilot’s visibility,” he adds.
“We went through quite an effort with FAA because we have the largest installation of solar I think of any airport in the country, and we were the first to do a major solar installation at a major airport. The FAA was very interested in how we went about doing this, and demonstrating to themselves primarily that there was a low risk of any interference with air navigation.”
The airport went through an RFP to select a firm to help develop a bid. DEN worked closely with FAA to sort out visibility and glare issues; a number of tests were conducted in 2006.
“Ultimately, FAA flight standards agreed that there was not a high risk in terms of pilot visibility, and we got approval of FAA Form 7460 [site plan and land lease & operating agreement approval process] for the three systems we have now.”
There are a significant number of tax incentives that private tax-paying entities can take advantage of, but which would be very difficult for the airport to take advantage of, explains Allee. “So it turns out that the cost of funds ultimately to the airport, even if we use tax-exempt bonds and our high credit rating, is lower for a private entity than it is for us to do this directly through our own bonds … hence the public-private partnerships that we’ve entered into.
“We have two agreements with regard to the two existing solar projects: a ground-lease agreement which conveys certain rights to the developer — the developer wants to be sure they have rights to the land for the next 20 years, and that we don’t build something that will shade the land; the other agreement is a power-purchase agreement (PPA) — where we essentially agree to buy the power that the developer generates from the projects.
“Our capital outlay for all three solar projects really has been nothing — it’s all paid for by private investors who will reap the benefits of the tax incentives.”
DIA [a common reference for the airport] Solar One was built when panel costs were fairly high; the overall cost to construct that system was about $13.5 million, and consists of 9,254 panels, says Allee. DIA Solar Two cost about $7 million, and there are some 7,300 panels.
Existing solar installations
Solar is good for DIA, explains Allee, because there is more than 300 days of sun here each year; the State’s RES created incentives for people to be able to build economic solar facilities.
“Xcel Energy [a Midwest electric utility] charges a rider on our electrical bills, and some 1 percent of that money goes into a pot to incentivize renewable energy,” he relates.
“The way you bid into the program is you sell the renewable energy component back to Xcel; they buy that component from the generation source.”
The airport has a couple of opportunities, says Allee. One, there are 33,800 acres here … a large land area, much of which is going to remain unused for a length of time. “We also have significant energy loads here; we are Xcel’s largest single load in this region,” he remarks. “So that load factor in proximity to available land makes the airport attractive for ground-managed solar technology; those factors help keep the costs down.”