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Definition

PV-Panels.jpg
Source: NFPA

Solar PV is a method of generating electrical power by converting solar radiation into DC electricity using panels comprised of special materials that can harness the photovoltaic effect. A fast-growing technology, it has become one of the leading alternative energy sources in the world.

A Solar PV system can either be connected directly to and feed power into the municipal grid, or store its electricity in batteries for use at a later time.


Issues Addressed


Currently, the majority of Solar PV in the United States is connected directly to the grid.[1] Unfortunately, this scenario means you lose power if the grid goes down.

In response to many recent natural disasters resulting in prolonged power outages, many experts are now advocating the use of micro-grids with battery-backup[1] . Micro-grids are scaled down versions of the municipal grid[2] . They are often found on campuses, eco-cities, or specific districts of a city. The benefit is from the efficiency of local power generation. By using backup batteries in a micro-grid, a district can continue powering its most important resources during a prolonged power outage independent of other areas of the municipality.

Battery-backup also has the capability of "islanding". This is the ability to temporarily disconnect from the grid while repairs are made, without losing power. This is an important feature to ensure worker safety.[1]

Hurricane Sandy knocked out power to over 2 million people in the City, most due to water damage (flooding of underground equipment) or wind damage (fallen overhead power lines). PV panels can significantly reduce this number by placing them above flood level (roofs) and away from trees, which is a requirement for them to access sunlight.

Special Initiative for Rebuilding and Resiliency (SIRR)

The SIRR makes the following recommendations regarding Solar PV:
  • Amend the building codes to allow building-mounted Solar PV
  • Solar PV installations reduce demand on the traditional power grid
  • Work with public and private partners to scale up distributed generation (DG) and micro-grids [with a special emphasis on Solar PV]
  • Increase the generation and use of renewable energy supplies such as... solar energy

Building Resiliency Task Force (BRFT)

Additionally, the BRFT makes the following recommendations:
  • Consider backup power sources that run continuously, such as... solar, increasing the chances power will work when the grid fails
  • Solar power systems should be designed to run during blackouts
  • Con Edison, NYSERDA, and other government agencies should continue working together to streamline permitting processes, reduce barriers in project schedules, and increase the allowable roof area for solar power


Considerations


Solar PV installations are not appropriate for every building. Considerations such as sun exposure, usable roof or exterior wall area, and electrical load can help determine whether an installation will be effective for a certain site. When used according to certain guidelines and sometimes in conjunction with other backup power sources, Solar PV can be an important part of our resilient power distribution system.

For years, the main drawback of Solar PV installations were efficiency and cost. As technology improves, the efficiency of panels continues to climb. Currently, efficiency varies from 17% - 27%, although Solar Energy Systems has recently lab-tested a 44.7% panel [3] .

Supply and demand has dramatically reduced the price of solar panels. The cost can vary depending on the type of installation needed and the difficulty of the site. Currently, the price of solar panels is about $0.30/kWh or 75% more expensive than conventional grid power, however the price has fallen rapidly - 50% in the past 5 years, and is expected to achieve parity with grid power in NYC in 2016 [4] .



Applications


Solar PV has been used for years on a diverse group of building types, including those like the DDC needs to consider. In regards to firehouses, the FDNY had a program in-place pre-Sandy to outfit some of its buildings with solar hot water. Although, unrelated to Solar PV, it nonetheless falls into the broader resiliency campaign set forth by PlaNYC. Four of the firehouses marked at risk on this wiki have thus far been retrofitted [5] . Many of the libraries and police stations on the at-risk list are of a similar stock to these firehouses. Another of the biggest at-risk group is high-rises that house many of the City's agencies. Many examples exist within NYC that incorporate Solar PV, such as 4 Times Square.

Engine 266, taking delivery of new solar hot water panels (a non-energy-related resilient upgrade).  Source: The Wave/Dan Guarino.
Engine 266, taking delivery of new solar hot water panels (a non-energy-related resilient upgrade). Source: The Wave/Dan Guarino.

FourTimesSquare.jpg
4 Times Square. Source: Lisa Zyga
























Related Reports

PlaNYC

References
  1. ^ Wilson, Alex. "Getting Power From Solar Equipment When the Grid Is Down."GreenBuildingAdvisor.com. Taunton Press, Inc., 08 Aug. 2013. Web.
  2. ^ "What Are Smart Microgrids?" Galvin Electricity Initiative, n.d. Web.
  3. ^ "World Record Solar Cell with 44.7% Efficiency." World Record Solar Cell with 44.7% Efficiency. Phys.org, 24 Sept. 2013. Web.
  4. ^ Underwood, Wade. "Solar Costs and Grid Prices on a Collision Course." Institute for Local Self-Reliance, 4 Apr. 2013. Web.
  5. ^ Guarino, Dan. "FDNY Goes Solar." Wave Publishing Co., 30 Aug. 2013. Web.