Written by Lisa Walsh

Developer’s Success Story – A Solar Integrated Green Roof in NE DC

By Lisa Walsh | Commercial Solar Developer | Solar Energy Services, Inc.

For the newly-finished Taylor Street Storage facility in North East DC, a 17,500 square foot green roof with fully integrated solar panel array that showcase a value-stacked, elegant design providing both a cost-effective solution to storm-water management. All without forfeiting the solar panels that generate income via federal tax incentives and DC’s superb solar production-based financial incentives.


With over three million square feet of green roofs in Washington DC and 50MW+ of solar installations – the City is no stranger to either technology. However, the integration of both on the same roof is less common, despite the symbiotic relationship between the two offering a number of advantages.


Beds of Sedums awaiting Fall planting at Taylor Street Storage, Oct 2018.
Photo Credit – David Gorman of Lock 7 Development

Completed 133.980kW Solar-Integrated Green Roof at Taylor St NE WDC
Photo Credit – David Gorman of Lock 7 Development

Storm-water Management


Approval for a commercial building permit in Washington DC must include a storm-water management plan as defined by DC’s Department of Energy and the Environment (DOEE). For Taylor St, the Development team could have chosen between:

  1. Lost parking spaces to house costly underground containers for capturing and storing runoff
  2. Payment of ever-increasing storm-water management fees
  3. Implementation of a multi-layered Green Roof to treat 100% of the rainfall obligation with a perennial, sedum based plant surface – as per DOEE requirements.
    The green roof offered a cost-effective storm-water management solution that required no additions or demo’s to the existing structure.
    Solar Panels

Solar Panels

Most savvy developers realize that an empty roof in Washington DC is money left on the table. With the best solar financial incentives in the USA, the payback is rapid followed by years of production-based paydays. Small wonder that the development team at Taylor Street were interested if – and how – a solar array could integrate with a Green Roof. The good news is not only does the solar system seamlessly integrate with the green roof but the relationship is one of symbiosis and cost-effectiveness. Here’s why:

BALLAST. Most solar systems installed on DC’s commercial flat roof areas are ballasted. i.e. an assortment of concrete blocks, along with the weight of the solar panels and racking, is engineered to hold down the weight of the array with minimal or no penetrations to the roof membrane.
With close to 35 PSF of weight, a green roof more-than provides this ballast negating the need for concrete blocks or supplemental attachments. This is worth mentioning as the Green Roof is now a fully engineered component of the solar system bringing the question of tax credit eligibility into play. Is the Green Roof, or portion of, now eligible for the 30% Federal Tax Credit? Certainly worth conferring with a tax adviser.

A close up of the Solar System mounted into the soil on the roof.

CREATION OF A MICRO-CLIMATE: Furbish designs their perennially healthy green roofs with a wide palette of sedum species. These drought-resistant succulants require little maintenance and have varying requirements for daily sunlight – from full-sun to all-shade. Contrary to first impressions the intermittent shading and weather protection provided by the solar panels provide a micro-climate highly conducive to the plants underneath, in between and around the solar arrays.

DESIGN: Most ballasted solar systems have ample aisles between each row of solar panels insuring that each solar panel is optimized and avoiding shading from the panel row in front. Solar panels can also be tilted anywhere between 5 and 35 degrees. This is adjusted to account for shading, panel count and orientation considerations. This flexibility of design was helpful for integration the green roof. Aisle spacing, solar panel size and tilt were designed with the Green roof in mind – not only as it relates to healthy plants, but also for annual maintenance access requirements.

Established Example featuring similar product and design as Taylor Street


CHALLENGES: Solar-integrated green roofs are not as common as their singular counterparts. Fair to say this project did not come without some challenges


DOEE DESIGN STANDARDS: Department of Energy and Environment is responsible for DC’s Stormwater Management and insuring all DC buildings comply with runoff standards. The burden was on SES and Furbish to ensure that the solar arrays were not going to impede the ability of the plants to thrive and provide the necessary water retention requirements. The design and permitting side of the project insofar as panel tilt, aisle spacing and racking integration were designed in collaboration with DOEE.


INSTALLATION TIMELINES: Furbish Company are Green Roof specialist, Solar Energy Services, Inc. are solar specialists. Integrating these technologies took heightened coordination between our installation teams, mostly in terms of labor efficiency, communication and timeliness. The latter was particularly stringent as the Certificate of Occupancy, required to meet the developer’s lease requirements, was contingent upon the completion of the Green Roof which now included solar racking, wiring and panel installations. Throw in some PEPCO Permission to Install challenges related to the solar portion, and the pressure was on.


The project came with some unusual PEPCO interconnection timing challenges at the end. Ironically not related to the Green Roof aspect of the application. Nonetheless, this system is now outputting electricity like gangbusters. All’s well that’s ends well.

Written by Rick Peters

Maryland Solar – Ready to Grow Again

For many years, Maryland has been a leader in solar policy and solar deployment.  In the last 3 years, we’ve fallen behind other states, watching our robust growth give way to several years of decline.  It’s almost hard to believe, but Maryland has been losing solar jobs for more than two years after peaking at approximately 5300 in late 2016.

Policy Clouds

Why is this happening?  One of the biggest reasons is the value of the state solar production incentive, the SREC (Solar Renewable Energy Certificate).  Those of you who own solar or have considered buying solar are probably all too familiar with SREC pricing.  Because Maryland property owners adopted so much solar in the first half of the decade, we outpaced the state’s goals, depressing the value of the market-based SREC incentive.  This was a good problem for the industry to have until it became clear that our goal (25% renewables by 2025 with 2.5% solar by 2022) was clearly not aggressive enough.

The Time is Now

We are now at a time of severe urgency for the Maryland solar industry.  With installations on the decline for over two years and job losses mounting, we are losing a trained employment base and leaving federal tax benefits on the table.   The solar industry has been working with other coalition members (wind industry, environmental organizations, etc.) for a few years to try to increase the state’s Renewable Portfolio Standard (RPS), but have been hampered by the Hogan Administration’s reluctance to incentivize more renewables until the completed RPS Study Report is released.  The study was due to be released in December of 2018, but has been delayed and some fear this is intended to stall an RPS increase for another year.  We cannot wait.

Governor Hogan has gone on record with his desire to fight climate change.  He recently coauthored an OpEd in the Washington Post with Virginia’s Democratic Governor, Ralph Northam to emphasize the urgency and the need for bipartisan solutions to climate change.  It is in this bipartisan spirit that we hope to see the Hogan Administration support the Maryland General Assembly in passing the Clean Energy Jobs Act
(CEJA)(SB0516, HB1158) of 2019 that will increase our renewable energy goal to 50% and the solar portion to 14.7 %. “Click here to read more about this

No-Brainer Investment for Maryland

One of the primary arguments against increasing the RPS has to do with the impact on utility ratepayers.  The preliminary indication is that the increased renewable goals associated with the CEJA will add approximately $1.85/mo. to the average electricity bill.  While this is not insignificant, it is important to note that a 2018 Daymark study, commissioned by the Hogan Administration’s Public Service Commission, found that for every $1.00 of investment in solar, we return approximately $5.00 in economic and health benefits to the state.   Solar jobs are good jobs that pay well, representing a path to economic stability for many installers.  And best of all, solar installation jobs cannot be exported.

We need YOUR help

As a solar advocate, we ask that you commit to express your support for CEJA in the Maryland legislative session this year.  The bill has been submitted and we should have a bill number shortly.  In the meantime, please continue to advocate for more solar whenever you can and be prepared to contact your Maryland state legislators to support this important legislation when the time comes.  Stay tuned for a special email notification with the bill number, and suggested talking points in the coming weeks.

Written by Anonymous

Baltimore Business Thermal SRECs

Maryland Solar Water Heating Bill Moves Forward

The House of Delegates voted 132-5 Saturday, following the Senate’s unanimous 47-0 vote March 17.

The legislation would allow owners of solar water-heating systems to sell renewable energy credits. The credits are bought by utilities and power companies that need to meet government quotas of renewable energy generation; if they can’t generate enough green power on their own, they can buy credits from someone else who has.

The ability to generate credits via solar water heating makes those systems a more attractive investment and rewards the buyers for using less fossil fuel. That is expected to be a boon for the green power industry, seen as a growing source of new jobs.

Gov. Martin O’Malley pitched the legislation along with dozens of lawmakers as co-sponsors. House and Senate versions of the bill still must be passed by the opposite chamber, which is expected since the two bills are identical. O’Malley is then expected to sign off.

Written by Rick Peters

SES Letter to The Capital

Your recent editorial (The Capital, April 18) suggested Gov. O’Malley should put more emphasis on the distributed approach to renewable energy, where solar and wind power are generated by smaller systems throughout the state. In fact, the governor intends to sign legislation next month to do just that. Delegate Sally Jameson and state Senator Robert Garagiola sponsored what is essentially budget-neutral legislation (HB/933/SB717) to open up the state’s solar goals to include solar water heating, a very mature and efficient technology, first patented in Baltimore in 1891.

This family friendly technology currently saves a typical family of four about $500 per year on electric bills by obtaining 75 percent of their annual water heating energy from solar. The new law will allow system owners to sell green credits to help utilities comply with the state’s solar goals. Consequently, homeowners will now see simple paybacks on these affordable systems shortened from five to eight years to a very manageable two to four years, on a 25-year lifespan.

Aside from advancing our solar goals, and allowing modest-income homeowners to participate in the benefits of solar, there are significant economic benefits too. Solar water heating is a labor intensive installation, which keeps dollars recirculating in the community. It requires trades people to install it, a group much in need of work.

The components are low tech, but heavy and bulky , so there is strong incentives to manufacture domestically, if not locally. A typical residential system only requires 40 to 80 square feet of sunny roof, drastically increasing the potential pool of participants.

As a daily consumer of solar-heated water himself, O’Malley is well aware of the opportunity for Maryland. I commend him and our legislators for their leadership on this issue.