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 Rick Peters

Solar is Booming in Washington DC

Washington DC has been a leader in solar development for many years.  In the last 12 years, DC legislators have set aggressive targets, helped to streamline solar permitting, introduced a solar access rights law, and passed a landmark community solar bill to increase access to solar for those without an available sunny rooftop.   Many of these policies include mechanisms to help bring the benefits of solar to communities of low and moderate income.  The collaboration between the solar industry and DC policymakers has helped to build a robust market where solar installations are happening throughout the city, from downtown office buildings to churches, warehouses and residential rooftops across the city.   These policies and the resulting private investments are creating good jobs in the District and reduced energy costs for many of its residents.

Double Down

Since solar and clean energy have been delivering in DC, the stakeholders decided they wanted a more ambitious goal.  In the summer of 2018 the District started on a path to double down with their commitment to renewable energy by proposing the most aggressive renewable energy target in the country when compared to other state policies.  The new goal calls for 100% clean energy (5.5% solar) by the year 2032, with 10% solar by 2041.  Hawaii and California are the only other states that have 100% goals, but both of those targets are positioned for 2045, quite a few years later than DC. 

Other Benefits of the legislation

In addition to doubling the renewable energy target, the proposed legislation would provide a few more benefits to solar advocates.  The bill:

  1. Limits geographic eligibility over time to concentrate the solar development in the District or on the District’s grid
  2. Pulls the current solar carve-out schedule forward by two years to increase SREC demand
  3. Extends the solar carve-out from 5.5% in 2032 to 10% by 2041
  4. Addresses specifics about previously contracted (“grandfathered”) load that is exempted from the newest RPS
  5. Includes transparency requirements on the energy suppliers to provide insight into the exempted load and associated time periods
  6. Modifies Alternative Compliance Payment (ACP) schedules to require $300 ACPs through 2041
  7. Increases the shelf-life of an SREC from three to five years, increasing SREC price liquidity and stability.
  8. Introduces various reporting requirements on the Public Service Commission in order to keep the Council and the Public apprised of the progress of renewable energy development.

We’re in the Home Stretch

The Clean Energy DC Omnibus Amendment Act of 2018 was introduced in July 2018 and made its way through the Council over the fall with hearings and two unanimous votes of support on November 27th and December 18th.  In January, the bill was submitted to Mayor Bowser for her signature and she obliged on January 18thClick here to read the bill“.   The remaining hurdle is for approval by the US Congress within 30 legislative days.  The only way that Congress can stop this legislation is with a joint resolution and the President’s signature.  As a result, passage into law is considered by most to be inevitable and in fact we are seeing market pricing for SRECs responding accordingly.

Thank your Legislators

So now that the law is almost passed, it is time to prepare to deliver.  The industry has a lot of solar to build and we’re working hard at that.  As a solar advocate who cares about renewable energy in DC, please consider taking a few moments to call or write to your Councilmember to thank them for their support of Clean Energy DC Omnibus Amendment Act of 2018.  It’s always important to show our gratitude.

Thank you for your support of solar!

Written by John Marrah III

Buy American and Save

For the month of February SES is offering $1000 off of any solar system that includes US Manufactured Panels.  That’s right, support US manufacturing and Save!  All you have to do is reference this offer during or before your site visit.

Here’s 5 More Reasons Why:

1.    Provides Jobs

The Solar Industry’s growth and inherent job creation is no secret, we are leading the pack among every other industry nationwide. Most of these jobs are being created on the installation side, but we also need to support the rest of the value chain.

2.    American Independence Includes Energy Independence

We as Americans have pride in our nation and in our independence. By generating our energy locally, with renewable resources, and US products, we strengthen our country and our independence, both individually and collectively as Americans.

3.    Do It for The Environment

Current technologies allow manufacturers in the US to support a greener, cleaner solar manufacturing process. If we invest in American-made products, we strengthen our manufacturing base, support US jobs, while insuring  that we are doing our part to contribute to a cleaner environment for ourselves, and the generations to come. Also, by reducing the need to ship overseas, the net carbon footprint is much lower

4.    We Control Labor Standards, They Don’t

The US is a leader in fair labor and safety standards. With minimum wage and safety regulations in the workplace being upheld, you can be sure that your panels are made by people who are being supported and treated fairly in the workplace.

5.    Guaranteed Quality of Goods

The term “Made in the USA” speaks of quality, excellent craftsmanship and a superior product. With a lower cost of labor abroad, many factories rely on fabrication and assembly processes by hand. This introduces higher rates of  failure when compared to the American Standard of automated soldering and assembly. While panel quality continues to improve in the aggregate, US products remain the leaders in quality and performance.  Price tags are slightly higher for Made in USA products, but you find true value among longevity and performance.

Home Solar Panel ,Solar Service
Written by Rick Peters

Peters’ Journey to Net Zero

Solar Service,Home Solar PanelsWhat Net Zero Meant for Us? Our Severna Park based, four-person family was looking to offset some of our home’s dirty energy, but we really did not have an expectation we could offset it all, but we had to start somewhere. We took our first step shortly after I joined the solar industry in 2008.

Low Hanging Fruit. In February 2009, we installed a 120-square foot solar water heating system to offset most of our water heating, and a small portion of our space heating for the first floor of our home. We saw big savings from this 3-panel system right away. Ever since, I enjoy the act of turning off the back-up water heating in April and leaving it off until almost October. For us, offsetting a dirty and expensive oil-fired boiler was the obvious low hanging fruit. We would later convert that remaining load to natural gas when the utility extended the pipeline to our home.

Solar Electric (PV) With the rest of the heat, A/C, and appliances all running off electric, it was time to look at the next opportunity. A few years later, when budget allowed, we decided to add a 5 kW solar PV system to our second story roof which faces SSE. My best determination was that we offset just over 40% of our electric load with that PV system. We were happy, but knew we’d want to find a way to get to NetZero eventually. , . I began to evaluate the remaining rooftops and consider what it would take to get us there. Solar panel efficiencies had improved a lot over the past several years so this reduced the remaining roof space we’d need to hit our goal

Phase 2 (PV). In the spring of 2016 we finished filling the balance of the south roof with some slightly higher wattage panels. As part of the same expansion, we added 24 relatively high efficiency panels to the E/W, low slope, rooftop of our one-story garage. We now had a total of 6.6 kW Equivalent of solar thermal and 13.8 kW of PV.

Not There Yet….We almost tripled our PV with the last upgrade and according to my calculations, this would get us to NetZero electricity. We’d know for sure by April, the annual true-up time frame for netmetering with BGE. When April 2017 came around, we were disappointed to come up a bit short (unfortunately, with a couple teenagers in the house, my usage predictions were a little off). Where do we go from here? I was not ready to put panels on the north roof, there had to be something available to us on the demand side.

Oops – More Low Hanging Fruit…One thing about Energy Efficiency, there’s always more opportunity. I had changed out many bulbs to LED over the prior several years, mostly through attrition, but I had not replaced any of the more than 2 dozen canister lights we had throughout the ceiling upstairs and down. Not only were these lights very inefficient, but the heat they generated in the summer was just adding to our air-conditioning load. We found the LED replacements on sale and replaced them all, as well as the remaining few incandescent lights in the house.

Commercial Solar Energy,Solar ServiceEureka. we have arrived!… In April of 2018 we received a $46 check from BGE for the annual overage from solar. With the kids heading off to college soon and a new refrigerator around the corner, I’m confident our checks from BGE will be getting bigger for the near future. At least until we purchase an electric car…

Solar Service,Commercial Solar Service
Written by Lisa Walsh

The Fairytale of the 25 year Solar Workmanship Warranty

Commercial Solar Service,Solar ServiceIf you’re like most solar shoppers, you prefer two or three bids on a substantial home improvement project; enabling you to sanity-check pricing, design options and find the overall best contractor-fit.  Included in these proposal comparisons is the Warranty. Most solar systems come with 3 warranties:

  1. Solar module manufacturer’s warranty; usually 25 – 30 years,
  2. Inverter(s) manufacturer’s warranty; usually 10 – 25 years (inverters convert DC energy to home-accessible AC energy)
  3. Workmanship warranty – entirely separate from 1 & 2 above. This insures the design and installation, insofar as contractor/labor portion of your install is covered for a given period of time, as determined by the installation company.

Industry Standard

As the popularity of solar has increased – so has the number of competing contractors and their accompanying solar proposals. All of these proposals should include a workmanship warranty. What will differ is the duration of the workmanship warranty. The standard duration for a residential solar system was always 5 – 10 years until a couple of years ago when some contractors started offering an unprecedented 25-year workmanship warranty. This is a good thing, right? On paper…sure.

Compete only to Beat

With over 35 years in the solar industry, it’s fair to say we’ve seen a lot of solar installers come and go; especially in the last five years. The go-ing usually brings with it a slew of phone calls to our service department as solar system owners panic about no longer having their contractor around to honor the workmanship warranty; particularly those looking to resolve existing issues. Ironically, these are sometimes homeowners that chose the contractor over us due to a workmanship warranty of shorter duration. We have stuck with the industry-standard of 10 years, whereas some other installers have increased to 25 years to match the manufacturer warranties.

So, the big question – and the reason for this current article is – Why? If some of our competitors are offering a 25-year warranty – why don’t we? Seems only natural, given the fact that we’ve been in business for longer than 99% of them – greatly increasing the probability that we’ll be around to honor an extended workmanship warranty.

The Big Answer (in two parts)

  1. We’re keeping it Real: Understandably, a 25-year workmanship warranty is attractive to a homeowner because – by design – it matches the 25-year solar panel warranty. This does not change the fact that a workmanship warranty exists entirely independent of the installed equipment warranty(s). A contractor’s history, fiscal health and future plans have little or nothing to do with the equipment warranties. Given this, we avoid inflating the language in our contracts to provide misleading comfort to a home or business owner, with the sole purpose of beating out the competition at contract-signing time.
  1. We’re still keeping it Real: Of all the orphaned solar projects we’ve come across – we cannot cite a single known instance where a homeowner has taken legal action over an abandoned workmanship warranty item; simply not worth the court fees or the hassle. Most exert their energy on finding a contractor who will fix the problem as soon as possible and get their solar system restored to full working condition. Hence, the true value of the workmanship warranty is contractor integrity and the likelihood of whether they both intend to and will remain in business to honor their contractual agreement. For most solar contractors, the standard ten-year commitment reflects a realistic forecast of longevity and commitment; avoiding the temptation to head off into fairytale land in order to beat-out the competition.
Eastern Shore MD,Solar Service, Home Solar Panels
Written by Lisa Walsh

Non-South facing solar panel installs in Maryland, DC and Virginia

The Design

Eastern Shore ,MD,Solar Service, Home Solar PanelsWhen planning a solar panel system for your home, the first consideration for any solar designer is the tilt and orientation of your roof areas.  We need to know which roof(s) will ensure the most optimum solar output – which translates to the best Return on Investment.   For us here in Maryland, the most optimum solar roof orientation is Due South at 180 degrees.  Of course, not everyone has this perfectly oriented roof and our customer base consists of homes that have South, West, East and everything-in-between orientations.  Occasionally we even install on North-facing roofs if the pitch of the roof is low enough that panels are close to flat, or can be tilted southerly.

For homes that face East-West, you may be wondering which roof would best suited for solar.  This is a good question given the fact that the output of your solar panels is directly related to your Return on Investment and how quickly the panels can pay for themselves.

If either East or West favors a more Southerly angle, then that would likely be a more favorable roof.  Assuming that there aren’t issues related to shadingor obstructions caused by chimneys, vents, skylights and other roof-placed items.

If the house has a perfectly split East-West orientation, with all things equal – the next consideration would be roof angle; the lower the tilt (i.e. closer to horizontal) – the more solar energy will be generated over the course of the day.  If the tilt on either side is the same then we would usually favor the West facing side.   Here in Maryland, DC and Virginia we tend to have cloudier mornings, and sunnier afternoons going into dusk.  Therefore we want to capture the late afternoon sun (west facing) more than early morning sun (East facing).  Of course, should you happen to have a tree, chimney or other obstructing factor(s) on the West roof – we’d favor the East.

The Economics

Homeowners looking at an East-West installation often have concerns as to whether or not their system will be profitable enough, compared to its south-facing counterparts.    Disqualifiers for cost-effective solar systems include shading and limited available roof space.  Rarely, however, is a home found unsuitable due to a Non-Southerly facing roof alone.

To illustrate, following is a comparison of a 10kW system’s output respective to East, West and South facing orientations.  Data compiled using the National Renewable Energy Laboratory (NREL) weather data patterns for Baltimore, MD –

10kW system installed on a 20 degree pitched roof with zero shade

 SOUTH (180 degrees)WEST (270 degrees)EAST (90 degrees)
ANNUAL OUTPUT13,224kWh11,389kWh11,328 kWh
*Annual $avings$1853 per year$1594 per year$1586

*Savings based on a conservative $3.00/watt installation, and $0.14/watt BGE rate

Data from PV WATTS

As illustrated, although perfectly South would be ideal, the East and West orientations provide a competitive amount of solar and would add only a few months to the payback period.  If you were choosing between East and West (as opposed to installing on both), the difference is nominal.  The choice of which roof may come down to aesthetic preference, distance to utility meter and regional weather patterns.

Solar Service ,Home Solar Panels
Written by Lisa Walsh

DC Property Owners: Big Hot Water load = Big Solar Incentives

Commercial Solar Service, Annapolis MD

A growing number of building owners, developers and condo associations in the District of Columbia have come to realize that their building happens to be located in the most solar-friendly city in the USA .  Solar contractors, investors and financing vehicles are falling over each other to get solar panels on District roofs and start generating  the lucrative solar renewable energy credits (SRECs).   Whether via Direct Purchase, or $0 solar leases – SRECs are undoubtedly the reason for the solar season in DC (more to follow on those below).

However, before you sign on the dotted line and fill your roof with a 25-year solar PV (electric) system, as offered by 9 out of 10 solar professionals, make sure that you’re not losing the opportunity to vastly increase your return on investment with a Solar Thermal System.

Solar Water Heating Feasibility

The pre-qualification for a Solar Thermal System involves three questions:

  1. Does your building have a substantial, daily (365 day) hot water need? (i.e. apartment building/condos, restaurant, laundry, brewery, health center)
  2. Does your building have a centralized water heating system (as opposed to individual units throughout the building)?
  3. Can the building accommodate additional storage tanks?

If you answered YES to these three questions you really (really) should first consider a Solar Water Heating system either before – or at a minimum – in tandem with, a solar PV system.  (Shopper Beware – unless your solar contact has experience with solar thermal – which many do not – you’re going to have to be prepared to shop further).

What is Solar Water Heating (or Solar Thermal)?

Other than using the sun for energy generation, Solar Water Heating Systems operate entirely differently from their electron-shaking PV counterparts.  These time-tested, technologically mature systems are mechanical in nature and relatively simple.

Moreover, a solar thermal panel is 60 – 70% efficient; whereas a solar PV (electric) panel is typically 17 – 24% efficient.  Therefore, solar thermal panels generate substantially more energy per square foot than PV panels,  monetizing many more SRECs.

Solar Service , Home Solar Panels, Solar Renewable Energy

 

Let’s Review SRECs…

SRECs (Solar Renewable Energy Credits) – along with the 30% Federal Tax Credit and 100% Year 1 depreciation– are what drive the tremendous economic benefits of solar in Washington DC; one of several jurisdictions that have enacted a Renewable Portfolio Standard requiring that a specific percentage of electricity consumed must come from solar.   Whether residential, commercial, or institutional, each time a solar system generates 1 Megawatt hour of energy – the solar system owner generates 1 SREC.  This SREC is then sold via aggregators to an SREC market where it is bought by competitive energy suppliers to allow them to meet their share of the compliance obligation, or else pay a legislated fine (Alternative Compliance Payment, or ACP) for every SREC they are short.  Washington DC currently generates the highest SREC values in the country, largely due to the fact that DC does not have the real estate to install large solar farms which can rapidly oversupply a market and drive down SREC prices.

How much are SRECs Worth?

Washington DC SRECs are currently trading at $395/SREC.  To provide a frame of reference, a 6000 sq ft rooftop in Washington DC outfitted with a 75kW solar PV (electric) system could generate around 90 SRECs/year (over $35,000/year).   Depending on variables such as system size, corporate tax rate and and project site attributes, this SREC income – combined with a 30% Federal Tax Credit and 100% Year 1 depreciation, typically result in IRR’s between 30% – 60% and a Simple payback of 3 – 5 years.    Assuming solar thermal is applicable, this same roof outfitted with a Solar Thermal System could fit a kWh equivalent of a 150kW+ system, generating 180 SRECs/year – and see an IRR of 50 – 80%, with a simple payback in the 1 – 2 year range.

Solar Service ,Home Solar Panels, Residential Solar PanelsMaintenance

Although Solar PV (electric) clients often opt for an O & M (operations and maintenance) contract through their solar installer, Solar PV Systems  have relatively minor maintenance needs; usually an annual inspection along with ongoing monitoring.    Solar thermal (water heating) requires a little more maintenance including a 3 – 5 yearly service which, at a minimum, includes a replacement of the propylene glycol/energy transfer fluid that can degrade with time.  Nonetheless, the impact of service costs on the overall IRR is relatively small and easily absorbed by the increased SREC income.

Written by Lisa Walsh

A Primer on Solar Power

Did you know that attempts to harness the sun’s power through the development of solar cells dates back to the late 1800’s? I am sure that this, and other information, may be new to our readers. This article will provide you with some basic facts about solar power and solar energy. That way, you can join the conversation, and the renewable energy movement!

  • The first successful solar cell was developed in the early 1950s. It was made of silicon, and able to power small electronic devices. This was hailed as the beginning of a new era of energy resources, even then being acknowledged as having the potential to offer a limitless supply of electricity.
  • The first true application of solar cells could be found in the space program at NASA and in Russia. They were the only ones who could afford this technology in the 1960s.
  • The cost of solar cells continued to decline incrementally, but not so significantly that solar was a common source of energy through the 1970s. But, as the 1980s dawned, and ever since, solar power has insinuated itself into all aspects of life, commercially and residentially.
  • The first solar panels for buildings were developed in the early 1970s. In truth, this initial foray into the potential for large scale residential solar power was actually a solar array built into a rooftop. Panel development followed, as the cost and manufacturing efficiency increased.
  • President Jimmy Carter had solar panels placed on the roof of the White House in 1979. Everyone was getting into the act!
  • Welcome to 2018. Today it is common to find solar-powered cars, solar-powered telecommunications, and even solar-powered aircraft. One car company, renowned for their progressiveness, has incorporated solar panels into the roofs of their vehicles!

But, there’s more! Technology continues to expand the horizons of solar energy, making it affordable and applicable in new ways and new places. For example, it is possible that eventually solar panels on rooftops will be replaced with solar shingles!

Or, consider this, a solar fabric is being finalized that can be attached to houses as a cooling device!

We here at Solar Energy Services are excited about the future applications of this renewable source of energy for personal and commercial uses. You can count on us to utilize our superior knowledge and expertise to your advantage. We look forward to serving you!

Commercial Solar Energy Residential Solar Panels
Written by Roger Perry

Would that be One Tank or Two, madam?

Solar veteran Roger Perry discusses the pros and cons of One Tank Vs Two for Solar Back-up

Commercial Solar Energy ,Residential Solar PanelsAll solar water heaters in Maryland, D.C. and the mid-atlantic provide a family of four with around 75% of their annual hot water load. Most customers use their existing electric or gas sources for the remaining 25% backup (usually needed dead winter). When installing a solar system one question that will come up is “Should I use my existing tank and have it fed by the solar system?” or “Should I remove my existing tank and use the electric back-up that comes in the solar tank?”. A couple of situations make this an easy decision;

  1. An existing electric water heater with no room for another tank. This is especially satisfying and cost effective if the existing tank is leaking or on it’s last legs. It’s like getting $1500 off the cost of a solar system because that money would have needed to be spent anyway. In this case you would definitely chose a single tank system.
  2. The other is if you have a gas water heater. While not as cut and dry as the example above, using the electric element would mean using a higher cost fuel for back-up (not so much with propane). Much of this extra cost would be mitigated because the single tank back-up would not run as much because it would be affected by solar input without running a faucet. You would need to run an electric circuit (30 amp, double pole breaker). This may be difficult or very easy depending on the breaker box location and available space in it. Most jurisdictions will also require a master electrician and a permit for this to be done. In this case, I think, most people would shy away from a single tank system unless there was just no room for another tank.

Let’s look at the pros and cons of each system;

SINGLE TANK PROS

  • Smaller footprint
  • Less heat loss
  • Electric element can sense the solar output and not come on from stand-by losses
  • Can go “all solar” just by turning off the element (essentially flipping a switch).

SINGLE TANK CONS

  • Less back-up in cloudy weather (can be compensated with a larger solar tank which will have a larger back-up capacity).
  • Less solar storage when the element is on (can be compensated for with a larger solar tank which will have more solar storage).

TWO TANK PROS

  • Usually greater back-up capacity

TWO TANK CONS

  • Greater heat loss
  • Larger footprint

The secondary backup tank can’t sense the primary solar tank temperature unless a faucet is turned on, sending the water through the two-tank system.  This causes the second tank to turn on from stand-by losses when the primary solar tank is already plenty hot.

Going all solar requires operating valves as well as turning off back-up.

Personally I’m a fan of single tank systems. For the most part their two main drawbacks can be compensated for by installing a larger tank. An upgrade from a 80 to a 120 gallon solar tank is only a few hundred dollars. For a 50% increase in solar storage it is a small price to pay.

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