“What about solar during a utility failure?”

For safety, grid interactive solar systems are designed to immediately disconnect and shut off if a utility grid failure is sensed. The system will automatically restart a few minutes after grid power is restored. As a result, no power will be available from the solar panels during utility outages. This protects utility workers who may be out working on power lines.

With new SMA transformerless inverters, a solar system can provide limited daytime power during a blackout. These inverters can be connected to household loads — like a fridge, lights, computers — and make up to 1,500 watts available while the sun shines.

Solar energy systems can provide around-the-clock, independent backup power during utility outages if they are connected to an appropriately-sized battery bank to absorb and store the energy they produce. Natural gas and propane generators are another option for backup power. We have installed solar panels and a generator on numerous jobs, when secure power is an absolute must-have.

Solar maintenance requirements are minimal.

Solar electric systems require no regular maintenance. The system operates silently and reliably for years, the same as the electricity we expect from the utility company.

Dirt and dust accumulation on the panels will reduce energy generation slightly. Customers who wash their solar panels typically notice about a 1% increase in power immediately following the wash, but washing is not necessary. Normal rain and wind are sufficient to remove most dust and debris.

Periodic monitoring of system performance is usually all that is required to ensure that the system is operating properly. Solar performance monitoring can be done manually, but for large public systems, automatic Internet-based solar monitoring is recommended. This allows remote solar monitoring by maintenance personnel, the solar installer and any other interested parties. Internet-based monitoring can also provide interactive solar performance displays for the public, and a cool way to show off your solar.

 

Solar electric provides intermittent power production — meaning, it produces electricity when the sun shines, but not at night. Solar energy systems must work in conjunction with some other power source (or incorporate energy storage, like batteries) to provide a round-the-clock energy solution.

That’s why most of the systems we design and install are grid-connected. The utility grid becomes your energy storage device — when the sun isn’t shining, the grid powers you. When the sunshine is strong, you add power to the grid.

People often ask, “Why not just add batteries?” And off course we can do that, and have built many solar energy systems with battery backup. But many solar users who started off-grid with batteries have migrated to grid-connected systems, for reasons of economy, ease of use, convenience, and long-term energy planning. Grid-connected solar currently offers the shortest and best return on investment (ROI), in most cases.

We are happy to provide strong reliable battery-backup solutions for our customers who need them. But adding battery storage to a solar system adds substantial a cost and maintenance burden to an otherwise low cost, maintenance free system.

There is widespread agreement that solar electric systems improve the capacity and reliability of your regional electric grid.

Solar electric systems generate the most power when the sun is strongest, during midday and afternoon hours. That is also the time when demand on the electric grid is highest. Solar energy systems can help the utility meet this peak demand. Distributed PV installations at multiple sites can produce power where needed, lowering transmission losses and further reducing the strain on the grid.

A study by Richard Perez (1) posits that the Northeast U.S. Power Blackout of August 14 2003 may have been avoided if local solar power systems amounting to just a few percent of regional peak loads had been available.

(1) Richard Perez et. al. “Availability of Dispersed Photovoltaic Resource During the August 14th 2003 Northeast Power Outage”

 

A solar electric system generates the most power when the sun is strongest, during midday and afternoon hours. That is also the time when demand for electricity is highest.

To meet this afternoon peak demand, utilities fire up smaller “dispatchable” power plants that are often more expensive to run and more polluting than the larger, base load generating plants.

Powering a home or business with solar energy can reduce the utility’s peak load and reduce the peak generation by the utility. This results in lower overall energy costs and cleaner air. Having many small grid-connected solar arrays also increases the capacity and stability of the grid.

For every 1 kW of solar power installed, utility power plant emissions are reduced approximately 1500 pounds per year. Over a thirty-year life, each 1kW of solar power prevents 21 tons of CO2 emissions from being released by conventional energy sources.

How noisy are solar panels? When operating, solar panels make no noise. They have no moving parts. Solar energy systems generate electricity in complete silence.

 

People often ask, “Is solar reliable?” Solar energy systems are highly reliable and have low maintenance costs. Solar electric systems installed by well-qualified solar installers typically have reliability rates above 98%.

 

Solar offers a fixed-cost hedge against future energy cost increases. It makes your future energy costs more predictable, and lower.

Solar energy systems have high up-front cost, but once installed, the fuel (the sun) is free forever. Due to the thirty-year system life and very low maintenance costs, once the system is purchased, the cost of energy is fixed at a known quantity. This compares with conventional electric energy costs, which have been rising at around 5% per year and may be expected to rise even faster in the future. Conventional energy prices, with their dependence on fossil fuels (coal, gas, and oil) are subject to the volatility of those markets, as well as any future costs of environmental remediation or carbon emissions penalties.

Several states have tiered energy prices in which the price per kWh of electrical energy consumption is lowest at night (when demand is lowest) and highest during the afternoon (when demand is highest). Because solar systems produce maximum energy during midday and afternoon hours, solar electric systems offset the highest-priced energy in a tiered pricing market. In Ohio, a solar electric system is a great bet on future adoption of tiered pricing in the Ohio markets. Install solar now, and if tiered pricing comes in, you’re equipped to offset the highest-cost energy and thereby save the most money on your electric bill.

 

Growing public awareness of climate change and energy sustainability issues means installing renewable energy systems can be a good public relations move, and can help improve corporate image in the public eye. So it is not unusual to see solar news coverage of a large installation in your area, whether at a university or on a corporate campus, or even on a local bakery.

For homeowners, the “PR-pop” usually comes in the way of attention and interest from local media and from friends and neighbors. People with solar on their homes tend to be looked upon as leading-edge, tech-savvy people. And they questions from others who are starting to have an interest in solar. Our customers are our best ambassadors.

The most common type are not. Crystalline solar panels are mainly silicon and aluminum. The chips are very similar ways to computer chips. They are sandwiched between glass sheets and surrounded by an aluminum frame. No toxic chemicals used.

Some thin-film solar modules use toxic materials such as Cadmium and Telluride, and we don’t usually use those. But even with Cd/Te modules, the only risk of exposure to these elements is during manufacturing. Once the panels are made, the elements are firmly sealed inside of the panel. Tests have shown that no toxins are released, even in a fire.

Cadmium and Telluride are by-products of aluminum mining, so it can be argued that manufacturing solar panels represent a great way to dispose of toxic waste that is being generated to make all kinds of aluminum products, from aircraft parts to beverage cans.

Solar panels are manufactured using similar methods as the manufacture of computer chips and glass panels.

How much greenhouse gas does solar panel manufacture emit? The answer depends on the type of solar panel, says Vasilis Fthenakis, head of the Photovoltaic Environmental Research Center at Brookhaven National Lab. Fthenakis and has conducted extensive research on the environmental impacts of solar and compared it with other technologies like fossil fuel to get a better idea of the big picture. “There’s nothing that’s completely risk-free,” says Fthenakis. “But photovoltaic compares very favorably with all other technologies.”

With today’s technology, the energy required to manufacture a solar panel is roughly equal to the energy that panel will produce in less than 2 years of operation. Given a 30-year panel life, a solar panel produces clean energy for over 28 years after its “energy debt” has been repaid.

Solar panels last 30 years or more. The industry standard panel warranty is this:

• 10 year workmanship warranty
• 25 year power warranty

Some modules, such as Trina, have a linear power warranty. Most however, have a two-tier step warranty that guarantees this:

• 90% power at year 10
• 80% power at year 25

Solar panels degrade gradually over time with exposure to sunlight, wind and weather. Panels are typically warranted 25 – 30 years and have a design lifespan of over 30 years. Energy production is expected to degrade by about one-half of one percent per year.

Inverters are warranted for 10 – 15 years and have an expected lifespan of 15 – 20 years. Future inverters will likely have longer lives. You may need to replace an inverter once in the system’s lifetime and we figure that cost into our financial predictions.

All other system components have service lives over 30 years.

Grid-tied solar electric systems automatically feed power into your house. Any excess electricity produced by the solar system and not used by your home is put onto the electric grid and spins your electric meter backward. Your utility credits you on your bill at the retail rate for the kWh produced.

Solar panels operate in this manner: When sunlight is on them, solar panels produce DC electric current. The DC electric current is passed through an inverter and converted to AC current synchronized with the local utility lines. The utility company provides power as normal. The solar panel system serves as an additional power source, fully integrated with the home or building’s existing power sources and the utility grid.

Most of the potential issues facing modules are covered by manufacturer’s warranties. Apart from those issues, we have replaced panels for the following reasons, not covered by warranties:

• Tree branch fell on array
• UPS truck backed into array
• Bullets fell from sky and pierced panels

This is what insurance is for.

However, the bulk of potential solar panel damage can be mitigated by choosing an experienced solar installer and using top-quality equipment.

We know of other installers who have replaced modules for these reasons:

• Baseball cracked modules mounted in the outfield of a ballpark
• System caught fire due to combination of poor design and poor installation
• Wind blew apart a poorly designed or poorly installed solar array

Solar modules are certified to withstand hail – not Texas-sized hail balls, but your typical hailstones. One quality solar panel manufacturer put it this way: “The panels are tested by shooting balls of ice at terminal velocity at the module in 11 specific spots. The ice balls can be of different sizes and the firing velocities change based on size. Typically solar panels are tested using 25mm balls fired at 23 m/sec. However, the spec also defines larger and smaller ball sizes from 12.5mm fired at 16 m/sec to 75mm fired at 39.5 m/sec. I have yet to see a panel with tempered glass fail using any size ball/velocity. I have seen a few cases of the roof being damaged beyond repair by hail and the unbroken solar panels need to be removed so the roof can be replaced. 

In short, we test our solar panels extensively for hail survivability. They pass quite well. However – all panels must pass this testing or they could not be certified to put on the roofs of houses, so this may not be a unique selling point.”

In other words, it is a common question, but usually a non-issue. Hail that will break car windshields is hail that will break solar panels. How often do we see such hail? Hardly ever.

“A competitor says his system has an AC-DC derate of 95%. Why is yours so low?”

On his blog, Dave Beumi notes: “Derates are the various locations and instances in a PV system where power is lost from DC system nameplate to AC power. This includes inverter loss, resistive factors, environmental conditions and issues relating to maintenance… The PV industry and its financing partners rely on simulation modeling software, which provides a fairly accurate multiple year forecast of energy production and economics, including [solar] financial payback. These models are thorough, sophisticated software packages which take into account the many variables which affect a PV system’s performance including weather, environmental conditions, technology and product performance, government subsidies, and cost of money among others… While the model takes into account the derate factors and a detailed weather history for a given location, its important to note that annual fluctuations in weather conditions is an important variable which can be significantly different year to year. Overall, simulation models are quite accurate and are a fairly good gauge for finance companies to make an informed investment decision.”

PVWatts makes it calculations using whatever derate number the user inputs. Our experience has born out that 81% is a reasonable but conservative derate. There are technical reasons why we could use a higher or lower factor, but that would take several pages of explanation and probably put you to sleep.

Suffice it to say, that 95% total derate is a physical impossibility. Any solar installer telling you that is not being truthful.

“Another company gave me a much greater energy production estimate than yours.”

We hear this occasionally. When asking the question, “How much electricity will a solar energy system produce” people sometimes get different answers from different companies.

Our production estimates are conservative — we try not to over-state the amount of energy you can expect to get from a specific-sized solar energy system. An internal company mantra of ours is, “Under-promise and over-deliver.”

That said, we use standard industry tools to make our energy production estimates. For most of our energy production estimates we use PVWatts, which is a publicly-available tool for solar energy estimating put out by the National Renewable Energy Labs (NREL) for anyone to use.

Like any calculator, NREL’s takes a bit of skill and knowledge to use. We have, on occasion, walked a prospective customer through the process to help them understand proper data input as well as how to interpret the results.

There are other solar companies that offer sky-high estimates and unrealistic promises. We do not.

 

We have sourced, tested, and used low-cost Asian solar panels — from reputable manufacturers. We don’t just investigate the panels themselves, we background-check the company that makes them. Solar panels carry 25-year warranties, and we want to make sure their manufacturers are financially sound and reputable, and will be around to support those warranties. This kind of careful research is an important part of the value we deliver to our customers.

We have a computerized pricing system that generates the total price for your solar project, based on the size of the system and your project specifics.

In general, the cost breakdown for a solar electric system is about 55-60% for the equipment itself (including panels, inverter, wire, conduit, switchgear, etc.); about 10-15% for overall project management, design, paperwork, permits and fees; and about 25-35% for the installation costs.

We can deliver excellent pricing on our projects thanks to two advantages: First, we pool our buying power with a national group of solar installers in a member-owned purchasing co-op to get advantageous pricing on the very best equipment (we will not compromise on quality where our reputation is at stake). Second, we are crazy about efficiency, and have been working for 14 years on how to deliver the very best-performing and longest-lasting solar installations with the least waste possible, thereby turning our customers into raving fans. It is a formula that works.