Which solar panels are best?

Which solar panels are best?

Here’s a solar industry secret: all solar panels generate the same amount of electricity on a per watt basis. In other words, twenty 300 watt panels will generate exactly the same amount of electricity as twenty-five 240 watt panels. Indeed, there are objective differences in panel cost, efficiency, aesthetics and ease of installation — and now with the upcoming tariff, even availability. But differences such as brand, assembly quality, country of origin and projected degradation rates are much more subjective since they are based on manufacturer’s claims and not based on objective third party studies. (more…)

Enphase Battery Storage System Review

Enphase Battery Storage System Review

Future energy sources in our homes and businesses will be a combination of rooftop solar, battery storage and power delivered by the local utility. Reliable and affordable battery storage has — to date – limited this vision to just solar and utility power. But battery storage systems have been improving rapidly, both in terms of up-front costs and overall performance. Get that image of 10,000 little AA batteries powering the new Mercedes AA class car out of your mind. Rather, envision an easy-to-install turnkey energy storage appliance designed to match up with existing and new solar installations.

To help bring solar installers up to speed on commercially available residential battery storage systems, the team at Cinnamon Solar has scheduled a series of hands-on reviews of commercially available energy storage systems. Reviews are based on the installation and usage of each system using commercially available products and software, provided by manufacturers. The intent is to provide useful real-world experiences to installers, home owners and manufacturers as Behind the Meter (BTM) battery storage systems become more popular.

The Enphase Storage System is a modular AC coupled battery storage system designed for residential customers with and without grid-tied solar power systems. Each modular battery is comprised of a 1.2 kwh lithium iron phosphate battery and 280-watt inverter in a 55 pound indoor-rated wall mounted enclosure.

The Enphase Storage System is ideal for customers who want to store locally generated solar energy or inexpensive grid energy so that this energy can be consumed during peak electric periods, thereby reducing electricity energy charges. Key benefits of the Enphase system are that the equipment is relatively inexpensive and easy to install. Since the system is AC coupled it does not require a PV system to operate, and is compatible with the entire installed base of grid-tie PV systems. Note that the Enphase AC Storage System does not provide backup power.

The simplicity and modular nature of the Enphase Storage System make it one of the most straightforward systems to design (with the Enphase AC Battery Sizing Tool), install (with the Enphase Installer Toolkit phone app), operate (with the Enlighten web portal) and maintain. Enphase is an established solar equipment supplier with a reputation for delivering good product and service quality.

For more about the Enphase Storage System, listen up to this week’s Energy Show on Renewable Energy World.

San Jose Mercury News Op-Ed: More solar panels and battery storage at homes could prevent power failures

San Jose Mercury News Op-Ed: More solar panels and battery storage at homes could prevent power failures

At 1:30 on a Sunday afternoon in June, I experienced the second power outage at my Silicon Valley home this year. Then, last weekend a transformer explosion at a Los Angeles Department of Water and Power substation left 140,000 people in the San Fernando Valley without power. In both cases these power failures occurred during a 100+ degree heat wave.

According to PG&E, there was a “local transformer issue” in our neighborhood; the Los Angeles utility is still investigating the cause of their transformer failure.
Local transformers are those big can-shaped things at the top of utility poles. Most were installed before electric vehicles were commonplace and when temperatures were a few degrees cooler. So when people crank up their air conditioners and plug in their EVs, transformers can become overloaded and fail.

Power was out in my neighborhood for about 12 hours while PG&E deployed a crew to diagnose the problem and replace the transformer. But the blackout would not have happened if just one more home in the neighborhood had a solar or battery storage system.

The output from that incremental solar or storage system would have supplied the electricity needs of that home — and the excess solar or battery power would have flowed back to the local grid, reducing the load on that transformer and preventing its failure.

High temperatures and new electric vehicle demands are causing outages like this all over California. Solar power coupled with battery storage is the cleanest and most cost-effective solution to this problem, but only if these systems are deployed in the right place.

The challenge is to get the power from remote utility solar plants to the homes and businesses that need it. Unfortunately, the local power grid is the weakest link, and it is expensive to modernize neighborhood grids to meet today’s higher power demands and two-way energy flows.

There are two solutions to modernizing overloaded local grids. The “business as usual” solution is to pay the local utility for upgrades that include bigger transformers, wiring, control systems and battery storage. Unfortunately, ratepayers get stuck with higher electric bills for this.

A much better solution is to encourage homeowners and businesses to install their own solar and storage systems. These customer-owned “Behind the Meter” (BTM) energy systems do not require expensive transmission and distribution grid upgrades. Since investments in them are made by homeowners and businesses, utility ratepayers are not burdened with upgrade costs.

With over half a million solar-powered homes and businesses, California leads the country in both solar power generation and solar jobs. This was the result of public policies that encouraged solar installations. As a result, solar costs have come down so much over the past 15 years that incentives are no longer needed.

We have the same opportunity now with battery storage systems as California moves toward an electric grid powered 100 percent by renewables. Two policies will help us achieve this goal.

First, as other states have done, we should ensure that there are no arbitrary limits on a customer’s ability to install solar and battery storage. Second, we need to reduce the up-front costs of battery storage systems, which are relatively expensive at this early stage of the market.

To jump-start the battery storage market and improve local grid reliability, California has proposed SB-700, the Energy Storage Initiative. It mimics the California Solar Initiative in a way that supports home or business-owned energy storage systems with incentives that decrease as costs decline. With policies like this, electric customers throughout California will be the first to benefit from a modernized electric grid that is both lower cost and more reliable.

Originally published July 12, 2017. Barry Cinnamon is the CEO of Cinnamon Solar and previously founded Akeena/Westinghouse Solar. He wrote this for The Mercury News.

Ten Tips For 25 Years Of Trouble Free Solar Power

Almost all solar panels sold in the U.S. carry a 25 year warranty, most inverters are guaranteed for 10 to 25 years, and as long as you get occasional heavy rain your panels do not need regular cleaning. So if you are thinking about solar for your home, the most important considerations – besides price – are the quality and reliability of the installation itself. With these factors in mind, here are my top ten tips for 25 years of trouble free solar power:

  1. Find an installer who has been in business for 5+ years and uses their own installation crews (not subcontractors).
  2. You get what you pay for – so be careful about selecting an installer based on the lowest price.
  3. Prices for battery storage systems are coming down fast, storage incentives in many states will be available soon, control software is being developed, and the reliability of this new technology is improving rapidly. My advice is to get a battery-storage ready system, while waiting for these improvements to settle down in the market over the next few years.
  4. Panels from the major manufacturers are all very reliable; the biggest difference is simply that higher efficiency panels cost more. In most cases it does not make sense to pay extra for highest efficiency panels if you have enough roof space for slightly lower efficiency panels.
  5. The most common customer service issue relates to inverter monitoring. A distant second is a problem with the inverter itself.
  6. Squirrels and rats like to nest under rooftop panels and chew wires. Pigeons prefer barrel tile roofs. If you have any of these pests on your roof, talk to your installer about installing screening around the perimeter of your panels.
  7. Make sure your installer uses the proper flashing and sealing techniques on your roof mounts. Flashings are mandatory on all composition shingle roofs.
  8. Heavy rain does a great job of cleaning off debris from rooftop panels. NEVER hose off your panels – mineral deposits from tap water can permanently damage the glass.
  9. Wiring should be securely tucked-up beneath the panels and racking. Contact your installer if there are any wires hanging down on the roof surface.
  10. To make sure your system is operating properly, keep an eye on your inverter display (or online display), as well as your monthly electric bill. Even if your installer is monitoring your system they might not always notify you if there is a problem – especially if there is a problem with your monitoring.

For details on these ten tips for 25 years of trouble-free rooftop solar, Listen Up to this week’s Energy Show on Renewable Energy World.

How Many Solar Panels Do I Need?

It may seem counter-intuitive, but you can have too many solar panels on your roof. With conventional net metering, your utility will not reimburse you at the end of the year if you produce more power than you consume. For example, last year my electric bill was -$46.86. Our roof has a 6kw solar system on it, but because we installed a new thermostat, LEDs and new windows, we generated a net credit with our utility last year. So I’m replacing my LEDs with old-fashioned incandescent light bulbs so I can use more power and get closer to a zero bill this year. The number of panels you need is based on two factors: the available space on your roof and the size of your electric bill.

A good installer will not take advantage of you by installing modules where there is a lot of shade or a poor north-facing orientation on a steep roof. Along the same lines, your installer should analyze your current electric bill and recommend the number of solar panels that will get you close to a zero bill.

Once you know these two boundary conditions – the number of panels that fit on your roof and the number of panels that you need to zero out your bill – you can see what size system fits in with your budget and method of financing. At the same time your installer should step you through the options for different levels of solar panel efficiency, module electronics (optimizers or microinverters), and changes in your future use of electricity (such as an EV or energy conservation measures). For more about determining the optimum size of your solar power system, Listen Up to this week’s episode of The Energy Show on Renewable Energy World.

Getting your Solar Investment Tax Credit

It’s that time of the year…tax time, that is. Every year we get questions from customers about filling out their solar investment tax credit (ITC) form. Now, we are not tax experts (so check with your accountant), but the rules are pretty straightforward for the solar ITC.

Basically, every homeowner who installs a solar electric system or solar hot water system (not a pool heating system) gets a 30% tax credit on the total cost of their system. This tax credit only applies to the owner of the system, not if you have a solar lease or solar PPA. There is no need to file for the ITC if you have a lease or PPA since the corporate entity that owns your system has already collected the tax credit and depreciation benefits – reducing your monthly payments accordingly.

It only takes a few minutes to fill out the IRS “Residential Energy Credits” Form 5695. For documentation, all you need are copies of all the invoices that apply to the installation of your home solar system. For more about getting your 2016 solar investment tax credit, Listen Up to the Energy Show on Renewable Energy World.