Overcast skies don’t stop photovoltaic cells from pumping out the watts
craig.sailor@thenewstribune.comMay 28, 2014
At some point just about every homeowner gives a thought to solar energy. Who wouldn’t like to power their house with the sun, watch their electric meter run backwards and never pay for a kilowatt again?
And then the clouds set in. This is the Northwest, after all, not sunny Arizona.
But the sun finally is rising for good on solar power. Costs have come down, efficiency has gone up and financial incentives are increasing the return on investment.
MYTHBUSTING
In California, Hawaii or Arizona solar panels can be seen on many rooftops, but in the Northwest you’re more likely to see Sasquatch than a solar electric array. Dispelling the notion that there’s not enough sun to make a solar power system worthwhile is job number one for solar advocates.
Solar power will be one of the many topics covered at this weekend’s Mother Earth News Fair at the Washington State Fair Events Center in Puyallup. The two-day event focuses on living green. (See below for details.)
“It absolutely does work here,” Puget Sound Energy’s Jake Wade said of solar power. There’s no substitution for direct sunlight, he said. But summer’s long days and lower energy needs (compared with power sucking Phoenix and Las Vegas) enable solar-equipped customers to produce more power than they need.
High heat makes photovoltaic solar panels less efficient. So, the Northwest’s cool days help solar cells produce more energy.
And while overcast skies are not as productive as direct sun they make orientation and pitch of solar panels far less important. (The light is multidirectional.)
PSE has 2,021 solar producing customers. Solar energy now accounts for 1.13 percent of total U.S. capacity, according to figures just released by the U.S. Department of Energy. Since 2010 solar capacity increased by 418 percent across the nation.
NET ENERGY METERING
While Northwest summers might be a solar paradise what happens during winter’s short, dark days when the furnace runs day and night? That, say solar proponents, is when the beauty of net energy metering comes in to play.
NEM allows utility customers who generate their own renewable energy (including wind and hydro) to earn credits for surplus power they deliver to the grid. The Department of Energy cites NEM as one of the main drivers of the increased popularity of solar energy.
The system is simple. During the summer the energy a solar customer produces is sent back to the utility company. Meter discs actually spin backward. In the winter, when more energy is needed than produced, it’s subtracted from the customer’s account.
“It’s like using the utility as an infinitely efficient battery,” said Wade, who is PSE’s net metering program manager.
Some customers, if they have a big enough system and/or are energy conservative, wind up paying nothing for their electricity. However, they still pay a small monthly bill to the utility for service.
COST
Each 1,000 watts of PV solar panel produces about 1,000 kilowatt hours of electricity per year. The typical home in Western Washington uses 900 to 1,000 kilowatt hours per month, Wade said. To be completely net zero that home would need an array that produced 10 to 12 kilowatts. The median size of a solar system for a PSE customer is 4 to 5 kilowatts, he said.
The biggest stumbling block for most solar power seekers is cost. A full system could set a homeowner back $30,000. But costs have dropped dramatically in recent years and have stabilized.
The solar panel industry is highly competitive. Federal prosecutors last week indicted five Chinese military officials for stealing industrial secrets from Hillsboro, Oregon, based solar panel manufacturer SolarWorld.
Other factors driving cost include choice of product and difficulty of installation.
TECH ADVANCES
The heart of any solar system is its PV cells. The delicate silicon-based wafers are interconnected and assembled in to sturdy panels, usually about 40 inches by 65 inches. Depending on manufacturer and model the panels can produce from 200 to 275 watts. After quality of the panels, buyers should be concerned with efficiency, price, warranty and aesthetics.
Panel maker SunPower sets the market record at 21.5 percent efficiency. That means that 21.5 percent of light hitting the cells is output as energy in ideal, laboratory conditions. That’s almost a doubling since the Carter administration when the president famously installed panels on the White House roof. They were later removed by President Ronald Reagan.
Scientists have recently announced the development of cells that absorb different wavelengths of sunlight and achieve efficiency in excess of 40 percent. But those cells are years from production and affordability. The development does mean that fewer cells will be needed to achieve the same power output of today’s systems.
Another breakthrough came in inverter efficiency. The inverter is what converts DC power (which the panels produce) to AC power (for home use.) Once at 80 percent efficiency they now run up to 97 percent.
Up until the early 2000s batteries were required but are now no longer needed. Batteries still can be added to a system but add cost and are not needed with NEM. Batteries are a must for off grid systems.
PLACEMENT
The optimum location for solar panels is a south facing, pitched roof. That takes advantage of the most light. A west facing roof is the next best choice but is 15 percent less productive.
A roof pitch of 30 to 35 degrees is optimum. (That equates to a roof rising 7 to 8 vertical inches over 12 linear inches.)
Even if a property owner has plenty of land a roof provides a ready-made, engineered structure and needs the least amount of wiring. At least 75 percent of customers place their panels on roofs. If a roof isn’t at the right pitch or orientation the panels can be racked to the correct placement. However, that will add to the cost.
Other locations include pole and ground mounted panels but both of those also add to installation costs. Some advanced pole systems allow the panels to track the sun through the day.
Some of Haffner’s clients get creative. He’s installed panels on car ports, pergolas and even on a chicken coop. David Lee attached an awning to his house made of solar panels. He plans on adding another soon.
Roof mounted systems come with flashing that prevents leaks.
INCENTIVES
But wait, there’s more. If free power isn’t a strong enough attraction the financial incentives don’t end there.
Aside from NEM, Washington utility companies administer an incentive program that buys the energy produced by individuals and companies (up to $5,000 per participant per year) regardless of whether it goes to the grid or is used by the customer. If the solar equipment used is made in Washington, then the kilowatt hours produced is paid at 54 cents. If out-of-state equipment is used, then it drops to 15 cents.
Additionally, a solar power customer can take 30 percent of the system cost off their federal income tax bill. That means a $30,000 system would end up costing $21,000 after taxes. Furthermore, all parts and installation costs are sales-tax free in Washington.
When it comes time to sell your home a solar PV system will add to its value. The Lawrence Berkeley National Laboratory found in 2013 that a home with a solar system added $24,000 to its sale price compared with homes without systems.
PUSHBACK
Solar energy might be a victim of its own success. Utility companies have recently begun to push back against NEM in the Sun Belt states.
Politicians in California and other sunny states are under pressure from utilities and their lobbyists to retool incentive programs. The companies say renewable energy customers need to share the costs of energy transmission and distribution. Environmentalists say the traditional utility business models are under threat.
Wade said PSE is looking closely at the situations in the Sun Belt states. He acknowledges that the battles will be fought there before they come, if ever, to the Northwest. But, he said, PSE will not stand in the way of renewable energy.
“If this is the direction our customers are going then this is the direction we’re going.”
DO YOU HAVE A SUNNY FUTURE?
The cost of a solar power system is equivalent to that of a new car. But the technology and financial incentives have never been better. If you’re thinking of going solar consider these points:
Budget: Know what you want to spend before starting out.
Financing: Some financial institutions offer solar-based loans.
Staying power: Will you own your home long enough for it to pay off?
Your site: Survey trees and buildings that might block light to panels.
System: Roof, pole or ground mount.
Placement: Does your roof face south? Is it big enough to hold the panels you desire?
Roof: Is it in good shape or will it need to be replaced soon?
Contractors: Find those that deal only or mostly in solar. Make sure they are licensed and bonded.
References: Check them.
RESOURCES
Incentives
Database of State Incentives for Renewables & Efficiency: dsireusa.org
Washington state solar equipment manufacturers
Silicon Energy: silicon-energy.com
Itek Energy: itekenergy.com
Itek Energy: itekenergy.com
WORKSHOPS
Mother Earth News Fair
Mother Earth News Fair at the Washington State Fair Events Center will feature more than 200 hands-on workshops that center on green living. Headlining speakers include actor and green advocate Ed Begley Jr., organic farmer Joel Salatin, Bob’s Red Mill founder Bob Moore and permaculturist Toby Hemenway.
When: Saturday, May 31 and Sunday, June 1
Where: Washington State Fair Events Center, Puyallup
Tickets: $25
Information: motherearthnews.com
Where: Washington State Fair Events Center, Puyallup
Tickets: $25
Information: motherearthnews.com
If you are interested in learning more about solar and can't make it to the Mother Earth Fair, Western Solar will be hosting a free Solar 101 Workshop on June 12th. Click here for more details and to register. If you would like to schedule a free site assessment, click here.
