In the past year or so, we had a few Title 24 clients who were interested in rebates from the New Solar Homes Partnership, an initiative offered through public utilities in the State of California. Since writing our earlier post we have discovered just how complicated a process this is, even more so now with the new Title 24 HERS reporting requirements. It really pays to plan ahead.

NSHP is only one of a dizzying array of rebates and incentives. The NSHP is part of the California Advanced Homes Project, which encourages greener, more efficient homes (not only solar). Some of these incentives, like the online rebates for EnergyStar appliance purchases, are targeted at individual homeowners. Other programs like the NSHP may be more easily handled by builders, developers, and solar vendors rather than by individual owners. Unless you have an unquenchable passion for paperwork, as an individual homeowner you may be better off going through a solar company, since you’ll have to use one anyway to obtain a solar system. An experienced solar company should already be familiar with the process (it’s something to ask them about).

Important Things to Know Upfront

The NSHP is for NEW homes only, and the main bar or litmus test is by how much you can exceed Title 24 requirements – either by 15% or 35%. It’s also  specific to solar renewable energy – it doesn’t cover wind, water, or quasi-renewables like geothermal or fuel cells. (If you are retrofitting an existing home with solar, check with the California Solar Initiative.)

You will need the following consultants:

• Solar vendor
• Title 24 consultant who’s a CEPE
• HERS rater, with special NSHP certification

To complete California's New Solar Homes Partnership process, you will need a solar company, a Title 24 consultant who's also a Certified Energy Plans Examiner (CEPE), and a HERS rater.

Obviously if you’re building a new home, you’ll have other professionals as well, including a licensed architect and a licensed general contractor. You might also consider a mechanical engineer with experience specifying and designing heating/cooling/water heating systems for renewable-energy buildings.

The NSHP rebate is specific to location and street address, and you should already have a proposed design for the home. You will need to be specific about your choices for mechanical, glazing, construction details, and appliances. Since all these features are explicitly called out in the application, any substitutions made during construction should be carefully reviewed. Even a seemingly minor change could necessitate a re-do of the Title 24 compliance report and/or parts of the NSHP application.

Before Applying for NSHP

The NSHP is handled through each local utility company, which in the Bay Area is PG&E. This list was taken from PG&E’s NSHP web page.

1. The home must get service from PG&E. If needed, fill out an application for new service for the selected location.
2. You’ll also need to fill out another PG&E application for Net Energy Metering.
3. Read the NSHP Guidebook, available from the California Energy Center (CEC). It’s 73 pages long. The latest version of this book, along with the various forms, is available here.
4. Get your Title 24 report (the CF-1R) done by a Certified Energy Plans Examiner (CEPE) using the performance method.
5. Price out your solar system to a vendor whose name and address are registered with the CEC.
6. Either the Title 24 consultant or the solar contractor uses the NSHP PV calculator, a free download, to get the expected performance analysis of your proposed solar system. This will go on the CF-1R-PV form, another CEC form. The PV calculator is a climate-specific performance modeler like the Title 24 modeling software, but it’s just for the solar system.

Forms and Paperwork – An Endless Supply

Before we get into the actual NSHP process, let’s familiarize ourselves with the various numbered forms that crop up at various points. Time is of the essence, because the NSHP doesn’t want to commit funds that will be tied up in projects that drag on for years.

Permit submittal phase

• CF-1R – Title 24 report completed by CEPE using performance method. It’ll need to beat the standard by 15% or 35% depending which NSHP tier you’re going for. Note any measures called out on the report as requiring HERS verification. For example, specifying insulation level in the Title 24 calcs doesn’t need a HERS field inspection, only a CF-6R installation certificate, but if you claim the quality of insulation installation (QII) credit on top of that, then you do need a HERS inspection. You’ll also have to specify your mechanical heating/cooling/water heating equipment and system design a lot sooner than you might be used to doing.

Construction drawings phase

• NSHP-1 – Reservation application form; this can also be done online. It’s not required for the permit submittal, but it’s good to get that going earlier rather than later.
• CF-1R-PV – output from PV calculator in step 6, done by solar vendor or CEPE
• NSHP Supporting Documentation – Every possible aspect of the project, including a full set of permit drawings, site map showing compass orientation, the CF-1R Title 24 report, drawings for electrical, mechanical, lighting, appliance specifications and EnergyStar certifications, and a copy of the solar contract.

Construction phase

• NSHP-2 – received after completing NSHP online reservation application, filled out incrementally over course of construction.
• CF-6R – one or more certificates of installation for each of the general energy efficiency measures specified in CF-1R. Completed by installer(s), probably subs of GC, for water heating, furnace, air conditioning, windows, ductwork, airtightness, insulation, lighting. Note that insulation may require HERS inspection prior to closing walls.
• CF-6R-PV - certificate of installation of solar system by installer, likely the same solar vendor or their sub
  Note if you swap things out like mech or windows, especially for something cheaper, you might have to re-do the Title 24 report and add new measures to keep your 15% margin. Makes it difficult to do design changes in the field.
• CF-4R – One or more verifications completed by HERS rater, one per HERS inspection.
• CF-4R-PV – Completed by HERS rater, not sure what they look for exactly or if they actually test it.
• NSHP-3 – a 10 year warranty on the solar system
• STD-204 – filled out by party who receives payment for the solar system, probably the solar vendor
• IRS W-9 – from the PG&E customer

Post construction

• Proof of PG&E hookup – no form is specified, so I don’t know what constitutes acceptable proof

NSHP – Actual Application Process

So you went through the “Before Applying for NSHP” checklist above and you’re good to go, right? Wrong! You haven’t even started to apply for the NSHP stuff. Listen my children and you shall hear, of the New Solar Home rebates oh so near. I came up with a flow chart of sorts, completely unauthorized of course.

New Solar Homes Partnership process part 1 of 2. This includes the new forms from the California Title 24 2008 energy code, which went into effect in 2010.

California New Solar Homes Partnership process part 2 of 2

The numbered steps below came out of the NSHP Handbook, but they’re not exactly the same as what’s shown on the diagram above, because the diagram includes items that aren’t NSHP-related – but which sometimes have to occur in tandem.

Step 0. Create an initial proposed design for the home.

Step 0a. Do Title 24 analysis and energy budget analysis. Try to optimize the energy budget, get it as small as possible. Make design or material changes if you have to. Remember you have to beat Title 24 by at least 15%.

Step 1. Choose your solar vendor and equipment. This will be a vendor who’s come up with a proposal that includes equipment such as PVs, inverters, and metering. The actual installers must be licensed.

Step 2. Complete an online reservation using your PG&E account or send in a hard copy reservation application form. This ensures that if eligibility requirements change after you’ve started this process, your hopes won’t be dashed in the middle.

Step 3. Do the PV calculation referenced in step 6 from previous “Before Applying” series.

Step 4. Refer to NSHP Handbook and send all required documentation thus far to PG&E. Supporting documentation includes site map, the PV calc, Title 24 report, Title 24 source files, PDF permit drawing set with title 24 info, electrical, mechanical, proof that all appliances are EnergyStar, solar contract.

======= wait =====

Step 5. Assuming that every possible “i” has been dotted, PG&E will review all this and send you an approval form called NSHP-2 stating the amount of funding that’s been approved. This form has several parts that are filled out during the course of construction by various parties. (My guess is PG&E fills out part 1, the solar installer fills out part 2, the HERS rater fills out part 3, and either or both of them may fill out part 4.) Note the expiration date on this form. You have to get through the entire project, meaning construction has to be completed and forms submitted, before this date. The implication is to send all subsequent forms at once because “there’s no guarantee” that info submitted piecemeal will be associated with the right project. (installers fill out CF-6R forms)

Step 6. Do the HERS verifications. HERS rater fills out CF-4Rs online for each verification or inspection. The PV inspection has to exactly match the PV calculations submitted earlier.

Step 7. Complete the remainder of form NSHP-2 by listing any modifications made to the equipment since the reservation was approved, and send the form back to PG&E. You also need the Ten year warranty form NSHP-3.

==== final stuff ====

Step 8. You might need to provide proof that system was actually hooked up to PG&E, meaning the building inspector has to approve it all.

Step 9. Yet another form, the STD-204, is required by the designated payee. This is specific to the payee, not the project so if you already filled one out for a previous project within the past year you don’t have to do it again unless of course your information changed.

Step 10. And PG&E customers need to provide an IRS W-9 form, probably this applies to businesses and corporations who need to show a Taxpayer Identification Number.

Nowhere in here are audits spelled out. The Title 24 reports that we submitted on behalf of our clients were reviewed with a fine-toothed comb against all other supporting documentation. I expect that PG&E has to verify everything on that report against all the drawings, mechanical, etc. That all happens on the PG&E side and is a black box. If there are any inaccuracies on the application, even down to the owner name listed on the Title 24 report, they can kick it back.

Nothing in here guarantees that there will actually be funds to cover the rebate.

Title 24 Model Versus Reality

In order to prove a minimum 15% compliance margin, the Title 24 consultant will need to use the Title 24 performance method, which is a specially approved energy modeling software package specifically used to demonstrate compliance with Title 24 requirements. Depending on the home’s projected energy budget, you may need to make design changes to the home in order to boost the compliance score. These could include additional insulation, better glazing systems, more efficient mechanical systems and appliances, or compliance credits for HERS testing. Having a more efficient home will also help reduce the size of the solar system needed.

Title 24 ignores certain real-world shading conditions including trees, adjacent buildings, and landforms. So, for the purposes of getting your 15% Title 24 compliance margin these things won’t matter, but for the purposes of actually having an effective and comfortable home, shading should be considered and is a crucial factor in solar designs. Having the house shaded will help with summer cooling; however, the area that will have the solar arrays should not be shaded, or you won’t get the full benefit from the solar equipment. Equally important to consider is the use of solar heat gain during the winter months.

One “gotcha” of sorts with Title 24 is that it’s very difficult to create an all-electric, all-solar home because Title 24 has penalties for electric resistance heat and water heating. I don’t think there’s a requirement that the home actually get all of its energy needs from solar, so it’s possible to submit for a home that uses solar power for household appliances, but uses a gas forced-air furnace for heating. It’s still important to make the home as energy-efficient as possible and to make the heating equipment as efficient as possible.

Client Experiences

Alan Aurich, Elevation Architects:

In my opinion, the #1 reason anyone should consider alternative energy systems is from a personal value system, tied to their commitment to protect and preserve our environment. Measuring a system from a “monetary” standpoint is moot and it’s a cost outlay for life of the system. And, no matter what, there has to be a “point person” to manage the effort and coordinate the respective needs of each party.

• It’s a 12-24+ month process from start-to-finish.
• The cost/benefit factor is likely nil and most likely, a long-term expense similar to a car.
• The process relative to the paperwork is extensive and intensive. To date, we still have not received our rebate that was “estimated” to arrive 3 months ago, and PG&E continues to bill us for electricity (3 months now) after the system went live in September.

Geoff Campen, Klopf Architecture:

We actually worked with three programs: NSHP, GreenPoint Rating, and California Advanced Homes. We had to prepare several packages for these programs. For NSHP we gave them the following documentation:

• Construction documents
• Mechanical drawings
• Title 24 report and digital input files (2008 energy code, even though project was submitted under the 2005 code)
• GreenPoint Rating checklist
• Spec sheets for specific systems
  
  • HVAC equipment
    
  • Roofing components
    
  • Appliances
    
  • Solar equipment
  • Glazing products
    

We went through our solar company for most of it, which was Cobalt Power Systems, Inc. in Mountain View, CA. They took all our information, put the application together, and submitted it on our behalf – or really, on behalf of the owner. It’s not done yet, either. We began the NSHP process in early February of this year. Construction on the home began in March, with an expected completion of March 2011.

There may be big differences among solar companies in this regard. Some are full-service, while others are technically adequate but not up on things like rebate processes for incentive programs. The Cobalt guys were really good, and knew what to do right away. But there are so many incentive programs out there, even our builder, a Certified Green Building Professional, didn’t know about them all.

Klopf Architecture client:

When you hire full-service solar installers their initial estimate already includes a reduction for a CSI or NSHP rebate that will be paid directly to them by the state.  I considered SolarCity (First Solar) and Cobalt Power Systems (SunPower), and selected Cobalt.  Both companies have documentation specialists that work with brisk efficiency to gather all the necessary documentation.

All I did was put Cobalt’s specialist together with our architects, and made sure our general contractor selected a GreenPoint rater who is also a HERS rater.  If SolarCity got the job, they would have hired the rater themselves.  I sincerely doubt that most PV customers would really know or care whether their rebate was CSI or NSHP, to them it’s just initials on the installers’ bids, and I’m sure a year later few would remember which was which or what paperwork was required.

As for CA Advanced Homes, we wouldn’t even have known about that one at all if the Cobalt office director hadn’t told us about it.  Because that is to be paid directly to us, we were left on our own to apply.  But as we could afford to pay the architects to look into it, even that was relatively painless.

• The NSHP application was managed by Bonnie Corwin at Cobalt Power, with docs provided by Geoff Campen.
  
• The CAHP application was handled by Geoff Campen.
  
• Both are relying on reports by Miles Hancock (CalCERTS), and Mark English Architects for the Title 24 report.
• Acknowledgments also to SunPower and Monterey Energy Group
  

Stay tuned for a follow-up interview with this design client, a homeowner who cares enough to commission a custom-designed home that is practical, energy-efficient, comfortable, and beautiful without being outwardly showy or ostentatious.

While researching solar technologies, we at Green Compliance Plus heard from solar installers  who all seem to think that architects are hard to work with. So, we spoke with Fernando Valenzuela of Alter Systems in Berkeley about how to design a solar-ready home. Note that only about 5-10% of Alter Systems’ customers are owner/architect teams. Usually it’s the homeowners approaching them directly because they want to “go solar”.

So… why are architects hard to work with? “They have a groupthink… they like design, the look, but they don’t understand systems. They ask questions like ‘why can’t we use this roof’ without realizing that you can’t split up an array. Their projects aren’t always quick, either, and rebates that were designed for may be gone by the time the project gets through approval.”

Valenzuela went on to provide various design tips, as well as insights into new technologies, best-of-breed products, the difference between grid-tied and off-grid systems, costs and returns compared with conventional power, financing options, and the importance of grid parity.

Solar Design Tips for Architects

Consider building shape, roof planes, and orientation: With a remodel, people engage with an architect after the house is already built. It’s really best to take solar into account and design for it from the start. This may include choosing a lot or site that allows for a good solar orientation. Assuming that you do have some power to determine the shape of the building envelope, just make sure you include a nice un-shaded patch of south facing roof around 20 x 30 feet for your PV arrays. It goes without saying to consider proper solar orientation for the building, of course, if you have the option to do so.

Until recently, a single contiguous area was needed for solar arrays, and many products are still configured to work only if all the panels are installed together as a group. The panels should be tilted for maximum solar angle. Some panels lay flat and others can be tilted up; flat panels are aesthetically preferable and better for the neighbors’ attitudes.

Optimize roof tilt: The optimum tilt for the solar panels is your the latitude minus 15 degrees. In California, allow for a south or west facing planar area that is tilted around 20-22 degrees. Utility-scale projects and off-grid systems sometimes use solar tracking devices, but typically residential panels are mounted in a fixed position. The “solar window” is the maximum energy harvesting hours, between 9am and 3pm.

The sun's path across the sky changes according to season.

Assuming that you design includes panels that are built directly into the roof, your roof tilt will determine the panel tilt. “Not too steep, either, ” says Valenzuela. A 30 degree roof tilt is too steep – it’s much harder, and more dangerous, to install the panels. “It works your abs and butt!” laughed Valenzuela. And it’s not exactly “green design” when crews get injured, is it?

The roof tilt also depends on whether you have a grid-tied or an off-grid system, according to Valenzuela.

• Grid tied should be your latitude minus 15 degrees. Grid-tied systems are optimized for summer, because that’s when you’ll get the most energy out of the system, and thus you’ll get more money back at the end of each year.
• Off grid, on the other hand, should ideally be your latitude plus 15 degrees. For off-grid you maximize for winter, because you need the system working even in the worst-case scenarios so that you’re not left in the dark. Basically you want to make sure the system will produce in the winter months.

Allow space for conduits: If solar power is an afterthought, then you may have a visible exterior conduit, which can be less aesthetic than building it into the wall. If you put the conduit under the sheetrock it won’t even show on the outside. But even if you’re not installing solar today, you can accommodate future solar in the design.

Left, a typical retrofit requires routing the conduits wherever you can. Right, allowing a place for solar conduits that's built into the house allows flexibility for future solar.

Be careful with vent placement. “Don’t put vent pipes in the middle of a rooftop solar array. If the pipes stick up too far, they’ll get in the way of the PV panels.”

Make the roofing strong. Roofing should be 2 x 6 or 2 x 10 at 16″ on center for strength. Modern codes want 2 x 4 at 24″ across to conserve materials. If the span is too long, however, this doesn’t account for the weight of the people walking on it to do things like install solar panels. For this purpose, spans over 8 feet need thicker rafters. “We do a lot of retrofits,” says Valenzuela. “Old buildings in Berkeley for example are often 2 x 4 at 24 off center. For these, we may have to put in a brace.”

Keep basic sizing guidelines in mind. The amount of surface area you need for your PV panels depends on how effective the panels themselves are, and how much power the house requires. A rule of thumb might be 500-600 SF of roof (or other area) for the solar array to generate 5 – 7 kW. This covers a lot of places, even desert climates. “Even in the hotter parts of California, with heavy air-conditioning loads, it’s not too far off base,” according to Valenzuela.

Understand the racking systems. It’s good to understand how racking systems operate. “No roof penetrations” are needed. In the future, each panel may come with an independent energy panels with built-in inverters. Innovations include reduced installation time and cost.

Process

Choosing Your Solar Companies: A solar systems company is essentially a contractor/consultant who supplies, specifies, and installs systems. “If your client wants solar power for heating, cooling, electricity, or water heating, then you as the architect will need to establish a good relationship with a company that you can rely on to supply a well-designed system that is appropriate for the programmatic requirements of the home.”

“Try to work with a few solar systems companies that you know well, to get standard products and sizes for components. But don’t rely on just one company, because some companies are over-scheduled right now and orders are going unfulfilled.”

How Long Does It Take? Allow a month turnaround including all permits and paperwork such as rebates.

Customer Experience: So what happens when someone comes to you and says they’re ready to go solar? Here’s what your clients can expect.

1. Site evaluation. The solar consultant will most likely want to visit the house to inspect the roof area, shading, and electrical box. Some houses just aren’t suitable for solar. “Usually it’s a mounting problem,” says Valenzuela. A general rule of thumb for say a 1,200 – 2,000 SF house is to have flat or south facing roof around 20 x 30. Using micro-inverters helps reduce the amount of roof area that you need (read on for more information).
2. Proposal. Assuming the house will support a solar system, the owner gets a price proposal. “I have to ask why they’re doing it to figure out if it’s off-grid, grid-tied, or hybrid system. If they sign off, the paperwork starts.”
3. Permits and Rebates. Local permits for installing a solar system can take as little as a day or up to around 2 weeks depending on locale. The paperwork for tax rebate programs takes 2-3 weeks.
4. Installation. Alter Systems takes 2 days to install, but schedules for 4 days to allow for contingencies such as rain. The owners or occupants can continue to use the home and live in the home while the installation is ongoing.

Grid-Tied and Off-Grid Systems

One basic decision the owners must make is whether to tie their new solar arrays int the power grid. Grid-tied and off-grid systems are totally different animals in some important ways, but as solar power gains mainstream acceptance, it must also be able to integrate smoothly into mainstream infrastructures as well.

• Off-Grid systems are the classic “1.0″ of solar renewable energy. Although they tend to be associated in the U.S. with environmental activism, survivalist movements, and early-adopting technology buffs, they’re also essential in parts of the world where a centralized power infrastructure either doesn’t exist or isn’t reliable.
• Grid-Tied systems are mainly intended to reduce or eliminate energy bills, as in Net Zero homes. It’s a more mainstream market than either the early adopters or the green contingent. A main motivation is likely to be cost savings.

Although grid-tied systems are a newer concept, they are likely to be the wave of the future in industrialized countries. The components of a grid-tied solar system are the panel arrays, a power inverter to convert the direct current generated by the panels into the alternating current used by household appliances, a manual power disconnect, and of course the utility company’s usual infrastructure: the meter and switch box.

A grid-tied system is simple and straightforward. There is no need to store power onsite. Power generated is fed directly back into the grid, and home power needs are drawn also directly from the grid.

An off-grid system has more components, because of the onsite power storage requirement. In an off-grid system, the solar arrays feed into a combiner box which balances the inputs from each array. The combiner box combines or branches together the PV arrays/modules and then takes all the power through one set of leads to the charge controller. The controller makes sure your battery is charged correctly, and prevent over-charging.

The advantage to this type of off-grid configuration is the ease with which you can add supplemental power-generation systems such as microhydro or wind turbines. The goal of an off-grid system is to keep the batteries fully charged at all times. If there’s a grid tie-in, the battery won’t “sell” back to the grid unless it is already fully charged.

Which configuration you choose for your solar system depends on the reason why you’re going solar in the first place. Homeowners typically adopt a grid-tied system to save on energy bills, reduce their carbon footprint, and perhaps to show off to their neighbors. Valenzuela cites an estimate from the Journal of Assessors and Appraisers that for each dollar you can shave off your annual home operating costs, you add $20 to the property value.

According to Valenzuela, based on his experiences with his own customers, homeowners might choose off-grid because they’re in a remote area, and either it’s too expensive to bring the grid out there, or it exists but is not completely unreliable. “Some people do it because they hate public utility companies just on principle,” notes Valenzuela. “They’re also more likely to be DIY types who are comfortable assembling their own systems,” he adds.

An off-grid system includes an onsite storage battery. It's designed to be self-reliant. The homeowner can add a grid-tie option as shown above.

So what are the pros and cons of each type of solar configuration? Grid-tied systems require less equipment and employ simpler configurations; on the downside, they’re limited based on inverter sizes.

With off-grid systems, it’s easier to add supplemental renewable-energy systems on the side for things like wind or microhydro.

It's easier to add supplemental power generation systems to an off-grid system with its own battery storage.

Off-Grid for Villages: A typical residential home might need a 6kW system. For sites such as an army base, a remote ranger station, or a farm with multiple buildings, a system called AC coupling can deliver 20 kW or more. Basically it’s a way to create your own micro-utility company, and collect power from solar arrays on several buildings, using one central inverter (such as the Sunny Island off-grid inverter from SMA Solar Technology) and a central storage area. “This type of installation is very useful in places like the Caribbean, island countries or places without any infrastructure,” says Valenzuela.

Could you implement something like that in a city neighborhood, I wondered? A residential collective of some sort, for people who live in urban areas but still want to have totally independent self-generated power, and who want to pool their money to invest in economies of scale? “You’d have to do all your own wiring,” Valenzuela responded. “They’d have to be fairly close together.”

Well… with the geek factor in this area of the country, I wouldn’t be surprised if it’s already happening. After all, if a few homes drop off the grid on a single city block, how would we ever know?

Solar Grid Parity

I didn’t even know what this was, but with all the talk about the ROI of solar systems vs. fuel cells vs. high-efficiency but conventional systems, it’s a very important concept. Solar grid parity is a tipping point in the energy marketplace when the cost of energy production for solar power will be equal to or less than the cost of generating conventional, fossil fuel-based grid power.

A common comparison is dollars per watt or cost per kWh. U.S. average power prices for last year ranged from 5 – 15 cents per kWh, averaging roughly around 10-11% (businesses were 1 cent cheaper).

This number includes upfront investment in equipment although of course there’s debate over how to calculate it and when this momentous day will actually come. 2012 seems to be a common guess, although coincidentally that’s also the end of the world, according to the Mayan doomsday calendar).

Prediction: “a number of solar companies will hit a long-pursued industry target of $1 per watt by 2012.”  This “race towards $1 per watt” means that “within a few years solar panels will be able to generate electricity cheaper than the grid in many regions of the world.” (Sunnier regions have a bigger solar payoff, not surprisingly.)

Another claim is that we can reach 2012 grid parity in “almost half the US” and he also notes that there are several ways to calculate grid parity.

Even 4 years ago, solar was still pooh-poohed as a boutique technology for wealthy do-gooders or conspicuous consumers. But that was before tax rebates and stimulus dollars made it easier for new owners to “green” their homes. Other factors include improved component efficiency and a wider array of creative financing options such as these options from SunRun to purchase solar power as a service, to lease the equipment to the owner, or to help owners seek solar financing through local municipal programs.

So, is it a sure thing that in 2012 we’ll all be putting PG&E out of business? Doubtful, but there’s definitely a sense that price parity is coming, it’s just a matter of when. For example, higher interest rates could hurt financing, and if grid prices fall, parity won’t be reached nearly as soon. For those who prefer to focus on equipment efficiencies, there’s a rather geeky engineering article from BP Solar that discusses current and future efficiencies, including emerging new technologies such organic photovoltaics and nanocomposite solar cells.

The $1 per watt number is disputed as overly simplistic on one investor blog: “PV’s competiveness with the grid varies wildly based on the region… The idea that module prices need to come down to $1/W for solar to be competitive is misplaced at best” because “PV is already at or near parity with the grid in a number of markets”. This blog also includes a good discussion of calculating the cost of various types of conventional power, including nuclear.

Solar Financing Innovations

For homeowners who want to finance their solar installation, three good sources are:

• Tax rebates
• Municipal funding options through property taxes
• Bank loans

In the second case above, this is a plan being adopted in some localities such as Santa Rosa. Basically, the city obtains the funds for solar installations at a very low interest, say 3%. The city then loans it out to homeowners at a slightly higher but still reasonable rate, say 7%. The owner then pays back the loan in the form of an extra property tax surcharge every year. If the house is sold, the new owner is responsible for continuing those payments as part of the home’s property tax bill, and the new owner of course enjoys the reduced energy bills in the meantime.

“Some owners just pay for it with a credit card,” said Valenzuela. I can’t imagine plunking down $35-$60,000 on my card but then again, I can’t imagine watching the national average of television, either. “Every dollar decrease in operating cost adds an extra $20 in property value,” said Valenzuela, “but equity is fake money. So, we don’t include this increased equity on our cost/benefit analyses that we show customers in our proposals.”

New Solar Products

During the course of our conversation, Valenzuela mentioned some of his favorite new solar technologies. In no particular order, here they are.

Solar forced air heaters. These devices are installed on a south-facing wall or roof and are best used as a complement to other heating systems, a boost but not a replacement. They’re small and relatively efficient, at least compared to PVs. A single 8-foot panel is enough to heat a small room. They use no fuel and have no moving parts except a fan to draw cold air into the panel and push heated air out directly into the room. They don’t work as well on cloudy days, obviously. And you don’t even need fancy PVs or heat collectors: here are some ingenious DIY solar air heaters made from recycled aluminum cans.

This 8-foot solar wall air heater from ClearDome Solar in San Diego can heat up to 500 SF of residential space.

Micro-Inverters. Green Compliance Plus has mentioned the breakthrough of micro-inverters in a previous post – basically, by having separate inverters for every PV panel in a solar array, you can harvest more energy because shaded panels no longer bring down the performance of the entire array. One maker of micro-inverters is Enphase Energy. Valenzuela waxed almost poetic about Enphase products: “At the recent Green Building Expo, their booth was mobbed while the big players were empty!”

FLEXpower ONE Off-Grid Solution. Valenzuela made special mention of one particular product from OutBack Power called the FLEXpower ONE. He recommended this for total off-grid systems including smaller installations such as boats.

Xantrex XW Grid-Tied Solution. The Xantrex XW from Schneider Electric is recommended for homes that are grid-tied with a battery backup. “It’s not quite as flexible as the OutBack for very small installations, but it’s easier for designers, because it’s a high-quality product and you can scale it up,” says Valenzuela.

But what should architects really know? “Use Enphase!” says Valenzuela.

Renewable energy companies must be doing well these days. Between green stimulus dollars, soaring energy costs, recession-weary homeowners, and increasing public demand for clean energy, it seems like homeowners would be queueing up for the next Net Zero Energy conversion. And those who can afford the initial outlay probably are. But what about the rest of us who don’t have $35,000 just lying around?

We spoke with Kent Halliburton of RealGoods Solar about the state of the art in solar technologies, focusing on products that are available today. “Here’s a stat for you,” he said. “At a recent solar symposium, it was said that 92% of customers want solar energy but 88% don’t know how to get it.”

Hmm… well, if I wanted a new furnace, I’d look in the papers for contractors who installed the type of system I wanted. So what’s stopping these people from typing “solar installers” into their favorite online search engine?

Maybe what he meant was they don’t know how to PAY for it. And until now, there weren’t good financing agreements that allowed people to pay as you go. “People talk about solar price points as if it were a deterrent,” Kent said. “People aren’t as upset about the price point for vehicles like a Toyota or a Chevy, because car dealers sell in terms of monthly payments, not total system cost.”

Solar as a Service

“We have a new financial product offering solar as a service,” he explained. Instead of having to purchase their own solar system, the homeowner contracts to have the system installed and maintained by a third party – in this case, Sun Run, our financial partner. The equipment is actually owned by Sun Run and is sized to meet about 80% of the home’s total projected energy needs. The other 20% is purchased as conventional power.”

In the arrangement described by Halliburton, a homeowner signs an agreement through Sun Run to purchase from Sun Run all the power generated by the solar system, locking in a fixed rate for the next 18 years. The homeowner also pays a certain amount down, anywhere from $0 to around $2,000. This pricing is a little different from the more familiar metered pay-for-what-you-use model, since the homeowner commits to purchasing ALL power generated by their solar system system, whether or not they use it. (Unused power is usually fed back into the power grid.)

System output is somewhat variable depending on the weather, and is usually estimated over a year’s time to average out seasonal ups and downs. The systems come with site-specific production guarantees. In any given month, the homeowner might under-produce and end up using a small amount of conventional power – but in the following month, a span of sunny days might generate a solar surplus that would then act to reduce the amount of kWh billed by PG&E at the end of the year.

A More Efficient Home Needs a Smaller Solar Array

Since the homeowners are already committed to paying for the output, the thinking is to size the system a little on the small side so they use up what they’ve already paid for. A conservatively sized system also encourages homeowner to reduce energy consumption. “For every dollar you save on energy efficiency, you can save $3-$5 on your solar system.”

Additionally, PG&E’s tiered rating structure means it’s cheaper to buy power from them at the lowest tiers – but not at the upper ones. And if the system produces more than they need, they’ve already paid for that portion of the power and it’s still overall cheaper than PG&E rates.

“But don’t wait to energy-proof your home first and then get a solar system, because it’ll take you months and during that time you’ll still be paying for conventional power. We encourage people to do everything possible to their home while installing the solar system.”

Latest Solar Technologies

So what’s the state of the art in solar technology? According to Halliburton, there remain two main technologies: silicon-based panels, and thin film panels. The tradeoffs are cost and efficiency – thin film is cheaper but less efficient, so you need more of it, and more roof space, to generate the same amount of power. So, what’s the best money can buy as of today?

• Silicon-based panels currently cost around $2.25/watt and are around 16% efficiency. That means that 16% of the sun’s rays that actually fall on that panel are converted to usable electric power.
• Thin-film panels are around $1.50/watt and around 8% efficiency.

[Note: These prices quoted by Halliburton are for the panels, not total installed system cost. On Sun Run's site the price is listed as closer to $8/watt.]

Large commercial applications can afford the space for huge arrays, but thin-film solar products can be flexible and more adaptable to portable off-grid field shelters.

What’s the most efficient, top-of-the-line system that’s available today? “SunPower and Sanyo both make products that are around $1 per watt more expensive than average. They’re around 17.5% or 18% efficient. You have to watch it though, because some manufacturers use a measure that is per cell, not panel efficiency. By contrast a so-called middle-tier ‘average’ system might be more like 14.5% to 15% efficient.” Today’s thin-film solar products top out around 9% efficiency.

“Silicon-based panels are better for residential and small commercial applications,” said Halliburton. Larger commercial applications have the real estate to install larger arrays of thin-film panels, but smaller buildings might need a smaller footprint and thus a more compact and efficient system is better, even if the initial costs are higher. “The most common choice is definitely the middle tier.”

Solar Inverters: The Hidden Factor

But even more important than the panels themselves are the inverters, and that’s something most people never think about. An inverter is necessary in order to convert the DC power produced by the solar panel into the AC power that’s used in a home. In the past few years, advances in inverter technologies and configurations have further improved the potential yield from an otherwise average solar array.

Halliburton described how inverters function. “The emergence of micro-inverters has done more to change the solar landscape even than the incremental gains in efficiency that we’ve seen over the years. In the older systems, there was one inverter for all the panels, but with a micro-inverter, you can have one inverter for each panel.”

To get an idea of why this is so important, consider a 4 x 4 solar array of 16 panels on a roof that is partially shaded at certain times of day. If even one of those panels is shaded, then its output is reduced – and the inverter can only gather the output from all the panels at the lowest common denominator. “With a single inverter, the weakest link brings down production for the entire array.”

With a single inverter, the two shaded panels will bring down the performance of the entire array during the time that they do not receive full sun.

By contrast, an array with micro-inverters is less sensitive to partial shading. I observed that this sort of thing must be a no-brainer for an engineer who already knew how the inverters worked with solar arrays.

With separate inverters, each panel is always producing the maximum possible based on the available light that reaches its surface.

Looking Ahead

What’s the state of the art now as compared to 5 years back? “Gains are incremental year by year,” said Halliburton. “For example, 5 years ago we had a 168-watt product from Sharp. That same product today is 198 watts. We try to avoid the ‘Apple syndrome’ where users hold off on buying a new computer because they’re always waiting for next year’s model.”

Halliburton stressed that homeowners didn’t need to wait to install a solar system, even if they were also planning other home improvements to increase building efficiency. Although they might think that a more efficient building with all the latest energy-scrimping appliances will need a smaller solar array, the systems are already sized with this possibility in mind, and in the meantime, why should the homeowner continue to throw away money on the electric bill for all the months it’ll take to complete their energy remodel?

Where do you see solar technologies 5 years from now? “It’ll become more ubiquitous, and continue to make incremental gains. I don’t see any silver bullets, meaning a brand new technology that’s disruptive in the market. In fact, I think the real change is going to be in education. People judge energy consumption based on the number of switches that they flip. They don’t understand what they can’t see. Customers will need to educate themselves and become more conscious of their consumption habits.”

What About Renters?

What’s really stopping people from buying solar systems? Well, not owning your own home is one barrier, although an arrangement called Virtual Net Metering can allow someone who lives and rents in one area but owns property in another town to install a solar system on the property that they own, and have the power it produces be counted towards the energy bills for their rental unit elsewhere. 

The Solar Homeowner Experience

What’s the solar homeowner experience? Do they notice any difference, or do they need to do different sorts of maintenance? Do they ever run short of power? Does the homeowner get an energy bill every month like the rest of us? 

“Other than washing the dust off the panels every so often to improve their performance, not much. They still get monthly statements. There’s online monitoring and automatic billing. The inverters might need to be replaced sometime between years 12 and 17; the panels themselves are guaranteed to produce up to 80% of their original efficiency even after 25 years.”

Visibility into System Stats

How much visibility do homeowners have into how well their system is doing? “The inverters tell them how much power their system is producing, and with online monitoring, they can see all the stats easily.” 

What about whether their panels are really operating at maximum efficiency? “Most customer don’t care about that level of detail, but one could install sensors to measure solar irradiance levels if someone really wanted to know that.”  What they typically get is a quote on what their system will produce on a monthly basis. 

The early adopters were more likely to be gearheads and DIY types with the engineering skills to really prove and verify their own systems. As solar power gains wider acceptance, people are more willing to trust it the way they would with a new conventional furnace unit.

Financing the Future

The impression I had after speaking with Halliburton, especially about the Solar as a Service arrangement, is that innovations in pricing structures and financial incentives will be as challenging – and as necessary – as any engineering improvements to the products themselves. RealGoods has been around for 31 years, in fact RealGoods sold the first solar panel in the U.S. back in 1978. They’ve installed over 5,000 systems to date, with around 200 customers signed up for the Solar as a Service plan that was introduced only a year or two ago.

It’ll be interesting to see where things are, even two years from now.

When I heard that German citizens and entrepeneurs could make money by selling excess renewable energy back to the utility companies, I said, “Well why aren’t we doing that here?” Apparently, PG&E has no plans to do this, although the smart-grid metering should be able to record how much power is put back as well as how much is used. A closer look showed that Germany enacted this by law rather than waiting for the utilities to do it themselves. In this country it’s being enacted by individual localities such as Gainesville, FL.

Basically a feed-in tariff is a government mandate that requires utility companies to pay above-market rate for “green” power for a specified period of time after installation. This means that anyone from an ordinary homeowner to an entrepeneur who wants to build a commercial green power plant can jump into the game.

Nellis Air Force Base solar panels (Credit: U.S. Air Force photo/Airman 1st Class Nadine Y. Barclay)

It’s not exactly a free-market, though. The German system fixes tariffs for approved renewable energy projects for a 20-year period from the plant commissioning and then applies incremental price cuts. Eventually the incentives and preferential rates go away, but by that time Germany might have enough of a renewable infrastructure in place that they would be far less vulnerable to sudden price increases in fuel.

Opponents say that it’ll raise everyone else’s rates. But by how much? Gainesville expects an average increase of .05%. And, one advantage of having homes which are grid-tied but also standalone is decreased vulnerability to infrastructure damage from earthquakes or other disasters.

So… why aren’t we doing more of that here? PG&E already charges the highest rates in the country, positions itself as a leader in energy conservation, and yet it hasn’t even considered this idea.

It’s relatively easy to let the Sun make hot water for us. Yet, for many contractors, architects and developers, Solar Heated Domestic Water (SHDW) is one “low hanging fruit” that is largely ignored. The hot tickets which thrill us are new technologies like photo-voltaic power or maybe even solar thermal power generation, but solar domestic water heating seems “old fashioned” and is often the last thing that residential designers want to think about when designing a home. For me at least, it reminds me of the 1970’s, Woodstock, hippies, “getting back to the land”, etc.

But the real truth is that in the past 30 years, Solar Water Heating has blossomed and today it is a mainstream sustainable energy efficiency industry. It is time for a second look. Today, changing over to Solar Heated Domestic Water (SHDW) is one of the easiest, and least expensive ways to save energy costs and truly “green” up a design.

So, when your client wants a “SOLAR HOUSE” but gets blown away at the exorbitant cost of Photo-Voltaic (which even after the current “stimulus Package” rebates still costs a fortune, and the un-rebated portion has a 30 year pay-back) you can offer them Solar Heated Domestic Water as an honest solar system which is also inexpensive. Where P-V has a 5-19% efficiency, SHDW has a 50-70% efficiency. When clients start hearing 70% efficiency, they will suddenly get interested.

WHERE TO FIND OUT: There is a great series of Do-It-Yourself (DIY) articles, which architects will find useful in understanding what the general contractor’s solar installer sub is trying to accomplish. Go on line to Home Power Magazine and sign up for a one year E-subscription ($9.95).

Next, you can down load  several articles, which will tell you what you need to know. I especially liked the one on System Sizing and Payback as compared to Photo-Voltaic.

• PV vs Solar Water Heating: Simple Solar Pay Back.
• Sizing Solar Hot Water Systrems
• Solar Simplified Hot Water
• Solar Hot Water: A Primer
• Do-It-Yourself Tips for Solar Water Heat
• Single Tank Solar Water Systems

FINALLY: Look at the TAX CREDIT REBATES allowed for a solar water heating system as compared to any other water heating system.

• ELECTRIC WATER HEATERS: NO TAX CREDIT for conventional electric storage water heaters or electric tankless water.
• HEAT PUMP WATER HEATERS: There is a tax credit for electric heat pump water heaters for 2009 and 2010 for 30% of the cost, up to $1,500. ENERGY STAR qualified electric heat pump water heaters are expected to reach the market in late-2009.
• GAS, OIL & PROPANE WATER HEATERS: There are also tax credits for gas, oil and propane water heaters (30% up to $1,500 in 2009 & 2010).
• SOLAR WATER HEATERS: solar water heaters (30% of the cost, NO MATTER HOW MUCH IT COSTS (no upper limit), through 2016.