Solar Panels on Tracy Sterns home

Tracy Stearns, a principal with 360 Architecture, was familiar with the benefits of solar energy, and wanted to explore ways to leverage solar power in his home office. Solar can be used to create electricity, heat potable water or swimming pools, or heat the air in a room. Tracy decided to take advantage of two of these applications in his home studio office in Linwood, Kansas, and brought in his friends from The Energy Savings Store to install a solar PV and solar water heating system.

The solar PV system consists of eighteen 208W panels by Sharp. The system is tied to the grid, so that in the event that consumption exceeds production, additional electricity can be pulled off the grid. On days when the system produces more energy than needed, the excess capacity flows back onto the grid once the battery backup system is fully charged. The battery backup system can provide up to a week of power to the home and office in the event of a power failure.

The solar water heating system uses an evacuated-tube technology by ThermoMax. This 5kW system heats all the water used in the home, with a backup system available in cases of extended cloudy days or extremely heavy use. While Stearns only uses the system to heat his potable water, a similar system could be used to warm a home with a radiant heating system.

The Kansas City Board of Public Utilities Build Green Energy Efficiency Award at the 2010 Build Green Conference was awarded to our proprietor, Bob Solger, and Ann Brandau-Murguia, Argentine Neighborhood Development Association (ANDA). 

The Energy Savings Store provided design and installation of Solar Hot Water, Solar Air Heating, Solatubes, and Solar Attic Fans for four new affordable homes in the Argentine neighborhood of Kansas City, Kansas.

ANDA secured grants to install the energy efficient systems. The ongoing electrical utility bills will be lower than the surrounding homes. Because these energy efficient homes will cost less to maintain,  it was easier for people to qualify for the home loans. ANDA was pleased with how quickly they were able to sell the homes....  and to bring renewable energy into the neighborhood.

Solar Panels on the Chapman Home

She was thrilled to find Greg Rothers at Rothers Design/Build .  Greg had experience with straw bale construction and had previously partnered with The Energy Savings Store on solar projects.  

Together, we built radiant-heated floors using solar energy and a solar hot water system. The water piped through the concrete floors is heated by 4 Heliodyne solar panel collectors mounted on the south wall of a detached garage.  The pre-heated water is stored in two tanks. Janet also uses it  for normal domestic hot water purposes. 

“We appreciate Greg partnering with us early in the process,” says Bob Solger, Proprietor of The Energy Savings Store (TESS).  “Many clients considering building a green home often come to us first and Greg is one of the builders we recommend because of our collaborative relationship.” 

Jim Kostucik, with Redstone Homes, is another builder assisted by TESS when a client was interested in using thin-film solar panels on a metal roof in Stillwell, KS.  “Involving us early in the design process can avoid problems and delays later on,” says Bob.  “Our engineering team and experience  can help builders wade through the enormous amount of information about wind turbines (windmills) and solar panels.”

This picture shows them standing in front of one of four new energy efficient homes in the Argentine area of Kansas City, Kansas.  Solger’s Lenexa, KS,  based wind energy and solar power company installed solar hot water units, Solatubes for natural light, SolarSheats for space heating, and solar attic fans on each home. Other energy saving features include improved insulation, vapor barriers,  and spray foam around the homes’ rims.

Solar home with Sharp solar PV panels

It's an interesting study to see how home building techniques and materials have evolved over time, and how new ideas that were once radical have become common.  Drywall, for example, quickly replaced lath and plaster as the standard for interior walls, and radiators were replaced by forced air systems.  As we began closing the windows in the summer to keep our homes cooled by our central air conditioners, insulation and thermal windows came about.   All-electric homes were all the rage until electric rates cooled owners' interest.

Today we find ourselves on the verge of a new set of building standards.  With concerns about climate change and declining fossil fuel resources, many homeowners are looking to harvest the clean, renewable energy of the sun.  In the 1970s, the US led the world in the development of solar photovoltaic (PV) technology, where sunlight is converted to electricity.  As energy prices dropped in the '80s, our enthusiasm waned, since the payback was no longer as attractive.  The recent increase in worldwide demand has brought PV prices down, and the uncapped financial incentives have made the payback on solar better than ever.

Energy Efficiency

At The Energy Savings Store, we always encourage solar and wind prospects to consider energy efficiency first.  As much as half of the energy we use in our homes is wasted, either by inefficient appliances, inadequate insulation or ineffective stewardship.  Energy Star appliances are now readily available, and the added cost is quickly offset by the reduced energy requirements. 

It's critical that the "building envelope" - or exterior shell exposed to the elements - be tightly insulated.  There are a variety of methods to achieve this, including 2x6" frames, high-efficiency foam insulation, and insulated concrete form (ICF) construction.  The latter uses stay-in-place concrete forms made of hard foam that are assembled much like Lego blocks.  The concrete is reinforced with steel bars, making this shell extremely durable while minimizing thermal transfer.

For larger homes, ground-source heat pumps are a great way to use the constant temperature of the earth to heat and cool the home.  Geothermal systems are relatively expensive but, coupled with a super-insulated building exterior, dramatically reduce expensive heating and cooling costs.

Adding Solar

The key requirement for solar is southern exposure.  If your existing home has a south-facing roof (or within 30 degrees of due south), you can likely incorporate solar onto your roof.  If you're building a new home, be sure to consider this important requirement!  The slope of the roof should be somewhere between 25 and 40 degrees, with 38 degrees being optimal for this latitude.  Conventional panels can be angled on racks to adjust or optimize the pitch, but for new roofs it's best to design the southern facing slope accordingly.

While conventional solar panels are most commonly used, there are a variety of new options to incorporate solar into the building design.  A number of solar roofing tiles, including SunSlate and SolarSave, are used alongside metal or asphalt shingles, and can be installed on the front of a home without detracting from the appearance of the home.  Other metal roofs can take advantage of solar PV laminate systems like Uni-Solar.   Even if you're not ready to invest in solar, you can pre-wire your new home to minimize costs

Micro-inverters enable you to start out with a small number of conventional panels and add to the system as your budget allows.  Inverters are used to convert the DC power produced by the solar collector to AC power used in your home.  Rather than using a single inverter that is sized for the entire system, micro-inverters are installed onto each panel, converting the DC to AC right at the source.  Battery backup systems are also available to keep your essential appliances powered during an outage.

Water heating accounts for 20-40% of typical home's energy requirements, and solar water heating systems have proven to be a very cost-effective way to harness the sun's energy.  While these can be used in conjunction with solar PV, they are an excellent alternative if you have limited space.  The VELUX solar water heating system is an attractive complement to the traditional skylights that they're renowned for.  Solar air heating systems, such as SolarSheat, are also available.

There are many other ways to harness the sun's energy and protect your home from unwanted heat in the summer.  Natural daylight reduces lighting requirements, using windows, skylights and solar lights like Sun Tunnel or Solar Tube.  Strategically-placed shade trees and passive solar design can capture the warmth of the sun in the winter, but shade the home in the summer.  It is essential that you consider the sun, which is ultimately the source of all of our energy, when you build your next home.

For more details on these and other strategies for incorporating solar into your home, see the online version of the May 2009 issue of Solar Today on page 32.  For a fun look at what the futurists have imagined, check out The Green House of the Future.

Solar and wind systems provide significant returns when rising rates are taken into consideration

While many people love the idea of using clean, renewable energy from the sun and wind, they find the investment significant enough to think twice about the purchase.  The installed cost of a mid-sized wind turbine or solar photovoltaic (PV) system is about $20,000, and does not provide the same visibility or utility as a new kitchen.  However, while a new kitchen provides a great new space to cook and congregate, and will bring back nearly every dollar invested if the house is sold soon after, it loses its value over time. The renewable energy systems, on the other hand, become cash cows that actually increase in value as energy prices rise.

A simple payback will show you that the money you initially invest in the system is offset by the value of the energy produced over time.  This becomes a little tricky, because we know that energy prices will rise, but can't predict actual rate increases without a crystal ball. Historical rate increases over the past 10 years or so have been about 4.5% per year, although this varies widely across the country.  Over the next 20 years, we expect rates to increase 6-9 percent per year, given supply pressures on fossil fuels and imminent carbon taxes.  Just like the miracle of compounding interest, the compounding effect of rising electric rates results in the system returning 1.5 to 3 times its initial cost.

While the life expectancy of a solar PV system is generally 40-50 years, we typically look at 30-years of operation to calculate expected returns on both solar and wind.  (Wind turbines require maintenance, and the turbine itself can be replaced with a more efficient unit at a fraction of the cost of the original installation.)  The chart below shows the value of the electricity produced over a thirty year period.

Estimated value of power produced by 2.4kW solar array*

*Assumes $0.09 p/kWh with 7.5% annual inflation on electric rates for 2.4kW solar PV system

Our February newsletter summarized the highlights of the American Recovery and Reinvestment Act of 2009.  With this legislation, the 30 percent tax credit for commercial and residential renewable energy investments was extended through 2016, and the $2000 cap was eliminated.  This tax credit effectively creates a 30% discount on all solar and wind installations, reducing your investment accordingly.  (For commercial projects, you can apply for a grant up front in lieu of the tax credit.)  Additionally, the state of Illinois offers a 30% state tax credit for solar, and is considering extending this to wind power also.  Historic tax credits of up to 25% are also widely available, depending on the area.

Finally, the recently passed Proposition C in Missouri will require that utilities produce 15% of their total demand with renewable energy.  The Public Service Commission is currently finalizing the rules, but at this point it is agreed that the investor-owned utilities (including AmerenUE, KCP&L, and possibly Empire)will  provide a taxable rebate of $2 per installed watt (up to 25kW).  In addition, they may buy Renewable Energy Credits (RECs) based on the amount of electricity produced by your system.  It is anticipated that the value of this taxable income would be similar to the rebate ($1.80-$2.20 p/watt) but this will likely be paid out over time as the energy is produced.

So the 2.4kW system described above might look like this:

* Actual figures are contingent upon the finalization of rules. Prop C rebates will go into effect January 1, 2010.

Using the assumptions above, the system will have produced a total of $4,400 in electricity in its 12th year of service, thus paying for itself.  However, in the 18 years after it's paid off, it will produce an additional $23,500 worth of power, yielding an internal rate of return of 11.7%.  Businesses will achieve even greater returns by depreciating equipment.

In spite of this return on the investment, for some people, this long of a payback is troubling because they may not intend to live in the house that long. The truth is, that, just like the kitchen, an investment in a solar or wind energy system will add to the value of the home, with a higher return than a kitchen or bathroom renovation.

While the return on your investment may not match some of the historic returns of the market, you can be sure that it will be much less volatile.  Probably more important than anything, you must place intrinsic value on producing your own clean, renewable energy.   As one of our customers put it, "No one ever expects to catch enough fish to pay for their new bass boat!"

Farm house has solar PV on the upper roof, and solar thermal (for water heating) on the lower roof

The Green Dirt Farm, located just north of Kansas City in Weston, Missouri, is a small community-based farm dedicated to producing healthy food in a sustainable environment.  The entire farm complex was designed to be a net-zero energy farmstead, producing 100 percent of the energy for the operation using a combination of solar and wind.  Chris DeVolder, the home's architect, calls it "the greenest house in the Midwest, possibly in the country."

From the ground up, this farm was built with sustainability in mind.  Most of the materials used in the construction were salvaged from local demolished buildings (including a reclaimed church railing as the rail in the loft of the barn!)  The designers largely limited themselves to these materials, and any new materials used in the home were considered environmentally-friendly.   It was a true collaboration between owner, architect and builder.

The house uses only 25 percent of energy required in a typical home of its size, and uses no fossil fuels to heat or cool. This is accomplished in part using a passive solar design that shades the home from the sun in the summer but absorbs the solar heat in the winter.  Complementing this is a geothermal heat pump, with radiant heating system in the floor.  In addition, the home uses a small word-burning masonry heater as a back-up heating source, and doubles as a Swedish oven for bread-baking.

2.4kW Skystream wind turbine provides half of the power used on the farm

The Energy Savings Store was selected to design, engineer and install the renewable energy systems used on the Green Dirt Farm in 2005.  The electricity used in the home and barn comes from a 2.4kW Skystream wind turbine, perched atop a 70' tower.  Complementing this is a 2.4kW Uni-Solar PV laminate system on the home's metal roof.  These two energy sources, coupled with the efficiencies designed into the home, enable the owners to live and operate their farm with a "net-zero" energy requirement.  The home is actually connected to the utility grid, so that in the event that more power is consumed than produced at any given point in time, the system can draw additional power from the grid.  On the other hand, when more power is being produced than consumed, the utility meter spins backward, pushing the excess electricity out onto the grid.  The home also contains a battery backup system, so that in the event of power outages, they can run safely on their own backup power.

Solar thermal energy is also used to heat the potable water in the home.  A 5kW SunEarth glazed panel solar water heating system was installed by The Energy Savings Store to heat water in a 120 gallon tank, enabling the owners to use very little energy to heat water used both personally and in the farm operations.  Solar water heating systems typically reduce energy use by up to 80 percent.

Finally, solar energy is used for space heating in another small building on the farm.  Several years after the home was built, a small cabin was built on the property to house the farm's manager, and the owners came back to The Energy Savings Store for guidance.   The house was designed with a south-facing wall, on which a 1.5kW SolarSheat solar air heating system was installed.  This glazed panel system is self-powered, using a small photovoltaic (PV) panel to power a fan that draws air from the bottom of a room up through a heated-duct and back out the top into the room.  The panels are ideal for a south-facing wall on a great room, but can be installed on a south-facing roof as well.

The Green Dirt Farm owner's commitment to healthy, organic food and a sustainable living gives us a great model for home development.  Everyone involved in the project shared and realized the same vision, and now the path has been cleared for others who wish to create a sustainable, environmentally friendly living space.