Articles
Solar powered homes are stimulating the California real estate market
Energy October 23, 2008, 5:00PM EST
Will Demand for Solar Homes Pick Up?
Builders find the savings from cheap power is making solar homes more attractive
http://images.businessweek.com/story/08/600/1023_mz_solar.jpg
By Adam Aston
As global financial markets melted down in October, Congress handed a gift to America's green energy industry: It renewed and broadened a set of tax credits for wind and solar power, geothermal, tidal energy, and more. The move did little to prop up eco-energy stocks, which have followed oil prices down. But the news did send a positive jolt to one of the economy's darkest sectors: homebuilding. Or, more specifically, solar-powered homes. Consumers recognize that green homes "save money month in, month out," says Rick Andreen, president of Shea Homes Active Lifestyles Communities in Scottsdale, Ariz.
Most of the sweeteners Congress conjured up will go to big projects such as wind farms. But aspiring buyers of green homes will benefit, too. The revised 30% one-time investment credit for solar means that a buyer who installs a typical $25,000 solar panel system on his roof will get $7,500 in income tax credits, up from $2,000 under the old standard. How long that investment takes to pay off will depend on local rules and utility rates. In markets with the most costly power, such as California, Connecticut, and New Jersey, the pretax compound rate of return on a typical home solar system will be better than 15% per year, says Andy Black, chief executive of OnGrid Solar, an industry research firm.
The fresh credits may mark a turning point for solar-powered homes. During the housing boom, when mortgages and energy were both cheap, green power was not a hot option; typical home buyers preferred granite countertops to solar panels. But even before the subprime crash, builders began to see rising interest in sun-powered dwellings. Ryness Co., which compiles sales data for homebuilders, found in a recent survey that homes with solar systems were outselling others by as much as 2:1 in 13 California communities.
Today there are about 40,000 solar homes in the U.S., but that number is set to spike. Shea is adding solar to communities planned for Arizona, California, Florida, and Washington State. And, responding to a shift in buyers' attitudes, big builders such as Centex (CTX), Lennar (LEN), Pulte Homes (PHM), and Woodside Homes are following suit. Consider Whitney Ranch, a development south of Sacramento. Sales there softened in the housing downturn, says Kathryn Boyce, an executive at Hanley Wood Market Intelligence. But when Standard Pacific Homes (SPF) put solar systems on a group of new models in the development, they sold out. The builder then decided to install panels on all 304 of the homes.
The appeal of solar homes could grow as the economic outlook worsens. The more utility bills cut into household reserves, "the more consumers recognize the value of efficiency," says Robert W. Hammon, principal of ConSol, a green building consulting firm. And there's growing consumer awareness that solar homes appreciate faster than ordinary dwellings. They also resell for a premium of up to 5%.
According to Ben Hoen, a researcher at Lawrence Berkeley National Laboratory who studies the effects of eco-features on real estate values, more homeowners now see solar panels as a long-term asset. Mortgage lenders, however, have been slow to make that link. The loan processes at Fannie Mae (FNM) and Freddie Mac (FRE) don't give special treatment to buyers who make improvements to lower utility bills, says Shea's Andreen. Builders wish lenders would start to take stock of eco-features. "Solar panels free up household cash flow," Andreen says. "Lenders should recognize that."
Aston is Energy & Environment editor for BusinessWeek in New York .
Wind power an alternative energy source for the future
It's
unknown why it took a full 15 months for a blue-ribbon panel to
recommend a limited test project to gauge the effects of windmills off
the New Jersey coast. The idea seemed like a no-brainer months ago
after the panel determined there wasn't enough data to draw conclusions
about offshore wind farms. But the panel finally recommended creating a
pilot offshore wind farm with up to 80 turbines. The state should waste
no more time getting this sensible plan up and running.
And
here's an idea - consider siting it off the coast of Atlantic City,
N.J., where residents and visitors already have seen the power and the
beauty of the wind turbines at the Atlantic County Utilities
Authority's wind farm. Talk about hurting tourism is misplaced.
Windmills off the coast might even be a tourism draw. Atlantic City's
Boardwalk long was a place where visitors could view the new, the odd
and the cutting edge of technology.
But beyond that,
wind power is necessary. The New Jersey Board of Public Utilities has
set a laudable requirement that 20 percent of the state's power be
generated by renewable, clean energy sources by 2020. The state
probably won't get there without wind power. And it's unreasonable to
expect that wind generation to come from someone else's back yard -
Pennsylvania, for example.
Wind power is a safer and
increasingly cheaper alternative energy source for the future. Believe
the forces of the marketplace - which are right more often than
editorial writers. The company that constructed the windmills at the
ACUA, Community Energy Inc., is selling out to a big Spanish
wind-energy company called Iberdroia. Why? Because, company officials
say, the market for wind energy is so hot right now that a small
company has difficulty getting equipment; turbines are backordered for
years.
With the sharp increases in oil and
gas prices, wind energy is extremely competitive - and environmentally
preferable. It doesn't pollute, doesn't contribute to global warming
and doesn't force the nation to rely on unstable, hostile oil-producing
countries.
What's not to like? For
starters, the narrow focus of some tourism and coastal officials. The
American Littoral Society, which was a member of New Jersey's Blue
Ribbon Panel on Development of Wind Turbines in Coastal Waters,
dissented from the group's recommendation, contending wind energy
wouldn't generate enough power to offset drawbacks. Some local
officials in shore towns contend it will hurt property values and
disrupt fishing.
Let's do the pilot program and find out. No more delays.
Press of Atlantic City, N.J.
Wind, water and sun are the best types of renewable energy, says Stanford professor
December 22nd, 2008 ·
After so many disappointments with
biofuels,
it comes no surprise that a new independent study has concluded that
“the best ways to improve energy security, mitigate global warming and
reduce the number of deaths caused by air pollution are blowing in the
wind and rippling in the water, not growing on prairies or glowing
inside
nuclear power plants”. The author is
Mark Z. Jacobson,
a professor of civil and environmental engineering at Stanford. Mr.
Jacobson also warns about so-called “clean coal”: it “is not clean at
all”, he says.
Jacobson has conducted the first quantitative, scientific evaluation
of the proposed, major, energy-related solutions by assessing not only
their potential for delivering energy for electricity and vehicles, but
also their impacts on global warming, human health, energy security,
water supply, space requirements, wildlife, water pollution,
reliability and sustainability. His findings indicate that the options
that are getting the most attention are between 25 to 1,000 times more
polluting than the best available options. The paper with his findings
will be published in the next issue of Energy and Environmental Science
but is available online now. Jacobson is also director of the
Atmosphere/Energy Program at Stanford.
“The energy alternatives that are good are not the ones that people
have been talking about the most. And some options that have been
proposed are just downright awful,” Jacobson said. “Ethanol-based
biofuels will
actually cause more harm to human health, wildlife, water supply and
land use than current fossil fuels.” He added that ethanol may also
emit more global-warming pollutants than fossil fuels, according to the
latest scientific studies.
The raw energy sources that Jacobson found to be the most promising
are, in order, wind, concentrated solar (the use of mirrors to heat a
fluid), geothermal, tidal, solar photovoltaics (rooftop solar panels),
wave and hydroelectric. He recommends against nuclear, coal with carbon
capture and sequestration, corn ethanol and cellulosic ethanol, which
is made of prairie grass. In fact, he found cellulosic ethanol was
worse than corn ethanol because it results in more air pollution,
requires more land to produce and causes more damage to wildlife.
And one for all the techies out there............
Taken from the Union of Concerned Scientists Web Site
How Solar Energy Works
Solar energy—power from the sun—is free and inexhaustible. This
vast, clean energy resource represents a viable alternative to the
fossil fuels that currently pollute our air and water, threaten our
public health, and contribute to global warming. Failing to take
advantage of such a widely available and low-impact resource would be a
grave injustice to our children and all future generations.
In the broadest sense, solar energy supports all life on Earth and
is the basis for almost every form of energy we use. The sun makes
plants grow, which can be burned as "biomass" fuel or, if left to rot
in swamps and compressed underground for millions of years, in the form
of coal and oil. Heat from the sun causes temperature differences
between areas, producing wind that can power turbines. Water evaporates
because of the sun, falls on high elevations, and rushes down to the
sea, spinning hydroelectric turbines as it passes. But solar energy
usually refers to ways the sun's energy can be used to directly
generate heat, lighting, and electricity.
The
amount of energy from the sun that falls on Earth's surface is
enormous. All the energy stored in Earth's reserves of coal, oil, and
natural gas is matched by the energy from just 20 days of sunshine.
Outside Earth's atmosphere, the sun's energy contains about 1,300 watts
per square meter. About one-third of this light is reflected back into
space, and some is absorbed by the atmosphere (in part causing winds to
blow).
By the time it reaches Earth's surface, the energy in sunlight has
fallen to about 1,000 watts per square meter at noon on a cloudless
day. Averaged over the entire surface of the planet, 24 hours per day
for a year, each square meter collects the approximate energy
equivalent of almost a barrel of oil each year, or 4.2 kilowatt-hours
of energy every day.
This
figure varies by location and weather patterns. Deserts, with very dry
air and little cloud cover, receive the most sun—more than six
kilowatt-hours per day per square meter. Northern climes, such as that
of Boston, get closer to 3.6 kilowatt-hours. Sunlight varies by season
as well, with some areas receiving very little sunshine in the winter.
Seattle in December, for example, gets only about 0.7 kilowatt-hours
per day.
These figures represent the maximum available solar energy that can
be captured and used, but solar collectors capture only a portion of
this, depending on their efficiency. For example, a one square meter
solar electric panel with an efficiency of 15 percent would produce
about one kilowatt-hour of electricity per day in Arizona.
One
simple, obvious use of sunlight is to light our buildings. If properly
designed, buildings can capture the sun's heat in the winter and
minimize it in the summer, while using daylight year-round. Buildings
designed in such a way are utilizing passive solar energy—a resource
that can be tapped without mechanical means to help heat, cool, or
light a building. South-facing windows, skylights, awnings, and shade
trees are all techniques for exploiting passive solar energy. Buildings
constructed with the sun in mind can be comfortable and beautiful
places to live and work.
Residential and commercial buildings account for more than one-third of U.S. energy use.
[1]
Solar design, better insulation, and more efficient appliances could
reduce this demand by 60 to 80 percent. There are several hundred
thousand passive solar homes in the United States, but there should be
many more. Simple design features such as properly orienting a house
toward the south, putting most windows on the south side of the
building, and taking advantage of cooling breezes in the summer are
inexpensive yet improve the comfort and efficiency of a home.
Besides
using design features to maximize their use of the sun, some buildings
have systems that actively gather and store solar energy. Solar
collectors, for example, sit on the rooftops of buildings to collect
solar energy for space heating, water heating, and space cooling. Most
are large, flat boxes painted black on the inside and covered with
glass. In the most common design, pipes in the box carry liquids that
transfer the heat from the box into the building. This heated
liquid—usually a water-alcohol mixture to prevent freezing—is used to
heat water in a tank or is passed through radiators that heat the air.
Oddly enough, solar heat can also power a cooling system. In desiccant evaporators,
heat from a solar collector is used to pull moisture out of the air.
When the air becomes drier, it also becomes cooler. The hot moist air
is separated from the cooler air and vented to the outside. Another
approach is an absorption chiller. Solar energy is
used to heat a refrigerant under pressure; when the pressure is
released, it expands, cooling the air around it. This is how
conventional refrigerators and air conditioners work, and it's a
particularly efficient approach for home or office cooling since
buildings need cooling during the hottest part of the day. These
systems are currently at work in humid southeastern climates such as
Florida.
Solar collectors were quite popular in the early 1980s, in the
aftermath of the energy crisis. Federal tax credits for residential
solar collectors also helped. In 1984, for example, 16 million square
feet of collectors were sold in the United States, but when fossil fuel
prices dropped and tax credits expired in the mid-1980s, demand for
solar collectors plummeted. By 1987, sales were down to only four
million square feet. Most of the more than one million solar collectors
sold in the 1980s were used for heating hot tubs and swimming pools.
Today, about 1.5 million U.S. homes and businesses use solar water heaters—still less than one percent nationwide.
[2]
In other countries, solar collectors are much more common; Israel
requires all new homes and apartments to use solar water heating, and
92 percent of the existing homes in Cyprus already have solar water
heaters.
[3]
But the number of Americans choosing solar hot water could rise
dramatically in the next few years. With natural gas prices at
historically high levels, solar water and space heaters have become
much more economic.
According to the U.S. Department of Energy, water heating accounts for about 15 percent of the average household's energy use.
[4]
As natural gas and electricity prices continue to rise, the costs of
maintaining a constant hot water supply will increase as well. Homes
and businesses that heat their water through solar collectors could end
up saving as much as $250 to $500 per year depending on the type of
system being replaced.
For more information about solar water heating for homes and swimming pools,
click here.
By
using mirrors and lenses to concentrate the rays of the sun, solar
thermal systems can produce very high temperatures—as high as 3,000
degrees Celsius. This intense heat can be used in industrial
applications or to produce electricity.
Solar concentrators come in three main designs: parabolic troughs, parabolic dishes, and central receivers. The most common is parabolic troughs—long,
curved mirrors that concentrate sunlight on a liquid inside a tube that
runs parallel to the mirror. The liquid, at about 300 degrees Celsius,
runs to a central collector, where it produces steam that drives an
electric turbine.
Parabolic trough concentrators. Source: NREL
Parabolic dish concentrators are similar to trough
concentrators, but focus the sunlight on a single point. Dishes can
produce much higher temperatures, and so, in principle, should produce
electricity more efficiently. But because they are more complicated,
they have not succeeded outside of demonstration projects.
A more promising variation uses a stirling engine to produce power.
Unlike a car's internal combustion engine, in which gasoline exploding
inside the engine produces heat that causes the air inside the engine
to expand and push out on the pistons, a stirling engine produces heat
by way of mirrors that reflect sunlight on the outside of the engine.
These dish-stirling generators produce about 30 kilowatts of power, and
can be used to replace diesel generators in remote locations.
The third type of concentrator system is a
central receiver.
One such plant in California features a "power tower" design in which a
17-acre field of mirrors concentrates sunlight on the top of an
80-meter tower. The intense heat boils water, producing steam that
drives a 10-megawatt generator at the base of the tower. The first
version of this facility, Solar One, operated from 1982 to 1988 but had
a number of problems. Reconfigured as Solar Two during the early to
mid-1990s, the facility is successfully demonstrating the ability to
collect and store solar energy efficiently.
[5] Solar Two's success has opened the door for further development of this technology.
To date, the parabolic trough has had the greatest commercial
success of the three solar concentrator designs, in large part due to
the nine Solar Electric Generating Stations (SEGS) built in
California's Mojave Desert from 1985 to 1991. Ranging from 14 to 80
megawatts and with a total capacity of 354 megawatts, each of these
plants is still operating effectively.
[6]As a result of state and federal policies and incentives, more
commercial-scale solar concentrator projects are under development.
Modified versions of the SEGS plants are being constructed in Arizona
(one megawatt) and Nevada (65 megawatts). In addition, Stirling Energy
Systems received approval from the California Public Utility Commission
in October 2005 to build a 500-megawatt facility (with the option to
add 350 megawatts) in the Mojave Desert using the parabolic dish
design. Beginning in January 2009, the plant will supply power to
Southern California Edison under a 20-year contract that will help the
utility meet its requirements under the state's renewable electricity
standard.
[7]
In
1839, French scientist Edmund Becquerel discovered that certain
materials would give off a spark of electricity when struck with
sunlight. This photoelectric effect was used in primitive solar cells
made of selenium in the late 1800s. In the 1950s, scientists at Bell
Labs revisited the technology and, using silicon, produced solar cells
that could convert four percent of the energy in sunlight directly to
electricity. Within a few years, these photovoltaic (PV) cells were
powering spaceships and satellites.
The most important components of a PV cell are two layers of
semiconductor material generally composed of silicon crystals. On its
own, crystallized silicon is not a very good conductor of electricity,
but when impurities are intentionally added—a process called doping—the
stage is set for creating an electric current. The bottom layer of the
PV cell is usually doped with boron, which bonds with the silicon to
facilitate a positive charge (P). The top layer is doped with
phosphorus, which bonds with the silicon to facilitate a negative
charge (N).
The surface between the resulting "p-type" and "n-type"
semiconductors is called the P-N junction (see the diagram below).
Electron movement at this surface produces an electric field that only
allows electrons to flow from the p-type layer to the n-type layer.
When sunlight enters the cell, its energy knocks electrons loose in
both layers. Because of the opposite charges of the layers, the
electrons want to flow from the n-type layer to the p-type layer, but
the electric field at the P-N junction prevents this from happening.
The presence of an external circuit, however, provides the necessary
path for electrons in the n-type layer to travel to the p-type layer.
Extremely thin wires running along the top of the n-type layer provide
this external circuit, and the electrons flowing through this circuit
provide the cell's owner with a supply of electricity.
Most
PV systems consist of individual square cells averaging about four
inches on a side. Alone, each cell generates very little power (less
than two watts), so they are often grouped together as modules. Modules
can then be grouped into larger panels encased in glass or plastic to
provide protection from the weather, and these panels, in turn, are
either used as separate units or grouped into even larger arrays.
The three basic types of solar cells made from silicon are single-crystal, polycrystalline, and amorphous.
- Single-crystal cells are made in long cylinders
and sliced into round or hexagonal wafers. While this process is
energy-intensive and wasteful of materials, it produces the
highest-efficiency cells—as high as 25 percent in some laboratory
tests. Because these high-efficiency cells are more expensive, they are
sometimes used in combination with concentrators such as mirrors or
lenses. Concentrating systems can boost efficiency to almost 30
percent. Single-crystal accounts for 29 percent of the global market
for PV.[8]
- Polycrystalline cells are made of molten
silicon cast into ingots or drawn into sheets, then sliced into
squares. While production costs are lower, the efficiency of the cells
is lower too—around 15 percent. Because the cells are square, they can
be packed more closely together. Polycrystalline cells make up 62
percent of the global PV market.[9]
- Amorphoussilicon(a-Si)
is a radically different approach. Silicon is essentially sprayed onto
a glass or metal surface in thin films, making the whole module in one
step. This approach is by far the least expensive, but it results in
very low efficiencies—only about five percent.[10]
A
number of exotic materials other than silicon are under development,
such as gallium arsenide (Ga-As), copper-indium-diselenide (CuInSe2),
and cadmium-telluride (CdTe). These materials offer higher efficiencies
and other interesting properties, including the ability to manufacture
amorphous cells that are sensitive to different parts of the light
spectrum. By stacking cells into multiple layers, they can capture more
of the available light. Although a-Si accounts for only five percent of
the global market, it appears to be the most promising for future cost
reductions and growth potential.
In the 1970s, a serious effort began to produce PV panels that could
provide cheaper solar power. Experimenting with new materials and
production techniques, solar manufacturers cut costs for solar cells
rapidly, as the following graph shows.
Source: NREL
One approach to lowering the cost of solar electric power is to
increase the efficiency of cells, producing more power per dollar. The
opposite approach is to decrease production costs, using fewer dollars
to produce the same amount of power. A third approach is lowering the
costs of the rest of the system. For example, building-integrated PV
(BIPV) integrates solar panels into a building's structure and earns
the developer a credit for reduced construction costs.
Innovative processes and designs are continually reaching the market
and helping drive down costs, including string ribbon cell production,
photovoltaic roof tiles, and windows with a translucent film of a-Si.
Economies of scale from a booming global PV market are also helping to
reduce costs.
Historically, most PV panels have been used for off-grid purposes,
powering homes in remote locations, cellular phone transmitters, road
signs, water pumps, and millions of solar watches and calculators.
Developing nations see PV as a way to avoid building long and expensive
power lines to remote areas. And every year, experimental solar-powered
cars race across Australia and North America in heated competitions.
More recently, thanks to lower costs, strong incentives, and net
metering policies, the PV industry has placed more focus on home,
business, and utility-scale systems that are attached to the power
grid. In some locations, it is less expensive for utilities to install
solar panels than to upgrade the transmission and distribution system
to meet new electricity demand. In 2005, for the first time ever, the
installation of PV systems connected to the electric grid outpaced
off-grid PV systems in the United States.
[11] As the PV market continues to expand, the trend toward grid-connected applications will continue.
This distributed-generation approach provides a new model for the
utilities of the future. Small generators, spread throughout a city and
controlled by computers, could replace the large coal and nuclear
plants that dominate the landscape now.
Solar
energy technologies are poised for significant growth in the 21st
century. More and more architects and contractors are recognizing the
value of passive solar and learning how to effectively incorporate it
into building designs. Solar hot water systems can compete economically
with conventional systems in some areas. And as the cost of solar PV
continues to decline, these systems will penetrate increasingly larger
markets. In fact, the solar PV industry aims to provide half of all new
U.S. electricity generation by 2025.[12] Aggressive financial incentives in Germany and Japan have made these
countries global leaders in solar deployment for years. But the United
States is catching up thanks particularly to strong state-level policy
support. The rolling blackouts and soaring energy prices experienced by
California in 2000 and 2001 have motivated its leaders to create new
incentives for solar and other renewable energy technologies. In
January 2006, the California Public Utility Commission approved the
California Solar Initiative, which dedicates $3.2 billion over 11 years
to develop 3,000 megawatts of new solar electricity, equal to placing
PV systems on a million rooftops.
Other states are following suit. Arizona, Colorado, New Jersey, and
Pennsylvania have specific requirements for solar energy as part of
their renewable electricity standards. Many more states offer rebates,
production incentives, and tax incentives, as well as loan and grant
programs. Even the federal government is offering a 30 percent tax
credit (up to $2,000) for the purchase and installation of residential
PV systems and solar water heaters.
As the solar industry continues to expand, there will be occasional
bumps in the road. For example, demand for manufacturing-quality
silicon from the solar energy and semiconductor industries has led to
shortages that have temporarily driven up PV costs.
[13]
In addition, some utilities continue to put up roadblocks for
grid-connected PV systems. But these problems will be overcome, and
solar energy will play an increasingly integral role in ending our
national dependence on fossil fuels, combating the threat of global
warming, and securing a future based on clean and sustainable energy.
