Renewable energy: The very words conjure up images of
rooftop solar panels and wind farms.
But if a new Design News survey is to be believed,
"renewable energy" is beginning to have slightly different meaning for many
engineers. For them, it's a matter of putting energy directly into their
products, rather than into the electrical grid. For them, renewable energy is a
source of power for a sensor in a farmer's field or atop a suspension bridge.
Or for a light switch, cell phone, thermostat or computer keyboard.
The trick is to draw wee amounts of current from tiny solar
arrays, then send the current to products that use power-stingy components.
Sounds like a bit of a stretch to many, but not to all. When
asked, "Do you believe you will ever be able to replace batteries or ac sources
in any of your products with renewable sources of energy?," 62.9 percent of
respondents to a Design News
renewable energy survey answered yes.
Moreover, experts aren't the least bit surprised by that
response. "What we're seeing here is very similar to what we saw in the
telecommunications industry about 30 years ago," says Chris Link, business
development manager for ultra-low-power and energy harvesting devices at Texas
Instruments. "Energy generation will become more personal in applications where
it makes sense. In the future, we're going to see more devices operating
autonomously." Click here to see all survey results
readers who responded to our renewable energy survey apparently
agree with Link. When asked if they foresee incorporation of solar cells in any
upcoming products, 57 percent said yes. Moreover, 12 percent of the respondents
said that they are already working on such products and 45 percent said they
plan to do it in the future.
ked for more details, respondents said they are using solar
energy harvesting technology on a wide array of products, including consumer
electronics, home automation systems, cell phones, water heaters, remote
sensors, e-readers, vehicle electronics, flow control valves, aircraft engines,
communications systems, defense products, lighting, robots, avionics, thermostats, calculators and alarms.
Readers' applications for energy harvesting varied dramatically.
"Our company is developing and manufacturing data acquisition equipment for
wildlife tracking," wrote one member on Design News'
Design Engineering" forum on LinkedIn. "One of our main challenges is the power
supply (for) longevity of field deployment. Environmental energy harvesting is
the future as far as I know ..."
In November, while we gathered information for this story,
Logitech International, a maker of peripheral devices for the computer
industry, reinforced our readers' confidence in solar energy harvesting. It
introduced the Logitech K750 Wireless Solar Keyboard, which is powered by
indoor light. The product, which costs $80, stays charged for at least three
months in total darkness.
But while Logitech's keyboard is a high-profile application of
solar energy harvesting, it's hardly alone. Design News
that St. Joseph Elementary School in Lacolle, Quebec endowed its school rooms
with temperature controllers that draw power from photovoltaic cells.
Similarly, Leggat McCall Properties in Boston, MA has installed light-powered
wireless occupancy sensors in its buildings as a means of reducing energy
consumption. And numerous solar panel installations now use their own current
to power MEMS sensors that track sunlight and re-position the panels for
maximum exposure to the sun.
Not a Slam Dunk
To be sure, a number of Design News
weren't convinced that they would ever use renewable energy harvesting systems.
"I can't see oscilloscopes, for example, relying on anything but
ac or battery power," wrote Jon Titus (who is also a Design News
contributing editor) on the LinkedIn forum. "Energy harvesting devices might
have a place, but so far, no one has a â€˜silver bullet' device or application. I
recently talked with people at six energy harvesting-related companies, and
they all told me that, so far, every application needs something different."
"If you or anyone else
does come up with some wonderful device that harvests power in quantities large
enough to be useful for a given project, there is still the need for the device
to be manufactured," added reader William Ketel in a typical response. "That
may not be a simple task."
Readers told Design News
that they need microcontrollers and other components to use less power, but
they were more adamant about the need for solar devices that provide more current. Twenty-eight percent of readers said
that solar cells need to supply more current, while just 8 percent thought it
was more important for electronic components to use less.
"Both sides allow for substantial innovation," says Link of Texas
Instruments. "An autonomous device is all about creating the right balance."
Still, Link says that there's greater need for innovation on the
solar cell side. "Electronic devices are clearly on a path of reducing the
power that they need and we will continue down that path," he says. "But for
solar panels, it's different. Solar panels have been fairly stagnant in their
improvement over time."
Applications in Waiting
Because much of the energy harvesting technology is still
new, many readers were unfamiliar with it. Battery-on-a-chip technology, for
example, was unfamiliar to about one-third of the respondents. The technology -
a thin film battery on a silicon substrate that allows applications to store
scavenged energy - could eventually jump-start more autonomous products as it
evolves. Of the 62 percent of respondents who were familiar with it, about
two-thirds said they foresee using it.
Clearly the biggest user of solar energy harvesting technology is
the industrial sector - at least for now. About 45 percent of those who
displayed interest in such technology said they plan to apply it in industrial
controls and automation. Other potential users (in order of interest) were from
consumer electronics, defense, medical, automotive, aerospace and computer
"The market is still looking
for the niche that will allow it to step over that very scary chasm between the
early adopters and the early majority," Link says.
Link believes that the consumer electronics industry will
eventually overtake the industrial sector in its use of renewable energy
"It will probably take (the
consumer electronics industry) longer to get going," he says. "But at some
point, a start-up will come up with a consumer application, and it will make
the world stand up and say, 'Wow.'"
to see the complete results of the survey used to develop this article.