Green Blog
A better web. Better for the environment.
Should you spring clean your solar panels?
7/31/09
Ever since we
assembled a 1.6 MW solar panel installation
at our
headquarters
in Mountain View in 2007, we've been wondering, "Does cleaning the solar panels make them more effective?" We thought it might, but we needed to be sure. So we analyzed the mountains of data that we collect about the energy that these panels produce — after rain, after cleaning and at different times of the year.
We have two different sets of solar panels on our campus — completely flat ones installed on carports, and
rooftop ones
that are tilted.
Since the carport solar panels have no tilt, rain doesn't do a good job of rinsing off the dirt they collect. (Also, our carports are situated across from a sand field, which doesn't help the situation.) We cleaned these panels for the first time after they had been in operation for 15 months, and their energy output doubled overnight. When we cleaned them again eight months later, their output instantly increased by 36 percent. In fact, we found that cleaning these panels is the #1 way to maximize the energy they produce. As a result, we've added the carport solar panels to our spring cleaning checklist.
The rooftop solar panels are a different story. Our data indicates that rain does a sufficient job of cleaning the tilted solar panels. Some dirt does accumulate in the corners, but the resulting reduction in energy output is fairly small — and cleaning tilted panels does not significantly increase their energy production. So for now, we'll let Mother Nature take care of cleaning our rooftop panels.
Accumulated dirt in the corners of a rooftop solar panel
We've also been crunching numbers on dollars-and-cents; the more energy our panels produce, the sooner we'll be paid back by our solar investment. Our analysis now predicts that Google's system will pay for itself in about six and a half years, which is even better than we initially expected.
If you want to learn more about our solar study, check out these
slides
showing the effects that seasonality, tilt, dirt, particulate matter, rain and cleaning have on Google's solar energy output. We hope you solar panel owners out there can tailor our analysis to the specifics of your own installation to produce some extra energy of your own!
Posted by Winnie Lam, Senior Product Manager
Smart Meters for Smart Energy Consumption
7/16/09
The new Swedish Presidency of the European Union has rightly put the climate change challenge as one of its priorities. Next week, Europe's environment and energy ministers will
meet
in the Swedish town of
Åre
. Together they hope to develop synergies on climate change, energy-efficiency, innovation and competitiveness.
We made the case recently on this blog for an
Energy Information Policy
that would harness the power of information technology to support social change. In general, information technology can play a key role in giving citizens access to data that helps drive environmentally friendly behaviour. In particular, we suggested that the deployment of smart meters was a huge opportunity, especially as we would be building on an area of existing European leadership.
Smart meters collect real, or near real, time information on energy use. When this is reflected back to users, studies show that this has a significant impact on end consumer behaviour: On average, household energy savings amount to 5 - 15%. Even greater savings are possible if this information is used to see the value of retiring an old refrigerator, installing a new air conditioner or insulating the home.
The potential impact of large numbers of people achieving similar efficiencies is even more exciting. For every six households that save 10% on electricity, for instance, we reduce carbon emissions as much as taking one conventional
car
off the road.
We wanted to leverage these large energy opportunities for our users, so we created Google
PowerMeter
. It receives information from utility smart meters and energy management devices and provides customers with access to their home electricity consumption right on their personal
iGoogle
homepage.
The positive effects are already visible in our
first pilot agreements
for Powermeter with utility companies around the world. Just recently, we announced our latest partner and first European utility,
Yello Strom
, in Germany. Yello uses one of the globally most advanced smart metering technologies, giving users real-time feedback on their energy consumption.
Many of our internal users have seen significant savings opportunities through being a pilot tester for PowerMeter, and
all
of them have become much more aware of energy lingo, and, much more importantly, just what it means to leave your HiFi on standby the whole day round (it translated to an impressive 140 Euros yearly savings
for me
).
When fed into a social network context, we believe the value of getting access to energy information could be even greater. For example, imagine setting a savings target for yourself, sharing it with selected friends, and getting pinged if you exceed or miss your targets.
"Energy education" - making users aware of kiloWatt hours, and the Euro costs they translate into, is one of the key tasks when trying to make this planet greener. We are only at the beginning, and PowerMeter is a small puzzle piece in this much larger challenge. Most people that you would ask on the street would be able to tell you the price of a litre of petrol, or what they spend on their mobile phone bill per month, but very few know hard facts about their energy consumption or cost. Do you? We strongly believe there's a lot of room for change here.
At Google, we have been interacting with policy makers, industry leadership and industry influencers a lot in the past year. It is truly exciting to see that many of the experts' expected developments in that space are well aligned with our idea of making more information accessible to the end user.
This will ultimately lead to lower energy bills, more informed users and a planet a little greener, and we greatly applaud technology, projects and policy that can help drive this trend.
Posted by Jens Redmer, Principal, New Business Development, and Benjamin Kott, Green Business Operations Manager, EMEA
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