Page 44 - Green Builder Sept-Oct 2016

Home Free: The Advantages of Net-Zero LivingRENEWABLE ENERGY SYSTEM that

includes a solar PV array, high-voltage

A battery and inverter technology from
SMA America gives The Arc House an
advantage over most net-zero energy homes.

One of the biggest arguments for grid-tied
rooftop solar is net metering—the ability to sell

excess energy generated back to the grid, often SOURCE: U.S. EIA
at the retail rate. But as more customers install
renewable energy systems, utilities in many states Going up? According to U.S. Energy Information Administration, residential electricity
are changing their approach to net metering. Some rates rose by about 30 percent from 2005 to 2014. That trend is likely to continue both
are lowering the rate of compensation below in the short and long term.
the retail rate and/or adding fixed charges to
customers with solar arrays. Others are eliminating storage more compelling.” times of high demand), it can potentially save
net metering altogether. A renewable energy system that includes storage money, if the utility utilizes a variable rate structure.

“A lot of utilities are moving toward time-of-use can store excess energy generated by a solar array Many states are currently deliberating how best
pricing, demand charges, and implementing zero and “spend” it during times of higher demand on to balance pressure from the utilities with renewable
export policies,” says Tim Stocker, product manager the electricity grid. This strategy not only provides energy goals. Residential solar installations that
for SMA America. “This is making the case for more stability to the grid (and potentially saves include storage will be ahead of the curve when
emissions from “peaker plants” used only during the utilities catch up.

and Tigo Energy ensures that the PV array will perform optimally, no optimize energy consumption.
matter what the conditions. The system includes of optimizers that This flexible system functions off the grid, as well. In off-grid mode,
are attached only to modules affected by shading or other conditions
that compromise performance. The Arc House would rely solely on power from the sun, ensuring it
does not contribute to fossil fuel-based carbon emissions. GB
Showcasing the next development in residential renewable
energy, the system relies on a Sunny Boy Storage battery inverter Independent power.
and Sunny Boy PV inverter from SMA America and a high-voltage The SMA Sunny Boy
storage battery. The Sunny Boy Storage transformerless battery Storage battery inverter
inverter converts electricity from high-voltage battery to the grid, can be used in both
and vice versa. The inverter, which was first introduced in Europe, retrofits and new
is lightweight, affordable and efficient, and it is compatible with PV installations. It will
high-voltage batteries from several manufacturers. be available in 3.8- and
6.0-kW models.
The SMA Smart Home allows occupants to better manage their www.sma-america.com
energy. Automatic load control ensures the most efficient use of
solar power and optimizes energy use so that the home doesn’t draw
from the grid when rates are high. This eases the burden on the
grid and reduces demand charges in regions where utilities employ
a tiered structure. Other features of the system include forecast-
based charging of the storage battery, which ensures optimum use of
excess PV power, and recommended actions to help users manually

42 GREEN BUILDER September/October 2016 www.greenbuildermedia.com