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Renewable Energy - Solar

The Pacific Northwest is not known for its abundance of sunlight nor wind power and yet both types of renewable energy are growing in popularity for residential and commercial use. In southwest Washington state, most of our electricity comes from BPA's 31 hydroelectric dams on the Columbia River. 

When considering the switch from natural gas to solar electric water heating, I would have to replace a natural gas water heater with an electric solar water heater. This involves a) finding a unit that will fit the needs of this property, b) finding a supplier and c) having a certified vendor install the unit. As a residential customer, I don't really care about the qualitative benefits (see pros and cons of solar below) of using sustainable energy. At the end of a billing cycle, it's all about the monthly bill and the lifetime cost of ownership of the unit. If I can get the meter to tick backwards, that'd be a big plus, but it's not the primary driver for research into this household appliance.

The case for solar

Year Cost of Gas Gas avg/month Cost of Electricity Electricity avg/month
2010 $614 $50 $249 $21
2011 
(thru July)
$385 $55 $155 $22

To look at actual water heater consumption, one would probably have to compare summer months to winter months. It does snow here and only a few days a year. During the winter, the thermostat is set to 62 degrees F. During the summer, it's been so mild, bordering on chilly, that I haven't turned on the a/c. The graph below shows annual natural gas and electricity costs; where energy consumption is a direct correlation to cost. 


When I think about it in this context, I don't really have a data-justified case to add a solar water heater since I'd still be consuming natural gas to heat the home. Natural gas consumption has already declined month-over-month since installing the programmable thermostat (a unit that has paid for itself in energy savings vs regular usage). I haven't done nearly enough calculations to proceed further.

Pros:
  • Zero emissions; no pollution
  • Quiet energy production
  • Installation in remote locations more cost-effective than high voltage wires
  • Able to use existing footprint (e.g. angled or flat rooftops)
  • Unlimited energy eventually pays for the installed unit(s)
  • Less dependent on fossil-fuel-dependent energy (e.g. coal, nuclear)
  • SmartGrid, NetMetering eligible
  • Cash incentives from regional utility providers (see below)
Cons:
  • Steep (initial) cost of the solar cells and/or panel array
  • Pollution in dense metro areas can affect collection efficiency of the panels
  • Effective during daylight hours; significantly less available "energy" during winter months
  • Collector efficiency is affected by severe weather conditions (snow, hail, blizzard blackout conditions)
Read more?
BPA Factsheet [PDF]
Solar-brewed beer at Lucky Labrador Brewing Company
Weatherization Specifications Manual
Calculator: Solar Water Heating
HomePower Magazine

Database of State Incentives for Renewables & Efficiency
Energy Trust of Oregon Residential Promotions
Northwest Natural Residential Promotions

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