Green Living

Green Energy for Your Home

Green Energy for Your HomeGreen Energy for Your Home is not a new concept, but it is now starting to get real traction. As individuals we want to reduce our impact on climate, we want to go green, if we can. Buying cars that have better gas mileage or they are electric is just now starting to have an impact. I have started to see homes here in Washington state that have solar panels on the roof, those early adopters have chosen this as an alternative to purchasing power created by burning coal; I am also starting to explore installing solar panels for my own home and here is what I have found.

Home Electricity Usage

Nationally the average consumption for a US residential customer in 2011 was 11,280 kWh, an average of 940 kilowatt hours (kWh) per month. Surprisingly Louisiana had the highest annual consumption rate at 16,176 kWh and Maine the lowest at 6,252 kWh.

The Growth in the US Solar Industry

The growth in the US solar market has actually been very impressive. The U.S. installed 832 Megawatts of solar power capacity in in Q2 2013; that is a 15% over Q1 of 2013. The US is forecasted to bring on line 4,400 MW of PV through the end of 2013; this represents a 30% growth over 2012 installation totals. Together, new solar electric capacity added in 2013 will generate enough clean energy to power over 860,000 American homes. Cumulative US PV capacity is projected to surpass 10 GW by the end of 2013.

The U.S. solar industry is booming. It is expected that by the end of 2013, a solar project will have been installed, on average, every four minutes in the U.S.

Costs Are Falling

Falling costs for solar energy, green energy for you home, are making solar more affordable than ever. The average cost of a completed PV system this year was a drop of over 11 percent over the past year which was around $3.05/W. The average price of a solar panel has declined by 60 percent since the beginning of 2011.

(All data from SEIA/GTM Research “U.S. Solar Market Insight: Q2 2013” unless otherwise noted.)

Green Energy for Your Home

More Washingtonians are showing interest in solar electric systems for their homes and businesses. The reasons for now considering this as a source of energy to heat and light your home are obvious:

  • Solar electric systems are safe
  • Reliable (there are really no moving parts)
  • Pollution free
  • Renewable source of energy
  • Systems have no moving parts and are increasingly easy to install.
  • The option of net metering, or interconnecting a customer generating system to the utility grid, makes solar electric systems more economically viable. When you generate more power than you need during a billing period, you earn an energy credit for later use
  • Federal, state, and local incentives to install solar electric systems

Why Solar

Looking at the numbers a solar electrical system for your home is not a good short term investment. If you have an investment horizon of less than 10 years you need to consider aggressive conservation measures. If you are looking at a longer investment horizon it makes a lot of sense. You are investing in a more sustainable future, you are investing in your property, you are mitigating the risk of increasing utility rates, and you have an opportunity to sell green energy to the utility that reduces the amount of electricity produced by burning coal.

What Equipment Is Needed

A solar electric system consists of basic components for generating and delivering electricity to your home. There are two fundamental types of solar electric systems: independent, or “off grid” systems, and interconnected, or “grid-tied” systems. Grid-tied systems are the system of choice for those of us who are city dwellers and can choose to generate electricity in parallel with our local utilities distribution system. For systems less than 100 kilowatts (kW), grid-tied systems are often referred to as “net metered” systems.

Common Components

The basic building block of solar electric generation is the solar “cell.” Cells are wired together to produce a “module”, which looks like and is often called a “panel”. (This sometimes is confusing because panels also describe solar thermal systems for heating water.) Solar electric modules range in power output from about 10 watts to 400 watts. Many recent residential applications use modules that are 200 watts or more to minimize the number of modules and amount of wiring required. A group of modules wired together form a solar “array”. Various mounting rails and hardware are used to attach modules to a building or other support structure and are often called “racking”.

In addition to solar modules, a solar inverter, solar meter and AC & DC disconnect switches complete this solar electric system.

An inverter is an electronics device that converts direct current (DC) produced by the modules into conventional alternating current (AC). Modern inverters also provide important safety features to meet the latest National Electric Code standards, as well as monitoring and diagnostic capabilities. AC and DC power disconnect switches allow components to be safely shut down and isolated from the utility grid.

Batteries are optional in a net metered system and are only used if a customer wants to provide backup power during utility power outages. They add significant cost.

A separate utility-grade kilowatt-hour meter or “production meter” is also optional but is required to receive renewable energy production incentives (selling green power to your utility)

Solar Electric System Cost

The numbers vary but a house that is 1600-2000 square feet and having electric appliances except for the furnace use an average of 1500Kwatt-hours per month making 50 Kwatt-hours per day and a total of 18,000 Kwatt-hours per year.

Unlike electricity purchased month to month, solar electricity comes with an initial investment but no monthly charges. It’s like paying for years-worth of electricity all at once. You’ll probably appreciate having lower electric bills as you harvest “free” electricity but the initial expense of a system may be jolting. Financing may be an option to help spread out initial system costs.

The upfront cost of an installation with panels and needed additional equipment will run between $25,000 and $40,000. The federal government incentive is a 30% tax credit; In Washington if you buy made in Washington components there is no sales tax which is an 8% plus deductions. Both Puget Sound Energy and City Light will buy green energy from you at a maximum rate of $0.54 per KWH. Based on the four quotes that I got for my home I would start to see a positive return on my investment in 6 to 10 years. In a 20 year time frame I would pay for the system and by selling energy to the utility I would also earn between $30,000 and $45,000. The other interesting thing I learned was that if I put a $20,000 solar system into my home, it would raise in value by $20,000. I don’t know of any other home improvement where this is possible. When I checked on tax rates for my home and on insurance costs I also found that neither were affected…pretty positive picture if you have an investment of 10 to 20 years.

Please Note

Just like the furnace in your home if you do not maintain these systems the efficiency is affected.

Also, small deviations from “ideal” system orientation (due south) and tilt (30 – 45 degrees) will affect annual performance, but not by more than about 5%. Also annual electricity production may vary by up to 20% due to annual variations in local weather.

You could also ask you’re a local provider for a written estimate of the average annual electricity production for any system proposed, which should take shading into account.

How much is that electricity worth? There is no simple answer to this question since it depends on how much electricity you use, your current rate schedule (residential, general service, etc.) as well as how much and when you generate solar electricity.

In Seattle net metering customers (those selling power back to the utility) receive full retail value for their solar electricity. However, residential customers pay different rates and different times and seasons. This needs to be factored.

Green Energy for Your Home

Information You Need To Get Started

US Department of Energy – Database of State Incentives for Renewables & Efficiency

Washington State Incentives and Information

U.S. Department of Energy- Solar Energy Technologies Program: Photovotaics – A consumer resource

Solar Washington- the local chapter of the American Solar Energy Society



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