FAQ

General FAQ

 

What is the Warranty on the Solar Power System?

Solar panels have a manufacturer’s warranty of 25 years.  SolarEdge optimizers also have a 25 year warranty and the SolarEdge inverter has a 12 year warranty, extendable to 25 years.  Micro-inverter warranties vary, depending on manufacturer.  Suncatcher Solar has a 5 year installation warranty and provides free installation of warranty replacements.

What is the expected lifetime?

The expected lifetime is 35 or more years.  Solar panels already exist that have been producing for longer.

If I have to replace my roofing, what would you recommend?

Metal roofing or asphalt shingles with a 35-year warranty both have a long lifetime.  A light color will keep the house cooler in the summer and light colored shingles also last longer.

Will solar panels be damaged by hail?

Solar panels are mounted in aluminum frames with tempered glass faces.  They are very robust and would only be damaged by extremely severe hail storms,  See a hail test in this Tips article:  Solar Panels and Hail.  In this case, the panels should be covered by your home insurance policy.  Contact your insurance provider for details.

What happens in winter?

Solar energy varies throughout the year.  Typically, the average roof angle combined with the short days of winter makes production low in the winter but optimal during the summer. Snow cover typically slides off or melts off once the sun shines again.  Net metering takes advantage of the high summer production to offset the much lower production in the winter.

 

Grid-Tied Systems

 

What does the Rebate include?

The rebate applies to the equipment, installation and design costs for a solar power system that   is connected to the electrical utility company.  The rebate, to a maximum of $20,000, is  available for customers of SaskPower, Saskatoon Light and Power and the City of Swift Current.

What happens during a power outage?

During a power outage, your solar power system will not continue to produce. Your system must shut down automatically so that the problems with the electrical utility system can be safely repaired.  When utility power is restored, your solar system will automatically restart and again produce power for your home.

What are the options for backup power?

If you have critical loads or frequent power outages, battery backup can be added to your grid-tied system or you can use a backup generator.  Costs vary depending on how much backup you want.

How do I read the bilateral meter?

Solar Saskatchewan Meter - received from customer

rEC – Received from you and credited to your account

When your solar power system starts producing, a bilateral meter will be installed to replace your regular meter.  This will record the excess power you feed back so that your account can be credited.  Reading the bilateral meter can be confusing.

The bilateral meter has 3 rotating displays.  Display 1 is a series of ‘8′s.  Display 2 is ‘dEL’ followed by the number of kWh that SaskPower has delivered to you.  Display 3 is ‘rEC’ and the number of kWh that SaskPower has received from you for your excess solar production.  This number will be credited on your utility bill at the current rate.

Get a Quote for a Grid-tied Solar Power System:

Call toll free: 1-877-441-2355 or email

Keeping Pests and Debris away from your Solar Panels

A Problem with Pests

As it turns out, pigeons and squirrels love to nest under roof-mounted solar arrays. Squirrels, in particular, can do serious damage to the wires hooking up your inverters to your solar panels. These damaged wires then become a fire hazard. The detritus from nests (as well as dried leaves that can accumulate under panels) can cause damage to your roof and lead to roof rot. Beyond all the mess and the hazards, there is the issue of noise that pigeons cause. All that to say, unprotected arrays can cause you serious problems and headaches.

Prevention

Because of the fire hazard caused by damaged wires of string inverters*, it is now code that all systems using string inverters must have some kind of protection around the panels to keep pests out. For our solution to this problem, we use a beautifully designed aluminum trim created by SolaTrim.  SolaTrim has several advantages over a simple wire mesh. It is a strong product made of lightweight aluminum with an aviation grade adhesive tape that seals it thoroughly to your solar panels. It is extreme temperature tested and comes with a 25 year warranty. We like that it is designed to be a permanent solution that will last the lifetime of the panels. We also chose this solution because we wanted to use a trim that didn’t detract from the beauty of your home. SolaTrim adds curb appeal to your house by providing a clean and elegant finish to the array.

Suncatcher Solar System on Triangular Roof

Roof-mounted solar Array with SolaTrim around the panels to keep out debris and pests.

*Systems using either SolarEdge or Micro Inverters are designed to shut down automatically if there is damage to the wires. For this reason they don’t present a fire hazard, and installers are not required by code to install any sort of mesh protection. However, we always install trim, regardless of the type of inverter, to avoid the noise and protect your system and your roof.

 

Gardenview Solar Home

The Gardenview solar home is an example of  a passive solar home that fits on a city lot.  It was designed by Suncatcher Solar and built in partnership with Jaylin Homes in Saskatoon, Saskatchewan.

It features energy efficient building construction, radiant in floor heating and a solar power system.

Passive Solar Design

Living room in late October

Living room in late October

The south side of the completed home, shown here, faces the back yard, where the owners are planning a large garden.  Normally the south wall is the long wall of the house but the shape of the house was constrained by the size of the lot.  Despite these limitations, however,  the home’s south windows are 9%  of total floor area.

Stone facing stores the winter sun's heat

Stone facing stores the winter sun’s heat

Abundant sunshine into the house warms the home during the winter.  The roof overhangs keep the sun out in the summer, when the sun is higher in the sky, so that the house stays cool.  Thus, a passive solar home typically does not need air conditioning in the summer.  Stone facing on the fireplace and a granite countertop act as a thermal mass to store the winter sun’s heat for overnight.

Wiinter and Summer

Wiinter and Summer

North side of Gardenview home

North side of Gardenview home

The attached garage is on the north side of the home, with the bedrooms above.  Fewer windows are needed here, increasing the energy efficiency of the home.

Energy Efficiency Features

The bitter cold winters in Saskatoon, plunging to temperatures as low as 40 degrees below zero, make energy efficient building methods an important component of the passive solar design.

Upper floor landing

Upper floor landing

The Gardenview is built with wood frame construction with 2″ x 6″ walls and blown-in insulation.  Themal bridging – heat lost through the wooden framing members – is a major source of heat loss in this type of construction.  The Gardenview reduces this heat loss with 1″ foam board insulation applied to the inside of the exterior walls.  The inside of the foam board is faced with a reflective foil to reflect heat back into the home, cutting down on heat loss through radiation.  An air gap between the foil and the drywall is essential to make this method effective and can cut down on radiation losses.

Heating System

A woodburning fireplace provides renewable heat

A woodburning fireplace provides renewable heat

Radiant in floor heating on all levels of the home supplements the passive solar heating.   The attached garage also includes in floor piping, but the temperature is kept considerably cooler than the house.  A wood burning fireplace provides extra heat and ambience on cool evenings.

The in floor heating is supplied by a Wiessman natural gas modulating boiler.  The system uses a sophisticated central controller to program the heat requirements of the home.  The in floor system has a continuous flow and is automatically adjusted based on the reading from an outside temperature sensor.  When the outside temperature goes down one degree the temperature of the in floor system is increased by 0.7 degrees or whatever the controller is programmed to.  This can be adjusted to suit the preferences of the occupants.  A fine tune control knob lets the homeowner make minor adjustments as needed.  The advantage of this sytem is that, once it is set, it usually does not need to be adjusted often and the continuous flow means that the boiler can operate at a lower level (typically 25% of its maximum output), thus saving energy.

Bruce explains the in floor heating system to the homeowners

Bruce explains the in floor heating system to the homeowners

The system was designed and installed by Bruce Kell of Solaero Energy.  When he was going through the system with the new owners he commented that at a previous installation the natural gas utility had come and changed their meter because they thought it wasn’t working properly.  But it was – that’s just how energy efficient this system is.

Solar Power

A solar power system provides renewable electricity

A solar power system provides renewable electricity

The homeowners were very excited when the day came to commission the 2.3 kW grid-tied solar power system that will offset some of the home’s electrical usage with clean, renewable power.  The system can be expanded in the future, once they have lived in the home for a few months and have a clearer idea of how much power they will need.  The system qualified for a rebate on the upfront costs and Saskatchewan’s net metering program means that excess power produced over the summer months can be fed back to the electrical utility for credits on future bills.

enphasedisplay

Click here to see the Live Display for the Gardenview

The solar power system features a monitoring system that lets you see – live – exactly what each of your solar panels is producing at any time, as well as your overall production per day, per week, per month and since you installed the system.  The webpage will also show what this means in terms of the environment, showing the greenhouse gases offset by the system.

The solar panels and Enphase inverters have a 25 year warranty and an expected lifetime of over 35 years.

Owners’ Comments

The Gardenview has a bright, sunny kitchen

The Gardenview has a bright, sunny kitchen

After only a few days in their new home, the owners were already amazed by the solar heat coming through their south facing windows.

“The solar gain on sunny days is absolutely incredible – we turn down the fine-tune dial as far as possible in the morning and with opened windows in the afternoon, it’s still 24C on the main floor!”

Their in floor heating settings were tweaked to moderate the heat gain and heating costs have been very moderate for their first winter – under $300 for natural gas during the first year they lived in the home.

For more passive solar home designs see Suncatcher’s Solar Home Designs.  You can also buy a Study Set to have a more detailed look at the plans before deciding to purchase the full set of drawings.  Plans are priced at $995 for the Construction Drawings and $29.95 for the Study Set.

Solar Power Mounting Options

Solar panels take space – 400 to 1200 square feet or more, depending on how much solar electricity you want to generate. If you want to get top solar production in Saskatchewan, the panels should face due south and at an angle to best capture the sunlight.  But what, exactly, is that angle?  The sun moves across the sky during the day, constantly changing position.  It is also much higher in the sky during the summer than it is during the winter.

1.  Solar Trackers

Solar Trackers

Solar Trackers

A system that tracks the sun would be an ideal solution.  However, a tracking system needs a massive mount to accommodate all the panels and a complex control system to make the tracking automatic.  This makes the system expensive and the moving parts will require maintenance.

Solar panels have come down in cost so much that it is far cheaper to buy more solar panels and put them on a mount that is fixed at an angle that provides a good compromise.  Typically, for the 30% extra power production that you can get from a tracker, you could easily buy 50% more solar panels if you have the room for them.

Solar trackers do make economic sense if you are short of space or if there is a reason to squeeze maximum production out of a fixed size of solar power system.  This is the case, for example, in Ontario, Canada where the feed-in tariff pays a premium rate for systems up to 10 kW.

2. Roof Mounts

Solar Power on House Roof

A roof clear of obstructions is best for mounting solar panels

The least expensive way to mount your system is directly on your roof.  The mounting system fastens to the roof trusses and provides rails on which to mount the panels.  The rails keep the panels a bit above the roof itself to provide ventilation for the panels.  Solar panels are more efficient at lower temperatures, so ventilation is important.

A simple roof mount is the way to go if you have enough south facing roof space at an angle approximately equal to your latitude.  If this is a grid-tied system a lower angle can also work well since you usually produce a lot more power in the summer when the sun is higher in the sky.  With grid-tied systems you can usually feed that extra power back for credits in the winter or sell it back to the utility.

Ballasted Solar Mount for a flat roof

Ballasted Solar Mount for a flat roof

If your roof is flat, or just doesn’t have  a steep enough slope, the roof mount angle can be adjusted to compensate for that.  This adds some expense, but can significantly improve the production.  Ballasted roof mounts, that don’t require any roof penetrations, are also available for flat commercial roofs where the possibility of leaks is a big concern.

Keep in mind that you also want your solar array to be free of any shading.  Watch for dormers or trees or a roof on a more southerly part of the house that might shade your panels.

3. Ground Mounts

Ground mounted Solar Array

Ground mounted Solar Array

Perhaps you have no suitable roof space but lots of room on the ground.  This is often the case on acreages and farms.  A ground mounted array is the second most economical choice.

A rack for the panels is set up at a suitable angle and mounted high enough above the ground to account for snow cover.   The racks require more material than a sloped roof mount, so this adds some expense, as does the screw pile foundations.

Ground mounted arrays have their advantages.  You can more easily choose a good location with minimal shading.  The array is also easily accessible for cleaning and clearing off any snow cover that accumulates on the panels.

4. Pole Mounts

Solar Panels on a Pole Mount

Solar Panels on a Pole Mount

Another alternative for smaller solar power systems is one or more pole mounts.   These are like a tracking mount but without the expense and complexity of the tracking system.  Pole mounts are more expensive than ground mounts but can be manually adjusted for seasonal angles.   It is also easier to select a good location for a pole mounted array.

The limitation with a pole mount is that you don’t want to mount too many panels on one pole.  The array of panels is like a sail in the wind, so the larger the number of panels you mount on a pole, the more massive the pole and foundation will need to be.  The other alternative is simply to use more pole mounts but each mount will need a pole and concrete foundation, with its attendant costs.

Contact Us for help in choosing the best solar mounting system for your home.

How Much Solar Power Do You Need?

The second question customers often ask us at Suncatcher Solar is “How many solar panels will I need?”.  The first question is usually “What will solar power cost?” but we need to answer the second question before we can answer the first.

Solar panels come in many sizes.  They can be used alone or combined to make up a solar array. To figure out the size of array you would need for your home you will need to know how much electricity you use and how much sunshine is available where you live.  Saskatchewan has excellent conditions for solar energy.

How Much Electricity Do You Use?

electrical meterIf you already have electricity from an electrical utility, this will be an easy question to answer.  Take a look at your utility bill and find the current and previous meter readings.  The difference between these readings is the amount of power that you have used between the two dates of the readings.  The amount of power will be a number of kWh.  Looking at the dates for which this reading applies, you can calculate what your monthly or annual electrical usage is.  Most homes use in the range of 600 – 1200 kWh per month.

If you don’t have electricity yet and are planning to use a solar power system instead of connecting to an electrical utility, you will need to estimate what you are going to use by doing a load analysis.

Now that you know what you need for electricity, it’s time to see how much power a solar panel can produce and how many of them you will need.

How Much Electricity Does a Solar Panel Produce?

Solar panels derive their power from sunlight.  The brighter the sunlight the more power the panel produces – up to its rated capacity, which is given in Watts.  When you buy a solar panel you will see that the panel size is given as, for example, 10 Watts or 100 Watts or 240 Watts.  Combining ten 100 Watt panels into one system will give you a 1000 Watt – or a 1 kiloWatt (kW) solar array.

If you have full sun shining on the array for one hour (1 Sun Hour), the array will have produced one kiloWatt-hour (kWh) of electrical energy.  This is the same unit as the electrical utility charges you for on your electrical bill.

Solar Array

The average number of sun hours per day for your area can be found on a global solar insolation map or you can focus more closely on a map of your own area.

World Map of Sun hours

 

What Size of Solar Array Do You Need?

Multiply the daily energy in kWh from the map by 30 days/month – this will give you the sun hours available.  Then divide the kWh per month that you are being billed by the electrical utility by the monthly sun hours available. This will give you the size of the solar array (in kW) that would generate enough electricity to meet your monthly bills.

The actual size of solar array you decide to invest in will depend on a few other factors as well:

  1. Space for solar panelshow much space you have for panels a large array can require considerable space and may need to be ground mounted if there is not enough suitable roof space available.  For a roof mounted system measure the dimensions of clear south facing roof space (length of the roof and height to the peak or to obstructions such as a row of vents.
  2. whether you are doing a stand alone system or a grid-tied system– an off-grid, or stand alone system, will have to be large enough to supply all your needs, even in the winter, but a grid-tied system can be smaller since the electrical utility will supply any shortfall.
  3. whether your local electrical utility offers net metering or feed-in tariffs – net metering is a program that credits you for extra power you produce against future bills from the utility.  The best size of system is one that will provide most of your electricity so that you effectively offset your electricity bill.  Feed-in tariffs actually pay you for the electricity you produce, usually at a premium rate, so for this type of program it may be worthwhile to invest in a larger system and use the production as a source of income.
  4. your budget – sometimes it’s not possible to purchase the optimum size due to budget constraints, but you can always start with a smaller system and add on later as you can afford it.  In the meantime, the system you have installed will be saving you money.
Call us toll-free at 1-877-441-2355 or send an email with your electrical usage and space you have available for solar panels and we will give you a free estimate.

Choosing Solar Power for Your Home

Girls from a Science Camp check out my solar home

My solar home

live in a solar home – it is powered by the sun.  When I make my morning toast, grab my drink from the fridge, sit at my computer and write this post, it is powered by the sunlight striking the panels  on my roof.

It is an exhilarating and  liberating feeling – I am using solar power, something that is already shining on my home in clean and limitless supply.

If you live in an area with plenty of sunshine, like Saskatchewan, you can make this happen for your home.  This article explains what’s involved in deciding on solar power for your home, farm or business.

Choosing a Location for the Solar Panels

Solar panels work by converting sunlight to electricity – the more sunlight that strikes the panels, the more electricity they produce.  The best position for maximizing the amount of sunlight is facing the equator (true south in the northern hemisphere, true north in the southern hemisphere).  The more panels you have, the more sunlight they will receive and the more electricity they will produce.

House Roof

Solar Power on House Roof

A roof clear of obstructions

Solar panels take space. The most convenient place to put them is on your roof if you have a large enough area facing close to true south (true north in the southern hemisphere).   A typical city home will need about 10 solar panels.  Those 10 panels will require 35 feet by 15 feet of south facing roof space. The roof should be as clear as possible – no vents, antennas or other obstacles that would interfere with mounting the panels or shade the panels. East and west roofs will also work but will need 20% more panels to produce the same amount of electricity.

Outbuildings

If you don’t have room on your roof there are other places to mount panels.  Look at a garage or shed roof – see if these have a clear south facing roof that’s large enough to accommodate the panels.

Pole Mounts and Trackers

Solar Panels on a Pole Mount

A Pole Mount

Solar panels can also be mounted on a pole  – some of these can be adjusted for the seasons.  If you are really short of space and need to make the most of what you have a tracker is another, though expensive, option.  This automatically tracks the sun over the day and the seasons.

Ground Mounts

Solar panels on a Groundmount

A Ground mounted Rack

A simpler, less expensive option than pole mounts is to mount panels on a rack on the ground.   You will need room in your yard for these mounts – they will need to face south and have a clear area in front of them so that there is little or no shading.  Large trees or brush, other buildings or farm structures can shade the panels if they are too close.

Getting the Most from your Solar Investment

Solar panels will produce the most power if they are set at the optimum angle and orientation for your geographic location, and in an area with no shading.  This ideal position may not be practical for your roof or yard but very good power production can often still be achieved with the apace you have available.

Minimize Shading on the Solar Panels

If you plan to mount the panels on your roof, look to see if you have chimneys or gabled dormers that would shade the panels at some times of day.  Snow can also build up beside dormers covering any solar panels that are mounted close to them.

Other sources of shading are tall trees in yours or your neighbor’s yard and any outbuildings on your own or neighboring properties.  The key is to find the least shaded area in which to mount your solar array.

What About Snow Buildup?

If you get lots of snow in the winter, you will want to do something to avoid snow buildup on the panels or have an easy way to remove the snow.  A steeper roof angle will help because the snow will slide off more quickly when the sun comes out and warms the glass surface of the panels.  As the surface becomes slippery the snow will slide off fairly readily.

If your roof is not too high up you can use a roof rake on an extended pole to remove the snow from the panels on those few occasions when it will be needed.

Some Other Things to Think About

Solar Panels on House Roof

A solar power system is a substantial investment with a long lifetime (over 25 years) so it’s a good idea to think about the condition of the roof on which those panels are mounted and how the immediate surroundings may change during that time.

The Future of Your Roof

If you are thinking of roof mounting the panels, make sure that your roof will last for this time period.  If your shingles need replacing now is the time to do it – before mounting the solar array. Shingles with a longer warranty (35 years or more) or other roofing materials such as metal would be a good choice. A lighter color of roofing material will last longer and also keep your house cooler in the summer.  Once the panels are up, they will have to be temporarily removed and then reinstalled for any roof repairs.

Landscaping and Building Plans

Solar panels work best if they are not shaded.  Do your landscaping plans include trees that will grow and eventually shade the solar array?  Are you (or your neighbor) planning a future garage of shed that will block the sun?  Look at those possibilities when you plan the location for your solar panels.

Call us toll-free at 1-877-441-2355 if you are interested in a site assessment to determine your potential for solar power.

5 Benefits of Net Metering – Spinning the Meter Backwards with Solar Power

Home Solar Power System

Home Solar Power System

Producing your own solar power is exciting. You now have free renewable energy when the sun shines – and Saskatchewan is the sunniest province in Canada.

But what do you do at night and on cloudy days? In the early days of solar power, you needed a bank of batteries to store the power for those times. Sometimes even the battery bank was not enough to survive weeks of cloudy weather so a backup generator was another necessity.

Now net metering, a program offered in Saskatchewan by SaskPower, offers a much easier and environmentally beneficial answer to this problem.

5 Benefits of Net Metering

Grid-tied Solar Power System

Grid-tied Solar Power System

Net metering is a program that allows you to connect your solar power system to the utility company’s system.  This means that you can feed back any extra solar power you produce to the utility company for credit.

1. Financial Credit for Extra Solar Power Produced

A bilateral meter tracks what you use and the solar power you feed back with an alternating display

A bilateral meter

You will receive a credit for your excess solar power at the utility’s going rate for electricity. When there is not enough electricity from the sun, the utility company will supply your electrical needs. You will pay only for the difference between the power supplied by the utility and the power produced by the solar panels. Typically, extra solar power that you produce can be banked for up to a year at which point the utility company has some arrangement for handling any excess. For net metering, a bilateral meter is installed that records the solar power you have produced and fed back to the grid as well as the power you have used from the utility. When you produce more than you use, you are effectively “spinning the meter backwards”.

2. No Battery Storage System Needed

A battery bank of 2V cellsWith net metering the utility company essentially “stores” your extra solar power for times when you don’t have enough. This means that you don’t really need an expensive battery bank, unless you want a small battery backup system for power outages. When you have a grid-tied system like this your power will go down when the utility power goes down. This is for safety reasons, to protect the repair crew who are not expecting any power generated in the lines when they go out to repair the problem.

3. No Backup Generator for when Solar Power is Not Available

Another expensive part of early solar power systems that you won’t need is the backup generator. Generators are expensive, noisy and need fuel (gasoline, diesel, natural gas or propane). The electrical utility is there as your backup when solar power is not available.

4. Seasonal Storage – Solar Power Produced in Summer Saves on Winter Costs

One of the frustrations of off-grid systems which are not connected to the utility is that the extra power in the summer months can’t be stored for the winter. Battery banks typically store power for only 3-5 days. When the batteries are full there is no way to store the extra energy. But, with net metering, you are feeding back your power over the summer and you get credited for it in the winter – now you have seasonal storage.

5. No Maintenance – Solar Power Without Hassles

Handy systemWith net metering, we have now eliminated the batteries and the backup generator – the two components of a solar power system that require maintenance and have the shortest lifetimes. The only components you need for a grid-tied net metering system is the solar panels, which produce the power, and an inverter that converts the DC power from the solar panels to the standard AC power produced by the utility. Neither of these components requires maintenance. The solar panels, which have a 25 year warranty, are made from a semiconductor material and usually protected by a tempered glass front. The inverters, some of which also have 25 year warranties, are solid state and also maintenance free.

A grid-tied net metering system gives you the advantages of producing your own clean renewable energy without maintenance hassles and with very durable components.

Solar Panels and Hail

 

Everyone who has talked to us at Suncatcher Solar about solar panels invariably asks about hail. It’s an understandable question. Canada, especially around Saskatoon, and the rest of Saskatchewan can’t go a year without hail of some sort. These panels are supposed to last a long time, and the majority of the front face is glass. Glass that is going to be outside, with no cover or protection above it. Hail can cause a lot of damage, it can ruin entire crops, total off vehicles, and destroy siding and shingles.

What makes solar panels any different? Well for one, solar panels are built to last. They use tempered glass instead of plastics or regular plate glass. Tempered glass is much more resistant to impacts than regular glass. It’s able to with stand impacts at twice the speed that would break regular glass. If you know your physics (F=mv2), this translates into being four times as tough.


How tough are solar panels? Watch the video above of a solar panel taking a direct hit from a ball of ice the size of a billiard ball at 120 kph.

Hail isn’t as perfectly spherical or solid as what is shown in the video. It’s loosely held together, has many weak points and a lot of air trapped inside. Also, panels are rarely mounted in such a way that they would take a direct perpendicular impact from hail. Hail impacts will generally be at an angle, sometimes as much as 45 degrees – that’s more of a glancing blow than an impact. The one weakness of tempered glass is its edges. Impacts here can cause the entire sheet to shatter. This is why solar panels also have an aluminum frame. Aluminum keeps the weight down, provides corrosion free protection for the edges of the tempered glass and is a convenient mounting surface to secure the panels. Solar panels will last just as long if not longer than any other feature on the outside of your home.

Come hail, wind, rain or snow – solar panels do their job.

Off-Grid or Grid-Tied – What’s the Difference?

Solar Power Array on the Experimental HouseSolar Power Center“I want to go off-grid and use solar instead of bringing in SaskPower!”

The desire for independance prompts many a call to Suncatcher Solar from people who want to be self sufficient and hope that solar power holds the answer to that dream.  But what does that really mean? What’s the difference between “off-grid” and “grid-tied” and what kind of lifestyle does each one entail?

What Does it Mean to Go Off-Grid?

Going off -grid means going it on your own. You have to produce and store all your own power and if you run out you start up the backup generator. There is no power utility to fall back on. On the other hand, neither is there a power bill.

Basic-Solar-Power-System1-e1318386617230

Off-Grid Solar and Wind Power System

An off-grid system needs a storage system for the electricity that you produce so that it will be available for times when there is no source of electricity. This storage system is one of the main features that distinguish an off-grid system from a grid-tied system. The other is a backup generator for long periods of cloud or calm.

The figure at the right shows the basic components for an off-grid system. A solar array and an optional wind turbine provide electricity to run the appliances in your home. Whatever you don’t need immediately is stored in the battery bank. Since you are completely reliant on your own resources the battery bank must be large enough to see you through at least 3 days without any solar or wind charging. This typically means very large battery cells forming a bank that requires a space that is a minimum of 2′ wide by 4′ long and 3′ high.

Remote Solar Power System

Remote Solar Power System

You will need to plan your energy use using a load analysis so that the charging system and battery bank is large enough to meet your needs. Heating your home in a cold climate will present some challenges. Some heating systems are difficult or prohibitively expensive to operate with an off-grid system. For example, you cannot run a geothermal system with off-grid power – the power requirements for the pumps are too large. Passive solar design and an in floor heating system are usually the best options for off-grid systems.

What is a Grid-tied Solar Power System?

Grid-tied Solar Power System

Grid-tied Solar Power System

A grid-tied system is connected to your electrical utility company’s power “grid”. The utility is now your backup generator. There is a basic monthly cost for a grid connection (usually around $25) but this is much less expensive than the $6000 or more for a generator and the fuel that the generator uses.  You can see the utility meter and subpanel for the large solar array shown in the photo on the right.

Grid-tied Solar Array

Grid-tied Solar Array

A grid-tied system often includes a net metering agreement. This means that when you produce extra power you can feed it back to the grid and receive a credit on your power bills for those times when you use more than you produce. Some utility companies may also pay you for your excess power, or buy power from you at higher than the going rate (this is called a Feed-In Tariff ).

Grid-tied solar power system

Grid-tied Solar and Wind Power System

The grid now also becomes, in a sense, your battery bank. Because you feed back your excess power for a credit, it is effectively “stored” for you until you need it. Usually this means that you feed back extra power in the summer and then use the credits in the winter when you need the power for your heating system. This is much less expensive than buying and maintaining a battery bank.

Looking at the figure on the left you can see that the grid-tied system is the same as the off-grid system but without the battery bank and its charge controller and without the emergency generator.

A Cost Comparison

This means that it is much less expensive to set up and maintain a grid-tied system. It also means that most of your money is going to what you really wanted to buy in the first place – solar and/or wind power. The inverter system, which converts the DC solar power to normal household AC power, is the only other expense for materials. Installation is also less expensive if there is no battery bank, charge controller and generator to install.

This typically makes a residential grid-tied system at least $15,000 less than an off-grid system. So why would you want to invest in an off-grid system?

Off-grid systems are still cost competitive if you live sufficiently far from the closest grid connection. If you need to have power brought in it may cost you at least as much or more to connect to the grid as to pay for the batteries and generator required for an off-grid system. If it will cost you $20,000 or more to bring in power, for example, the off-grid system quickly pays for itself, especially since there will be no ongoing power bills.

A Benefits Comparison

Off-grid System Pros and Cons:

Off-grid Battery Bank

Off-grid Battery Bank

Pros:

– ideal for more remote situations where power is expensive to bring in.
– no power bills.
– no power outages.
– self sufficiency on a clean, renewable energy source.

Cons:

– batteries and generator are expensive and require maintenance.
– lifetime for the batteries and generator(10 – 15 years) is less than for the solar array (35+ years) and wind turbine (20-25 years).
– no seasonal storage. Batteries can only store power for a few days and have a maximum capacity. When they are full, the rest of the power is wasted unless you can find an immediate use for it.
– power use must be carefully planned.

Grid-tied System Pros and Cons:

Pros:

– easy backup from grid power.
– eliminates need for expensive batteries and generator (which also requires fuel).
– provides seasonal storage if a net metering or Feed-in Tariff program is available.
– maintenance free for a solar power system (wind requires some maintenance and repair).
– internet monitoring available with inverters designed to be used for individual solar panels (Example).
– you are providing clean energy to the grid.

Cons:

– power outages. When utility power goes out your system also goes out unless you invest in a battery bank. This is a requirement by the utility company and is for the safety of those repairing the system.
– you still have to pay the basic utility bill, just not for whatever power you’ve produced.
– you are still using non-renewable resources when there is no solar or wind.

Making the Choice

Choosing the power system that’s right for you depends on your building site and the lifestyle that you prefer to live.

Contact us and discuss the options with us.