Tag Archives: solar power

Best Source of Off-grid Power

Best Source of Off-grid Power

Reader CONNIE in WAUKESHA writes:

“When you’re off grid 1. What is the best source of power 2. Is there any window and door window grates to keep bears out?”

Solar power jumps to mind for most of us when it comes to off-grid energy. This sun-powered option, including photovoltaic solar panels, an inverter and batteries, can provide lots of electric power (especially if you get a lot of solar exposure where you live) for a long time, without any moving parts and a little maintenance. Downside, at least for now, is cost: it is rarely cost-effective to power an entire home entirely with solar, even allowing for several decades for a positive return on investment. Add to this wide variance of solar exposure by location and solar only works when sun is shining, and it’s easy to see why solar remains only an answer part, and not everything.

If you get good news after you contact your local weather service to check on average wind speed in your area, generating electricity from residential-sized wind turbines is another option for off-grid energy. Knowing average and wind speed ranges, you can estimate how much electricity a given system will produce. Keep in mind, wind speeds on a specific lot can vary significantly from regional averages depending on local topography.

When it comes to picking a turbine size matters. According to U.S Department of Energy’s Wind Guidebook, if a typical home uses an average of 830 kWh of electricity per month, a turbine generating between 5 to 15 kW is required (taking into account average wind speed). Rotor size for a 10 kW turbine is about 23 feet in diameter and is mounted on a tower often more than 100 feet tall. If you live in town or on a small plot, a big one may not work as well, but many people have a necessary real estate for this size.

As with solar, there are pluses and minuses to going with wind energy off grid; biggest, most obvious one is a need for breeze: if wind doesn’t blow, turbine stays still and electricity isn’t generated. Wind turbines also have moving parts, meaning more things potentially requiring maintenance and have a possibility of failure. But if you’ve got a good consistent stiff breeze blowing through your back yard, you can harvest its energy for years to come.

Probably least-known off-grid energy system is microhydro electricity. It uses a source of running water, like a stream, to generate electricity; it’s produced from energy in water flowing from a high level to a lower level turning a turbine at system’s bottom end.

Microhydro electricity generation can be most cost effective of these three. If your source is good, it runs 24 hours a day, seven days a week, providing lots of off-grid energy for a long, long time; because it produces so much more consistent energy, fewer batteries are needed to store energy because there is less (or zero) time system isn’t harvesting energy. Of course, as with other two, it requires pretty specific on-site conditions; if you don’t have a stream in your backyard, you can’t use microhydro.

Yes, there are solutions to bears. While I have not used (or had a need to use) any, this particular provider appears to have thought of a few: https://www.tahoebearbusters.com/bear-deterrents/bear-fences/

Cool Solar Stuff

I’ve been doing some of my own research on solar power lately, and have found some interesting stuff. The real interesting part of this article is not in the cool solar product – it is on how to solve the problem they do not know they have with the pole barn (post frame) building in the background of their photo.

First, the cool solar technology:

The city of Sandpoint, Idaho will start work soon on the first public pilot project with Solar Roadways Inc., the North Idaho startup which aims to transform roads, sidewalks and parking lots into heavy-duty solar surfaces capable of generating power and melting ice.

The city has received a $48,734 Idaho Gem Grant from the state Department of Commerce to install a 150-square-foot solar surface at Jeff Jones Town Square at Third Avenue and Main Street in downtown Sandpoint.

The Sandpoint Urban Renewal Agency is kicking in another $10,000 for the project, and Solar Roadways owners Scott and Julie Brusaw, of Sagle, will donate installation costs.

The solar surface will go down in June, according to the city’s project schedule.

“In addition to the potential for long-term economic development, this project will draw many visitors, locally, regionally, national and worldwide to view the project … drawing much needed tourism to other downtown businesses,” said Aaron Qualls, the city’s Planning and Economic Development director, in a March 29 letter to the urban renewal board.

The company also will benefit from the attention the pilot project is expected to attract, Scott Brusaw told city officials. “This will help lead to the building of a mass manufacturing facility in Idaho, where even more jobs will be created,” Brusaw said in a March 17 letter.

Solar Roadways also met this spring with officials at the University of Idaho to discuss a similar demonstration project on the Moscow campus. The university has applied for a grant from Avista Utilities to pursue their project. A location has not been selected.

The company raised over $2.26 million from the public in an Indiegogo crowd funding campaign and has used some of the money to hire employees and open an engineering and manufacturing shop at 721 Pine St. in Sandpoint.

The Brusaws believe their technology can transform U.S. highways and cityscapes into sprawling networks of energy generation and provide surfaces which are durable, safe and less expensive to maintain than concrete and asphalt.

The hexagon-shaped, inch-thick panels collect solar energy which can power heaters and lights under the glass, with electricity to spare. The Brusaws built a small parking pad next to their workshop using 108 of the panels, and it stayed free of snow and ice through the winter.

The panels also feature LED lights which can illuminate road lines and project warning signs onto a surface. In another application, electric vehicles would be able to recharge at rest stops, restaurants and other businesses which incorporate the solar road panels into their parking lots.

For those of us here in the great white north, this could be an interesting product.

Now, I’ve got you warmed up, here is the pole building tip, thanks to the Brusaws’ photo with their workshop.

What is wrong with the picture?

The entry door has wood jambs and probably only primed instead of painted is one, however it is not a solvable problem wsolar panel conceptsithout replacement with a high quality door.

Look at the wall steel and you will see there are two overlaps to the right of the door which just do not appear to be laying down smoothly. This is an installation problem which can easily be solved.

Steel siding panels are designed for a 36-inch net coverage, no more, no less. The best installers are measuring along the wall as they place panels, to make sure the coverage is exactly 36 inches.

Here, at least two of the panels were placed with the overlap pushed too hard to the left, they probably do not cover all of the 36 inches and the overlapping edge of the steel panels is “riding up”.

To solve, remove all of the screws from one panel at a time except those along the far right (in this case) underlapping edge. Now push on the rib to the far left of the panel, towards the right. When the overlap fits tight place screws in the holes immediately to the right of the overlap.

Last, replace the screws in the field. Repeat this process on any other panels which are not overlapping as they should.

What is the Best Solar Panel Roof Slope?

Hansen Pole Buildings’ Designer Rachel asked me today what the best solar panel roof slope?

Solar Panel Pole BarnThere are three main factors which go in to the calculation of how much sun a roof receives. Roof angle or pitch, roof orientation (how south-facing a roof is) and location. Since Rachel asked about roof slope, I will focus on this one aspect.

There is an optimum angle for solar panels on a roof. This is the angle where, over the course of the whole year, the panels get the most amount of direct sunlight which produces the greatest amount of electricity.

The question is: what is the perfect angle, and if the roof is not at exactly this angle how much energy will be missed out on? I’ve arbitrarily picked a location of 49 degrees north (generally the United States – Canadian border in the western U.S.) and a south-facing roof for this example.

So for this roof the optimum angle is 35° (a bit over an 8/12 roof slope) and at this angle the roof generates 1,265kWh/m2/day. The energy reduces as we move away from this optimum angle. At 30° the energy drops to 1,260kWh/m2/year – a reduction of just 0.4%. At 20° (15° away from the optimum angle) the energy drops to 1,229kWh/m2/day – a reduction of 2.6%. It’s only with very steep roofs – say over 60° – when the solar energy really drops off.

If you want to see how this works for your roof you can create a free report at:  https://www.solstats.com/ – take a look at the bottom of the report and you’ll see a version of the chart above for your location. WARNING: Entering your zip code will NOT take you to United States locations, it takes scrolling across the world map on the website.

It is obviously preferable to have a roof at the perfect angle. While I am not a fan of government subsidies, they are very generous when it comes to solar energy. Including them in the calculation, it absolutely makes sense to install on roofs which are not at the perfect angle. You’ll lose a few percent of solar energy but it should still make financial sense.