Panel Shading Tools

Your solar provider should provide a very thorough analysis of your roof and near-by obstructions before you accept your contract. There are many websites that list tools and calculations. I found PVResources to be quite handy. [There is actually a lot of info on PVResources.]

There are some very handy tools to use, the primary one is the Solar Pathfinder. A solar installer would be able to provide a quantitative analysis of your roof and show you the areas that would be affected by shade.

Another interesting tool by Sustainable by Design that I found quite helpful was for tilted panels on flat roofs. I am sure you could use it on a sloped roof to estimate the impact of obstructions too. But I found it equally interesting to see the impact on our roof. See below! We don't have any obstructions from trees, etc. You can see with the white blocks our panels are fully illuminated, but after 4 or 5 pm the sun has gone far enough westward that it no longer strikes our SE facing panels.

Plotting Revenue Up To 14 May 2012

A quick chart to show the revenue generated from our system. The orange line is our daily loan payment amount. We don't pay daily of course, but I plot the line for illustrative purposes.

Figure 1. Daily revenue to 14 May 2012.

Here Comes the Sun!

A short blog update to provide you the latest data from my solar PV system. I have the data below for the first 2 weeks of May added to my monthly kWhr of generated power generation.

Sum - Daily kWhr	Years
Date	2010	2011	2012	Total Result
Jan		169.71	255.84	425.55
Feb		275.02	322.52	597.54
Mar		560.81	569.29	1130.10
Apr		492.89	625.74	1118.63
May		534.31	320.48	854.79
Jun		707.22		707.22
Jul		769.01		769.01
Aug	164.00	658.47		822.47
Sep	438.00	528.05		966.05
Oct	450.00	391.09		841.09
Nov	355.39	316.33		671.72
Dec	78.23	219.84		298.07
Total Result	1485.62	5622.73	2093.87	9202.21

I've mentioned in earlier posts that we need to generate approximately 375 kWhr per month to have the system pay for itself. As we've seen, December and January can be poor due to clouds and snow shading the panels. But March, April, and the first half of May have been good and more than cover the low generation from Dec-Feb. We are quite pleased that we are approaching 10,000 kWhr - likely by mid-June.

Ontario Power Authority 2 Year Review of Feed In Tariff Programme, Minister's Directive of 5 April 2012.

The Ontario Power Authority released the scheduled 2 year review of the FIT programme on 22 March. Yesterday they held a webinar to provide information to the public about the changes to the microFIT programme being proposed. There is a comment period and readers may see these details on the OPA website. The points below are the proposed changes to the programme, contract, and rules, take verbatim from the OPA website (I've put my comments in brackets):

Key changes to the FIT and microFIT Programmes include:

• As a first step, the FIT and microFIT program rules will provide for the awarding of 50 MW of microFIT and 200 MW of small FIT contracts as soon as possible. (applications in the queue will be processed and released soon)
• FIT applications will now be accepted only during an application window, rather than on an ongoing basis. (a more planned application approach -likely to help the OPA assess applications based on grid capacity and their ability to process the applications)
• Small project FIT applicants will now need to submit application security if they wish to apply or re-apply under the new program rules. (likely to reduce the number of speculative applications)
• Applications will be prioritized with points awarded based on applicant type, municipal support, Aboriginal support, project readiness and electricity system benefit. (allowing for greater community involvement in the development process)
• Solar rooftop projects must reach commercial operation within 18 months of receiving a contract, compared with three years previously. (if you get an application you need to build - this way the price you have to pay for the system reflects the price you'll receive for the electricity sales. Also, if you have grid capacity allocated to you then build now or give the capacity to someone else)
• Ground-mounted solar projects need to be located on lands that are not used for residential purposes and also cannot be adjacent to lands that are used for residential purposes. (proximity and land use decisions)
• Ground-mounted solar projects are permitted on commercial and industrial lands as long as it is the secondary use of the property. However, if the project is the only use of the property, it will be ineligible. (ground-mounted solar is the the main use of the land but ancillary. This will encourage more solar to be put on roof tops)
• In addition, ground-mounted solar projects can be located only on property that does not contain any Class 1, 2 or 3 soils, organic or specialty crop soils, regardless of zoning, or any mixed soils that contain Class 1, 2 or 3 soils. (protection of highly valuable lands)
• For projects other than rooftop solar that receive prioritization points related to the type of applicant, there are new restrictions on changes that would reduce the equity held by a community, Aboriginal group or health or education entity below the level that enabled the project to qualify for such prioritization points during the entire term. For rooftop solar projects that receive prioritization points related to the type of applicant, such restrictions apply from the contract date until five years after the commercial operation date. (ensuring significant community investment {and community benefit} and reducing the risk that "token" community investment will be used for the project only to be transferred to the main developer after project approval)

These points above are derived from the Minister's Directive released on 4 April 2012. This directive has many very important details and people should read this directive very carefully.

March 2012 Power Yield and How RETScreen is Doing

I've downloaded the data up to 13 April and I've put it in my spreadsheet to calculate the power yield for March 2012 (table below). It was marginally better than 2011. I am looking forward to the rest of April because so far the bright, cool days have been good energy producers. March 2012 was just 9 kWhr over last year. However, RETScreen calculations show that my system should have yielded 584 kW, so, two years in a row RETScreen is overestimating the system. Two years of data is not enough to say RETScreen is not accurate, but the overall trend with my system is underestimation. RETScreen calculated that my system should have produced 9128 kWhr to the end of March whereas my system did 8256 kWhr (10.6% under estimation). Most of the deviation came from the winter of 2010-2011 where snow substantially reduced the panel output. So, with this limited dataset, it points to people being conservative when estimating their payback expectations.

Sum - Daily kWhr	Years
Date	2010	2011	2012	Total Result
Jan		169.7	255.8	425.5
Feb		275.0	322.5	597.5
Mar		560.8	569.3	1130.1
Apr		492.9	313.5	806.4
May		534.3		534.3
Jun		707.2		707.2
Jul		769.0		769.0
Aug	164.0	658.5		822.5
Sep	438.0	528.0		966.0
Oct	450.0	391.1		841.1
Nov	355.4	316.3		671.7
Dec	78.2	219.8		298.1
Total Result	1485.62	5622.72	1461.16	8569.52

Other Solar Blogs from Ontario

I like to see what other people are sharing about their own solar project experiences. Here are a couple blogs I'll share with you. I don't endorse them.

• http://www.solarontarioblog.ca/ 
• opps, that's it! I searched for some blogs on solar and found that 80% were companies, 19% were organisations, and 1% were political (or some similar breakdown). So, enjoy solarontarioblog.ca and feel free to read all the other blogs. 

Little Snow Means Better Solar Production in 2011-2012

Spring is already here but our 2011-2012 winter ended a long time ago. There has been very little snow - I didn't have to shovel much since Christmas. The sky seems to have been clearer too and this has enabled our solar array to generate more power than last winter. It means a lot too, financially. Last August was our 1 year anniversary and on a $30k investment after 10-year loan payments, we netted $460 - not a great return on investment so hopefully 2012 will be better. So far, so good. Here is our kWhr generated by month in Table 1.

Sum - Daily kWhr	Years
Date	2010	2011	2012	Total Result
Jan		169.7	255.8	425.5
Feb		275.0	322.5	597.5
Mar		560.8		560.8
Apr		492.9		492.9
May		534.3		534.3
Jun		707.2		707.2
Jul		769.0		769.0
Aug	164.0	658.5		822.5
Sep	438.0	528.0		966.0
Oct	450.0	391.1		841.1
Nov	355.4	316.3		671.7
Dec	78.2	219.8		298.1
Total Result	1485.6	5622.7	578.4	7686.7

If I use Dec-Feb to define winter, then we yielded 523 kW in 2010-2011 and this year 798 kW. That is a 275 kW difference or $220.55 difference in revenue. We'll see what this March brings to be able to compare two full winters. December 2010 and 2011 were especially different because Dec '10 was dark, dreery, and frequent intermittent snow that accumulated on the panels and seldom fully melted off or slid off.
The system didn't get connected until 25 August, so ignoring that we can see that most months are better than the year before, other than Oct and Nov 2011. We had a "dark" fall, but otherwise, I see it is all going well.
As you may read in this blog, I focus on the numbers, kW, dollars, and cents of our solar system. I am interested in these results today as it shows that you can't use a single year to determine if production data. Or any coefficients either. In an earlier posting I calculated the typical coefficients people use to estimate the power generation for our first year. I look forward to calculating this year's coefficients, plus to calculate the values for the duration of the system - that way we'll get the general values to expect for a multi-year estimation of coefficients.
So far, so good.
Oh, a little note about how I analyse these data. I use OpenOffice Calc to store and analyse the data. I use the Data Pilot tool [Pivot Tables in Excel] to summarize the data very quickly and easily.