28 June 2011
27 June 2011
Solar Energy Information Sessions Across Ontario in July 2011
Four solar sessions are planned for Ontario in July. These will provide information to those who are recent solar generators or to those considering solar installations. Back by popular demand, Thomas Boehni, a Swiss pioneer in solar energy with over 16 years experience in solar systems will share his expertise and tips. Invited speakers to join Mr. Boehni include: OMAFRA and Hydro One.
This would be your best $35 spent if you are thinking about solar, or already have it.
Workshop locations are Ridgetown, Woodstock, Guelph, and Kingston.
This would be your best $35 spent if you are thinking about solar, or already have it.
Workshop locations are Ridgetown, Woodstock, Guelph, and Kingston.
Labels:
Solar Workshops,
Thomas Boehni,
University of Guelph
Location:
Guelph, ON, Canada
08 June 2011
PV Generation Output Levels Over Time
I will attempt to answer the question of "how much power is the system generating right now"? I'll expand on this to summarize how often the 4.9 kW system is generating at different levels. This is very interesting once you see the results. For example, during a day with sun and cloud the output may be less than 1 kW much of the time, but when the sun finally appears for an hour the output may be 4 kW. So, how much money do I make during cloudy periods and how critical are bright sunny days? Let's look!
The Questions :
Revenue resulting from 3000 watts and more represents the highest revenue levels! And our 4.9 kW rated system produced over its rated limit for 2 3/4 hours and earned $11.25 over this time.
Additional observations :
The Questions :
- How often is the PV system generating at different levels [in watts]
- How much money is earned at each output level
- How often are the panels generating near maximum output or above
- Fronius Datalogger Pro installed on PV system noon 2010-10-31
- Wattage output averaged and reported by data logger every 15 minutes
- Continuous monitoring when inverter putting power to the grid [greater than 15 W]
- 2011-06-07 17:15 is last measurement event
- Data points n = 9658
- 15 minute interval data downloaded from datalogger and imported into spreadsheet
- Watts used to calculate kW, revenue at $0.802/kWhr, and watts generated per wattage of panels [20 SolarWorld SunModule poly panels at 245 kW each]
- Frequency distribution curves generated by pivot tables function
Raw data
Figure 1 shows the raw data used for the analysis. You can see the output levels for each 15 minute period of the day when the system is operating [it shuts down automatically at dust when the panels generate less than 15 watts]. During November the maximum output is around 4000 watts. This drops to 100-200 watts during December other than a few days when it rises above 500 watts when there is no snow on the panels. A similar pattern is seen at the end of January 2011. From February to June there are many days when generation is over 4000 watts, even over the 4900 watts which is the maximum rated output of the panels. The maximum level seems to decrease back down to 4000 watts after March. This could be partially explained by the warmer temperatures during the Spring daytime compared to the colder February and March air temperatures. Power output decreases significantly when the panels are over 30 degrees Celsius. Of course the panels only output their maximum daily limit for a short period. The morning and afternoon output is much lower and this is a larger duration of the day compared to the peak generation time period. Cloudy days also decrease the output level.Figure 1. |
Power Generation Levels
The shape of the power generation frequency distribution curve should come as no surprise when you consider the many points in Figure 1 that are less than 1000 watts. Sixty two per cent of the time the PV system is generating less than 1000 watts. Snow shading, mornings and afternoons, and clouds do not yield a lot of solar energy. Considering our house consumes about 300 to 400 watts continuously [1200 when the pool pump is running], the data show our house is a net power exporter much of the daytime over the year. The similar frequency of output from 1000 watts to 4500 watts is interesting. It suggests to me that once the sun rises there is quite a lot of time when the clouds are partially blocking the sun. Also, if we assume that the system can generate at least 3000 watts once the sun is up [i.e. 9 am to 6 pm] then we can see that Guelph has had a fairly cloudy period. There are 1327 15 minute intervals when the output is over 3000 watts, or 331 hours of "bright sunshine" out of 2415 hours of generation time! Let the Beatles some "Here Comes the Sun" come true this summer! Also:- 45 minutes was 5000 watts to 5130 watts over this period - end of March. 5130 watts is 4.7% over the panel rated output, and that does not include the derating factors such as DC power line losses and inverter efficiency losses
Figure 2. |
Revenue by Output Level
As frequent as <1000 watts may be, is it important for overall revenue, or what about the sunny periods. This really shocked me initially and now I know why I am so happy when it is sunny outside! Before I blab on any further, here is Figure 3. And this figure shows some very important information that relates to solar PV designs. I'll no doubt discuss this figure in future postings.Figure 3. |
Additional observations :
- total revenue to date generated is $2,229
- most revenue is earned at <3000 watts, but not by much
- about $100 was earned when revenue was greater than 4500 watts. If we use a common solar industry practice to oversize the panels relative to the inverter by approximately 10%, we would have lost approximately $100 in potential revenue. This undersized inverter is rationalized that a larger inverter may be considerably more expensive. In fact this may not be the best economically decision based on the data presented in Figure 3. [Of course, sizing the inverter and panels is more complicated than that]
- my initial solar configuration was going to be 4.9 kW of panels and a 4 kW inverter. Lost revenue would have been close to $400 [assuming that inverter efficiency across the power level range is equal for the inverter sizes]
- the generation frequency distribution in Figure 2 is opposite to the frequency distribution curve of Figure 3
- the frequent low sunlight levels is financially less important than sunny periods
- your solar system should be designed to maximize the higher sunlight levels. Shade, ventilation, panel orientation, inverter sizing are all very important factors that must be explicitly accounted for when you have your PV system installed
- sizing your panels and your inverter is critical. Use the inverter manufacturers' software to properly design the number of panels, types of panels, the number of strings
- ensure that the inverter is sufficiently large to handle the high end of your panel output levels. Under-sizing the inverter by over 10% should be seriously rationalized unless there are upper limits to amount you are permitted to generate
- for example, the Ontario Power Authority's micro Feed-In Tariff Program has a 10 kW upper limit. You could maximize the amount of low sunlight level generation by increasing the number of panels, thereby shifting the mode of the Figure 3 revenue chart to the right. But this can only be done after using the inverter manufacturers' system configuration software. Failing to do this may result in lost power generation or damage to the inverter
- the 5100 watt inverter on our system is able to take advantage of the few periods of very intense sunshine yet this has earned me significant revenue. Over the period of 10-20 years of our microFIT program this will add up to a sizable income cohort
- choosing the location and orientation of the panels should try to maximize the bright sunlight periods of the day
Location:
Guelph, ON, Canada
06 June 2011
Ontario Power Authority FIT and microFIT Program Stats and the Price of Electricity
The Ontario Power Authority FIT and microFIT program application statistics [pdf] are updated every two weeks and posted on their website. This website has a wealth of information on it, and people interested in the details of the programs and in renewable electric energy development will find much valuable information on that site.
However, to begin to understand [?possible?] the electricity demand, supply, and the price you also need to know information from the IESO.
I am going to do a little exercise here to show what the current microFIT program electricty is supplying to the provincial grid and what it is costing. I summarizing things with many assumptions.
Solar data :
IESO electricty data:
* = uFIT short for microFIT, I can't type the Greek character mu, so I use "u" instead. A throwback to my bioclimatology modelling days where mu was commonly used to denote "micro". A bit of a misnomer when micro means 1x10^-6 whereas a large FIT project is 1x10^4 kW and a microFIT project is 10 kW.
However, to begin to understand [?possible?] the electricity demand, supply, and the price you also need to know information from the IESO.
I am going to do a little exercise here to show what the current microFIT program electricty is supplying to the provincial grid and what it is costing. I summarizing things with many assumptions.
Solar data :
- uFIT* stats
- Total applications = 30,168 [276 MW, or 9.15 kW project average size]
- Applications terminated [ineligible, no grid connection, etc] = 3,049 [10%! 29 MW, 9.5 avg size so proportionally it is the bigger uFIT projects and most likely in rural areas that are having more difficulty connecting to gird]
- Conditional offers = 21,255 [193 MW, 9.1 kW avg size. OPA has made progress processing applications]
- Contracts executed = 5,093 [44 MW, 8.64 kW avg size]
- 16.9% of applications to the uFIT program are actually connected under contract. This suggests it has been slow to get to the contract stage with the OPA and it is taking the solar installation companies quite a long time to get their clients' projects installed and connected.
- 3.0 to 3.5 hours per day per kW of installed panel capacity is general average output of the panels
- 3.0 is a more conservative estimate, some salesmen use 3.5, sun-orienting tracking systems may be higher
- 2.61 hours per day per kW is my system's current average for the first 3/4 of a year as of 3 June
- 99.9% of the uFIT applications are solar PV
- uFIT PV power receives $0.802/kWhr
- 132,000 kWhr/day = 3.0 hrs/day . 44,000 kW, or
- $105,864/day = 132,000 kWhr/day . $0.802kWhr
IESO electricty data:
- IESO market update
- 90 days from 1 Jan to 31 March
- 37,430 GWhrs over 90 days, or 415.9 GWhrs/day [415,889 MWhrs/day]
- $0.0328/kWhr average price over this period [uFIT price $0.77 higher than market rate]
- $13,441,159/day = 415,889 MWhr/day . $0.0328kWhr . 1,000 kW/1MW
- 0.03174% of our electricity is coming from uFIT projects
- 0.776% of the electricity cost is coming from uFIT projects, even less if you consider the new pricing set out by the Ontario Energy Board
* = uFIT short for microFIT, I can't type the Greek character mu, so I use "u" instead. A throwback to my bioclimatology modelling days where mu was commonly used to denote "micro". A bit of a misnomer when micro means 1x10^-6 whereas a large FIT project is 1x10^4 kW and a microFIT project is 10 kW.
Labels:
Electricity Price,
microFIT program,
Ontario,
OPA FIT program,
solar
Solar Images Viewable
Sorry, the images in yesterday's two postings did not appear correctly to some - because they were using [your adjective] Internet Explorer, not a more web-compliant browser like Firefox or Chrome. I use the latter and the images appeared fine. They should appear okay now in everyone's browser.
05 June 2011
May 2011 Cumulative
December and January could be a bad memory when you have grid-tied solar panels. But you need to have the long-term view. Even with the dreary May weather, the microFIT program is working out. At this point it is still too early to say what the ideal price is to achieve a reasonable return on investment. We are roughly 3/4 through the year and we are nearly equal to our loan payment [10 yr amortization]. However we are going into the long summer days and will more than exceed the loan. But that is only reasonable - many businesses require a 3 year return on investment so why shouldn't a homeowner have their own small solar business on their roof and get 7-10 year return on investment?
I show the cumulative revenue below.
The blue revenue curve is the daily generation from 24 August 2010 to 3 June 2011. I've discussed the low generation in earlier posts, but here we see there are enough sunny days that we are catching up to the cumulative loan. The net revenue was higher from August to December where it dropped below the loan payment. However, we now how enough data to see the growth in revenue that started in February has allowed the system to virtually catch up to the cumulative loan payments. On 3 June loan payments was $3043 and generated power was $2900. However, we should be expecting a cheque from Guelph Hydro soon - payments received to date have been $1762.
I show the cumulative revenue below.
The blue revenue curve is the daily generation from 24 August 2010 to 3 June 2011. I've discussed the low generation in earlier posts, but here we see there are enough sunny days that we are catching up to the cumulative loan. The net revenue was higher from August to December where it dropped below the loan payment. However, we now how enough data to see the growth in revenue that started in February has allowed the system to virtually catch up to the cumulative loan payments. On 3 June loan payments was $3043 and generated power was $2900. However, we should be expecting a cheque from Guelph Hydro soon - payments received to date have been $1762.
May 2011 Daily Results
It has been wet, cloudy, and not very bright in Guelph since mid-April. Not so great for solar or the farmers. We need the rain to keep the dust off the panels and to help the crops grow, but not this much!
The daily solar data is shown in the figure below. I cheated a bit - the first couple of days of June have been so sunny that I had to download the data off my Fronius datalogger to see how many kWhr we generated. I get wo pleased to the see the sun on the panels and the Fronius inverter purring away in the garage. These data are included in the daily results to date. The beginning and end of May had several days where generation was 20 kWhrs. Despite the intermittent cloud, the generation has been quite good on sunny days. My observations:
Now, the important thing is to see the revenue generation that is resulting from the chart above. The chart below shows the daily revenue plus the daily loan equivalent [I pay loan biweekly].
There are indeed many days in May that are below the $10.70 daily loan equivalent, but whew!, it sure isn't December again!. Maximum daily generation in May was $26.83, the minimum was $2.98, avg $13.82.
The daily solar data is shown in the figure below. I cheated a bit - the first couple of days of June have been so sunny that I had to download the data off my Fronius datalogger to see how many kWhr we generated. I get wo pleased to the see the sun on the panels and the Fronius inverter purring away in the garage. These data are included in the daily results to date. The beginning and end of May had several days where generation was 20 kWhrs. Despite the intermittent cloud, the generation has been quite good on sunny days. My observations:
- 1, 2, 3 June 2011 - 33.5, 32.9, 32.4 kWhr respectively are the about equal to a few days in early May
- 1 June is 15 hrs 11 min 9 long whereas 1 May is 14 hrs 19 min long! Of course sky clarity is not equal between these dates and can be a notable factor
- 15 April is only 13 hr 25 min long and we generated 35.1kWhr, and 24 March is only hr min long yet 35.0 kWhr was generated
- Despite the cloudy days, overall generation has been fair to very good, meaning we are catching up nicely from the winter generation drop
- May generated 534 kWhr, or $428. This is a little below my RETScreen.net model which predicted 667kWhr in May for our system. This makes sense as May 2011 was generally recognized as much cloudier and rainy than normal.
Now, the important thing is to see the revenue generation that is resulting from the chart above. The chart below shows the daily revenue plus the daily loan equivalent [I pay loan biweekly].
There are indeed many days in May that are below the $10.70 daily loan equivalent, but whew!, it sure isn't December again!. Maximum daily generation in May was $26.83, the minimum was $2.98, avg $13.82.
Subscribe to:
Posts (Atom)