Julian Egelstaff
4th May 2011, 14:42
Hello,
On the website I created to explain about our microFIT system, http://www.yourturn.ca/solar, on the first page it says that "On an average day, it produces 50% of the electricity we use."
I'm wondering how people read this, or what it means to them. Someone recently pointed out that some people might interpret this to mean that our electricity bills, and our grid consumption, is now halved. Which is sort of true, and sort of not true. We do consume, on average, 50% less grid power than we used to, when you look at it on a net consumption basis (we're connected in series, so it's literally true that our *net* grid consumption has been cut in half).
But our electricity bills are not cut in half obviously, since microFIT has no bearing on your bill. And our actual grid consumption is not cut in half because of export/import factors.
This is a complicated issue, because on any given day, the relevant numbers are going to be all over the place. To make it concrete, look at May 2...you can see the whole truth here:
http://www.yourturn.ca/solar/our-system/graphs-and-logs/daily-graph/?date=2011-05-02&type=consume
8.4 kWh of solar power generated
4.7 kWh of solar power consumed in the house
3.7 kWh of solar power exported to the grid
10.4 kWh consumed from the grid
15.1 kWh consumed in total
So on that day, approximately 66% of the electricity we used came from the grid (10/15).
But because we exported nearly 4 kWh of solar power, our net consumption from the grid was less than 50% when compared to all the electricity we used that day (10-3.7 / 15)
Over a 12 month period, the total solar power production equaled about half of our total power consumption (from the grid and from solar combined). The easiest way I could find to explain all this in one phrase on the front page of the website was, "On an average day, it produces 50% of the electricity we use."
Does that make sense? Is that misleading? Does it imply to people something other than what's really going on?
Does it mater that our actual grid consumption will almost always be higher than our net consumption, because of the export/import dynamic? If someone is connected in parallel, their grid consumption is technically unaffected, except a lot of the grid power they consume will be generated from their own house. So for that case, does it still make sense to express what the system produces as a percentage of what you use?
The reason I put that text on the front page, first line, is because I find people often have no idea how much power a solar array can produce, and they're surprised when they find out how much. So this is a way of answering that basic question, "How much power do you really get from it?". As we know, there's not really a simple answer to that question, but I hope this answer gets at what people mean when they ask the question.
However if this answer is implying something else, or otherwise off the mark, I'd like to revise the text, so the point gets across as intended.
Thanks for reading, take it easy,
--Julian
On the website I created to explain about our microFIT system, http://www.yourturn.ca/solar, on the first page it says that "On an average day, it produces 50% of the electricity we use."
I'm wondering how people read this, or what it means to them. Someone recently pointed out that some people might interpret this to mean that our electricity bills, and our grid consumption, is now halved. Which is sort of true, and sort of not true. We do consume, on average, 50% less grid power than we used to, when you look at it on a net consumption basis (we're connected in series, so it's literally true that our *net* grid consumption has been cut in half).
But our electricity bills are not cut in half obviously, since microFIT has no bearing on your bill. And our actual grid consumption is not cut in half because of export/import factors.
This is a complicated issue, because on any given day, the relevant numbers are going to be all over the place. To make it concrete, look at May 2...you can see the whole truth here:
http://www.yourturn.ca/solar/our-system/graphs-and-logs/daily-graph/?date=2011-05-02&type=consume
8.4 kWh of solar power generated
4.7 kWh of solar power consumed in the house
3.7 kWh of solar power exported to the grid
10.4 kWh consumed from the grid
15.1 kWh consumed in total
So on that day, approximately 66% of the electricity we used came from the grid (10/15).
But because we exported nearly 4 kWh of solar power, our net consumption from the grid was less than 50% when compared to all the electricity we used that day (10-3.7 / 15)
Over a 12 month period, the total solar power production equaled about half of our total power consumption (from the grid and from solar combined). The easiest way I could find to explain all this in one phrase on the front page of the website was, "On an average day, it produces 50% of the electricity we use."
Does that make sense? Is that misleading? Does it imply to people something other than what's really going on?
Does it mater that our actual grid consumption will almost always be higher than our net consumption, because of the export/import dynamic? If someone is connected in parallel, their grid consumption is technically unaffected, except a lot of the grid power they consume will be generated from their own house. So for that case, does it still make sense to express what the system produces as a percentage of what you use?
The reason I put that text on the front page, first line, is because I find people often have no idea how much power a solar array can produce, and they're surprised when they find out how much. So this is a way of answering that basic question, "How much power do you really get from it?". As we know, there's not really a simple answer to that question, but I hope this answer gets at what people mean when they ask the question.
However if this answer is implying something else, or otherwise off the mark, I'd like to revise the text, so the point gets across as intended.
Thanks for reading, take it easy,
--Julian