Solar wasted watts/volts

PWM, https://www.youtube.com/watch?v=QqxI-l5a6d4

Anyone got an explanation for what Ontario Hydro does when it’s heavily subsidized solar panels produce too much power? They give it to their good neighbours in the northern states, and sometimes pay those power companies to take it. I suspect it is due to deals made by politicians that require the utility to buy all the solar power available at prices 5 to 10 times the cost of other power sources. Electricity behaves logically but politics often doesn’t.

As for the question in the first post, the mechanism is that a tiny flow of current into a full battery runs the battery voltage up to match the charging voltage. Since a voltage difference is required for current to flow, it doesn’t.

jolooote wrote:
Have you ever wondered why, as our electric usage in our homes and businesses gets more efficient using less Watts, our electric bill gets more expensive? The power generator( Power Company) must generate the POWER regardless of whether or not its used. As for u'r local Power Co. they have the same cost of production but less income as less power being not used is also Not paid for. As for we campers, we are the producers and always must pay for it. lol

I just gotta dogpile here. I am the Superintendent of Operations at a large power plant in Wyoming. Each of our 4 units has a nameplate rating of 530 megawatts. As I type this, our 4 units are generating:

U1 = 394 MW
U2 = 400 MW
U3 = 419 MW
U4 = 221 MW

Why aren't they at full load? According to you, they should be, and we should be charging our customers to do it. Ironically, the reason we aren't at full load is because our customers don't need the power.

And right in line with this discussion, one of the major reasons we are down on load during the day anymore is from a large increase in solar generation being put on the grid (both large generation facilities and individual rooftop solar installations).

As the sun comes up, we come down. With subsidies, solar is cheaper. But you can't make power with solar when the sun doesn't shine. You can, however, burn more coal.

Lest you forget, most power companies are regulated utilities. I can assure you 100% that a state's public utilities commission would never allow us to charge customers for energy they don't use or need. Another poster hit the nail on the head, you are charged for the electricity you use, nothing more, nothing less.

As for why your power bill goes up over time, well that's a different story. Inflation is one reason. Federal regulations requiring increasingly expensive pollution control equipment to be installed on units is another one. You don't honestly believe the power company just absorbs the cost when a $150 million SCR is mandated to be installed, do you? You, the customer, pay for it.

When you can mo longer absorb more power, the extra power goes "away"!

Hopefully good things won't get wasted.

I didn't notice any mention of controller, only that it will be MPPT. There is no such thing as "too much solar", your main concern should be the controller size.

Solar planning steps: 1. estimate or measure your daily consumption -> 2. estimate how much panel wattage you need -> 3. choose controller size suitable for a given array.

On the step 2 you might want to add 30-50% if possible. 24V panels are same size 65" by 40", be it 200W or 260W. Panels are cheap, and the price difference btw 30A and 40A MPPT like Tracer EP is insignificant.

Thanks all for the good advice.

starcraft69 wrote:
I am curious what happens to the watts /volts when your system is fully charged and you have no demand? Were does the extra power go?

there is no "extra" power. the panel supplies the power needed up to it's output limit. No different than a battery when you don't draw power it doesn't supply any power.

There are calculators to estimate the output of 400W panel. Here is one that I used when planning my system https://pvwatts.nrel.gov/ but right now it doesn't seem to work, can't enter any city.
These calculators are based on historical data on solar radiation and weather for the last few decades, so they are as accurate as can be. Minor drawback is that they are meant for solar homes and provide data in KWH/month. Easy enough to multiply by 1,000 and divide by 12.7 and by 30.5, to get a daily AH data.

So, - run the numbers. If it comes short of needed 127 AH (and if this is really your average draw), getting more battery capacity will help to make it through some bad weather spell.

There might be 9 hours of daylight, but there are also mountains, trees, clouds, rain and low sun early and late in the day. Leave yourself a safety margin. I often hear a suggestion to add 50% to estimated solar harvest that you think you need, - and agree with this.

MW = MicroWave, in offgrid-related talks. At least, in this corner of the wide wobbly web. Frequent readers usually know.

Almot wrote:
Another option would be to limit your MW use when on solar.

Avoiding megawatt usage with TT solar is always advisable.