Grid-tied solar

[MossRoad]

^^^ thanks for posting the story...

I've made some minor adjustments at the hospital to minimize the demand factor such as staggering start time for the HVAC systems... so not everything starts at 5 am in the morning causing a peak for power usage during a 15 minute interval.

Amazing what timers can do! :laughing:

We had air compressors, and HVAC simultaneous starting issues for a while. Staggered the start times. All O.K. :thumbsup:

 

[dave1949]

US lower 48 annual solar insolation by county, 1979-2011, in an interactive map. Also insolation maps by month.


Map: Where America’s sunniest and least-sunny places are - The Washington Post

 

[houstonscott]

45 kWh in May - you will see higher output once the sun angle changes in the spring and fall Today we have exceeded 40 kWh and in Monday too do a good month so far

Carl, how often do you clean your panels. Mine seemed to look dusty so a hosed them off, how much can dirt and dust effect production. I use rainX on my cars and it makes the glass so slick almost nothing sticks to it, I'm thinking of putting rainX on my panels to keep them clean. HS

 

[Redneck in training]

Carl, how often do you clean your panels. Mine seemed to look dusty so a hosed them off, how much can dirt and dust effect production. I use rainX on my cars and it makes the glass so slick almost nothing sticks to it, I'm thinking of putting rainX on my panels to keep them clean. HS

I have three banks of PV panels and I live on a gravel road so dust on panels is way of life here. It also provides for easy experiment when I will wash only one bank and compare the performance. I just washed one bank and I have to report that small amount of dust (about 4 days after last rain worth) cuts about 3-4% of production.

 

[Redneck in training]

Here is and article about distributed energy storage. I think that is a beginning of change how we generate and use energy.
Falling energy storage costs and steadily increasing solar capacity stand to catalyze a paradigm shift from net metering to distributed energy storage.

 

[houstonscott]

I have three banks of PV panels and I live on a gravel road so dust on panels is way of life here. It also provides for easy experiment when I will wash only one bank and compare the performance. I just washed one bank and I have to report that small amount of dust (about 4 days after last rain worth) cuts about 3-4% of production.

That's significant. I'll keep them clean. HS

 

[houstonscott]

Here is and article about distributed energy storage. I think that is a beginning of change how we generate and use energy. Falling energy storage costs and steadily increasing solar capacity stand to catalyze a paradigm shift from net metering to distributed energy storage.

We need that battery breakthrough. That would be a game changer. HS

 

[Carl_NH]

I have three banks of PV panels and I live on a gravel road so dust on panels is way of life here. It also provides for easy experiment when I will wash only one bank and compare the performance. I just washed one bank and I have to report that small amount of dust (about 4 days after last rain worth) cuts about 3-4% of production.

HS - I hose them down so far 2 times when we had a lot of pollen on them and no rain

I couldn't see a huge difference with the pollen but it I can tell you snow covering and part of the panel it does impact production

Carl

 

[KiwiBro]

Is everybody clear on the difference between feed in tariff and grid tie ?

Would be great to have this explained please. Here, the buy-back rates vary between power co's (there are no mandated feed-in tariffs) and, alarmingly, they won't be locked into any significant periods. The only way it stacks up financially here at the mo' seems to be when the cost of connecting to the grid is prohibitive. Looking out my window, there's a house and shed/workshop building site I'd like to relocate buildings to, that will cost $60k to get power connected.

We had a power cut here two nights ago. I made a point of looking out across the whole valley. There was just one house that still had lights on.

 

[Redneck in training]

Would be great to have this explained please. Here, the buy-back rates vary between power co's (there are no mandated feed-in tariffs) and, alarmingly, they won't be locked into any significant periods. The only way it stacks up financially here at the mo' seems to be when the cost of connecting to the grid is prohibitive. Looking out my window, there's a house and shed/workshop building site I'd like to relocate buildings to, that will cost $60k to get power connected.

We had a power cut here two nights ago. I made a point of looking out across the whole valley. There was just one house that still had lights on.

If I understand it correctly GB (and most likely other European countries) has feed in tariff (FIT). If the system is 4kW DC or less the current rate is 50% of estimated production that is used to offset energy charge. Since it is not measured (Yet) people use various devices that redirect excess energy generated by the PV to in example hot water immerSUN | immerSUN. The goal is not to supply any energy to grid but lower consumption of in example natural gas used to heat the water. If the system is larger than 4 KW the the FIT rate decreases. Some European members might give us more precise description I suppose.

Most large utilities that are regulated by states have to offer some version of net metering in the USA. Some are settled monthly and some yearly. In any case utility will install "smart" meter that keeps track about energy consumed and energy pushed to the grid. Whatever is pushed to the grid is accumulated and used to offset energy consumption when sun is not shining. If you still have excess then utility will pay you the wholesale rate (typically 0.035 USD/kWh) or it will just pocket the energy and give you nothing. Settling the account once a year produces the best results because summer generation excess is used to offset winter deficit. Some utilities charge a "connection" fee to clients with PV. Some small utilities (electric cooperatives) that are not regulated by the states are very supportive of alternative energy and provide net metering, grants, loans etc, some are indifferent and some are openly hostile and punish you in example by canceling so called heating rate (if you have geothermal or high efficiency heat pump heating) that is less than half of retail rate (0.048 versus 0.115 USD) increasing your energy billing by several hundred dollars/year.

You can look at net metering as a battery with 100% charge/discharge efficiency. Net metering provides for short ROI especially if you can shift energy load to electric in example you switch from oil fired boiler to a heat pump.

 

[buickanddeere]

Here is and article about distributed energy storage. I think that is a beginning of change how we generate and use energy.
Falling energy storage costs and steadily increasing solar capacity stand to catalyze a paradigm shift from net metering to distributed energy storage.

There are no cheap, reliable and safe ways to store commercial amounts of energy. Although there is no shortage of researchers who are happy to take your money, make promises and spend the money tinkering in a lab.
Unless the Almighty adds some new elements to the periodic table. There are no energy density or price break throughs in batteries.
Ever calculate how many golf cart batteries it would take to power NY with just wind and solar power?

 

[KiwiBro]

Most large utilities that are regulated by states have to offer some version of net metering in the USA.

Thanks Redneck. Are they locked into those rates and if so, for how many years? Enough to give the customer confidence in the payback period required to cover the costs of their installation?

 

[farmer2009]

Our utility company buys all its power from TVA. So it has to follow the net metering regs for TVA. And a couple of years ago when I checked on it. They had a 10 year rate guarantee at market price then an additional 5 or 10 year rate at a % of market. I don't remember the numbers but that's the way it was explained to me by the solar people. I couldn't get there numbers to work out though. That was a hands free system. They build you pay. It did have micro inverters and was 50KW. Prices quoted were about 150-160k.

 

[Redneck in training]

There are no cheap, reliable and safe ways to store commercial amounts of energy. Although there is no shortage of researchers who are happy to take your money, make promises and spend the money tinkering in a lab.
Unless the Almighty adds some new elements to the periodic table. There are no energy density or price break throughs in batteries.
Ever calculate how many golf cart batteries it would take to power NY with just wind and solar power?

Energy density is only minor issue for stationary use. Life and cost of the storage are the major issues though. The joke is: It can be cheap, reliable and long lasting but you can get only two out of three at present time.
Presently our utility doesn't offer net metering so I am thinking about energy storage. Since the major energy user is our geothermal heat pump I am thinking about storing energy as heat or lack of it. The best solution would be variable speed heat pump with a current sensor on the utility feed line. The power consumption of the HP would then be adjusted such a way that the energy flow to utility will be zero. The HP would heat or cool a large tank with liquid that would be used to heat/coll the house when sun is not shining.

 

[Redneck in training]

Unthinkable while ago might happen:
$1 Trillion Solar & Wind Finance To Outstrip Oil & Gas Industry | CleanTechnica

 

[houstonscott]

With net metering solar becomes very attractive because the electric company becomes a 100% efficient battery, that's free. Without net metering your kWh prices are going to have to be very high in your area to justify the expenditure financially. HS

 

[buickanddeere]

Net metering is good for the consumer but it leaves the utility holding the bag. Solar As disturbing to electrical distribution grid operation and generation as it is. It works great compared to wind turbines .
The only place where solar and wind is practical is small users too far from the distribution grid. Or in Hawaii and other isolated regions where generation is $$$ oil fired diesel or gas turbine . Where any power is is better than no power.
Most people don't seem to realize that fossil generation has be kept on spinning reserve to backup solar and particularly wind.
A power plant generating 5% of rated power burns more than 5% of the fuel used at 100% power. Operating costs from wear and tear are not 5% of rated power either. CO2 output isn't 5% either.

 

[houstonscott]

Net metering is good for the consumer but it leaves the utility holding the bag. Solar As disturbing to electrical distribution grid operation and generation as it is. It works great compared to wind turbines . The only place where solar and wind is practical is small users too far from the distribution grid. Or in Hawaii and other isolated regions where generation is $$$ oil fired diesel or gas turbine . Where any power is is better than no power. Most people don't seem to realize that fossil generation has be kept on spinning reserve to backup solar and particularly wind. A power plant generating 5% of rated power burns more than 5% of the fuel used at 100% power. Operating costs from wear and tear are not 5% of rated power either. CO2 output isn't 5% either.

I agree, as long as solar remains one or two customers here and there, the electric company will look the other way with net metering and stay in governments good graces. Most electric companies don't offer net metering and those that do will in all likely hood if solar gets to big will drop it, doesn't make sense for them to suppy in essence your battery at no cost. It does seem with some simple weather attention and a record of arrays in their area, electric companies could every easily predict just what there solar customers are going to produce tomorrow and adjust their production plans for tomorrow. HS

 

[buickanddeere]

No net 10Kw metering according to Hydro One on the 4800V three phase line running past my place to the 2.1MW transformer station 2-1/2 miles away. As it will overload the system.
I can however update my utity service to three phase , 600V and 200amp , 207 KW no problem.
I smell a rat.
The utility courtesy of the rate payer spent over 1 billion last year to subsidize electrical rates for green power . Then turn around and have to pay New York and Michigan to take surplus power on nights and weekends.

 

[houstonscott]

927kwh's so far this month. HS