3kW Grid Tied Solar PV: Watts and Warts.

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103 posts

Master Geek
+1 received by user: 11

#1164590 29-Oct-2014 19:45

Yeah, there have been a few interesting comments recently by Generators/Retailers. Everyone is understandably protecting their business, which in many cases is 51% NZ Inc Shareholder. There is currently no "penalty" as such for grid tied self-Gen, although some of the delays in getting import/export meters installed may be seen as contrived. The positive is that in a totally un-subsidised market with subtle barriers by established players Solar PV is totally viable. Our Electricity regulatory regime & the Commerce Commission are the envy of many globally, and I'm personally pretty confident that any test case will work for local/self Gen. I've modelled & tendered a business PV System with an 11 year pay back (disregarding use of money or NPV) to a (very high user) customer paying under 12c/kWh so there is no doubt about the economics even without any export tariff regime. PM me if you want to explore a long term money maker.

k14

631 posts

Ultimate Geek
+1 received by user: 94

#1164778 30-Oct-2014 07:35

Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

SumnerBoy

2079 posts

Uber Geek
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#1164806 30-Oct-2014 08:59

That is not good news either...

freemark

103 posts

Master Geek
+1 received by user: 11

#1164987 30-Oct-2014 13:00

k14: Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

Disagree. The economics are based around what power usage you are able to replace with your system, and the price you are paying for your electricity (which you don't then have to buy).

Porboynz

110 posts

Master Geek
+1 received by user: 47

#1165271 30-Oct-2014 20:00

freemark:
k14: Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

Disagree. The economics are based around what power usage you are able to replace with your system, and the price you are paying for your electricity (which you don't then have to buy).

The problem is exaggerated for existing installations where the PV array is sized well beyond the daytime usage requirements and the ROI depends more on the time shifting commercial model of getting paid for your exported kWh close to what you pay for imported kWh. In my case I very nearly installed a 5kW PV array but when I realised my daytime usage was averaging about 1kW I downsized to 3kW. I would struggle to use all 3kW during summer, but in Autumn Spring and Winter I can use much of my panels energy excess to heat my HWC.

Here is a graph of the kW I have diverted to heat my HWC over the last week.

I can see a bigger market for gadgets like my PV Router that can divert excess power to storage if the retailers cut back to paying wholesale for exported power. It might even encourage me to build a 5kWh battery bank to provide power from midnight to 6am when the load is a fairly static 0.5kW. Interesting times indeed.

***If only I did not know now what I did not know then***

freemark

103 posts

Master Geek
+1 received by user: 11

#1165321 30-Oct-2014 21:30

Porboynz:
freemark:
k14: Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

Disagree. The economics are based around what power usage you are able to replace with your system, and the price you are paying for your electricity (which you don't then have to buy).

The problem is exaggerated for existing installations where the PV array is sized well beyond the daytime usage requirements and the ROI depends more on the time shifting commercial model of getting paid for your exported kWh close to what you pay for imported kWh. In my case I very nearly installed a 5kW PV array but when I realised my daytime usage was averaging about 1kW I downsized to 3kW. I would struggle to use all 3kW during summer, but in Autumn Spring and Winter I can use much of my panels energy excess to heat my HWC.

Here is a graph of the kW I have diverted to heat my HWC over the last week.

I can see a bigger market for gadgets like my PV Router that can divert excess power to storage if the retailers cut back to paying wholesale for exported power. It might even encourage me to build a 5kWh battery bank to provide power from midnight to 6am when the load is a fairly static 0.5kW. Interesting times indeed.

Good on you. What I love about PV in NZ is that it is unsubsidised & hopefully won't need (much) regulation unless the Retailers and/or Generators start abusing their positions. I'll bang away on this thread that a good quality Solar Powerplant on your roof (or wherever you can put it) is a totally wise & economically sound decision. Inverters & storage will develop and will be relatively & increasingly inexpensive to swap out. Had a new Lithium hybrid offering today which while still pretty costly is about 40% cheaper than previous packages and the size of a bar fridge - will cover most household's overnight usage if like you the HWC is on daytime self gen power. I think what will happen is that in a Country with one of the highest proportions of clean generation anywhere we will (& are) utilise imported tech to make PV increasingly viable. But I don't think quality Modules will get much cheaper per installed Watt somehow - our next container is costing 4% more landed than the last (purchased in July/Sept). Most of that exchange rate, a little factory cost. Interesting times indeed :)

bfginger

1330 posts

Uber Geek
+1 received by user: 191

#1165405 30-Oct-2014 23:55

Once solar PV takes off the feed in tariffs may be restricted to times of the day with no or low insolation.

k14

631 posts

Ultimate Geek
+1 received by user: 94

#1165444 31-Oct-2014 07:34

Porboynz:
The problem is exaggerated for existing installations where the PV array is sized well beyond the daytime usage requirements and the ROI depends more on the time shifting commercial model of getting paid for your exported kWh close to what you pay for imported kWh. In my case I very nearly installed a 5kW PV array but when I realised my daytime usage was averaging about 1kW I downsized to 3kW. I would struggle to use all 3kW during summer, but in Autumn Spring and Winter I can use much of my panels energy excess to heat my HWC.

Here is a graph of the kW I have diverted to heat my HWC over the last week.

I can see a bigger market for gadgets like my PV Router that can divert excess power to storage if the retailers cut back to paying wholesale for exported power. It might even encourage me to build a 5kWh battery bank to provide power from midnight to 6am when the load is a fairly static 0.5kW. Interesting times indeed.

I don't want to be sounding like a downer (I would love to have the economic justification to install a PV array) but why would you use a PV array to heat your hot water when a solar hot water heater is 3 or 4 times more efficient (someone correct me if I am wrong??) and costs less to install.

I am currently in the process of building a new house and solar hot water is a very easy justification. But PV is no where near even remotely economic with the current up front capital cost. In maybe 5 years if the cost of install halves it will be economic but at the moment I just can't see it.

Porboynz

110 posts

Master Geek
+1 received by user: 47

#1165465 31-Oct-2014 08:18

You do not have to sell me on the benefits of Solar hot water, I installed a twin plate collector about 6 years ago. The economics were not so great then but it has already paid for itself. The PV panels I have installed May have a longer payback, agreed.

The key statement I made in my post is that I am able to divert excess PV power to the HWC. During the shoulder seasons and winter the flat plate collectors are augmented by electricity and in Auckland we do not have the benefit of cheap off peak power. Therefore it makes good sense for me to divert excess PV during the day into my HWC. If I had access to $0.11 per kWh off peak power then not so.

I agree PV is more expensive that solar water, but you cannot run your beer fridge on your solar hot water collectors.

***If only I did not know now what I did not know then***

wellygary

8816 posts

Uber Geek
+1 received by user: 5300

#1165589 31-Oct-2014 10:11

Porboynz:
I agree PV is more expensive that solar water, but you cannot run your beer fridge on your solar hot water collectors.

Well you can, but its even more expensive than PV hot water :)

http://www.scientificamerican.com/article/solar-refrigeration/

freemark

103 posts

Master Geek
+1 received by user: 11

#1166865 2-Nov-2014 13:31

k14: Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

I can't find any record of that anywhere..can you source that? Ta.

k14

631 posts

Ultimate Geek
+1 received by user: 94

#1166879 2-Nov-2014 14:07

freemark:
k14: Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

I can't find any record of that anywhere..can you source that? Ta.

The letters were sent out to current customers on Monday. I can't link to the info because I am not sure if it has made it to the contact site yet though.

wellygary

8816 posts

Uber Geek
+1 received by user: 5300

#1166901 2-Nov-2014 14:33

k14:
freemark:
k14: Yesterday Contact also announced they will be dropping their feed in tariff down to 8c per kwhr for new customers (current customers will continue at the old rate for the time being). This will be making some of the solar installers a bit nervous. Without the >15c per kwhr feed in tariff any residential install becomes uneconomic.

I can't find any record of that anywhere..can you source that? Ta.

The letters were sent out to current customers on Monday. I can't link to the info because I am not sure if it has made it to the contact site yet though.

Here's the Press release

http://www.scoop.co.nz/stories/BU1410/S01121/contact-changes-rate-for-electricity-generation-customers.htm

Friday, 31 October 2014, 10:08 am
Press Release: Contact Energy 31 October 2014
Contact changes buy back rate for new distributed electricity generation customers
From 1 November 2014, Contact is changing the rate paid to all new distributed generation customers for excess electricity they generate and sell back to the electricity grid to 8c/kWh excluding GST.
Distributed generation is a term that describes small scale electricity generation that is installed by consumers close to their source of energy use, which in home use within New Zealand is typically wind or solar generation.
Consumers then use the electricity they generate to power their home or business, purchasing any additional electricity required from the electricity grid via their energy retailer and also selling any excess electricity generated back to their energy retailer.

“Our new distributed generation electricity buy back rate signals Contact’s desire not to favour one particular renewable electricity form over another and is in line with the cost of purchasing new forms of renewable energy,” says Contact Chief Executive, Dennis Barnes.

“Contact is a huge supporter of renewable generation - last financial year almost 70% of our total electricity generation came from our five geothermal power stations and two hydro power stations.

“We also hold consents to build further geothermal generation which we will explore in years ahead when market conditions signal the need for new or replacement generation capacity.”

Contact’s new distributed generation electricity buy back rate change is the first in over five years and is competitive with other energy retailers’ rates, which are from 3.5c/kWh and upwards.
The price change only applies to new distributed electricity generation customers, although buy back rates for all distributed customers are subject to change with 30 days’ notice as per Contacts terms and conditions of supply.

ENDS

freemark

103 posts

Master Geek
+1 received by user: 11

#1166929 2-Nov-2014 15:50

Thanks for that. Contact were a bit unwieldy anyway, but the risk is that Meridian will drop soon. Still, 30 years of good output from decent Modules is on the cards, and a lot will happen to power prices in that time - definitely makes System sizing and smart usage more vital. We can now offer a very handy little hybrid system with Li-ion batteries that will allow at least some people to go off grid ( or chop 90% off their bill) for under $30k including Modules. But yesterday was a cracker for PV.. 13.6 kWh from a 2.12 kW system and it was often cloudy. ?

wellygary

8816 posts

Uber Geek
+1 received by user: 5300

#1169643 6-Nov-2014 06:17

And as expected here is meridian's cut.....

Key point,
But today the rate for new customers has been cut to 7c/kWh during summer, and 10c in winter

"Further shadows have been cast on the solar power industry after a second major electricity supplier cut its buy-back rate for new customers.

Meridian Energy will today announce it has cut its buy-back rate for customers generating solar power to nearly a quarter of its existing rate, following competitor Contact Energy's drop earlier in the week.

Users of renewable energy - such as solar or wind - use the electricity to power their homes or businesses, and can sell back any excess electricity to their supplier, to be used on the national grid.

Meridian Energy currently buys solar electricity at 25 cents a unit for the first 5 kilowatt hours generated, and 10c after that.

But today the rate for new customers has been cut to 7c/kWh during summer, and 10c in winter.

General manager external relations Guy Waipara said after Contact Energy slashed its buy-rate by more than half, from 17c/kWh to 8c, Meridian had been left with the most attractive rates in the market.

But solar energy uptake was becoming more popular, which meant it was increasingly important for Meridian to get its rates right to stop encouraging "wrong, unsustainable, uneconomic things to go on".

http://www.stuff.co.nz/business/62963249/Meridian-cuts-solar-subsidy

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