Solar panels - first full year verdict

Well, the electricity company finally sent us the last 6 months worth of bills, plus an adjustment for the 3 months before that (don't even ask...) so I can finally do a year on year comparison of electricity bills pre and post solar.  Which means it's time for a chart!!

I'm pretty happy with a 63% saving, particularly as we had to run the reverse-cycle most of winter for heating when the wood burning stove died. I think that if we'd had the alternate heating source our annual bill would have been more like $350.

The panels themselves generated $1,445 worth of electricity, but of course some of that has gone to paying availability charges and GST. This amount represents 15% of the cost of the panels, so if we repeat this kind of result each year they will have paid for themselves in about 6.5 years, as the feed-in tariff is guaranteed for 15 years. Of course there's also the incremental savings from the "free" energy we get when using the solar generated power during the day - probably between 5-10 kwh.

For those who like details we have a 3kw system, and we get a feed in tariff (gross) of 60c - so every kw we export earns us 60c. In an average day we would export 6-10kw. Since they were switched on 523 days ago our panels have generated 6247 kw of power, so that's an average of around 12kw per day. The best production has been 17, and the worst 1. In an average day we would export 6-10kw - less in winter and more in summer.

I have tried to adjust where possible our electricity usage so that we send as much as possible during the day, and then run dishwashers, washing machines when the panels aren't producing (early mornings and evenings). BUT, I still use the oven, and heaters during the day in the office, and of course I work from home so have lights and computer stuff on a lot of the day. So this result is really more about solar than behaviour change.

It was interesting (read: scary) to see that in the winter when we were running the reverse cycle and extra heaters our average daily off-peak use almost trebled compared to the same period last year. And not only that but I never felt as warm as I did with the fire going. Thank goodness we will have our new energy and emissions efficient wood burning stove in place in a month or so in time for this winter.

Solar update - first full bill

A few weeks ago we received out first bill where we'd had solar on the roof for the entire period. We were $170 in credit, which is nice!

For the stats geeks out there:

• from our 3kw system we exported 823 kWh of energy over the 94 day billing period - almost 9 per day. We got paid 60c per kWh for these. 
• In that same period we generated 1922 kWh - or an average of 13 per day.
• Average daytime consumption is 4kWh - although this obviously varies. 
• Our average daily buy-in from the grid was 7.6 kWh of premium (ie peak energy), and 6 kWh of super saver energy (hot water only, and not many baths were had in Oct-Jan, so you see why we need to get a new hot water service at some point!!)
• We're on a green power tariff, so some of our savings went on that extra cost, otherwise our bill would have been over 200 in credit.
• The minimum power produced by our panels since they were installed is 2kWh, and the maximum has been 16.
• By using the solar power during the day (av 4 kWh) we've saved $64, plus the power that the panels have generated has more than paid for the bill, with some credit to store over for winter, when there will be less sunshine.
• With savings and power generation payments, we've "paid off" about 5% of our outlay in this 3 month period.

All in all a good start!

How about you - do you have panels? How are they performing?

It's just a box...right?

Wrong... it is actually almost 2kwh per day!

This my dear reader is a magic box that will turn my chest freezer into a fridge, and will save me power and money in the long term.

It is actually an external thermostat unit that you plug the freezer in to and then feed the temperature probe into the freezer. This box then turns the freezer on and off as required to maintain a temperature of 4 degrees. No messing around with freezer internals :).

Thanks to Mr Rudd's money, we've purchased the kit, and will purchase a slightly larger chest freezer as our new freezer (to hold more bulk purchased meat as well as frozen home grown produce). Our current chest freezer will be moved into the kitchen (luckily it fits in the space that our current fridge occupies) and will become our new fridge. Our old (17yrs) fridge that is on it's last legs will retire to the shed to enjoy a new life as a rodent proof food store.

Why a chest fridge?

• It is much more energy efficient than a standard upright fridge or fridge/freezer. Our current unit uses on average 2kwh per day. A chest fridge uses around 0.1kwh per day according to the maker and people I know that have them. That also tallies with our chest freezer that uses about 0.4 per day.
• A chest freezer is a LOT cheaper to buy than a new fridge/freezer

We're lucky that we can make all this work with only minor modifications in the utility room (where the freezer will live) and with no modifications in the kitchen so in total we will still spend less than if we had purchased a new upright unit. Thanks Mr Rudd!

If you want to read more about chest fridges click over to Mt Best, who sells the kits. I'll post updates once we are underway with the room modifications.

Cutting back the kilowatts

It's like cutting back calories, but easier! And you don't have to give up chocolate!!

I started out with the best intentions to get the filing done, but got sidetracked when it came to electricity bills. I wonder how our usage has changed over 3 years.........

An hour and a few excel charts and formulae later I discovered our annual average KWh per day has dropped from 25.8 in 2006 to 19.8 in 2008. That's a decrease of 23%. This is in spite of the fact that I started working from home during this time, which meant more electricity use during the day. 19.8 is still higher than I would like, but given that we use electricity to pump our water, plus the home office, I'm really pleased by this progress.

I should point out that we currently do not have solar hot water (it's coming when the existing system finally needs replacing), AND our hot water system is too big for just 2 people, so 5-14kw per day (depending on whether we have a bath or not) is accounted for by hot water.

You can see in the chart below we have made the biggest savings in the 'winter' quarters: Apr-Jul (29% decrease 06 - 08) and Jul - Oct (39% decrease 06 - 08!!!).

But the best thing about these decreases? We didn't have to spend a lot of money to make these savings. We did spend money on:

• gradually replaced curtains with blockout-type curtains for better insulation (when they were on sale, of course!) (2007 - 2008)
  
• making old fashioned draft-stoppers for all the doors (2008)
  
• replacing power hungry old electric oil heaters with newer electric ones that have timers and temperature sensors so they cut in and out as required, and can go off overnight (eg in the bedroom) (2008)
  
• I bought a power meter to track how much power individual pieces of equipment use (2008)
• converting to cf bulbs
• replacing the electric kettle with a stovetop kettle (we have a gas storevop)
  

But there were still more simple behavour changes we made that have clearly made a huge impact:

• over time I've gradually turned down the temperature on the hot water unit to minimise reheating time
  
• we 'curtained off' the end of the house that we don't use unless guests are here, so we're only heating the part of the house we use
• in 2008 we 'decomissioned' the second bathroom unless guests were staying - so that meant turning off the second small hot water unit for that bathroom, and not having to heat the bathroom in winter. I think this was strangely the 'hardest' adjustment as we quite liked having our own bathroom each!!
• in 2008 I relocated my home office to the end of the house that we use in winter - so I now share this room with Jerry. This was also something I resisted as I quite liked being able to have the office a bit more seperate to the rest of the house, and Jerry liked having his own room. However, as my office was in the "curtained off", and therefore unheated part of the house, I was using a lot of power to drag the temperature up from 12 to 16 every day, and running a heater 5-7 hours per day. It was a bit mad looking back on it. In the new study I might only have to run the heater for an hour or so on really cold days. And I can always just pop around the corner and warm up by the fire.
• in 2008 I also 'bubble-glazed' the study/office windows to keep the room warmer, but still let in light.
• I switched to only using 'eco' mode on the dishwasher (which saves about 50% of the power compared to the normal cycle that includes drying)
• I use my slow cooker as much as possible in winter rather than the oven to cook meals - and I try to make enough for 4-6 serves per meal to make the most of the power use
• We have progressively removed light fittings from our halogen track lighting eg over the dining table we had 6 (or maybe 7) and now we only have 4. In the main living area we had 5 and now we have 3. In addition we try to use lamps with cf bulbs rather than the track lighting whenever possible.
• We have used insulting foam or mud to seal gaps that were letting in drafts
  

But of course, there is still more we can do! On the power saving to do list are:

• solar hot water
• finish replacing old curtains with insulating curtains in the rest of the house
• moving from rod and ring style curtain fittings to track fittings so we can get the curtains closer to the window (pelmets just woudlnt work in our style of house)
• replacing the old standard fridge with a chest fridge
• keep up with the gap-sealing work
• opening up the chimney to expose more flue and replacing the fireplace with one that I can put a pot/kettle on to slow cook food during the day / keep water hot for a cuppa .
  

Alas most of these need some serious $$, so I'd best get back to work!!