Using permaculture ethics & design principles to transform an old energy guzzling bungalow into a showcase of sustainable design. It's about energy cycling, building community, self-reliance,creatively using & reusing materials... all without spending heaps of money.

Tuesday, January 31, 2012

Using grid interactive solar (or not)

Principle 3: Obtain a yeild

Since we got our 1.5kW PV solar system switched on at the end of July last year, just on six months ago, we have generated 1375 kW and exported 1164.9 kW. So we have used 210.1 kW (the difference bewteen the two) from our system plus the 204.4 kW that we imported from the grid. That's 414.5 kW over six months, about 2.27 kW per day being a 20% reduction on the same period last year. I attribute this to our greater awareness of our power generation and further energy conservation efforts.
We received our first bill (actually a $30 credit) from our energy retailer, Origin, recently - three months overdue. The bill does not show our total energy useage because we use power from our system as it is generated (the 210.1kW figure above). What I noticed on our bill was that is that we are not being paid the 66c 'premium feed-in tariff' that we were told that we would be, but are instead receiving the new rate of 23.5c.
I contacted Origin to try and work out what was going on and got a call back yesterday with an appology stating that Origin have made an error, and are not going to pay me the premium feed-in tariff rate (after assuring me in writing that they would). I was also told that I would be compensated for this error. What a stuff up! I assume that they didn't send in the Contract of Acceptance that I submitted to the right government department in time, so wont be getting the subsidies for exported solar power, which are no longer available.
I thought it best that I calculate what I think that the compensation should be based on current figures so that when they come to me with an offer I have an idea whether it is reasonable or not - somehow I have the feeling it wont be. The contact that I was entering into with the premium feed-in tariff was for 15 years (I think), so:
1165kW exported over six months
= 2330 kW exported over on year (estimate)
= 34,950 kW over 15 years
The difference of the 66c tariff and the 23.5c tariff that I am receiving is 42.5c
34,950 x 42.5c = $14,853
Wow! Not bad. That's what I'll be asking for in compensation, wonder how I'll go?

UPDATE 20th Feb 2012: One thing that I've been thinking about since I wrote this was about our intention to reduce our energy usage further by: purchasing more energy efficient appliances in the future, LED lighting, installing a pressure tank and / or header tank to reduce water pump usage and stand by, and the contruction / purchase of a solar oven (we have been using an electric one for a while) - along with any other measures that we can think of. This would affect our compensation into more positive territory (for us).

Since our fridge died at the start of the year we have been using water frozen in bottles stored in the freezer compartment of the old bar fridge to keep food cool

In other energy related news, our 23 year old bar fridge died at the start of the year, during a hot spell. This is just a few weeks after we bought a freezer. We had trialled the use of a esky (23lt cooler) to replace the fridge for a few days (before it died), using 2 x 1lt ice blocks from the freezer which lasted a few days before melting completely.  The esky wasn't big enough so we put the idea on ice (pun intended) until we got the cool cupboard finished off. The cool cupboard would store most fresh food (fruit, vegies, butter, cheeses & eggs) that we would normal store in the fridge, keeping it at an estimated 14-18 degrees - see Melliodra eBook. I hope to get this finished soon, but have been put off by the difficulty in getting the doors to seal with my limited skills.
In the mean time we have continued to use the fridge with the inclusion of about 4lt of ice (2 x 2lt milk bottles or 3 x 1.25lt bottles filled with water) kept in the freezer compartment, which is changed each morning. It takes about one minute each day to do and saves us buying a new fridge and the running costs of about 600W + per day. The bar fridge with ice doesn't stay as cool as a powered fridge, but it's not bad. Important to use up food quickly. Beer is chilled in the chest freezer before drinking.
In a short term energy audit (36 hours) our 150lt chest freezer used 600Wh, about a third less energy that the small bar fridge on it's own. Owning the chest freezer has been great (what a luxury!), we've been able to take advantage of bulk food purchase, another option for preserving and have home made icey poles on hot days to help keep cool. It uses less energy and give us more options than a bar fridge, with only a small amount of work (putting ice in each day). Worth exploring further, in combination with the cool cupboard.

UPDATE 14th Feb 2012: Our new freezer uses about 466Wh per day, measured over a 8-9 during summer, which is far less than the 2 star energy rating of 836Wh per day (305kWh p.a.) that it's been given. This could be because its pretty full and got plenty of room for air movement.


Gina said...

The system worked for our icebox when I was a child, so why not today? (Did they have ice delivery by horse and cart in Australia? Ah, fond memories...)

Anonymous said...

congrads on choosing to step out of the box the rest of us are trapped in ,Iam working on the same thing in a much smaller way your freezer is possibly more efficeint because of age and also because all the cold air doesnt fall out every time you open the fridge door.

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