GroenGemak generates 1000 kWh in half a year

Groen:    Gemak:

On May 31st of 2009, at 11:57 GMT, the solar cells on the rooftop of GroenGemak passed the milestone of 1000 kWh, or 1 MWh. This energy yields EUR 564 in energy paybacks, or lesser cost. It also saves the world 410 kilograms of CO2 and 0,24 grams nuclear waste, compared to the local default supplier. All this on a normal rooftop in a city, in about half a year!

Keywords: energy habitat peak oil

The following graphs show what happened up to the point of this milestone. The first shows the energy dripping in as a function of time, the second is the efficiency of the convertor (which sometimes peaks over 100% if it was charged at the time of measurement, but which averages at about 96% efficiency).

Production in the 24 uur up to the milestone. Efficiency of the convertor in the 24 hours up to the milestone. Production in the days up to the milestone. Production in the month up to the milestone. Production in the months prior to the milestone.

The major advantage of solar cells is that they help to discouple from dwindling energy reserves. Variations in energy prices don't matter anymore; the yields are fixed at a particular amount per kWh. This installation has been setup to fully supply the energy needs for a household, so it is dimensioned at 2640 Watt peak power.

The installation served its first full day on the 6th of November 2008, so this energy has been captured in 7 months. The installation seems to be right on track to deliver the anticipated annual energy of 2112 kWh, with the Summer peaks still coming up. This anticipated amount of energy would pay back EUR 1191 in supplied/avoided grid energy, or 865 kilograms of CO2-reduction and half a gram of nuclear waste. Per month, that is EUR 99, 72 kilograms of CO2 and 0,042 grams of nuclear waste.

Update June 18: Since the above, 18 days have passed. In those days, all figures were raised by as much as 20% -- awesome! This means that those last few days my panels generated 200 kWh, or 11.11 kWh a day. This sells at EUR 6.27 a day, saving 4.6 kg of CO2 a day (just imagine carrying this weight to a dump every day!) and 27 mg of nuclear waste. Well done, Sun!

Details: Prices vary lightly depending on the actual supplier's energy prices, but the subsidiary arrangements keep the minimal pay-off stable for the first 15 years of service. The comparison to the local default green/gray energy supplier Essent is made on the basis of this table.

Nuclear waste: Saving half a gram of nuclear waste may not seem like much, but it actually builds up at an incredible pace. Assuming it takes 10000 years to break down, then solar cells evade 50 kilograms would have been built up at the end of this period, for this household alone. This is an incredible amount if you consider how much conrete and politics is needed to store it away "safely".

Doubled the results: All the results above were doubled (2 MWh was generated) on Wednesday August 26, 2009 at 15:30 Dutch time.

Live data: If you are interested in seeing recent developments, just have a look at the live measurements. The kWh-measurements started after the installation already generated 1234 kWh, so you must add that to the totals reported here.