enjoy your net-metering company. i wish the same in our country.
what e-cars do you own?
i am deciding to buy ioniq electric

Mark,
if it's anything like the Model S,
GO FOR IT.
Thanks for reminding me, I had to get on my phone and start the charging (car).

I would like to pose a question:

If one were to build a purely renewable energy powered crunching system that only powered up machines when the PV/wind output was great enough....

What method would you use to control such a system?

Hi,

Starting from solar power historical data of 2016 for Romania I've done some simulations and indeed: one cruncher with some additional battery storage has 2x the number of WCG points per Euro spent than 2 crunchers with minimal battery storage.

The details of the assumptions I've took are the following:
- crunching unit price: 1000 euro
- WCG points/day: 40000
- daily energy consumption: 6KWh (250W/h)

- solar panels: 1000 euro/KW
- battery pack: 100 euro/KWh
- charge controller: 50 euro
- inverter: 100 euro/crunching unit

- charging efficiency: 70%
- inverter efficiency: 90%

- energy price: 0.15 euro/KWh

Assuming a 5 year life period and doing some trial-and-error we've got:

1. for 1 cruncher with 1.75Kw solar panel and 4 KWh battery packs a total setup cost of 3338 euro with a running time of 71% for the year. Electricity cost would have been 1171 euro so cost is 3338-1171=2167 euro. WCG points for the 5 year period and 71% running time = 52,031,944.

Thus WCG points per euro spent: 24,013

2. for 2 crunchers with 1Kw solar panel and 1KWh battery pack (didn't set it to 0 to ensure the crunchers have a relatively stable power supply) the total setup cost is 3350 euro (so in line with option #1). Running time is only 23% for the year. Electricity cost would have been 746 euro so cost is 3350-746=2604 euro. WCG points for the 5 year period and 23% running time = 33,141,667.

Thus WCG points per euro spent: (12,726)



Will do also a simulation for wind powered system and share the results.

later edit:

Results of simulation for wind energy:

1. for 1 cruncher(s) with 1.25 Kw wind turbine and 1.75 KWh battery packs a total setup cost of 2,588 euro with a running time of 65% for the year. Electricity cost would have been 1,069 euro so cost is 2,588-1,069=1,519 euro. WCG points for the 5 year period and 65% running time = 47,490,278

Thus WCG points per euro spent: 31,265



2. for 2 cruncher(s) with 2.25 Kw wind turbine and 3.25 KWh battery packs a total setup cost of 4,888 euro with a running time of 61% for the year. Electricity cost would have been 2,023 euro so cost is 4,888-2,023=2,865 euro. WCG points for the 5 year period and 61% running time = 89,891,667

Thus WCG points per euro spent: 31,376

Hi,

last autumn we installed a PV on our roof and an AC-battery in the basement.
Panels: 5.88 kWp (21x280 incl solaredge poweredge optimizer)
Inverter: Solaredge 5K 3phase
Battery: Varta 5.8kWh net capacity.

Since spring I run my home server a HP 360e Gen8 with 1 x E5-2450L V2 24/7 at full utilization to support WCG.
The server draws 77Watt from the wall. The total IT stuff (switch, access point, ...) 100 Watt so 2.4kWh per day. Without the full utilized WCG virtual machine my home infrastructure would consume 1 KWh/per day leaving WCG with 1.5kwh per day (62Watt for 10x1,9 Ghz+Hyperthreading ~ 70-100K WCG point per day, depends on the projects).

Since late April I had less days where it was raining / cloudy for a longer period so that the battery fully drained. The calculated self-sufficiency is currently >90%. So I can crunch 100% green during day and night.

In Germany a kWh costs in average 29ct (standard terms). Electricity which exceeds my batteries capacity is sold to the grid and the operator reimburses 12,3ct/kWh. So the lost opportunity cost for me is around 15ct (there is a minor VAT impact on self consumption).

Summarizing, my donation to WCG for the 6 months (end of April until beginning of Oct) is estimated for 1,5 kWh x 180 days x 15ct = 40€ instead of 79€ resulting in about 14m WCG points (180 days x 75.000 ppts per day). No idea if this good / bad / efficient but it is altruistic and solar-green-IT.

Best,
Thomas