Net Zero Carbon Calculation

[steve66]

I've been asked to do an electrical load estimate to determine how much on-site power needs to be generated to make a building "net carbon zero" - i.e. all the electric power that the building uses has been generated without any carbon emissions.

Of course, this is very different than the standard load calculation I normally do. I have no idea how to start. To make it even more difficult, this is a combination new building and remodeled building.

Has anyone done one of these calculations? Any insight on how to proceed?

 

[jdcpe17]

correct me if i am wrong, but it sounds like they want something along of the lines of having a net metering setup, where they produce exactly the same amount of electricity that they consume. so you would go about finding out how much is totally consumed, then model various green energy sources such as solar cells and wind turbines as contributing loads to get it to arrive at half of the total usage. done. right??

i know utilities can also buy credits that officially equate to just using green energy.

 

[steve66]

correct me if i am wrong, but it sounds like they want something along of the lines of having a net metering setup, where they produce exactly the same amount of electricity that they consume. so you would go about finding out how much is totally consumed, then model various green energy sources such as solar cells and wind turbines as contributing loads to get it to arrive at half of the total usage. done. right??

i know utilities can also buy credits that officially equate to just using green energy.

Yes, thats the idea. The building may use more than they are generating at peak times, but on average, the generated energy should cover the buildings energy use.

 

[jaggedben]

then model various green energy sources such as solar cells and wind turbines as contributing loads to get it to arrive at half of the total usage. done. right??

It has to be the total usage, not half of it.

 

[jaggedben]

Has anyone done one of these calculations? Any insight on how to proceed?

I wouldn't know how to proceed given that they are asking you to predict the usage of new construction.

One approach might be to take their kWh usage for a year before construction began, and multiply it by the ratio of the new+existing load calcs compared to the existing loads. That would be pretty crude but lacking more specific info it might be the best you can do.

 

[sameguy]

Remember to add the carbon foot print from the making, shipping, etc. of every thing.

 

[steve66]

I wouldn't know how to proceed given that they are asking you to predict the usage of new construction.

One approach might be to take their kWh usage for a year before construction began, and multiply it by the ratio of the new+existing load calcs compared to the existing loads. That would be pretty crude but lacking more specific info it might be the best you can do.

Good point, but they've thrown a wrench in that by remodeling the existing building and adding geothermal.

I'll probably see if I can suggest they contact someone who specializes in this.

 

[steve66]

Remember to add the carbon foot print from the making, shipping, etc. of every thing.

Don't give me another calculation to do if you can't help me solve the first one

Just kidding. You are probably right, carbon neutral should probably take that into account. I guess that shows how little I know about the subject. I'll have to find the time to do some research.

 

[Twoskinsoneman]

Remember to add the carbon foot print from the making, shipping, etc. of every thing.

I had been thinking the same thing. Zero carbon footprint must take into account the hateful carbon spewed by the processes to make PVs and wind turbines.

 

[jaggedben]

Remember to add the carbon foot print from the making, shipping, etc. of every thing.

I wasn't going to raise that issue because it turns a mostly answerable question into a mostly unanswerable question, but yes, this is right. The concept of 'net zero carbon' in our present economy involves some wishful thinking.