(Half) MEGAWATT
We generated our first half megawatt hour (500 kWh) this Sunday, roughly 11 days since we turned on the system. Weather depending, we’re on track to generate our first megawatt hour before the end of the month. We might have to have a first megawatt party July 4th weekend. Kick-ass!
Up Hill House 
So what does that mean in dollars? How much did you save?
Arthur, you’re taking this mega non-sense a bit seriously. I’m just having fun. Who wouldn’t want to have a MEGAwatt generation party?
But seriously, I won’t know our real savings until we install an energy monitor. For now I have to read our solar meter and electric company meter and subtract to find out how much power we used and then multiply that by 14 cents a kWh. For instance in the first week we generated 230 kWh and sent 205 kWh back to the grid. Subtracting, that means we used 25 kWh. At 14 cents a kWh that would have cost us $3.50 if we bought it from the utility. That’s just for one week but now you see why we have an 18 year estimated payback.
But, if New York state enacts legislation for SRECs like other states have, we could potentially sell an SREC for every megawatt we generate. The price of 1 SREC in New Jersey a few months ago was $200-300. Generating an additional $2,400 to $3,600 a year would significantly shorten our payback period. That makes my wallet happy.
Now, I put my tree hugger pants on and ask the question a little differently. What did we save? Not you and me, but the planet? Theoretically every megawatt we produce is a megawatt the electric company doesn’t have to burn coal or oil or build nuclear power plans to generate. Actually it’s even more than that because for every megawatt the power company generates, only a third actually makes it to your house. The rest is lost due to inefficiencies in transmission. All my closest neighbors get to use my sun powered electricity very efficiently because it doesn’t have to travel far. It’s obviously more complicated than that because it took energy to mine the materials, create the panel components and transport them to our house. But over time our system will recoup all that embodied energy and still come out ahead. That makes the tree-hugger in me very happy.
Sorry, but you asked. 😉
Larry,
Thank you for the detailed explanation and I appreciate you just having fun. I expect nothing less. Energy management is a fascinating and complicated subject. Just trying to put my head around what all these figures mean. I wonder, do they have carbon footprint meters you could put in your house? That would be cool to see.
Agreed, it can be a complicated subject and I can get stuck in the weeds. I promise to do a better job explaining.
Most energy monitors will show carbon emissions associated with your energy use. Our inverter that converts the panel’s DC current to AC will show us carbon emissions avoided. One of the big difficulties is that most households use multiple forms of energy, electric, natural gas and oil, whereas home energy monitors can only measure electricity. To get a fuller picture of your carbon footprint, you’d need to track those too. Not to mention your commute to work, air travel, the type of food you buy and where it comes from, etc… There’s quite a few carbon footprint calculators on the web. It’s a fun exercise to plug in some data and see where you’re at and how you compare.
For example, I quickly ran the numbers at carbonfootprint.com, and I can see that our one and only car is responsible for the largest portion of our carbon footprint yearly, 9 out of the 13 metric tons. One of the reasons I oversized our solar array was in the anticipation that we would get a plugin hybrid, which should significantly reduce our footprint. Again, these numbers are very rough, but a good starting point.
with fireworks? 🙂
Correction! I can’t count. We generated our first half megawatt in 18 days, not 11. So its more likely to be a megawatt approximately every 5 weeks.