You possibly can see that we’re needing to pay to import power from the grid in a single day. This is without doubt one of the massive challenges with photo voltaic, or many other forms of renewable sources of power – absent some form of storage resolution, you want to align energy era with energy consumption each minute of the day.
From Tom:
One of many questions we’ve puzzled is whether or not it will make sense for us to shift our automotive charging sample to extra carefully align with the photo voltaic era sample (assuming that having a automotive plugged to cost in the midst of the day is logistically possible). Like many questions, the reply is sophisticated, and will depend on your body of reference.
To take a look at it from an financial standpoint, we would have liked to take a look at the best way PG&E is charging us for energy and crediting us for energy that the photo voltaic system is producing above what we’re consuming. After downloading our utilization information and dealing by some spreadsheets, we’ve come to the conclusion that aligning our automotive charging with the photo voltaic era (vs. in a single day) in all probability doesn’t make a lot of a distinction, and we would truly make out a bit of bit by charging it in a single day.
Our utilization information exhibits that our price per kWh from PG&E is similar because the credit score per kWh that we get when our panels are producing greater than what we’re utilizing. These charges differ by time of day — proper now, about $0.18 per kWh between midnight and 3PM; about $0.36 per kWh from 3-4PM and 9PM-midnight, and $0.46 per kWh from 4-9PM. Since most of our solar energy is getting generated between 8AM and 4PM, we’re getting credited at about the identical price as we’d get charged if set the vehicles to cost between midnight and 7AM. We would make out a bit of bit charging within the early morning, after which promoting again to PG&E at that greater 3-4PM price, however that’s not an enormous distinction.
Although the time of day we select to cost our vehicles might be an financial wash, there’s something that feels odd about charging the automotive when our panels aren’t producing energy. Is there an environmental influence? Charging our automotive in a single day signifies that we’re pulling energy from the grid, with no matter sources of electrical energy the grid is utilizing at the moment. Whereas we speak about getting our energy from PG&E, technically we’re getting our energy from MCE Inexperienced Power, which signifies that 60% of the electrical energy is getting generated by renewable sources (photo voltaic, wind, hydro), however with our in a single day charging sample, it’s doubtless that the electrical energy we’re utilizing is getting generated by hydro and a few set of non-renewable sources. If we have been to cost our automotive noon, we’d know {that a} bulk of the electrical energy to cost it comes from our photo voltaic, versus these different sources.
All informed, at this level we’re going to maintain our in a single day automotive charging sample. This analysis has led us to a slight adjustment (beginning charging at midnight as an alternative of 10PM), in order that we are able to keep away from the upper 9PM – midnight charges. There’s additionally the comfort of charging the automotive when no one is seeking to drive it.
After all, we’re additionally solely a couple of month into this. It’ll be attention-grabbing to see how our electrical energy era and utilization varies over the course of the 12 months.
From Elizabeth:
What I’ve realized, and could seem apparent to a lot of you, however it actually wasn’t to me, is that the facility we’re producing from our photo voltaic panels isn’t coming instantly in to our home. It goes into the grid. If we have been on a homestead someplace, and we weren’t related to any municipal energy firm, then we’d have our home equipment related on to the photo voltaic panels. At night time, missing a battery stack, we’d have to make use of candles or oil for mild, and a wooden hearth for warmth (additionally not terribly sustainable). As a result of our home was constructed to be related to the grid, the facility we generate goes into the grid. We’re nonetheless shopping for all the facility we want; nevertheless, we’re incomes again the identical price for the facility we generate.
This feels a bit of disappointing. We’re not power impartial. If PG&E decides to chop the facility as a way to curtail the possibility of a fireplace on a extremely popular, dry, windy day, then our energy will likely be lower, too. If a terrorist assaults our energy grid, we’re going to be out of energy similar to everybody else.
Nevertheless, the excellent news is that we’re contributing. The quantity of energy we generate utilizing the solar replaces energy that’s being generated by different sources. Right here in California, numerous our energy is supplied by photo voltaic, wind, and hydro crops, however we do additionally use numerous pure fuel and nuclear for electrical energy era. Right here is latest information from EIA (US Power Info Administration):
