Saving money driving an electric car on sunshine: Jason's storyAugust 19th, 2013
Wondering about the benefits of installing solar electric panels on your home? Curious about driving an electric vehicle that’s powered by sunshine? It’s not just green; solar helps families save money.
Let me tell you a little bit about my story. I installed solar panels on my house in 2011 and bought a Nissan LEAF at the same time. Many people I’ve spoken with assume that I’ve made huge financial sacrifices to go green, but that’s not how the numbers worked out for me.
Here is one year of our electrical energy numbers in simple kilowatt hour (kWh) and dollar terms. Thanks to Time Of Use Net Metering (provided through our utility), we use about 50% more electricity than we generate, and yet pay nothing for our electricity, because of the difference between the higher value of the electricity we generate compared to the lower value of the electricity we use.
- Our home use: about 4,500 kWh
- Our electric vehicle (EV) use: about 3,000 kWh
- Our total use: about 7,500 kWh
- Our home solar photovoltaic energy (PV) generation: about 5,000 kWh
- Our cost: about $0 (we actually 'gave' about $30 of electricity to the utility)
Why I save money: the electricity we generate with solar is worth about 150% the value of the electricity we use. This is because Time of Use Net Metering measures the amount of electricity we generate (i.e., the electricity we put on the grid because we are creating more power than we use at the time of generation) and compares this against the amount of electricity we use at the exact time we use it. In a sense, we "sell" electricity to the utility at the time it’s generated, which is during the "peak" time of day when the sun is brightest and also when lots of electricity is being used. Therefore this electricity is worth more to the utility and to the electricity users of the utility. We "buy" electricity from the utility for our home needs and for charging the EV mostly at the "off-peak" time of day, when there is little electricity being used, so this electricity is worth less to the utility (in fact, often the utilities have too much electricity because they have to keep their turbines spinning even in the middle of the night when few people using electricity). This is why we can use 50% more electricity than we produce and still come out even.
And just so you have total info:
- Our PV cost: about $12,500
- Our gasoline and maintenance savings: about $2,500
- Our electricity savings: about $1,000
- Complete return on investment break-even point: about 4 years
How much I expect to save over time: over $400,000 with compounding interest, given of the projected increase in the price of gasoline and electricity based upon the past ten years of price increases and given the guaranteed lifespan of PV (it's true, feel free to check the math). Of course there are several assumptions built into this number: such as the assumptions that we would have kept a car with average MPG, and that electricity costs will continue to rise. While these assumptions might not prove to be accurate, alternatively the increases in the cost of gasoline and electricity may turn out to be even greater over time. Who knows exactly what will happen over 25 years?
What is certain is that we will save a great deal of money. What is certain is that we have taken the greatest possible step in reducing our carbon footprint by getting rid of our gas-burning car, thereby putting 10,000 fewer pounds of carbon dioxide into the air. What is certain is that we are creating local jobs and supporting American suppliers. What is certain is that I love driving an EV, knowing that I refuel it with an endless supply of the sun's photons, and therefore I have totally guilt-free motoring.