If we can avoid burning fossil fuels to make electricity (or heat our homes), we can avoid carbon dioxide emissions which cause global warming.  Fortunately, we can do just that by buying green power and making our homes energy efficient.  Can we quantify the benefits of green power and efficiency?  Yes, we can!  Here’s how:

The organization that runs the New England power grid does an annual assessment of air emissions made by generators in the region.  The assessment reports on how much sulfur dioxide, nitrogen dioxide, and carbon dioxide are emitted in a given year, both on average per megawatt hour and at the margin.  By “at the margin” we mean the last megawatt hour (MWh) produced.  When we consider how avoiding emissions is a benefit, we calculate the benefit by looking at the marginal rate, which is the rate associated with the last megawatt hour we are using on the New England Power grid.  For those of who are concerned about climate change, we are interested in the marginal rate of carbon dioxide emissions because we want to replace that last megawatt hour of dirty energy with something that is zero-emission.   The point is that that we claim credit for avoiding the marginal rate rather than the average rate. 

In the 2012 assessment, the most recent report, we can see that the marginal emission rate of C02 was about 900 pounds per megawatt hour, depending upon the methodology used in the calculation. 

So here is how that plays out when you and others buy green power:

• You buy 500 kilowatt hours (or one half a megawatt hour) of New England Wind per month, that’s about what the average customer uses in a month.  Because New England Wind is 100% “Class I” renewable energy, you avoid 450 pounds of C02 in a month (900 lbs. per MWh divided by two). 
• In the course of a year, you avoid 5,400 lbs or 2.4 metric tons of C02 (450 lbs. per month times 12).
• As of today, Mass Energy and People’s Power & Light (we are one nonprofit organization doing business under different names in Massachusetts and Rhode Island) have 8,000 members.  On an monthly basis, we expect our members to consume about 4,000 MWh of green electricity. 
• 900 pounds times 4,000 MWh of green electricity = 3.6 million lbs of avoided carbon dioxide per month!
• When we determine how much CO2 we are avoiding, we count only the megawatt hours delivered by MA Renewable Portfolio Standard “Class I” renewable resources (recently built, local renewable generators). We project that our members will consume about 1,200 MWh per month from Class I renewable resources (about 30% of the megawatt hours we deliver are Class I). If we multiply that by 900 lbs, we get 1.08 million lbs per month.

Think about that – our members are saving 24 lbs per minute.

Similarly, if you do not buy green power, here is how you can reduce carbon dioxide emissions by using electricity more efficiently at home:

• You buy 500 kilowatt hours per month before improving your home’s efficiency.  This means your carbon footprint is 5400 pounds or 2.4 metric tons per year, the same as in the example above.
• Then you replace inefficient appliances (i.e. refrigerator and air conditioners), and upgrade lighting to LEDs.  This results in reduced consumption to about 400 kilowatt hours per month, or 4,800 pounds or 2.2 metric tons per year.  You cut your carbon footprint by 20%.  And because the efficiency costs less than what you would pay to buy the electricity, you are getting a return on your investment.

Morals of the story: 

• If you can refer a friend to New England Wind or New England GreenStart, you can help avoid even more carbon dioxide.

• When it comes to green power, more is better!

• And if you make your home more efficient, what you save by using less should roughly pay the premium charged for green power.