–by Tom Owens —

As you consider buying one of the new all electric cars, some thought should be given to their environmental impacts. Since they run on electric energy, we should look at where that energy comes from and what environmental impacts that causes. There are at least three ways to consider this issue.

First, you can take the view that electric energy here in the San Juan’s is all from clean hydro.   In fact, OPALCO contracts with BPA for our electric energy. BPA is predominately hydro based, with some nuclear and natural gas generation. So some people claim our electricity is clean from a CO2 point of view. The sad fact is that electricity does not follow the contractual path from BPA’s hydro to your new electric car. Our energy source is not all clean hydro.

Second, you can take the view that the electricity here in the San Juans comes from the closest generating plants. There are simple cycle and combines cycle natural gas units nearby. There are also small and medium size hydro plants in our area. At times, power comes south from BC Hydro. The Centralia coal fired plant at 1340 MW is also a potential source for us. BPA moves hydro power from east of the mountains via its transmission lines. However, we live in an interconnected world particularly in terms of electricity. Our electric system includes the 14 western US states, British Columbia, Alberta and a portion of northern Baja California. So, the idea of our electricity being supplied by the nearest plant is questionable.

Third, you can ask the question, when the 55,000 electric vehicles that our governor wants to put on the roads plug into the interconnected electric grid, how does this vast grid respond? This is a true test of our question and it is a little complicated. Please bear with me.

First, you need to understand how generating plants are “dispatched” or added to the grid as new demand comes on line. Generally, power generating companies will ensure that the lowest incremental cost (very close to the fuel cost) plants are on line first. They then add plants one at a time to meet increasing demand, up to the highest incremental cost plants, which come on line last. So what does this stack look like? Hydro, solar and wind have virtually zero fuel cost so they are on line first if they are available. Nuclear plants, in Washington and Arizona, also have very low variable cost. Next might be combined cycle natural gas plants, depending on the cost of natural gas. Mine mouth coal plants like those in Montana, Colorado, Utah and Wyoming would be next in line. Rail delivered coal plants, like Centralia would be next. Finally oil and perhaps simple cycle natural gas plants would be last. There are other issues involved in dispatching power plants like contractual constraints, transmission issues, fish migration and spawning requirements and plant operational issues, so it is not as simple as I describe.

To understand where the electricity to charge your new electric car will come from, you have to know which plant will supply your needs. The electric demand on this interconnected system changes during the day, day to day and season to season, so the answer changes all the time. The plant meeting new demand will be the plant that is the next in the dispatch order that has unused generating capacity. At times of peak load, this will be the very highest cost plant. At other times, it will be the mid-cost plants, coal for example. Rarely will it be hydro plants.

So to answer the question, “What is my “electric” car really running on?” is that your car is running on coal and perhaps natural gas, not hydro. The answer would be the same for any new load placed on the interconnected system. Likewise, if you use less energy through energy conservation or put a solar system on your home, you are reducing the amount of coal or natural gas that is being burned.

But is an all-electric vehicle still better for the environment than one running on gasoline? Perhaps it is, but not as much as you are being lead to believe.

(Owens will address that question in a future article).

Tom Owens is a retired energy industry worker with 35 years experience.

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