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Comment: Site C is ideal clean-energy option for B.C.

Most observers believe that we need to move away from our existing fossil-fuel-based economy, in which 80 per cent of our primary energy is derived from fossil fuels, to a lower-carbon alternative.

Most observers believe that we need to move away from our existing fossil-fuel-based economy, in which 80 per cent of our primary energy is derived from fossil fuels, to a lower-carbon alternative.

Achieving this goal will almost certainly usher in the “electricity economy,” in which electricity becomes the energy carrier of choice. We are already seeing this evolve as automotive manufacturers continue to expand their offerings of hybrid vehicles, as well as pure-electric vehicles.

To make the electricity economy truly sustainable, however, the primary means of generating electricity must use low-carbon sources, such as renewable energy or nuclear power. In this regard, B.C. is already a leader, as virtually all of our electricity is produced by hydroelectric power.

One of the best and most cost-effective projects designed to continue our path toward a clean-energy future is already underway in northern B.C. This is the Site C hydroelectric plant on the Peace River, being built by B.C. Hydro to add 900 megawatts of electrical-generation capacity to the provincial grid.

Some people oppose this development because they see hydro power as “old” technology built on a large scale. They seem to believe that a very large number of small, intermittent generators, using windmills and solar panels, are much more effective and environmentally “friendly.”

In fact, just the opposite is true. Both wind and solar power are intermittent sources of generation that can be relied upon only when the wind blows or the sun shines. To provide reliable and predictable electricity, there must be large-scale and cost-effective backup power available, or a large battery-storage capacity. This adds huge cost to the intermittent sources of electricity, or requires a large overcapacity in the hope that the wind will always be blowing somewhere.

Hydro power has a substantial advantage by being based on large-scale energy storage in the form of water stored in a reservoir upstream of the dam. With the Site C development, the small reservoir behind the dam will provide a modest addition to the overall Peace River energy storage.

However, one of the real strengths of the Site C proposal is that it can rely on the large energy storage already in place in Williston Lake upstream of the W.A.C. Bennett Dam, and the small reservoir behind the Peace Canyon dam.

Although not widely recognized, it is this large energy storage on the B.C. Hydro system that enables the utility to make large profits in most years. Powerex, the energy-trading subsidiary of B.C. Hydro, buys and sells electricity on the open market, in which B.C. is connected to utilities in Alberta and along the U.S. West Coast.

Electricity in Alberta is generated primarily by large thermal power plants, which can’t easily be cycled up and down. They therefore usually have a surplus of power at night when demand is low, and Powerex can buy this at very low rates. B.C. Hydro then reduces hydro-power generation overnight, keeping large reserves of energy stored behind its hydro dams.

The next day, at peak power-demand times in the morning and early evening, it uses this stored energy to generate electricity in excess of B.C. needs. The surplus power can be sold to California at peak rates, which is often many times the overnight purchase cost.

It is this pure arbitrage that enables Powerex to contribute millions of dollars each year in profit to B.C. Hydro’s bottom line. According to the National Energy Board, for the first nine months of 2015, the net revenue to the province from buying low and selling high in this way was more than $200 million. This is primarily due to the large energy-storage capacity in the water reservoirs on the B.C. Hydro system.

Critics sometimes argue that the power from Site C is not yet needed in B.C., but this is really irrelevant. In the near term, once the new source of power is built, it can be used to increase the net profit generated by B.C. Hydro, which is then returned to the province as a dividend. Then, as domestic demand increases, more of the new power capacity can be used in B.C.

This will ensure that the province has a sufficient supply of low-cost and low-carbon energy to fuel the new “electricity economy” for many years to come.


Robert L. Evans is a professor emeritus of mechanical engineering at UBC. He is the author of Fueling Our Future: an Introduction to Sustainable Energy. He lives in Sidney.