On September 29, I was asked to participate on a panel titled “Evolution of Energy Generation and Distribution in Canada’s Smart Power Grid” at the Innovation 360 conference in Gatineau, Québec (http://innovation360.ca). Here is the essence of what I contributed.
By definition, in an electricity network, energy consumption plus losses equal electricity generation. This must be true at any point in time, or protection systems will shed load or trip generators.
There are 4 ways to balance load and generation:
1) Traditionally, dispatchable generators that can easily ramp up or down were tasked to follow the load. Big hydro plants and natural gas generators are particularly good at this. However, we are running of big hydro opportunities, and natural gas are sources of greenhouse gas emission, contributing to global warming.
2) Another way to balance load and generation is to interconnect with neighboring network that may not have the same load profile. Today, all of North America is interconnected in some way. However, building transmission lines is a lengthy process that typically faces major local opposition. As a result, most transmission lines run at capacity during peaks, weakening the bulk transmission system as the Northeast blackout of 2003 demonstrated.
3) In the last couple of decades, we have started to control load, like turning off air conditioning units by pager or getting large industrial like smelters to go offline for a couple of hours during a major peak. Time-of-use or market pricing are also attempts to have loads better follow available generation capacity. However, much of the conservation focus thus far has been on energy efficiency, not peak load reduction.
4) Very recently, energy storage has been getting attention. Traditionally, the only utility-scale storage technology available was pump-storage, like the Sir Adam Beck plant in Niagara, but few of those plants are possible, and they are not efficient. Going forward, batteries, either utility-scale or distributed storage, will grow, although for now utility-scale batteries are MW-class, when hundreds of MW or GW are needed.
Balancing load and generation is also becoming more and more difficult. On one hand, consumption is getting peakier, partly due to side effects of some energy saving programs, like turning down thermostats at night in the winter, and then turning them back up in early morning, just in time for the morning peak. On the other hand, wind and solar generators are replacing fossil generators, adding unpredictability to generation and taking away controllability, thus requiring even more balancing resources.
Integrating renewable into the grid is not only causing balancing problems. It also creates voltage management and protection problems. Those are solvable, but significant, engineering problems that require expensive upgrades to the electricity grid.
Ultimately, load and generation balancing, voltage management and grid protection adds costs that are ultimately born by subscribers. It therefore quickly becomes a political issue.
As a society, we have been subsidizing fossil fuels. Clearly, going forward, we will need to greatly invest in the grid if we want to limit the predicaments of global warming for our children and grand-children.