One big grid is the solution to secure electricity

Professor Michael D. Mehta of Thompson Rivers University makes a number of good points in his article regarding a secure electrical system (Armchairmayor.ca, March 6, 2021).

However, he’s thinking in the wrong direction when he suggests that the solution is microgrids.

image: Student Energy

The recent electrical blackouts in Texas have focused the problem of electricity security. In a state that prides itself on independence and abundance of energy, it was the height of irony that they should suffer from an electricity shortage that left people freezing in the dark.

Texas’ problem was that its electrical grid was too small. In an attempt to avoid federal regulation, Texas constructed a grid that is a virtual island.  So when the cold snap hit, when wind turbines froze and natural gas generators quit, they had only themselves to rely on.

But not so for all of Texas. El Paso in eastern Texas did just fine, thank you. That’s because they were not connected to the Texas grid but rather to the much larger Western grid.

You see, there are three major electrical grids in North America: the Eastern Grid, the Western Grid and the Texas (ERCOT) Grid, El Paso picked a winner.

The big problem facing green energy is storage. Wind turbines and solar panels are great when the wind blows and the sun shines. But they usually produce too much power when we don’t need it and too little when we do. Storage seems like the answer.

However, as Professor Mehta mentions, no affordable storage system exists with the capacity needed. A number have been proposed; batteries, small-scale pumped hydro, compressed air, and flywheel technology.

Mehta suggests that the solution is not a bigger grid but smaller microgrids: “A microgrid is a local network of generators, often combined with energy storage.”

“Such systems can increase reliability and drive down carbon emissions when renewable energy is used,” says Mehta. “When combined with smart meters that reconcile inflows and outflows of electricity, microgrids provide real-time energy data. When a microgrid goes down, it only affects the local region and not an entire state or province.”

With one big continental grid, there is no storage problem and no one has to go without electricity.

One big grid solves the storage problem by virtue of its size.

The demands on one big grid are predictable. Cold snaps can be are forecast. In that case, thousands of generators, from big hydro dams to small run-of-river, solar and wind generators can be activated.

On an ordinary day, demands on one big grid are even more predictable. As people rise and shine on the Atlantic coast and turn on toasters, heaters, air conditioners in the summer, the demands on the West coast are minimal.

As the sun rises across the four and one-half time zones of our continent, the demand follows the sun. While the demands are not exactly constant they are predictable.

Of course, Canada doesn’t have a cross-country grid and neither does the U.S. Most of our connections are oriented in the worst way: they are North-South, in the same time zone where demands occur at the same time.

As Professor Mehta says, transmission lines are costly to build and lose power. The power loss can be minimized through use of High Voltage Direct Current transmission lines.

The construction of lines is a political problem, not one of cost. When the Trudeau government decided that the Trans Mountain Pipeline was in the national interest, he bought it and built it.

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Germany pays customers to use electricity

German power companies paid customers to use electricity on one hundred occasions in 2017. Companies paid customers a lot relative to what they normally receive -1,720 times more per kilowatt hour.

   photo: CleanTechnica

The reason why power companies were so eager to pay customers had to do with the wind. Wind turbines were generating too much power on the grid and they had to dump it quickly. Surplus electricity is a dangerous problem that has to be corrected quickly.

While wind turbines can be switched off quickly, fossil fuel and nuclear sources can’t. Power grid managers have to agile to compensate for gusty winds.

The problem with surplus electricity is that voltage quickly rises and that can damage equipment. Power grid engineering is complex but one thing is simple: power in equals power out. Managing the grid requires a balance in the production and consumption of electricity. The sum of all the power used by your TVs and toasters, and all that of your neighbour’s, equals the power produced by generators. If the power produced is more than what’s used, something has to give.  What gives is a precipitous rise in voltage.

Christmas Day, 2017, was pleasantly warm in Germany and the wind was strong. As well, demand was abnormally low being a holiday when factories and offices are shut down. Suddenly, the wind blew and power companies had to shed a lot of power from the grid. So the plea went out from power companies to start wasting electricity. Turn on your electric heaters and all the lights in your house. Open the doors. We’ll pay a lot is you do.

Too much wind power is not unforeseen. Germany spent $250 billion to develop wind turbines and they now produce 20 per cent of the country’s power. The remainder of Germany’s power comes from fossil fuels and nuclear.

Germany has obviously solved one part of the greenhouse gas problem by investing heavily in renewable sources but the other side remains unresolved –how to store surplus energy. Battery technology doesn’t have the capacity to store huge amounts of power. If it did, surplus wind power could have been stored.

Batteries will work on a smaller, household scale. Elon Musk sells his Tesla Powerwall battery for $7,000 and it holds enough power to run your house for about 3 days. Imagine being paid to store electricity and then to use it to supply your energy needs for days? In Germany, you’d be doing yourself and the power company a favour.

If you live in B.C., not so much. British Columbia has the enviable position of generating power by hydroelectricity; 95 per cent of it with the remainder by natural gas plants.

B.C. can’t reduce greenhouse gas emissions substantially by switching to wind and solar. Small scale installations in houses can reduce the cost of electricity for homeowners. Because dams hold stored power, storage of surplus electricity is not a problem.

Germany has reduced the burning of fossil fuels with wind and solar. Now, if they could only find some way to store the surplus electricity.

Smart water and you

We’re told to turn off lights to save electricity. But when you move up the energy chain, turning off the lights means saving water.

In turn, more water means more food. Nowhere is that more obvious than in California which grows one-half the fruit and vegetables in the U.S. and for much of Canada. The recent drought has prompted the California governor to order a 25 per cent reduction in water consumption.

As well, water produces electricity for many parts of North America. Water behind a dam is a versatile resource: energy, food, potable water. Turning off the lights can mean more food. In other words: energy = water = food.

Smart water can be achieved in a number of ways. One of the problems with renewable energy is storage. Solar panels and wind turbines produce electricity but not necessarily when it’s needed. What’s to be done with the surplus?

Sure, surplus renewable electricity can be stored in batteries or other devices.  Another option would be to store the surplus energy as water. Once the water is pumped behind a dam, it can be used for electricity when it’s needed, or for food. Another option would be turn unusable groundwater into potable water. Michael Webber at the Energy Institute, University of Texas at Austin, puts it this way:

“We can also rethink how to better use energy and water to grow food in unlikely places. In parts if the desert Southwest, blackish water is abundant at shallow depths. Wind and solar energy are also plentiful. These energy sources present challenges to utilities because the sun does not shine at night and the wind blows intermittently. But that that schedule is fine for desalting water because clean water is easy to store for later.”

As climate change drives drought into parts of the Canadian prairies, that calculation applies here. Surplus renewable electricity could provide water to prairie towns that would otherwise dry up, providing drinking water and even irrigation for crops.

As well as turning off the lights, we could throw away less food to save water. It takes 15,000 litres of water to produce one kilogram of beef, 1,600 litres per kilogram of bread. Yet, we throw away about one-third of the food we buy. When you throw away 1/2 kilo of over-ripe apples, you’re throwing away the 400 litres of water it took to grow them. That represents more energy than a couple of lights turned off.

Too many perfectly good fruits and vegetables are thrown out because they have minor imperfections. Restaurants throw out tonnes of food from the plates of customers who order more than they can eat. But even if more cosmetically imperfect food was consumed and plate portions were reduced, some waste may be unavoidable.

Instead of throwing waste food into landfills, it could be placed in anaerobic digesters along with other agricultural waste such as manure to produce methane, which could be used to produce electricity, which could be used to pump water, which could be used for . . . well, you get the idea.