In a recent segment, PBS’s program NewsHour took a look at an interesting experiment currently taking place in the small island town of Bornhold, Denmark.
Denmark as a whole is far ahead of the curve with regard to renewable energy, when compared to most other first world nations. Currently, 40% of its power comes from wind power, and the nation hopes to be 100% green energy powered by 2050. And tiny Bornhold is at the forefront of the country’s advance towards that day. A closer look at Bornhold hints at how everyday life will change in Denmark–and likely the rest of the world–over the next few decades.
Consistency is not green energy’s strong suit.
As the NewsHour segment explains, a major challenge currently faced by green energy producers and consumers is that power output from renewable sources is much more inconsistent than from traditional, pollution-producing energy sources. In a coal- or gas-powered plant, energy output can be easily regulated. If you need more energy, you can just add more fuel to the fire (literally). But renewable sources are fickle. Wind and solar power are at the mercy of the weather–and the weather forecast doesn’t care about whether or not you want to run the air conditioner when you get home. Erik Malmkvist, who runs Bornholm’s power grid, neatly illustrated the inherent tension between supply and demand for the show’s producers by showing them a graph of Bornholm’s power demand over the course of the day, which depicts a smooth uptick in consumption that starts like clockwork at 5 am every morning, and then trails off over most of the day, as seen below.
Malkvist then compared this smooth, predictable schedule with a 24-hour graph of the available power supply, more than half of which is supplied from renewable sources.
The incompatibility of the two should be immediately obvious, as well as the reasons for the energy supply’s shaky seimograph-like dips and bumps: solar cells and wind turbines are both dependent on the weather. And you can’t just expand green power plants or build more of them to fix the issue, because when the wind doesn’t blow or the sun doesn’t shine, none of those plants can produce energy.
While some energy can be stored when the supply is ample and then released during dips in production, it’s impossible to completely make up for the shortfall. This means that a future in which society is completely reliant on green power will have to be a future in which we think of power and how we use it in a very different way.
A green future requires that casual energy consumption can respond to the current energy supply.
The first part of the NewsHour segment illustrates the problem; the second shows the first steps towards finding a solution, a project called Ecogrid E.U. The goal of Ecogrid is a simple one: to get people to use more electricity when there is a larger supply, and less electricity when its scarce. This works through a process called “demand response.”
Ecogrid’s project leader, Maja Bendtsen, explains how it works by describing a common event during the chilly Denmark winters she grew up in as a child. When she was young, Bendtsen’s father installed a wind turbine on their property, and “[w]hen it was windy, we turned up all the radiator valves full open and could heat the house. But because it was windy and the wind turbine—the wind turbine was spinning anyway, the energy was free and abundant.” In short, they only turned on the heat when they had enough electricity to do so.
Ecogrid wants to replicate this in a high-tech way. There’s an easy way to tell how scarce electricity is at any given moment: just look at the price. The many Canadians who are on flex price programs will be familiar with the fact that the going rate for electricity varies constantly based on many factors, including weather, demand, types and number of power plants currently operating, and even international politics. But generally speaking, the biggest influence on the price of energy is how much of it there is available. Low demand and/or high supply = low prices. High demand and/or low supply = high prices.
Ecogrid’s team understands that in the Western world, the majority of energy consumed by residential users is used for space heating and cooling (i.e. running the air conditioner and furnace). Thus, adjusting when and how heating and cooling systems are run can make a massive difference in overall energy consumption. With this in mind, Ecogrid has developed a thermostat regulator that tracks the local energy price in real-time via the Internet. When the price of energy is low–meaning that supply is high–heating and cooling units will run full blast. But when the price spikes due to a drop in supply, Ecogrid’s device will automatically reset the thermostat to a more moderate target temperature.
The system is still in its infancy, as evidenced by one test subject who uses the Ecogrid system mentioning on the show that her Ecogrid unit stopped working months ago. But it is hoped that with time, the Ecogrid system or one like it will become stable enough for widespread use. The large-scale adoption of such a system would have a massive, positive effect on how money is invested in energy infrastructure. As Jorgen Christensen–the chief technology officer for the Danish energy association Dansk Energi–succinctly explains, “We are over-investing [in energy production] because we are not utilizing the energy that we produce in a smart way.” With a customer base that could automatically react to and compensate for changes in energy supply, much less money could be spent on building more power plants.
The NewsHour clip is only a few minutes long, and is definitely worth a look. You may well catch a glimpse of what the future holds for all of us.
