With all the talk about green (renewable) energy and the worries about global warming, I figure it’s time to visit some of the issues that are coming to light. Most particularly, how do we connect all these alternative sources to our somewhat fragile power grid without rendering it unstable, potentially causing blackouts?
My thoughts take me back to 1960, and a task I had while working for the US Army Ordnance Corps. The job was to set a governor for a 24vdc motor driven 120vac, 60 Hz generator used on one of the cavalry’s tanks. A simple task, you say? True enough, with today’s multimeter capable of measuring frequency, but a frequency counter of the day was a line-powered 18-inch cube with neon lamp readouts. A frequency counter was expensive, and we didn’t have one conveniently available.
The solution was to connect one end of the generator’s output to the bench ground and then connect two 120v light bulbs in series between the hot leads from the generator and the bench outlet. When the output frequency of the generator was within 1 Hz of the desired line frequency the lamps would range from dark to full brightness as the voltage went from zero, when the sources were in phase, to 240 volts when they were out of phase. When it took ten seconds to complete one bright-to-bright sequence, we knew that the generator output was within 0.1 Hz of the desired 60 Hz setting.
Believe it or not, bringing a turbine-driven generator on line at a hydroelectric dam uses a similar process, but with a much greater degree of precision - for good reason. Not only must the generator output be at the correct voltage and frequency, but it had better be at the same phase, or something is likely to break when you throw the switch. I witnessed such a process many years ago, and all I can say is that there must have been a phase difference of a few degrees, because there was a loud noise and I felt the floor move under my feet when the generator came on line. That can’t be a good thing for the rotor or for the drive shaft of the turbine.
So where does our electrical power come from?
According to the US Department of Energy, in 2003 roughly one-third of the energy used to generate electricity reached end-users (3,675 billion kilowatt hours). The other two-thirds wound up mostly as waste heat dissipated into the environment. That’s not too surprising when you consider that most (69.2 percent in 2009) of our power comes from using coal, oil or gas to generate steam to power turbine-driven generators. Nuclear generation (also a heat conversion process) provides another 20 percent.
When I read these statistics, my mind wandered to the possibility that heat recovery processes using heat pumps might reclaim some of these losses. I wondered if Fluke non-contact thermometers and thermal imagers might help somehow to implement such projects. I’ll have to give this idea more thought - I don’t want to be accused of proposing some sort of perpetual motion machine.
What about the renewable resources we’re hearing so much about?
Hydroelectric generation today provides 6.88 percent of our energy, and alternative renewable resources, primarily wind generators, provide most of the balance (3.57 percent). Wind generation is the fastest growing segment in the mix today. The problem with these sources is that they aren’t necessarily constant or easily programmable. By that I mean that the wind may not be blowing when the nearby power system experiences peak demand.
Introducing the smart grid
There have been regional ties between power producing and consuming entities for a long while, with the idea of moving power to handle peaks in different time zones. This leads to connecting and disconnecting major systems in a coordinated way. We don’t want the system to experience impulses, such as I felt and heard at the dam years ago, as power is routed over great distances.
In addition, there are opportunities for major industrial customers to harvest energy from their processes and provide co-generation to supply some portion of their electrical power off-grid. This also involves switching loads on and off the grid.
These processes require careful measurement and management of energy flowing to and from the grid.
The calibration group within Fluke recently received a grant from the Department of Commerce to develop a Smart Grid Calibration Standard to assist in implementing Smart Grid protocols.
Read more about the Smart Grid Calibration Standard »
So what can you do today?
Industrial and domestic power consumers can manage their use of power to minimize their demand on the stressed system. This helps the system, and it also reduces cost of plant or home operation. Better building insulation, more efficient lighting, and modern heat pump technologies can all make your operation a more economical one.
And Fluke offers a range of tools that can help.
Read about an example of a three-day energy audit that discovered $510K in potential savings from energy conservation and waste management improvements »