Distributed generation is a big part of the anticipated new grid. Distributed generation refers to having many small sources of power on the grid. A traditional power company can own distributed generation or someone else, perhaps the building owner, can own it.
Wayne Longcore has described distributed generation today as akin to the early days of personal computing. The big centrally managed power plants have the role of the mainframe, the site where all real power generation occurs. Pocket generation plants, including solar generation on household roofs, are akin to the poorly networked early microcomputers, only able to get on-line with great difficulty, and unable to do much in the big grid. In fact, today, grid operators often cannot tell if some homes are selling power back to the grid. I guess this means that industrial sites with in-house cogeneration are the equivalent of the old minicomputers. Some readers might recall minicomputers and large workstations made up much of the early internet.
Wayne’s point was that users of the sluggish single-purpose computers of the day would have had trouble imagining the internet revolution of the 90’s. They would have had even more trouble imagining a conference like the one Wayne was speaking at, where most people carried several small computers, more powerful than the minicomputers of the day, ones able to play music and videos and surf the web at speeds unimaginable just a little while ago. After all personal computers were toys. Just like micro-generation today.
Pervasive communicating computers required the development of many small light-weight protocols. IP defined inter-computer communication. TCP defined how communications travel a wider network. DNS defined the way to find computers at a distance. Distributed generation will need many small protocols as well. The power of these protocols is that different brands of computers, or even quite different types of systems, can use them, making no distinction between mainframes, personal computers, or, now, even phones.
One protocol we need for distributed generation is a small lightweight pluripotent protocol for connecting small generation to the web. Today, grid operators expect to see a large and complex interface, specific to each type of generation, just as they do on their own substations. While new variants are derived from old, it can take as long to develop a new standard as it does the technology. The sheer number of these standards makes it difficult to integrate new generation points.
Zero Net Energy Buildings will have a mix of generation and storage systems. In most places, any building with storage is not allowed to sell energy back to the grid. Under today’s rules, a building with some solar power, a wind generator, and a diesel generator would need three separate interfaces to sell back to the grid. There is no defined interface for the myriad of low-voltage DC generating systems soon coming to market. These may not sell power to the grid, but may offset other internal needs, and thus influence power sold by “normal” generation. If each of these scenarios needs to be connected to the grid using current approaches, we will not connect many of them.
We need a common lightweight protocol to support agile integration of these new point sources of power to let distributed generation develop. There are some facts that grid operations needs to know about each substation, and it needs to know them about generating buildings as well. The grid needs this information not only for safety, but also for interoperability. But it does not need to know everything about the underlying technology, technology which may change over time. It certainly does not need the information to operate the underlying technology.
I will write about what I see as the requirements of this interface soon.