In the 20th century electric grid, adding a variable source of power generation like wind or solar upset the paradigm: big coal and nuclear plants run constantly, efficient natural gas plants meet intermediate demand, and fast gas, hydro or diesel peakers fill the peaks.
But the 21st century grid is different and the best strategy for utilties may be to flip their outmoded paradigm on its head.
The Nippon Paper Industries mill in Port Angeles, Wash., which makes paper for telephone books, has an average load of 53 megawatts, which is roughly 1,000 times the peak load of a typical house. But the mill’s load can run up to 73 megawatts.
One of the big electricity consumers at the plant is the pulping operation, which turns wood chips into an intermediate product on its way to becoming paper.
While the mill pulps the paper at the rate at which its machines are the most efficient, it could pulp faster, turning pulp into a kind of battery. “What we’ve looked at is the possibility of more storage capacity,’’ said Harold S. Norlund, the mill manager. “A phone call could come and say, ‘We have a problem for 24 hours — can you use more energy?’“ he said…[the mill] would switch to electricity from wind at certain hours and save the wood pulp for burning as needed later.
The adjacent graphic illustrates the reversed paradigm. By planning on variable sources first (wind, solar, etc) – as in the bottom frame – utilities can think creatively about how to match supply and demand. In some cases, it means finding flexible generation sources to fill the gap. In this case from Wald, it means moving the black demand line.
None of these options is limitless (or always cost-effective), but each is key to making a renewable-first grid work. These example are also instructive in questioning the old grid paradigm’s role in a renewable energy world: should the electricity system limit new wind and solar power just because we’re used to running a lot of big power plants 24-7?
No. And with simple solutions like demand-shifting, we shouldn’t have to.