RICE, Reciprocating Internal Combustion Engine generators

[David B. Benson]

As backup for wind turbines, RICE generators may have advantages compared to open cycle combustion turbines. Installed in Europe, there are now some installations in the USA. For the tradeoffs with turbines, see

Questions and Considerations for RICE Generation Facilities
Arvind A. Patel et al.
2017 Apr 18
Power Engineering

A strong advantage over batteries is that the RICE generators will continue as long as there is fuel.

[Roger Clifton]

Here is a link to the article that David is speaking about:
www.power-eng.com/articles/print/volume-121/issue-4/features/questions-and-considerations-for-rice-generation-facilities.html

RICE generators might be more familiar to us as the backup diesel generator out the back of the pub. When the lights go out, the drinkers fall silent as they listen for the thudding sound as it starts up... Then the lights come back on, the drinks continue to be chilled and the revelry resumes…

Currently, windfarms are disruptive to the quality of the electricity on the grid and are consequently vulnerable to the politics of the government of the day. However, if each wind farm can stabilise its electricity injection into the grid with its own RICE generator filling the gaps in the wind generation, it gains the respectability of a commercial bidder on the electricity market.

Casual readers may be interested to see how an energy market works to supply a more or less constant voltage, phase and frequency on the electricity grid. A variety of commercial companies big and small bid to supply a short period of constant electricity, say 10 MW for five minutes. The energy market operator then (automatically) selects from the lowest bidders to provide the baseload for that period. There is also a (possibly separate) market to supply a reserve of electricity to cover surges in demand. Further reading might start with Wikipedia, en.wikipedia.org/wiki/Electricity_market

[Engineer-Poet]

Mar 30, 2019 4:35:20 GMT 9.5 Roger Clifton said:

 A variety of commercial companies big and small bid to supply a short period of constant electricity, say 10 MW for five minutes. The energy market operator then selects from the lowest bidders to provide the baseload for that period.

This is a very good way to purge from the market generators which cannot start up and shut down on a time scale of minutes.  This includes nuclear.  And of course it locks in the fossil fuel demand from those now-essential backup generators; as Robert F. Kennedy Jr. says, "the plants that we're building, the wind plants and solar plants, are GAS plants."  We need to make certain that the system is not rigged in such ways.

FWIW Cal Abel and co-author posited a way to make a fully load-following nuclear plant based on S-PRISMs and "solar salt" heat storage.  Only 4 pages, a must-read.

[Roger Clifton]

Having a RICE, a small fossil generator, on site would allow a wind farm (itself a small generator) to take responsibility for the quality, though it would not reduce the total carbon emitted by the grid. The duration of guaranteed output from wind or solar has been moved from seconds (wind or solar alone) to minutes and the contract period. The period could be extended as far as the collected generators' capacity to supply reserve. With enough reserves, say molten salt, on the grid, the period might be extended to hours, but a similar quantity of energy would have to be dumped (or idled) when not used. RICE and gas turbines are relatively cheap to idle, and their reserve energy lurks in the tank/pipeline.

The five-minute period works well in the Eastern Australian Energy Market (AEMO), where the competition is between steam and once-through gas turbines (OCGT). Being more efficient, steam has always underbid OCGT for baseload. Gas has always been much more expensive there than dirt-cheap local coal, so coal-fired steam not only underbids OCGT, it usually underbids gas-fired steam (CCGT) as well. However, coal is more vulnerable to future increases in the carbon price, which will eventually reverse that inequality.

Wind backed by OCGT uses a similar amount of gas to CCGT alone for the same energy output. So once coal burners have gone, such wind generators cannot benefit further from a change in the carbon price. Neither can they reduce our rate of emissions, but their highly visible presence provides forgiveness to those light sleepers haunted to feel guilty about it.