How can alternaives work in an always-on world? |

How can alternaives work in an always-on world?

Bill Sepmeier and Matthew Charles
Vail, CO, Colorado

In our last column we discussed the problems that large-scale wind and other renewable energy sources can pose to electrical grid operations throughout the nation.

Nature is, by nature, an intermittent source of power. Until the modern era, the world lived within the confines of this intermittent energy supply. When the wind blew, merchant seamen sailed across the oceans at speeds similar to today’s ships. When it was calm, sailors spent days, even weeks sometimes, tuning and tarring the ship’s rigging and mending their clothes, waiting for the breeze to return. Life and commerce ebbed and flowed in harmony with the energy source. There simply wasn’t any choice in the matter.

Times have changed. Today, when the wind responsible for generating tens of millions of watts of electricity slows or stops, independent system operators in charge of balancing loads with supply match fluctuations with reserve power available from their “spinning stock” of hydroelectric generators.

Like wind, other sources of renewable energy are subject to fluctuations of availability. With solar photovoltaics, when the sun goes behind clouds or sets for the day, electricity production stops and other sources must be used to balance loads.

As wind and solar power become a larger proportion of the grid’s source of energy (Colorado law requires that 20 percent of the power must be from renewable sources by 2020), reserve power sources must be available to keep loads running during natural fluctuations of wind and solar availability. This might be accomplished in several ways:

– Freeze growth of electrical use at an arbitrary level. This will allow the present hydroelectric, fossil fuel and nuclear generation plants to be used as reserve spinning stock to back up renewable sources as more and more come online. We would still need the constant presence of existing generating plants, due to the unpredictable fluctuation of renewable energy sources.

– Build nuclear power plants as energy demand continues to grow and more large-scale renewable energy is added to the grid. Nuclear plants typically deliver hundreds to thousands of millions of watts of power from each reactor and produce no greenhouse gasses, although there is the issue of what to do with the byproducts, which can be dangerous for 10,000 years or so.

But nobody likes nukes and even with generous incentives and production tax credits backers can’t raise the capital to build them in this country these days. There are a handful of new nukes on the drawing boards, but when Warren Buffet scrapped his plans to invest in the industry not long ago, the market followed him. Without nuclear power, however, we’ll have to build and operate more conventional coal and gas generators to maintain the reserves needed to offset nature’s changes.

– Adapt, so that a “green grid,” fed by large amounts of wind and solar power, is allowed to ebb and flow naturally. In order to maintain our modern, “always on” lifestyle, we will need to implement localized, intelligent backup energy storage systems. These backup systems would use solar and other green grid power to charge batteries when the energy is available in order to make power available when the grid cannot.

In this scenario, everyone would maintain their own power reserves, buying as much as they wanted or needed to maintain their lifestyle while the grid took its regular, natural time-outs.

Based on the growing popularity of home solar energy today, many people are already building parts of this new localized energy backup system by using batteries in conjunction with the grid. When power goes out, those with this type of system in employment enjoy an uninterrupted power supply.

– Or we could do nothing. But can we really afford to do that?

Bill Sepmeier is chief technical officer and Matthew Charles is marketing director for Grid Feeders in Eagle-Vail. To learn more, go to

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