Keeping The Grid From Overloading
by Keith D. Foote
Hawaii, California, and other states with strong winds and consistent sunlight are challenging assumptions about the boundaries of renewable energy. As the limits of what engineers and experts believe to be possible continues to expand, so does the the interest of investors in new technologies and resources.
In February of 2013, energy officials in California sat down with executives in the power-industry to make plans to avert a possible disaster. They were concerned about the rapid rollout of solar and wind technologies supplying electricity which could stress the state?s electrical grid. As more renewable energy was added, the chances the power supply could fluctuate wildly due to clouds or a windy storm. Some people attending the meeting warned of such problems as rolling brownouts, fearing they could begin later in the year.
These same concerns have been expressed from Hawaii to Florida. Authorities have struggled to maintain their aging electrical grids while handling increasing amounts of renewable electricity. Renewable energy now makes up approximately 14% of California?s electricity.
At present, California will often receive as much as 30 percent of its electricity from alternative energy resources. And there are times of the day when off-grid generation can provide as much as 40%. California legislators have recently approved a plan requiring half of all electricity to be generated from renewables by the year 2030. Though they have sustained fluctuating power levels at 40 percent, maintaining the fluctuations at higher and higher level may become difficult, and raises the question, can we be 100 percent reliant on renewable energy.
There are actually a large number of risks, but achieving 40 percent support for the grid is causing massive changes industry expectations. Utility companies are feeling most of the stress.
It is predicted electrical generation at the large central plant will decline, with solar and wind supplying continuously more of the load. This, in turn, is altering how investors spend their money. Utility companies are now planning investments for upgrading and improving the distribution network, making the grid capable of carrying power back and forth, rather than just downstream to the homes.
The changes will impact the core way utility companies do business. Once the slumbering giants of the power industry, they will have to deal once-captive customers now having the option of generating their own energy, and even selling it back to the utility company. To retain their customers, the utility companies will need to develop more flexible relationships. Some customers will be selling electricity they generate, while others will be buying.
Occasionally, California's grid has reached its maximum carrying potential, usually the result of multiple coincidences. The majority of wind power in California is generated at night, but at times continues blowing in the morning. At the same time, the sun starts powering solar panels. With demand normally light right around dawn, the grid can surge with excess electricity. Those kinds of a surges can fry equipment and cause service to be interrupted.
To keep this from happening, officials at Ca-ISO, one of California's grid operators, are solving the problem by using something called an energy-imbalance market. This is a fast changing market with power being traded every 15 minutes, or even at 5 minute intervals. This market is now made up of several power companies, including ones from Oregon and other states in the area. Soon, Arizona Public Service will become a market member, to be followed by Nevada.
Energy-imbalance markets work as a relief valve, offsetting the pressure in the electrical system. However, solar panels are being added at a very quick pace. States and power companies are in a race to stay ahead of the fluctuation problems that come with renewable power.
Having so much solar power on the grid, an abrupt weather shift can still leave utility companies scrambling to keep up. A number of tech companies have stepped in arguing the solution isn't better power generation, but better software.
For example, the Boston-based company, EnerNOC Inc., sells software to power companies which is used to receive warnings from about possible electricity insufficiencies. Companies can quickly respond, and receive some kind of compensation for turning off air-conditioning or shutting off temporarily unneeded equipment. Some predict, as utilities attempt to manage more frequent fluctuations in the renewable energy industry, they will also use more intricate, more complicated pricing plans.
There will be an evolution of rate structures. It is being pushed by the continuous installation of digital electric meters. These allow utility companies to communicate constantly with consumers, a practice called time-of-use metering. The utility companies can raise their prices if there is a shortfall in electricity, or lower prices if they expect a excessive electrical generation.
Some changes have to do with homeowners, who are installing batteries in their homes. Having electrical storage and photovoltaic panels, and the software regulating it all, allows the grid to communicate with the home when it's realizing a potential power overload. The grid, theoretically, could instruct the home system to charge the battery. Afterwards, when power is needed, the grid can call on the battery to deliver it.
The solution to wild electrical fluctuations in the grid seems to be a combination of ideas. Solar, batteries ,and software will solve a many of these problems.