Saturday, October 2, 2010

Why Can't the Electric Grid on Maui Take all the Alternative Power Available?

I'm often asked why Maui Electric has a limit on adding alternative energy such as Wind or Solar. Actually Maui has quite a bit of alternative power with Kaheawa, now called First Wind operating 20 Windmills that are running down the slopes of the West Maui Mountains. The equipment has been sitting on Maui waiting for the approvals.

On the southern slopes of Haleakala is another set of big Windmills called Auahi that will be built soon. This project was first started by Shell Oil Co. and was preferred over a second set of Windmills at the First Wind site because of the possibility that if the wind stops at one wind farm, it might still be blowing at another.

Sixteen years ago I helped to maintain a joint venture solar electric system located back up in the keawe trees above what is now the Maui High Tech Park. It was a very large installation, at least at that time, with 3 inverters feeding up to 15 kw into each of the 3 phases of the grid.

We spent many hours tracking down burnt connections under the solar panels because of the high DC voltages and current. A loose or bad connection becomes a resistor and generated heat or wattage that would literally melt the box covers. In fact, that was part of how we found the problems, by visually inspecting the covers, but as time went on the parts became scarce and reuse of old covers were the practice. After that it required a bit more logical trouble shooting of the panels to find the fault.

Another draw back was the dusty conditions would drop the output significantly and require us to take a big tank of water mounted on a trailer with a power washer, normally used to wash lines, insulators and substation equipment, to wash down the panels.

Eventually the installation was decommissioned after at least one rebuild and rewiring.

There are plans in the works for third party Algae production to be used in the fuel supply. Some Hydro, but as early as the 1920's, Maui was run mostly by Hydro Electric Plants built by the Sugar companies. In fact, Maui Electric was only a distribution company. They ran the lines and sold the power and the latest lines of Kelvinator and other Electric Appliances, as they were produced and people had lines run to them and the money to buy and use them.

In the 1930's, Maui experienced several years of drought conditions and the Sugar Companies had a tough time supplying their needs, let alone the needs of a now growing consumer base of electricity.

Eventually Maui Electric built it's first steam generation plant that is still in operation by the Kahului harbor. The next plant built was in the undeveloped Maalaea mud flats. It began as a couple of small diesel powered generators. Today it operates a number of different generators, driven from tractor style Diesel engines, a couple of locomotive engines that actually look like two train cars without the rails, about 5 more diesel run engines that look like they are from small cruise ships, and some that look like they came off a huge cruise ship and then the back bone jet engine type generators that use the waste heat to run another generator.

Because of the time to start and stop all these engines, it's very hard to just come on line or drop off line easily. They all don't like being jerked around. Based on load and now some automation, the plants generally run the more efficient ones all the time and bring on the less efficient engines as the load is required or predicted.

In addition, HC&S (Hawaiian Commercial and Sugar), supplies an agreed upon amount to the grid. So this is an expected source. There used to be other sources like the Lahaina Sugar Mill and the Paia Sugar Mill, but those shut down and the difference had to be made up by adding more generation to Maalaea.

Even without intermittent energy feeds like wind and solar, Maui Electric was required by the Public Utilities Commission (PUC) to meet the needs of Maui's Consumers. This means that then and even now, engines have to be running as reserve power. This adds to the expense, but is the only way Maui Electric can insure enough power for the consumers.

On any given day a tree, car accident, birds and even geckos in equipment can cause a fault that can take a big generator off line and the sudden loss has operators scrambling to try and maintain the grid, but many times it can result in a cascading loss of power as relays automatically turn off power to various section of Maui and try to protect the equipment and keep power flowing to most of the people.

A few years, ago prior to the approval of adding new generation, during peak loading times like when everyone is working or just getting home and turning on their whole house on a hot day, generation was pushed to the Max. It was a familiar and tense time to see the main dispatchers watching closely, as demand increased and voltage was on the verge of dropping, while they were online with the power plants and their hand on the switch ready to drop entire neighborhoods in the event the maximum output was pushed beyond it's limits. Better to lose one area than the whole island.

The problem with losing power in most cases is that it's not a matter of just switching the power back on. It has to be increased slowly and brought back a section at a time. If the reason for the fault was unknown, it required a complete inspection of miles of line before the power could be restored. So as not to restore power back into a fault that could be caused by a tree branch, fallen line or a car accident, restoring power in these situations could result in a deadly result if a line is in close proximity of people or draped across a car.

So now as alternative energy providers come on the grid with intermittent power, such as windmills that can stop turning in less than a half hour or only see wind at a limited number of places. With solar, a cloud rolls over and there goes that power.

So what is the answer?

Well storage of energy is a way to bridge those gaps and help maintain a reliable grid. The problem is in waiting for the technology and costs to make it affordable. It one thing to require a multi-million dollar operation to provide the storage, but it's pretty much cost prohibitive for the average consumer to invest in the solar or wind and provide the storage. People off the grid can attest to the cost and maintenance involved.

While technology catches up and costs go down, it's not too likely that every house and business will be able to afford and install systems without some sort of incentives or subsidies.

That's my non engineer explaination of the situation, but for more on the situation as it relates to the mainland North America, check out this National Geographic article by Joel Achenbach called "The 21st Century Grid--Can we fix the infrastructure that powers our lives?" published in the July 2010 edition, and get an even better explanation by Joel.

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