产业观察

过去几十年，经常由于夏季电力短缺，电力公司鼓励居民少用点。而如今，由于风电的崛起，导致西北太平洋电力公司面临了一个相反的局面，有时候，电网会出现电力过剩的局面。
因此，Bonneville电力管理局在今年夏天制定了一个策略，通过远程控制，调整志愿者家庭的设备，达到供求平衡。

当Bonnevill电网出现电力过剩的情况时，几百英里以外的控制室内的运行人员可以开启志愿者家庭的冷水加热装置，将水加热到60多度的恒温，而处于电空间加热器附近的陶瓷砖，可以加热至几百度。

100加仑的家庭加热器可以储存大约26kWh的能量。电空间加热器的陶瓷砖可以储存40kWh或更多的能量，通过风扇，将加热器附件的热空气送入居住区域。这些瓷砖也可具有像热电池一样的功能。

部分这种设备的使用可追溯到20世纪80年代末，当时的设计最初是为了提高“时间使用率”，家庭可在在电家便宜时购买电力并储存。但在一个公共事业管理区域内使用是一种新的尝试。
For Bonneville, the full dangers of excess supply first hit home during the June 2010 emergency, when a severe storm whipped through the region. The transmission network had so much power that the agency turned off all its fossil fuel generation, gave electricity away to neighboring networks and even told the system’s only nuclear plant to slash its production by 78 percent, a highly unusual step.

Go to Blog » .The region squeaked through, but the agency was stretching its resources “to their limits,” said Doug Johnson, a spokesman for Bonneville. At one point the system was running almost entirely on renewable energy.

“This is probably about the only place in the country where that could happen,” said Michael Milstein, another spokesman with the agency.

The problem was complicated by environmental rules involving the hydroelectric dams.

The dams were built with spillways, or paths where operators can divert water without passing it through the power-producing turbines. But when the water goes through the spillways, it picks up nitrogen bubbles that can kill juvenile fish, so there are strict limits on their use.

Operators can usually keep the system in balance without excessive use of spillways, but in the June 2010 case, they were coping with as many as 2,000 megawatts of wind power, roughly double Seattle’s power use or what two nuclear plants can deliver.

Wind installations have grown since then. So Bonneville began advertising for volunteers to accept extra electricity, mainly homeowners with electric heat and with water heaters of recent vintage.

Plumbers install a mixing valve on the water heaters to keep the faucet temperature safe, and new wiring and a small computer keep track of energy flows.

The agency says that some 200 homes will soon have the adapted water heaters, space heaters or both. In hundreds more, it is installing more traditional controls that will allow it to turn water heaters off. Another utility in the region, Portland General Electric, is about to begin a similar program paid for by the federal Energy Department.

For the time being, the storage devices collectively can absorb the output of only a handful of wind turbines.

A 100-gallon home water heater can store about 26 kilowatt-hours, or about a day’s worth of electricity for a typical house, or less if the house relies on electricity for heat.

The ceramic bricks in the space heater can store 40 kilowatt-hours, or more in some larger configurations. The heat can be drawn off by passing air and delivered to living spaces by a fan, with the bricks also functioning as a thermal battery.

Some of this equipment dates from the late 1980s and was originally designed for offering “time of use” rates, so that a homeowner could buy electricity during hours when it was cheaper and store it. But coordination over a broad area by a utility to manage regional flows is new.

One nagging question is who will pay for the installations if they are carried out on a larger scale.

While Bonneville pays for them now, Philip D. Lusk, the power resources manager for the utility department of the city of Port Angeles — the Rothweilers’ retail supplier — said the agency might have to find additional ways of compensating consumers to get the thousands of volunteers it will eventually need to make the system effective.

If the installations are judged to benefit everyone because they improve stability, the cost might be spread among all ratepayers. But if Bonneville decides that they mainly benefit the wind generators because they never have to unplug their turbines, the agency could try to charge that industry.

Either way, said Mr. Johnson, the Bonneville spokesman, the agency will have to come up with a solution to “the cranky nature of wind.”