Showing posts with label frequency. Show all posts
Showing posts with label frequency. Show all posts

Thursday, May 17, 2018

ELON MUSK'S MEGA-BATTERY SAVES SOUTH AUSTRALIA $35 MILLION IN FOUR MONTHS

Last year, Elon Musk made the State of South Australia an offer they couldn't refuse. He promised to install the world's largest lithium-ion battery in 100 days and at a bargain price in order to store surplus power from the Hornsdale Wind Farm and use it to stabilize South Australia's power grid.

The crash project has been enormously successful. In the first four months of operation it saved the state government $35 million (Australian dollars, equal to $26.3 million US). That's an amazing return on investment, given that the project cost the state just $50 million (37.5 million US). It looks as though it will pay for itself within its first 18 months.

Hornsdale Power Reserve battery with three of the Wind Farm's 105 turbines in background
Credit: David Clarke 

The giant battery's primary function is to stabilize the frequency of electricity flowing through the state's power grid. When a generator or transmission line goes down, the grid frequency drops until backup power can fill the gap. If there's insufficient backup, disruptive brownouts or blackouts occur. But even if a backup plant comes on line or power can be purchased from a neighboring grid, the price of that stopgap power can soar. A grid operator might have to pay $10,000 or more per megawatt-hour, compared to a normal price of $150 or less.

Most of the $35 million that the huge battery saved the South Australian government came from the battery's ability to switch on and re-stabilize the grid extremely quickly--within 200 milliseconds, far faster than other kinds of backup power plants. According to RenewEconomy, the battery now commands 55 percent of the stabilization market in South Australia, and has reduced the cost of back-up power by a stunning 90 percent.

By the end of 2018, the savings surged to an estimated $40 million.

Critics of renewable energy cite intermittency--the fluctuating supply of energy from wind and solar--as a major obstacle to the urgently-needed transformation to renewables. Although the Hornsdale project shows convincingly that batteries can solve the short-term back-up power problem, the battery doesn't store enough energy to make coal or gas power plants obsolete. But it's clearly a step in the right direction. South Australia agrees, with several giant battery projects being developed in the state, and several more in other parts of Australia.

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Here's an interesting and extremely positive follow-up to the above story. Basically, South Australia's continuing development of carbon-free energy, including storage, has been an incredible success.


Monday, January 09, 2017

HERE'S TO "WEEKEND WARRIORS"--THE EXERCISE YOU GET IS LIFE-SAVING

We all know that exercise is good for us. Decades of research has shown that even moderate physical activity--such as brisk walking--improves health and lengthens lives.

Based on this, both the US Department of Health and Human Services (HHS) and the World Health Organization (WHO) recommend at least 2 1/2 hours of moderate physical activity or 1 1/4 hours of intense exercise per week, spread throughout the week.

Biking and other exercises add miles--and years--to your life/Credit Connie Ma

Recognizing that many people can't build daily exercise into their schedules, but might hit the streets, the courts or the trails on weekends, a team of British researchers set out to see if even "weekend warriors" are healthier because of the the exercise they do.

The short answer is--you bet they are.

Writing in this week's edition of the prestigious medical journal, JAMA Internal Medicine, Gary O'Donovan and his colleagues conclude that men and women who got the recommended amount of exercise in just one or two outings per week were 40 percent less likely to die from cardiovascular disease, 30 percent less likely to die from any cause, and nearly 20 percent less likely to die of cancer, compared to inactive adults.

The health benefits for weekend warriors were similar to those for people who exercised the same amount, but more regularly during the week.

"The weekend warrior and other physical activity patterns characterized by 1 or 2 sessions per week of moderate or vigorous-intensity physical activity may be sufficient to reduce risks for all-cause, CVD [cardiovascular disease], and cancer mortality regardless of adherence to prevailing physical activity guidelines," the researchers write.

Their study tracked almost 64,000 men and women 40 years and older over the course of 8 years, as part of a long-term English-Scottish health survey. Exercise patterns were determined from self reports while causes of death came from death certificates. The study's findings are particularly useful because of its length and the large number of participants.

Here's the take-home message from O'Donovan:

If you already are a weekend warrior, keep up the good work. If you are thinking of becoming more active, begin with a moderate-intensity exercise like brisk walking. Walking is associated with low risk of injury and it's important to set realistic goals that provide motivation and build confidence. I would recommend that middle-aged and older adults take part in at least 12 weeks of moderate-intensity exercise before introducing any vigorous-intensity exercise.

A new study, published in the prestigious British Medical Journal, analyzed 39 separate studies and concluded that both aerobic and resistance exercise can improve cognitive functioning in people over the age of 50. The exercise can be moderate, yet the cognitive gains are significant.

The bottom line--get up, get out, and exercise, even if you can only manage it once or twice a week.