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Tag: utility

Making Solar Pay

Posted by tomwiles at 8:54 PM on May 8, 2013

I have always been fascinated by the idea of generating my own electric power. Back in late 1998 I installed a solar power system that has sixteen 75 watt solar panels, along with a 4,000 watt power inverter/charger and a bank of expensive deep-cycle batteries.  Mention solar power, and most people think that all of these elements are necessary, including the expensive bank of batteries.

It turns out there is a much better way to think of home solar energy – use solar energy equipment strictly to push power back into the electric company utility grid. Batteries should never be considered to be part of a solar installation unless utility power just isn’t available, say in a remote location. Battery technology is an albatross when it comes to being able to store enough power to meet real-world needs.

If electric grid power is available, there are only two elements necessary – the arrays of solar panels, and what are called grid-tie inverters. In this battery-free scenario, the math of pushing power back to the utility to offset electrical use becomes much more interesting.

Power companies in the United States are required by law to “buy back” consumer-generated power. A grid-tie inverter takes the DC power being generated by the solar panels, inverts it into AC power, and then sends it back directly into the grid via a standard AC power plug plugged in to a regular 110 volt outlet. It is possible to have more than one grid-tie inverters, which also come in different sizes.

The relatively high-end inverter that I have is capable of producing 4,000 watts sustained output. So, if I wanted to push 4,000 watts back into the electric company utility grid, I would need at least two more arrays of solar panels feeding DC current into the inverter.

In my case, the batteries died within about the first three to four years. I simply turned the equipment off and my youngest brother sold the battery carcasses to a battery recycler. The equipment sat dormant until yesterday. A friend that does solar as a hobby helped me check the inverter and get it up and running again. I contacted my electric company and they sent a man out this afternoon to look over and approve my system, an absolutely necessary step. So the net effect is that now whenever there is daylight, the inverter is pushing power back into the grid. Obviously the maximum amount of power is generated when the solar panels are in direct sunlight.

The electric company performed a test of the inverter to make sure that if there is a grid power failure that the inverter automatically cuts off its own output. This is quite critical to the power company, because they want to be absolutely certain that in case of a grid power failure, no user-generated AC current is being fed back into the downed power lines.

I was able to verify that my inverter was pushing power back into the grid by turning off all internal breakers in my house so that no power was being used. At that point I looked at the power meter out on the utility pole and it was actually running backwards! Of course, in normal operation with different things consuming electricity in the house it is unlikely it will run backwards much, but it will be slowed somewhat.

My local electric company is a rural electric cooperative and they actually encourage customers to set up these types of “selling” consumer-generating power systems. It helps them reduce peak demand, thus reducing the need for more electrical generating capacity on the utility’s side. Solar panels are generating electricity at peak capacity when peak demand is likely to occur when air conditioning demands are at their highest.

Can a system like this ever pay for itself? It depends on the initial cost of the equipment, installation expenses, and how long of a payback period you are able to live with. If you can do most of the installation work yourself, then obviously the math works better. Eliminating the batteries really helps the cost come down.

An HQRP 1,000 watt grid-tie inverter sells for $287.95 on Amazon.Com. Aleko brand 75-watt solar panels sell for  $149 dollars each. Sixteen of these solar panels multiplies out to $2,384 dollars. With brackets, wiring and installation let’s estimate a total package price of $4,000, which may or may not be wildly off one way or the other. The 1,000 watt electrical output of the inverter would have to offset $4,000 dollars worth of electricity over a period of years before it would pay for itself, which is likely a long period of years. If the price of the equipment and installation can be brought down, then the payback period shortens.

My electric company will only allow this type of setup to function as an offset. So, let’s say that someone was putting more power back into the grid than they were actually consuming. My power company will never issue a check for the power, so it’s really just an offset for how much I consume. With enough equipment feeding power back into the grid, it would be possible to bring electrical grid usage down to zero.

Many local and state governments offer tax rebates for new solar equipment installations, which could also help mitigate the cost.

The beauty of a battery-free grid-tie solar user-generated power system feeding into the electrical grid is that once it is initially set up, everything happens automatically. Since I already have the equipment and it is long since paid for, I might as well be utilizing it to offset a portion of my power usage.

The Internet is a Utility

Posted by Andrew at 7:50 AM on March 11, 2012

Router and CablesLast week, I moved to a new Internet Service Provider (ISP). Nothing particularly unusual about that except that I had been with my old ISP, Demon, for nearly twenty years. That’s almost the whole of the my adult life and I’m sure it’s the longest customer relationship I’ve had. To be quite clear, I didn’t leave Demon as a dissatisfied customer and on the contrary, I would recommend them to anyone. So why did I leave?

To answer that, we’ll have to take a little trip down memory lane. Back in the early 90s, the 486DX2 was the CPU of choice, 8 MB was a lot of RAM, 120 MB hard drives were huge and dial-up modems were specialist items. JANET, the UK’s university network was the closest thing to the Internet, and it was email, ftp, telnet, Usenet and gopher. I imagine that some readers will be thinking, “gopher?” Never heard of that.

In 1992 and in an early example of crowdsourcing, Demon ISP was setup by persuading 200 people to pay in advance for a year’s dial-up access. I wasn’t part of that group but after publicity in the leading UK computer magazine at the time, Personal Computer World, I signed up for their £10 a month dial-up service. You had to buy your own modem in those days – no freebie wireless router – but it came with unlimited email addresses, 10 MB of ftp space and Usenet newsgroups.

Demon provided their own email package called Turnpike as this was all pre-Outlook, and a certain level of skill was needed just to get on-line. The connection software was a command line program called KA9Q that was originally amateur radio software. Winsock fortunately arrived shortly afterwards, which made life considerably easier with Windows 3.

One of the great things about Demon in the early days was that the support staff were technical folk too and quickly got the measure of the caller. If you said to them that you were having problems with DNS resolving, they’d understand that you had a reasonable grasp of the problem and work with you, rather than blindly follow the procedure written in the training manual.

Since then there have been many changes in the world of technology, not least the arrival of ADSL broadband, which single-handedly changed the web from geek toy to consumer product. In the end, two things conspired against Demon. The first was free web email such Gmail and Hotmail which meant that I no longer needed my ISP to provide me with an email address. The second was video-on-demand which had the twin impacts of volume and speed. My new ISP, Sky, offers twice the speed of Demon and no data caps for less money. Bit of a no brainer, as they say.

Demon provided a great technical service for geeks 20 years ago, but as the web has become a consumer product, the need for technical features such as ftp space has faded. All that is needed is the connection. The Internet has become a utility like water, gas and electricity, always there and always ready. No understanding of the technology is needed to use it, just as turning on a light doesn’t need knowledge of volts and amps.

I’ve no doubt that Demon has a successful future working with business but I think that the future of the independent ISP in the consumer space is bleak. People will choose consumer brands linked to utilities or telcos – Sky, BT, Virgin, Orange - and get one bill for multiple services at a reduced price…as I did.

Routers and Cables 2” image courtesy of BigStock.