Ramp Creates Power As Cars Pass 426
Ant wrote to mention a BBC News report on a ramp that generates power via passing cars. From the article: "Dorset inventor Peter Hughes' Electro-Kinetic Road Ramp creates around 10kW of power each time a car drives over its metal plates. More than 200 local authorities had expressed an interest in ordering the £25,000 ramps to power their traffic lights and road signs, Mr Hughes said."
Re:Great idea! (Score:5, Informative)
Creator's Website (Score:2, Informative)
There's some videos on the site, but the "Technical" section is laughably vague.
Re:Great idea! (Score:3, Informative)
More info from the website (Score:3, Informative)
Home Page: http://www.hughesresearch.co.uk/ [hughesresearch.co.uk] with other photographs and some short & long video clips.
Re:Great idea! (Score:3, Informative)
The force of the car of 1000kg is 1000*9.8 is about 10,000N (F=ma)
The Energy the car makes moving 2cm is 10,000*0.02 = 200Nm, not Watts.
The Power is measured in Watts, and depends on how long it took for the car to impart the energy. (P=E/t)
So, to get their 10kW quoted, it means it must have taken the car 200/10000 = 0.02s.
So, it takes 20ms to depress the bump....
power != energy (Score:3, Informative)
Re:Hmm (Score:5, Informative)
An automobile is a wonderful thing, and modern ones even give a smooth ride. The reason we get a smooth ride is this wonderful energy absorbing system called 'suspension', which absorbs about 95% of the energy of a road bump before it actually transfers to the vehicle occupants. The reverse is also true. The suspension has a few major components, the first being the sidewall of the tire. When you hit a bump, the tire deforms, and aborbs a significant portion of the impact energy. Typically, tires are designed so they can continue absorbing such bumps long enough that the tread wears out before the sidewall fails, but, if you spend a lot of time driving on real bumpy roads, you'll know, sidewalls fail long before the tread is worn. The second portion of the suspension is the shock absorber, and like a tire, it has a life expectancy. After absorbing some finite number of impact shocks, it ceases to function. It is quite possible to calculate a 'cost per bump' based on the replacement cost of tires and shock absorbers.
So, in the overall energy transfer equation here, we start with an internal combustion engine, that takes gasoline as an input, provides torque as an output, and is approximately 35% efficient. That torque is then transferred thru the drive train to provide propulsion, a process that typically runs 95% efficiency. Now, for a vehicle in motion hitting this bump, the vehicle suspension will absorb 95% of the impact, so the transfer of energy from the car to the bump is only about 5% efficient, with the vehicle suspension absorbing most of the impact. Tally up all the efficiencies along the way, 0.35 * 0.95 * 0.05 and you get 0.0166. So, to generate 1 kw of electricity from this device, you have to burn the equivalent of 60Kw of gasoline, and then let it flow thru the inefficient transfer mechanisms. To top it all off, you are purposely introducing extra bumps into the system, ie causing mechanical wear on the vehicles, which will in the long run have a measureable cost, probably substantially higher than the value of the electricity being generated.
If this is a 'step forward' for renewable energy, I'd sure like to know how that comes to being. To me, it looks like the most wasteful mechanism I've seen yet to convert gasoline into electricity. I cant remember EVER seeing any hair brained method of generating power thats LESS efficient than this one, with the exception maybe of the cartoon method of driving a windmill with an electric fan.
I can see one, and only one application where this is potentially 'viable', and thats to power traffic lights at locations that are so far out of the way, no grid power of any kind is available. I know of a few tunnels in the remote parts of northern british columbia where that would be the case, it would mean they dont have to keep the generators running on diesel 24x7 to light them up. Then again, from a pure pollution point of view, it's probably wiser to run an efficient generator 24x7 than to consider this kind of low efficiency energy transfer device.
Then again, if i was in the business of selling tires and shock absorbers, I'd probably consider the idea of offering a subsidy to towns looking to purchase this device. One of these at every traffic light in the jurasdiction would likely do wonders for my tire business, probably give full payback in a couple of years. Then when folks do come for replacements, upselling them to good quality steel belted tires that can withstand the extra abuse would be a trivial upsell, just point at all the artificial bumps in the road, and make sure they understand, normal tires just wont survive on these roads....
Re:Cost vs. benefit... (Score:5, Informative)
As far as electricity usage goes, I would guess that each bulb might be 200 Watts. Depending on the design of an intersection, there would probably be between 8 and 16 of these lights on constantly. According to http://www.ukpower.co.uk/running-costs-elec.asp [ukpower.co.uk] the cost per month would be about £130/month, or a bit more than £1500/year. Assuming there is no interest (or increase in the price of electricity) it would take almost 16 years before these savings make up for the cost of the equipment. Many governments make investments on this time-scale anyway. Additionally, if it could be used to power more than one traffic light, it might only take 7 or 8 years to pay for itself.
Re:This is THE dumbest idea I've ever seen... (Score:1, Informative)
Re:Kilowatts mean nothing, it's Kwh we need to kno (Score:3, Informative)
1.5 Volts * 2.5Ah = 3.75 Wh
I just wrote a K too many, but besides that all the numbers are valids as for the 50 cars to make the equivalent of a 2.5mAh AA battery.
Re:Great idea! (Score:3, Informative)
Re:Kilowatts mean nothing, it's Kwh we need to kno (Score:1, Informative)
FTFA:
Re:Are you sure it's just wasted energy? (Score:4, Informative)
Another good spot for them is where speed bumps are currently going in anyway to slow down traffic, such as near schools or on rat-runs (small residental roads that commuters drive quickly down to bypass traffic on major roads) - the power could then be used for additional lighted speed signs. Speaking of which, I live in dorset, and there's recently been a bunch of signs with radar-guns on that light up with the speed-limit if you're going above it. They have much the same effect as speed-cameras, without all the hassle of collecting fines, so I think they're great.
Another effective spot for these would be rural areas (which dorset has a lot of, for england), where you have to run extra grid power lines just to power the traffic lights or lights on the motorway signs. Something which removes the need for that could save a lot more than £25,000 per installation, given the cost of the extra lines and decades that these things need power for, especially if a bunch can be powered off a single speed bump. Admittedly, you'd want to put it on off-roads on the motorway, but again, there's often rumble strips or speed bumps anyway to make sure people slow down sufficiently coming off the motorway.
Re:Thanks (Score:2, Informative)
Re:Great idea! (Score:4, Informative)
You are (1) wrong and (2) stupid. Now think about it again. The ramp is pushed down to the level of the road by the weight of the vehicle passing over it, thus driving a generator. Now; do you see that there is no "greater linear distance" involved here?
Re:Cost vs. benefit... (Score:2, Informative)
No. The majority of LED aspects for traffic lights are much LESS efficient than the halogen lamps usually fitted - LEDs are only used because they require (in theory) less maintenance.
>>I don't know how many light installations one of these is supposed to power, but the only easy way to power more than one would be to hook it directly into the grid. So basically they're taking the amount of energy being produced by these things and subtracting it off the city-wide electricity bill.
You're overlooking some of the problems with traffic light installation (I know, because I do it for a living!) - one of the major problems is provision of power. In rural areas, this can be the most expensive part of the job! If you can generate locally, the initial cost of the equipment may be similar to the installation of miles of power cable.
>> If Salt Lake ever starts looking at these, I'll be looking over the city charter, trying to figure out where it requires the city to generate electricity at all, much less in the most inefficient and annoying way possible.
You will probably welcome the addition of these generators if you actually look at the benefits. The losses incurred by passing vehicles will be insignificant!
Maybe if you only installed them on downhill slopes...
Doesn't make much difference - see above!
Re:10kW of power? For what time span? (Score:4, Informative)
That's not the point. For what period of time does it pump out 10kW?
Most likely, it 100kJ for 0.1 seconds or so.
100kJ in 0.1s would be 1000kW, or 1GW.
Your electric meter doesn't measure things in J, it uses kW.
My electic meter measures energy in neither joules nor kilowatts. My electric meter measures in kilowatt-hours (kWh), which is how much energy you use if you use one kilowatt of power for one hour. A kilowatt hour is exactly 3.6 megajoules.
Honestly, if you have no understanding of the subject, why do you post?