Raser low-temperature binary geothermal plant goes online

[Texas]

"May 5, 2009 Raser Technologies has begun delivering 10 megawatts (MW) of clean, renewable electricity to Anaheim, California, from its first low-temperature, binary geothermal plant, the Hatch Geothermal Power Plant in Beaver County, Utah. Traditionally, the lead time on a geothermal plant is three to five years, but the USD$33-million Raser plant has been powered up just five months after ground-breaking. To help meet such rapid construction schedules, the plant uses off-the-shelf modular components, taken from the air conditioning industry, which are essentially running in reverse.

The geothermal plant uses an organic Rankine cycle (ORC) that generates power from ground-sourced geothermal brine, at temperatures ranging from 200ºF to 300ºF (93ºC to 148ºC). At normal atmospheric pressure, water boils at 212ºF (100ºC), but under pressure, typical of a geothermal system, the temperature can increase much higher before flashing to steam. Typical geothermal plants require the temperature to be at least 360ºF (182C) to be feasible. The Raser plant uses an ORC to make use of geothermal resources, previously considered unusable. Depending on the type of organic fluid used, temperatures as low as 158ºF to 176ºF (70-80°C) can be used in an ORC to generate electricity. "

http://www.gizmag.com/raser-low-temp...-online/11612/

[Andy0x1]

Interesting article. I actually use a Geothermal HVAC system to heat / cool my home.

A compressor is used to create a high and low pressure side. When heating, the high pressure (hot) side is used to heat the house, and the low pressure (cold) side is pumped through the ground so that the ground can heat it.

It sounds like this setup consumes yet more power to run the compressor harder effectively generating yet higher temperatures. High enough to boil "mystery substance". The boiling is used to generate steam which runs a turbine, which generates the energy required to not only run the system, but also power a grid?

Sounds almost like perpetual motion other then the fact that they are pulling heat from the ground. Ground loop is apparently large enough that this isn't a problem? I suppose if the cost of distrubtion (insulating piping) weren't so high, they could almost "sell" refrigeration (a free byproduct of this process)

Mabye they can sell ice-cubes

Wish I Could convert my system to generate electricity too!

[rhodomel]

This is not bad at all! Assuming a life span of 30 years and 7% interest rate on Capital, the amortized cost, finance charges and Principal, in terms of electricity is only $0.0306891/kWH. Of course, you'll have to add the maintenance and operation cost. But this is a lot better than solar PV.

[Texas]

This is not bad at all! Assuming a life span of 30 years and 7% interest rate on Capital, the amortized cost, finance charges and Principal, in terms of electricity is only $0.0306891/kWH. Of course, you'll have to add the maintenance and operation cost. But this is a lot better than solar PV.

People should just remember that the energy we are talking about is just the trapped energy in our planet. The inside is hotter than the outside. Anytime you have a thermal difference there is a potential to harness that energy difference to perform useful work.

We don't yet know how the cost of this system will compare to solar PV. Solar PV is moving towards very high volume roll-to-roll production (just like how garbage bags are made). They make it by the miles 24/7. The price of those panels is going to fall dramatically over the next decade.

With a thermal plant you always have to move the heat around. There are pumps, compressors, valves, etc. It's not completely free, just like harnessing the sun is not completely free. However, the fuel cost is basically free. The sun will shine and the core of the earth will remain hot for billions of years.

Thus, we need full scale production plants in full operation to get a better idea as to the actual costs over many years of operation. When we have all of that data and scope out what energy system is most appropriate to use and where then we can pull together a nation energy plan that makes the most economic, political, physical, scientific sense. It sounds so logical but the U.S. has no such plan or policy. Crazy but true. We are driving with our foot on the gas towards a brick wall at 100 miles per hour, whistling Dixie.

[Andy0x1]

Do they indicate what type of ground temperature's they are taking advantage of at this facility?

I know over the winter months with my system, I see loop field temperatures around 32 degrees which makes perfect sense given the science behind it.

e.g. it takes 1 calorie to raise (or lower) the temperature of 1g of water 1 degree.

it takes something like 80 calories to change the phase of 1g of water from a liquid to a solid or vise versa.

Hence once the ground loop reaches 32 degree's, It would take a lot of energy transference to make the phase change.

Conduction / prorogation of ground heat adds a recovery rate variable.

In the summer months, (I have yet to measure) but I imagine my loop will be closer to 50 degrees as the pump is reversed.