Sea water district cooling feasibility analysis for Hawaii [pdf] (2002)

https://energy.hawaii.gov/wp-content/uploads/2011/10/SeaWaterDistrictCoolingFeasibilityAnalysisfortheStateofHawaii2002.pdf

by geothermal_all • 6 years ago

76 40 6 years ago

energy.hawaii.gov

codetrotter• 6 years ago

Millions of kWh. Aka, many GWh. Why call it the former instead of the latter?

BooneJS• 6 years ago

I assume it makes it relatable to people who are accustomed to seeing kWh on their electric bills.

lostlogin• 6 years ago

Bills for thousands of cents.

boulos2• 6 years ago

That's what the submitter chose as a submission title. The document's title is "Sea Water District Cooling Feasibility Analysis for the State of Hawaii".

schoen• 6 years ago

If you want to normalize the SI units, you could also replace "many GWh" with "many TJ".

Tyr42• 6 years ago

I also think we should say the moon is 384 Mm instead of 384,000 km. Mega meters are awesome, we should use them more. And the earth sun distance is 150 Gigameters.

toomuchtodo3• 6 years ago

(October 2002)

Any more recent developments on this front?

snissn2• 6 years ago

Since then there's been a lot of wind farms installed in Hawaii and most homes have solar powered water heaters (from personal observation). Don't know anything about the sea cooling concept but it seems viable and for long time cornell has done it or at least on a tour they said they did https://fcs.cornell.edu/departments/energy-sustainability/ut...

https://www.ithacajournal.com/story/news/local/2015/10/02/co...

Interesting..

snissn2• 6 years ago

Ah here is the older one I remember from a tour https://fcs.cornell.edu/departments/energy-sustainability/ut...

m-ee• 6 years ago

Talking to locals in Maui most aren’t very happy with the wind farms. They’re considered an eye sore and they were sold under the pretense of lower electricity bills which never happened.

boulos2• 6 years ago

Looks like a deal was "reached" in 2018 [1], but just this week "Honolulu Seawater Air Conditioning to end development after 15 years" [2] and their website is now a scam. The Wayback Machine has the original [3].

[1] https://www.bizjournals.com/pacific/news/2018/10/09/hawaii-f...

[2] https://www.bizjournals.com/pacific/news/2020/12/19/honolulu...

[3] http://web.archive.org/web/20200929031903/http://honoluluswa...

supernova87a2• 6 years ago

I just don't understand why Hawaii government has been so slow to mandate the most economically-net-positive renewables, given their astronomical electricity costs (old, shipped-in fuel, diesel-fired generators).

Solar hot water, solar PV, wind. Stop being held over a barrel with these electricity costs. They live in the most conducive place for it in the world, yet don't take advantage of it, really.

toomuchtodo3• 6 years ago

Minor quibble: It’s more efficient to use a heat pump water heater, and max out your PV solar instead of splitting PV solar with solar water heating.

abdullahkhalids• 6 years ago

Is it? Solar PV overall efficiency is probably 15-20% of the incoming solar power. While, a solar thermal hot water system can reach 50% or higher efficiency, even accounting for storing the hot water for several hours.

Solar thermal also just requires fairly cheap mirror like surfaces, while solar PV requires semiconductor chips.

supernova87a2• 6 years ago

Oh, well I mean for simple cheap residential don't-have-a-lot-of-money-to-spend, a do it yourself hot water solar system is just about the cheapest, easiest thing you can do, right?

aphextron• 6 years ago

I just don't understand why Hawaii government has been so slow

Island time is a real thing. And politics in Hawaii takes nepotism and "good old boys" networks to the next level. Things are the way they are because the people in charge are happy with it.

metanoia• 6 years ago

HART (the light rail system they're building) is a complete disaster, for the same reasons.

I can't see the government there being able to handle much of any major infrastructure project. The airport expansion is moving at a glacial pace as well. And it's a miracle the H3 ever got built.

nradov• 6 years ago

No need for mandates. Power and fuel are expensive so people already have a strong incentive to invest in renewable power and efficiency improvements.

jcims• 6 years ago

Out of state folks are investing into 8,000 acres of solar plant in central Ohio. My guess is that there are material administrative impediments to the process rather than lack of demand.

rurabe• 6 years ago

As is usually the case, it's complicated.

The government has actually taken steps to push us down that road by mandating that all generation is renewable by 2045. Of course that's easy to say and harder to do, but I'm not sure it should be up to the government on how we get there.

The entity with the most responsibility to get there is HECO, which has a bit of a mixed record.

On one hand they have been pretty good about encouraging customer generation with net metering, and later grid supply options. Unfortunately there is a bit of an engineering problem there as we have pretty much reached the saturation of customer solar such that in the middle of cold sunny days, there is more electricity being produced than consumed (see duck/nessie curve). This would sound like a good thing, but with an extremely old grid and no utility level storage, it's kind of not.

A more reactive utility perhaps would have done a better job upgrading the grid to allow for distributed generation, but HECO spent the better part of the last 5 years trying to get themselves sold to a mainland utility to drive returns to shareholders instead of placing institutional focus on solving current or future problems for ratepayers. Serving two masters, etc.

Kauai has a much more interesting situation as their utility went through that whole sale to the mainland thing in the 90's, which failed and provided the opportunity for the ratepayers to buy the owners out and created a cooperative utility. I don't live there but from the outside looking in it looks like they are being much more proactive about renewables and more importantly, storage.

Absent some kind of massive game changer in wave or wind generation, the whole game is really storage. I know a lot of people who would love to install solar, but HECO is already at max capacity absent a way to store electricity at scale.

Finally the part that gets talked about the least is economic inequality. Hawaii's real estate is expensive, but it is driven by investment from outside the state, making it almost impossible for people who live here to afford homes. That interacts with the energy piece because you have to be a homeowner to benefit from solar, so solar contributes to wealth inequality as people who are fortunate enough to own homes also reap the benefits of government subsidies and cheap electricity, while people too poor to own homes are left paying the retail rates. And this is before we even get into the distortions of behavior that net metering encourages when you treat a kwh of solar in the day as equal to a kwh of petroleum at night.

hourislate• 6 years ago

I've read about this before when Toronto was implementing a system like this. The City of Toronto cools a large portion of it's downtown office towers using this method. They draw cold water from deep in Lake Ontario to be pumped into chillers to cool the office buildings. Seems to be environmentally friendly and cost efficient.

A couple of links:

https://www.acciona.ca/projects/construction/port-and-hydrau...

https://www.toronto.ca/community-people/get-involved/public-...

Scoundreller2• 6 years ago

Sorta. They run heat exchangers between the in-bound municipal water and loops that go to the office buildings.

So it helps with some eco-effects (ie: there’s no dumping of the heated water), but everyone’s municipal water is a bit warmer in summer. I don’t think the effects of that have been calculated. Can offset water heating a bit; but other office towers use that water for their a/c cooling needs.

They deepened the water intake too, so it definitely means colder tap water in winter too, which residents mostly have to heat up inefficiently.

dzhiurgis• 6 years ago

Is there a limit how hot or cold your waste water can be?

In many eastern europe cities heating is centralised and uses quite expensive wood or oil burners. Wondering if extremely deep geothermal bores could serve 200-500k people.

404mm• 6 years ago

It’s kinda hilarious (to people living in areas with actual seasons) to hear about summer and winter in Hawaii. Based on the temp averages I see on weather.com, there is some variation. But how does it actually feel? Does “Hawaii winter” feel like actual different season or is it just “slightly less hot summer”/every other day?

antsar• 6 years ago

deepened the water intake too, so it definitely means colder tap water in winter

Would it be so expensive to have two intakes?

fghorow• 6 years ago

Cornell University has a similar cooling system using cold water from Cayuga Lake.

https://fcs.cornell.edu/departments/energy-sustainability/ut...

mianos• 6 years ago

It would be interesting economics to revisit this now with much lower interest rates, higher labour costs and very different plant costs due to changes in technology and lower cost manufacturing of some of the components.

dave333• 6 years ago

Skytherm roof is better. No need to pump sea water or lake water just put the water in containment on your roof and uncover it as you want solar heating (winter daytime), radiant cooling (summer nighttime), or cover it if you want thermal capacity heating (winter nighttime) or thermal capacity cooling (summer daytime).

http://www.solarmirror.com/fom/fom-serve/cache/30.html

londons_explore• 6 years ago

How far is it practical to move hot/cold water?

Could a big pipeline (say 5 yards diameter) be built between the north and south of the US to bring icy water for cooling in Texas and take back hot water to heat detroit?

Pipes could be tapped in any place for water too, ending per-state water shortages while other states have flooding...

ClumsyPilot• 6 years ago

you can move water with canals just fine, but it won't be cold any more

Sea water district cooling feasibility analysis for Hawaii [pdf] (2002)

Related Stories