Some years ago we had extended discussions about Hawaii’s electricity generation on the Climate Change board, noting it had the highest electricity prices in the country because they relied mainly on burning diesel fuel for their grid. Some relatively generous federal subsidies for household solar back in the day made it a nice deal for Hawaiians to cut their electricity bill, to the extent that the utility had to curtail new additions of solar, because it was destabilizing neighborhood grids, and they lobbied for changes to the state laws to make it less appealing.
Now, years later, they realize that they’re still stuck with the expensive diesel powered grid and have decided to embrace household solar and household grid-attached battery systems, and expect them to be a major part of their grid going forward.
https://www.nytimes.com/2022/05/30/business/hawaii-solar-ene…
"Nearly a third of Hawaii’s single-family houses have rooftop solar panels — more than twice the percentage in California — and officials expect many more homes to add panels and batteries in the coming years…
Electricity rates in Hawaii jumped 34 percent in April from a year earlier because many of its power plants burn oil, about a third of which came from Russia last year…
State officials in recent years have gone back to encouraging the use of small-scale energy systems. To manage the supply and demand of electricity, for example, Hawaii offers up to $4,250 to homeowners on Oahu, home to about 70 percent of the state’s population and Honolulu, to install home batteries with their solar systems, defraying as much as third of the cost of doing so. Utilities can tap those batteries for power between 6 and 8:30 p.m., when energy demand typically peaks.
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Interesting approach to solving the duck curve. I suppose that subsidizing household solar and batteries is going to be a more expensive solution than building industrial scale solar and battery farms, but it’s a incremental, distributed approach that will have limited costs in any given year and doesn’t require large areas of land to be set aside for a single use. I’d assume/hope that most of these homes with solar and batteries are also equipped with grid disconnect equipment so that they can continue to have power if/when the grid goes down, a major benefit of the distributed approach.
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I’d assume/hope that most of these homes with solar and batteries are also equipped with grid disconnect equipment so that they can continue to have power if/when the grid goes down, a major benefit of the distributed approach.
That is how a normal installation of a battery like a Tesla powerwall works.
What I wonder is does it automatically reconnect to the grid when the grid come back on line?
Disconnecting is easy, relatively. But to reconnect you have to synchronize to the grid’s 60Hz frequency, which is almost for sure out of sync with your in home frequency which drifted since you disconnected. This means that devices internal to your home will see a glitch of some kind.
Mike
Solar panels generate DC and batteries store DC. You use an inverter to convert to AC. Syncing with the grid should not be difficult.
Wind turbines have the same problem. Rotation speed must be controlled to make synchronized AC. Easier to make DC and then sync with an inverter.
The grid systems across the US are not synchronized with each other. When NJ buys power from Pennsylvania, it must be re-synced. Same problem.
Thank goodness for solid state power equipment.
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The grid systems across the US are not synchronized with each other. When NJ buys power from Pennsylvania, it must be re-synced. Same problem.
FWIW, NJ and Pennsylvania are synchronized with each other, as both are part of the Eastern Interconnection.
https://en.wikipedia.org/wiki/Eastern_Interconnection
Yes, I’m aware of the Linden VFT. It isn’t necessary for synchronizing frequency. It’s there to finely control the flow, better than a PAR (phase angle regulator) and cheaper than a DC tie. As the wikipedia states, it is connecting New Jersey to NY - one of many connections between the two. Electrically it is one of the many connections between the NYISO (NY Grid Operator) and PJM (originally stood for Pennsylvania, Jersey, Maryland - grid operator for several states including New Jersey).
Syncing with the grid should not be difficult.
When you generate solar (DC) you use an inverter to convert to AC but you use the grid 60 Hz as your input clock signal to be synchronized. When you disconnect from the grid your inverter uses its own internal clock signal to generate the 60Hz to supply your home.
When you want to connect back to the grid you now have the issue that your two clock signals are not in sync with each other…you can’t change the grid signal. In large power plants you can slightly change one frequency to get them in sync then connect them. Not sure how cheap home systems do this, but they probably just momentarily disconnect the home then reconnect.
Mike
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Which means the lights blink for less than 1/60th second.
Not a problem for lights. But computers can glitch, routers disconnect, etc.
Mike
I suppose that subsidizing household solar and batteries is going to be a more expensive solution than building industrial scale solar and battery farms, but it’s a incremental, distributed approach that will have limited costs in any given year and doesn’t require large areas of land to be set aside for a single use.
Well, more than that, an industrial scale solar and battery farm is a 100% cost to the utility, but if they’re “subsidizing” private systems by 1/3, then only 1/3 of that cost belongs to the utility.
It’s the same reason fast food companies franchise: it’s a lot easier to use someone else’s capital than your own. In the utility sphere it’s probably easier to get capital projects approved by regulators when they’re only 33% as big as doing it the other way.
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Not only what Goofy said…but there is no real estate costs with using other people’s roofs.
And it is a better use of land, most likely.
Mike
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Ben wrote:
Some years ago we had extended discussions about Hawaii’s electricity generation on the Climate Change board, noting it had the highest electricity prices in the country because they relied mainly on burning diesel fuel for their grid.
Its not really diesel fuel, but residual oil left over from the refining process. The refineries in Hawaii take in crude oil, and refine it into gasoline, jet fuel and diesel for transportation. The heavy stuff that is left over is sold to the electric utilities to fuel their dispatchable power plants.
Solar and wind, along with some biomass, geothermal (active volcanoes) and hydro provide some renewable electricity, but the majority of power is still produced from burning oil and coal.
Below are the electricity mixes for Hawaii from 2011 and 2021, and the percentages, to show how things have changed.
Hawaii electricity
2011 2011 2021 2021
GWh Percent GWh Percent
Petroleum 7818 75.3% 6007 57.4%
Coal 1414 13.6 1085 10.4
Hydro 109 1.0 109 1.0
Other 169 1.6 342 3.2
Wind 326 3.1 674 6.4
Biomass 322 3.1 287 2.7
Geotherm 224 2.1 166 1.6
Solar-Large 0 0 519 4.9
Solar-Small 0 0 1273 12.2
---- ---- ---- ----
Total 10,382 100% 10461 100%
Small scale solar is now the second largest producer of electricity. Wind power has doubled since 2011, but has not increased as much as solar.
Hawaii has an official goal of reaching 100% renewables for electricity by 2045. This will be a big challenge, since they don’t have a dispatchable source of clean power that can be scaled large enough. I don’t see them building large hydro projects in the mountains, and biomass and geothermal have actually decreased since 2011. Solar + batteries might work for individual homes, if they have enough solar panels, but scaling that up for all of the hotels (large tourism industry), businesses, industry and military installations will be more of a problem.
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Hawaii has an official goal of reaching 100% renewables for electricity by 2045. This will be a big challenge, since they don’t have a dispatchable source of clean power that can be scaled large enough. I don’t see them building large hydro projects in the mountains, and biomass and geothermal have actually decreased since 2011. Solar + batteries might work for individual homes, if they have enough solar panels, but scaling that up for all of the hotels (large tourism industry), businesses, industry and military installations will be more of a problem.
Yeah, they have a LONG way to go. There will have to be huge investments in a lot of different technologies to get there.
At Princeton Univ., where they have a 2046 target of net zero emissions, they are moving forward with plans for massive geo-exchange facilities to move away from their current natural gas fired power plant with co-heating. They expect to have over 1,000 boreholes averaging about 850’ deep into which they will dump heat in the summer and retrieve it in the winter using heat pumps to heat and cool university facilities. Ground source heat pumps like this are vastly more efficient than air source heat pumps and radically cut the amount of energy consumed to heat and cool buildings and potentially produce hot water too.
Large investments, like this, in radically improving the efficiency of energy use is probably going to be required for Hawaii to meet their goals.
https://facilities.princeton.edu/sites/facilities/files/geoe…
Perhaps floating offshore wind turbine technology can be used, or tethered wind power that operates far above ground? With the volcanoes in Hawaii, geothermal seems promising for re-expansion of use.
Where there is a will there’s a way, and with ~$.35/kwh prices on electricity, Hawaii is a great place to push hard for new cleaner energy technology that will be cheaper in the long run, though will require big investments up front.
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